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  • 1.
    Algarra, Andres G.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Computational Insights into the Isomerism of Hexacoordinate Metal-Sarcophagine Complexes: The Relationship between Structure and Stability2015In: European Journal of Inorganic Chemistry, ISSN 1434-1948, E-ISSN 1099-1948, no 3, p. 503-511Article in journal (Refereed)
    Abstract [en]

    The hexacoordinate complexes that the macrobicyclic ligands {(NH3)(2)sar)(2+) and {NMe3)(2)sar}(2+) (sar = 3,6,10,13,16,19-hexaazabicyclo[6.6.6]icosane) form with transition metals such as Co-III, Co-II and Cu-II can adopt several isomeric structures. In this article, we have firstly employed DFT methods lo compute the relative stability of their Delta-ob(3), Delta-ob(2)lel, Delta-lel(2)ob and Delta-lel(3) isomers, as well as the activation barriers for their interconversion. In agreement with the experimental data, the results show that, in general, the different isomers of the Co-III and Co-II complexes present similar free energies, whereas the Cu-II complexes show a strong tendency towards the lel(3) form. In addition, the interplay between the structure and stability of these species has been studied by combining shape maps with a distortion/interaction energy analysis. In contrast to the geometries close to the ideal octahedron that all the studied Co complexes present, the le)3 structures of [Cu{(NH3)(2)sar}](4+) and [Cu{(NMe3)(2)sar](4+) are better described. as trigonal prisms. In such structures the ligand adopts a conformation significantly more stable than in the other isomers, and this drives the formation of lel(3)-[Cu{(NH3)(2)sar}](4+) and lel(3)-[Cu{(NNe3)(2)sar}](4+). Overall, the results show a clear relationship between the stability of a given isomer and its degree of distortion with respect to the ideal octahedron (or trigonal prism), with the latter being ultimately dependent on the transition metal and its radius.

  • 2.
    Anderlund, Magnus F.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science.
    Högblom, Joakim
    Shi, Wei
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science.
    Huang, Ping
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science.
    Eriksson, Lars
    Weihe, Högni
    Styring, Stenbjörn
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science.
    Åkermark, Björn
    Lomoth, Reiner
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science.
    Magnuson, Ann
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science.
    Redox chemistry of a dimanganese(II,III) complex with an unsymmetric ligand: Water binding, deprotonation and accumulative light-induced oxidation2006In: European Journal of Inorganic Chemistry, ISSN 1434-1948, E-ISSN 1099-1948, no 24, p. 5033-5047Article in journal (Refereed)
    Abstract [en]

    A dinuclear manganese complex {[(Mn2L)-L-II,IIII(mu-OAc)(2)]-ClO4} has been synthesised, where L is the dianion of 2-{[bis-(pyrid-2-ylmethyl)amino]methyl}-6-{[(3,5-di-tert-butyl-2- hydroxybenzyl)(pyrid-2-ylmethyl)amino]methyl)-4-methylphenol, an unsymmetric binucleating ligand with two coordinating phenol groups. The two manganese ions, with a Mn-Mn distance of 3.498 angstrom, are bridged by the two bidentate acetate ligands and the 4-methylphenolate group of the ligand, resulting in a N3O3 and N2O4 donor set of Mn-II and Mn-II, respectively. Electrochemically [Mn2(II,III)L(mu-OAc)(2)](+) is reduced to [(Mn2L)-L-II,II(mu-OAc)(2)] at E-1/2(1)=-0.53 V versus Fc(+/0) and oxidised to [(Mn2L)-L-III,III(mu-OAC)(2)](2+) at E-1/2(2)=0.38 V versus Fc(+/0). All three redox states have been characterised by EPR, IR and UV/Vis spectroscopy. Subsequent oxidation of [(Mn2L)-L-II,III(mu-OAc)(2)](2+) [E-1/2(3)=0.75 V vs. Fc(+/0)] in dry acetonitrile results in an unstable primary product with a lifetime of about 100 ins. At high scan rates quasireversible voltammetric behaviour is found for all three electrode processes, with particularly slow electron transfer for the II,III/II,II [k(o)(1) = 0.002 cms(-1) and III,III/II,III [k(o)(2) = 0.005 cms(-1)] couples, which can be rationalised in terms of major distortions of the Mn-II centres. In aqueous media the bridging acetates are replaced by water-derived ligands. Deprotonation of these stabilises higher valence states, and photo-induced oxidation of the manganese complex results in a (Mn2L)-L-IlI,IV complex with oxo or hydroxo bridging ligands, which is further oxidised to an EPR-silent product. These results demonstrate that a larger number of metal-centred oxidations can be compressed in a narrow potential range if build up of charge is avoided by charge-compensating reactions.

  • 3.
    Andersson, Claes-Henrik
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry, Organic Chemistry.
    Berggren, Gustav
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science.
    Ott, Sascha
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science, Molecular Biomimetics.
    Grennberg, Helena
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry, Organic Chemistry.
    Synthesis and IR Spectroelectrochemical Studies of a [60]Fulleropyrrolidine-(tricarbonyl)chromium Complex: Probing C-60 Redox States by IR Spectroscopy2011In: European Journal of Inorganic Chemistry, ISSN 1434-1948, E-ISSN 1099-1948, no 11, p. 1744-1749Article in journal (Refereed)
    Abstract [en]

    The synthesis of a new fulleropyrrolidine-(tricarbonyl)chromium complex: 1-methyl-2-(4-methoxyphenyl)-3,4-[60]fulleropyrrolidine-(tricarbonyl)chromium is described together with its characterization by IR, NMR and cyclic voltammetry. IR spectro-electrochemistry has been used to probe the redox level of the fullerene derivative via the relative position of the vibrational bands of the CO ligands, which are sensitive to the electronic state of the complex. Other strategies to incorporate a tricarbonylchromium moiety to fullerene C60 are also briefly discussed and evaluated.

  • 4.
    Arkhypchuk, Anna I.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics.
    Orthaber, Andreas
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics.
    Ott, Sascha
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics.
    Tuning the Optical Properties of 1,1'-Biphospholes by Chemical Alterations of the P-P Bridge2014In: European Journal of Inorganic Chemistry, ISSN 1434-1948, E-ISSN 1099-1948, Vol. 2014, no 10, p. 1760-1766Article in journal (Refereed)
    Abstract [en]

    2,5-Di(1-naphthyl)-1-phenylphosphole (2) was prepared from phenylphosphine and dinaphthylbutadiyne in 70% yield, and oxidized to its oxide 3. Treatment of 2 with a solution of potassium naphthalide results in selective formation of phospholide anion 4, which can be oxidized with iodine to afford biphosphole 5. The crystal structure of 5 exhibits an unusual s-trans conformation across the P-P bridge that is most stabilized by - stacking of the naphthyl substituents. Biphosphole 5 can be oxidized to its mono-oxidized 6 and dioxide 7. Generally, all phosphole oxidations lead to decreased pyramidalization of the P centres and, consequently, to significantly redshifted lowest-energy absorption maxima. Mono-oxidized biphosphole 6, which consists of an ordinary phosphole and an electron-deficient oxidized phosphole, features a unique low-energy optical transition (shoulder at 430 nm), which is tentatively assigned to a charge-transfer transition. The UV/Vis spectrum of dioxide 7 lacks this transition. At the same time, the emission maximum of 7 is bathochromically shifted by 80 nm relative to that of 5.

  • 5. Banyai, I.
    et al.
    Glaser, Julius
    KTH, Superseded Departments, Chemistry.
    Toth, I.
    Cyanide exchange on Tl(CN)(4)(-) in aqueous solution studied by Tl-205 and C-13 NMR spectroscopy2001In: European Journal of Inorganic Chemistry, ISSN 1434-1948, E-ISSN 1099-1948, no 7, p. 1709-1717Article in journal (Refereed)
    Abstract [en]

    Dynamics of cyanide exchange between Tl((CN)-C-13)(4)(-) and (CN-)-C-13 was studied by means Tl-205 and C-13 NMR. The rate law consists of two parts: w = k(CN)[Tl(CN)(4)(-)][CN-] + k(OH)[Tl(CN)(4)(-)][CN-][OH-] with k(CN) = 9.7(+/-0.4) x 10(6) M(-1)s(-1) and k(OH) = 5.4(+/-0.4) x 10(10) M(-2)s(-1). It was shown that the exchange between the two cyano species can be studied, not only by C-13 NMR, but also by Tl-205 NMR using the heteronuclear carbon-thallium scalar coupling as an indicator, despite the fact that only one Tl site is present in the system. The reaction mechanism is discussed in terms of an associative interchange mechanism, I-A. Penetration of the incoming cyanide ion into the coordination sphere of Tl(CN)(4)(-) Tl(CN)(4)(OH)(-) is suggested to be the rate-determining step for the two parallel reactions paths. Possible reasons for the strong labilizing effect of the cyanide ligand is discussed in the light of thermodynamic and structural data. The possibility of detection of an exceptional exchange reaction, namely cyanide exchange between two Tl(CN)(4)(-) entities by a direct encounter was theoretically settled, but found to be too slow to be detected.

  • 6.
    Bartoszewicz, Agnieszka
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Jezowska, Martina M.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Laymand, Kevin
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Mobus, Juri
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Martín-Matute, Belén
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Synthesis of β-Hydroxy and β-Amino Ketones from Allylic Alcohols Catalyzed by Ru(η5-C5Ph5)(CO)2Cl2012In: European Journal of Inorganic Chemistry, ISSN 1434-1948, E-ISSN 1099-1948, no 9, p. 1517-1530Article in journal (Refereed)
    Abstract [en]

    An efficient method for the synthesis of beta-hydroxy and beta-amino ketones from allylic alcohols catalyzed by Ru(5-C5Ph5)(CO)2Cl is described. The influence of the stereoelectronic properties of the catalyst on the reaction outcome has been studied. Optimization of the reaction conditions supressed the formation of undesired side products such as saturated ketones, benzyl alcohols, and a,beta-unsaturated ketones. Several aromatic and aliphatic allylic alcohols have been reacted with a large variety of aldehydes or imines to produce beta-hydroxy ketones or beta-amino ketones, respectively, in yields up to 99%. Based on experimental data, a mechanism via ruthenium alkoxides and ruthenium aldoxides is proposed. In addition, a C-bound ruthenium enolate has been characterized.

  • 7. Berg, K. E.
    et al.
    Tran, A.
    Raymond, M. K.
    Abrahamsson, M.
    Wolny, J.
    Redon, S.
    Andersson, M.
    Sun, Licheng C.
    Styring, S.
    Hammarstrom, L.
    Toftlund, H.
    Akermark, B.
    Covalently linked ruthenium(II)-manganese(II) complexes: Distance dependence of quenching and electron transfer2001In: European Journal of Inorganic Chemistry, ISSN 1434-1948, E-ISSN 1099-1948, no 4, p. 1019-1029Article in journal (Refereed)
    Abstract [en]

    Continuing our development of artificial models for photosystem II in green plants, a series of compounds have been prepared in which a RU(bpy)(3)(2+) photosensitizer is covalently Linked to a manganese(II) electron donor. In addition to a trispicolylamine Ligand, two other manganese Ligands, dipicolylamine and aminodiacetic acid, have been introduced in order to study Ligands that are appropriate for the construction of manganese dimers with open coordination sites for the binding of water. Coordination equilibria of the manganese ions were monitored by EPR. The interactions between the ruthenium and manganese moieties were probed by flash photolysis, cyclic voltammetry and steady-state and time-resolved emission measurements. The quenching of the Ru-II excited state by Mn-II was found to be rapid in complexes with short Ru-Mn distances. Nevertheless, each Run species could be photo-oxidized by bimolecular quenching with methylviologen, and the subsequent electron transfer from Mn-II to Ru-III could be monitored.

  • 8.
    Camenzind, Adrian
    et al.
    ETH, Particle Technol Lab, Inst Proc Engn, Dept Mech & Proc Engn, CH-8092 Zurich, Switzerland..
    Schulz, Heiko
    ETH, Particle Technol Lab, Inst Proc Engn, Dept Mech & Proc Engn, CH-8092 Zurich, Switzerland..
    Teleki, Alexandra
    ETH, Particle Technol Lab, Inst Proc Engn, Dept Mech & Proc Engn, CH-8092 Zurich, Switzerland..
    Beaucage, Gregory
    Univ Cincinnati, Dept Chem & Mat Engn, Cincinnati, OH 45221 USA..
    Narayanan, Theyencheri
    European Synchrotron Radiat Facil, F-38043 Grenoble, France..
    Pratsinis, Sotiris E.
    ETH, Particle Technol Lab, Inst Proc Engn, Dept Mech & Proc Engn, CH-8092 Zurich, Switzerland..
    Nanostructure evolution: From aggregated to spherical SiO2 particles made in diffusion flames2008In: European Journal of Inorganic Chemistry, ISSN 1434-1948, E-ISSN 1099-1948, no 6, p. 911-918Article in journal (Refereed)
    Abstract [en]

    The formation of nanostructured silica particles by oxidation of hexamethyldisiloxane (HMDSO) in co-annular diffusion flames is investigated by in-situ small-angle X-ray scattering (SAXS). This enabled the nonintrusive monitoring of the mass fractal dimension, the aggregate size, and the number of primary particles per aggregate, along with the silica volume fraction, the primary particle diameter, the geometric standard deviation, and the number density along the flame axis. Parallel to this, thermophoretic sampling (TS) of the particles and analysis by transmission electron microscopy (TEM) allowed for direct comparison of particle morphology to that obtained from the above SAXS analysis, which were compared also to the ultra-small-angle X-ray scattering (US-AXS) data for product particles collected from the filter. The flame temperature was measured by in-situ Fourier transform infrared (FTIR) spectroscopy. By increasing the oxygen flow rate, the laminar diffusion flame changed to a turbulent, premixed-like flame. Non-aggregated, spherical particles were formed in the former, while aggregates were formed in the latter flame. The relatively long high-temperature particle residence times in the laminar diffusion flame facilitated sintering of the aggregates formed earlier into compact spherical particles at later stages of the flame. ((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008).

  • 9.
    Carrasco, Sergio
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Martin-Matute, Belén
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Hydrazine-Free Facile Synthesis of Palladium-Tetrakis(Triphenylphosphine)2019In: European Journal of Inorganic Chemistry, ISSN 1434-1948, E-ISSN 1099-1948, no 14, p. 1951-1955Article in journal (Refereed)
    Abstract [en]

    We present an easy and very efficient procedure for the synthesis of Pd(PPh3)(4) using nontoxic reducing agents. The complex is obtained in a remarkable 83 % yield, and the method can be scaled up. A very detailed spectroscopic and spectrometric characterization is reported.

  • 10.
    Crispin, Xavier
    et al.
    University of Mons, Belgium.
    Bureau, Christophe
    CEA Saclay, France.
    Geskin, Victor
    University of Mons, Belgium.
    Lazzaroni, Roberto
    University of Mons, Belgium.
    Bredas, Jean-Luc
    University of Mons, Belgium .
    Local density functional study of copper clusters: A comparison between real clusters, model surface clusters, and the actual metal surface1999In: European Journal of Inorganic Chemistry, ISSN 1434-1948, E-ISSN 1099-1948, no 2, p. 349-360Article in journal (Refereed)
    Abstract [en]

    Density Functional Theory is used to study the influence of the size of copper clusters modeling the Cu(100) surface, on the electronic properties: ionization potential, electron affinity, electronic chemical potential, and chemical hardness. The model clusters are chosen to have a bilayer structure and range in size from 9 to 20 copper atoms. The chemical hardness being identified as the relaxation energy of the frontier levels when an electron is removed or added to the system, a simple expression is proposed to estimate its value from the eigenenergies of the frontier levels in neutral and partially ionized systems. A detailed comparison of the geometric and electronic structures is made between the model surface copper clusters, real copper clusters, and the actual metal surface; it is seen that the model surface clusters provide an easy extrapolation to the properties of the metal surface.

  • 11. Das, Biswanath
    et al.
    Daver, Henrik
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Pyrkosz-Bulska, Monika
    Gumienna-Kontecka, Elzbieta
    Himo, Fahmi
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Nordlander, Ebbe
    An Unsymmetric Ligand with a N5O2 Donor Set and Its Corresponding Dizinc Complex: A Structural and Functional Phosphoesterase Model2018In: European Journal of Inorganic Chemistry, ISSN 1434-1948, E-ISSN 1099-1948, no 36, p. 4004-4013Article in journal (Refereed)
    Abstract [en]

    To mimic the active sites of the hydrolytic enzyme zinc phosphotriesterase, a new dinucleating unsymmetric ligand, PICIMP (2-{[2-hydroxy-5-methyl-3-({[(1-methyl-1H-imidazol-2-yl)methyl](pyridin-2-ylmethyl)amino}methyl)benzyl][(1-methyl-1H-imidazol-2-yl)methyl]amino}acetic acid), has been synthesized and characterized. The hydrolytic efficacy of the complex solution (PICIMP/ZnCl2 = 1:2) has been investigated using bis-(2,4-dinitrophenyl)phosphate (BDNPP), a DNA analogue substrate. Speciation studies were undertaken by potentiometric titrations at varying pH for both the ligand and the corresponding dizinc complex to elucidate the formation of the active hydrolysis catalyst; these studies reveal that the dinuclear zinc(II) complexes, [Zn-2(PICIMP)](2+) and [Zn-2(PICIMP)(OH)](+) predominate in solution above pH 4. The obtained pK(a) of 7.44 for the deprotonation of water suggests formation of a bridging hydroxide between the two Zn-II ions. Kinetic investigations of BDNPP hydrolysis over the pH range 5.5-10.5 have been performed. The cumulative results indicate the hydroxo-bridged dinuclear Zn-II complex [Zn-2(PICIMP)(mu-OH)](+) as the effective catalyst. Density functional theory calculations were performed to investigate the detailed reaction mechanism. The calculations suggest that the bridging hydroxide becomes terminally coordinated to one of the zinc ions before performing the nucleophilic attack in the reaction.

  • 12. Das, Biswanath
    et al.
    Daver, Henrik
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Singh, Amrendra
    Singh, Reena
    Haukka, Matti
    Demeshko, Serhiy
    Meyer, Franc
    Lisensky, George
    Jarenmark, Martin
    Himo, Fahmi
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Nordlander, Ebbe
    A Heterobimetallic FeIIIMnII Complex of an Unsymmetrical Dinucleating Ligand: A Structural and Functional Model Complex for the Active Site of Purple Acid Phosphatase of Sweet Potato2014In: European Journal of Inorganic Chemistry, ISSN 1434-1948, E-ISSN 1099-1948, Vol. 2014, no 13, p. 2204-2212Article in journal (Refereed)
    Abstract [en]

    The heterodinuclear mixed-valence complex [FeMn(ICIMP)(OAc)(2)Cl] (1) {H2ICIMP = 2-(N-carboxylmethyl)-[N-(N-methylimidazolyl-2-methyl)aminomethyl]-[6-(N-isopropylmethyl)-[N-(N-methylimidazolyl-2-methyl)]aminomethyl-4-methylphenol], an unsymmetrical N4O2 donor ligand} has been synthesized and fully characterized by several spectroscopic techniques as well as by X-ray crystallography. The crystal structure of the complex reveals that both metal centers in 1 are six-coordinate with the chloride ion occupying the sixth coordination site of the Mn-II ion. The phenoxide moiety of the ICIMP ligand and both acetate ligands bridge the two metal ions of the complex. Mossbauer spectroscopy shows that the iron ion in 1 is high-spin Fe-III. Two quasi-reversible redox reactions for the complex, attributed to the (FeMnII)-Mn-III/(FeMnII)-Mn-II (at -0.67 V versus Fc/Fc(+)) and (FeMnII)-Mn-III/(FeMnIII)-Mn-III (at 0.84 V), were observed by means of cyclic voltammetry. Complex 1, with an Fe-III-Mn-II distance of 3.58 angstrom, may serve as a model for the mixed-valence oxidation state of purple acid phosphatase from sweet potato. The capability of the complex to effect organophosphate hydrolysis (phosphatase activity) has been investigated at different pH levels (5.5-11) by using bis(2,4-dinitrophenyl)phosphate (BDNPP) as the substrate. Density functional theory calculations indicate that the substrate coordinates to the Mn-II ion. In the transition state, a hydroxide ion that bridges the two metal ions becomes terminally coordinated to the Fe-III ion and acts as a nucleophile, attacking the phosphorus center of BDNPP with the concomitant dissociation of the leaving group.

  • 13.
    D'Imperio, Nicolas
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström.
    Arkhypchuk, Anna I.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström.
    Mai, Juri
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström.
    Ott, Sascha
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström.
    Triphenylphosphaalkenes in Chemical Equilibria2019In: European Journal of Inorganic Chemistry, ISSN 1434-1948, E-ISSN 1099-1948, no 11-12, p. 1562-1566Article in journal (Refereed)
    Abstract [en]

    Triphenylphosphaalkenes 1a-c were prepared in good to excellent yields in a modified phospha-Peterson reaction between PhP(Li)TMS and benzophenones with different para-substituents at the C-phenyl groups (a: R = H, b: R = O-octyl, c: R = F). Owing to the low kinetic stabilization that is provided by the P-phenyl group, compounds 1a-c engage in reversible dimerization and oligomerization reactions, some of which are not detectable by 31P NMR monitoring. The dimers and oligomers are in chemical equilibria with monomeric 1a-c, and can be converted quantitatively to phosphinites 4a-c by the irreversible addition of methanol across the P=C double bond.

  • 14.
    Durieux, Guillaume
    et al.
    CNRS, Ecole Normale Super, Dept Chim.
    Gerdin, Martin
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Moberg, Christina
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Jutand, Anny
    CNRS, Ecole Normale Super, Dept Chim.
    Rate and Mechanism of the Oxidative Addition of a Silylborane to Pt0 Complexes: Mechanism for the Pt-Catalyzed Silaboration of 1,3-Cyclohexadiene2008In: European Journal of Inorganic Chemistry, ISSN 1434-1948, E-ISSN 1099-1948, no 27, p. 4236-4241Article in journal (Refereed)
    Abstract [en]

    The chemical reduction of Pt(acac)(2) by DIBALH in the presence of phosphanes, which is used to generate active Pt-0 complexes in the Pt-catalyzed silaboration of cyclohexadiene by 2-(diinethylphenylsilyl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (1) leading to the 1,4-silaborated product, was mimicked by the electrochemical reduction of Pt(acac)(2) in the presence of 2 equiv. of PR3 (R = Ph, nBu). The electrochemical reduction generates free acac anions and neutral Pt-0-(PR3)(2) complexes. The kinetics of the oxidative addition of bromobenzene (used first as a model molecule) and silylborane 1 to the Pt-0 complexes was investigated and the rate constants determined. Pt-0(PnBu(3))(2) is much more reactive than Pt-0(PPh3)(2) towards 1. From the electrochemical study, it emerges that the acac anions released in the reduction of Pt(acac)(2) do not coordinate to the Pt-0(PR3)(2) complexes. Consequently, the rate of the oxidative addition of 1 to Pt-0(PR3)(2), generated either by the electrochemical reduction or by the chemical reduction by DIBALH, is not affected by the acac anions and a posteriori not by aluminum cations. The oxidative addition and the further step of the catalytic cycle [insertion of the diene into the Pt-B bond of the Si-Pt-B complex generated in the oxidative addition, with formation of the eta(3)-allyl)Pt-Si complex] were monitored by NMR spectroscopy. Pt-0 and Pt-II complexes involved in the catalytic cycle were characterized. The oxidative addition is faster when the ligand is PMe2Ph relative to that obtained with PPh3, in agreement with the electrochemical data. No reductive elimination within the ((eta(3)-allyl))Pt-Si complex is observed when the ligand is PMe2Ph, whereas reactions in the presence of PPh3 proceeded to give the final product. As a consequence, PPh3 is a better ligand than PMe2Ph for the catalytic reaction, as observed experimentally.

  • 15. Forcato, M.
    et al.
    Lake, F.
    Blazquez, M. M.
    Renner, P.
    Crisma, M.
    Gade, L. H.
    Licini, G.
    Moberg, Christina
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Chiral, enantiopure aluminum(III) and titanium(IV) azatranes2006In: European Journal of Inorganic Chemistry, ISSN 1434-1948, E-ISSN 1099-1948, no 5, p. 1032-1040Article in journal (Refereed)
    Abstract [en]

    Al-III and Ti-IV complexes of C-3-symmetric tetradentate trisamidoamme ligands with trigonal bipyramidal coordination geometry, containing chlorine or dialkylamido groups, or with a free coordination site in the apical position, have been synthesised by salt metathesis and amine elimination. Products with threefold symmetry were generally obtained for tetravalent titanium, whereas for the aluminium complexes either asymmetric structures with two of the three podand arms taking part in coordination to the metal or symmetric arrangements possessing the full threefold symmetry were formed depending on the steric properties of the ligands.

  • 16. Gao, Weiming
    et al.
    Sun, Junliang
    Li, Mingrun
    Akermark, Torbjörn
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Romare, Kristina
    Sun, Licheng
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Åkermark, Björn
    Synthesis of a [3Fe2S] Cluster with Low Redox Potential from [2Fe2S] Hydrogenase Models: Electrochemical and Photochemical Generation of Hydrogen2011In: European Journal of Inorganic Chemistry, ISSN 1434-1948, E-ISSN 1099-1948, no 7, p. 1100-1105Article in journal (Refereed)
    Abstract [en]

    In the attempted replacement of carbon monoxide by the bis(phosphane) dppv in a dinuclear [2Fe2S] complex, a trinuclear [3Fe2S] complex with two bis(phosphane) ligands was unexpectedly obtained. On protonation, this gave a bridged hydride complex with an unusually low potential for the reduction of protons to molecular hydrogen. The redox potential also appears sufficiently positive for direct electron transfer from an excited [Ru(bpy)(3)](2+) sensitizer.

  • 17.
    Gao, Weiming
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Sun, Junliang
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK), Inorganic and Structural Chemistry.
    Li, Mingrun
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK), Inorganic and Structural Chemistry.
    Åkermark, Torbjörn
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Romare, Kristina
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Sun, Licheng
    Royal Institute of Technology (KTH), Department of Organic Chemistry.
    Åkermark, Björn
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Synthesis of a [3Fe2S] cluster with low redox potential from [2Fe2S] hydrogenase models: electrochemical and photochemical generation of hydrogen2011In: European Journal of Inorganic Chemistry, ISSN 1434-1948, E-ISSN 1099-1948, Vol. 2011, no 7, p. 1100-1105Article in journal (Refereed)
    Abstract [en]

    In the attempted replacement of carbon monoxide by the bis(phosphane) dppv in a dinuclear [2Fe2S] complex, a trinuclear [3Fe2S] complex with two bis(phosphane) ligands was unexpectedly obtained. On protonation, this gave a bridged hydride complex with an unusually low potential for the reduction of protons to molecular hydrogen. The redox potential also appears sufficiently positive for direct electron transfer from an excited [Ru(bpy)(3)](2+) sensitizer.

  • 18.
    Gorlov, Mikhail
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Inorganic Chemistry.
    Hussami, Linda
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Inorganic Chemistry.
    Fischer, Andreas
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Inorganic Chemistry.
    Kloo, Lars A.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Inorganic Chemistry.
    Mononuclear eta(6)-Arene Complexes of Lanthanides: One-Step Syntheses, Crystal Structures, and Arene Exchange2008In: European Journal of Inorganic Chemistry, ISSN 1434-1948, E-ISSN 1099-1948, no 33, p. 5191-5195Article in journal (Refereed)
    Abstract [en]

    Gallium(III) halides react with cerium(III), ytterbium(III), or dysprosium(III) halides in the presence of alkylated benzenes yielding mononuclear complexes of the general formula [Ln(eta(6)-arene)(GaX4)(3)]. The X-ray structures of [Ce(C6H5Me)- (GaCl4)(3)] (1), [Ce(p-C6H4Me2)(GaCl4)(3)]center dot 0.5(p-C6H4Me2) (2), [Yb(C6H5Me)(GaCl4)(3)] (3), [Yb(p-C6H4Me2)(GaCl4)(3)]center dot 0.5(p- C6H4Me2) (4), and [Dy(C6H5Me)(GaBr4)(3)] (5) were determined. Arene ligands in the cerium-toluene compound 1 can be substituted by polycyclic aromatic hydrocarbons (PAHs); the compounds [Ce(naphthalene) (GaCl4)(3)] (6) and [Ce(pyrene)(GaCl4)(3)]center dot 0.5(pyrene) (7) have been isolated and structurally characterized.

  • 19.
    Gowda, Vasantha
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Sarma, Bipul
    Department of Chemical Sciences, Division of Chemical Engineering, Tezpur University, Tezpur, Assam.
    Öberg, Sven
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Telkki, Ville-Veikko
    University of Oulu, NMR Research Group, Division of Chemical Engineering, Faculty of Science, University of Oulu.
    Larsson, Anna-Carin
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Lantto, Perttu
    University of Oulu, NMR Research Group, Division of Chemical Engineering, Faculty of Science, University of Oulu.
    Antzutkin, Oleg
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Structure Elucidation of an Yttrium Diethyldithiocarbamato-Phenanthroline Complex by X-ray Crystallography, Solid-State NMR, and ab-initio Quantum Chemical Calculations2016In: European Journal of Inorganic Chemistry, ISSN 1434-1948, E-ISSN 1099-1948, Vol. 20, p. 3278-3291Article in journal (Refereed)
    Abstract [en]

    We present a structural analysis method for molecular and electronic structure of yttrium diethyldithiocarbamato-phenanthroline complex {[Y(S2CNR2)3PHEN] with R = C2H5 and PHEN = 1,10-phenanthroline} combining solid-state NMR spectroscopy, XRD, and first principles DFT calculations. Replacing the Nd3+ ion with Y3+ in the reported crystal structure of [Nd(S2CNR2)3PHEN] complex generated an approximate 3D structure of the title complex. The structure was then subjected to first principles quantum chemical geometry optimisation using periodic DFT method. The quality of the method is discussed by comparing predicted and experimental powder XRD patterns. Full assignment of 13C and 15N solid-state CP-MAS NMR spectra as well as analyses of the principal values of the chemical shift tensors were carried out using periodic scalar relativistic DFT modelling. Spin-orbit relativistic effects, estimated by SO-ZORA formalism for one molecular unit, were evaluated. Finally, the X-ray structure of the title complex was determined, which proved that the former procedure is appropriate. The most important orbital interactions were investigated by Natural Bond Orbital analysis. The isotropic shielding values for S2CN-carbons were analysed by Natural Localised Molecular Orbital analysis. The present approach can be further extended to study other rare earth metal complexes, particularly those having similar but not yet solved crystal structures

  • 20.
    Green, Joshua P.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström.
    Gupta, Arvind Kumar
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström.
    Orthaber, Andreas
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström.
    Effect of Arsenic Coordination State on the Structure, Aromaticity, and Optical Properties of Dithieno[3,2-b:2 ',3 '-d]arsoles2019In: European Journal of Inorganic Chemistry, ISSN 1434-1948, E-ISSN 1099-1948, no 11-12, p. 1539-1543Article in journal (Refereed)
    Abstract [en]

    A silylated derivative of 4-phenyl-dithieno[3,2-b:2 ',3 '-d]arsole (DTAs) was synthesized, and the effect of coordinating of DTAs compounds to Pd on their structural and optical properties was investigated. Coordination of the As to Pd was found to increase the structural aromaticity of the ring system as measured by the harmonic oscillator measure of heterocyclic electron delocalization (HOMHED), and the pyramidalization of the As atoms was also found to show a good correlation with the HOMHED values. However, coordination had a more subtle impact on the optical properties than seen for phosphorus-containing analogues as the metal-ligand interactions were weaker.

  • 21.
    Gudat, Dietrich
    et al.
    Univ Stuttgart, Inst Anorgan Chem, Pfaffenwaldring 55, D-70550 Stuttgart, Germany.
    Orthaber, Andreas
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström.
    Slootweg, J. Chris
    Univ Amsterdam, Vant Hoff Inst Mol Sci, Sci Pk 904, NL-1090 GD Amsterdam, Netherlands.
    Streubel, Rainer
    Univ Bonn, Inst Inorgan Chem, Gerhard Domagk Str 1, D-53121 Bonn, Germany.
    Phosphorus Special Issue in Honor of Koop Lammertsma and Edgar Niecke2019In: European Journal of Inorganic Chemistry, ISSN 1434-1948, E-ISSN 1099-1948, no 11-12, p. 1437-1439Article in journal (Other academic)
    Abstract [en]

    Guest Editors Dietrich Gudat, Andreas Orthaber, Chris Slootweg, and Rainer Streubel report the increasing importance of phosphorus chemistry in Europe and beyond, summarizing the contributions in this special issue in honor of the 70th and 80th birthdays of Professors Koop Lammertsma and Edgar Niecke.

  • 22. Hetterscheid, D. G. H.
    et al.
    Sun, Licheng
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Water oxidation2014In: European Journal of Inorganic Chemistry, ISSN 1434-1948, E-ISSN 1099-1948, no 4, p. 571-572Article in journal (Refereed)
  • 23.
    Hopmann, Kathrin H.
    et al.
    KTH, School of Biotechnology (BIO), Theoretical Chemistry.
    Himo, Fahmi
    KTH, School of Biotechnology (BIO), Theoretical Chemistry.
    On the Role of Tyrosine as Catalytic Base in Nitrile Hydratase2008In: European Journal of Inorganic Chemistry, ISSN 1434-1948, E-ISSN 1099-1948, no 22, p. 3452-3459Article in journal (Refereed)
    Abstract [en]

    Nitrile Hydratases (NHases) catalyze the conversion of nitriles to their corresponding amides. Two NHase classes exist, the Fe-III-NHases and the Co-III-NHases. Both harbour an intriguing active site, with a low-spin metal ion coordinated to deprotonated back-bone amides and oxidized cysteine residues. So far it has not been possible to conclusively determine the reaction mechanism of NHase. Here we employ density functional theory to investigate the recent proposal that a fully conserved second-shell tyrosine residue is the catalytic base of nitrile hydratase (J. Biol. Chem. 2007, 282, 7397-7404). In the proposed mechanism, the tyrosine is suggested to be in the tyrosinate state and to mediate nitrile hydration through activation of a water molecule, which attacks the metal-bound substrate. We have explored this mechanism employing quantum chemical active site models on the basis of the Co-III-NHase from P. thermophila JCM 3095 and the Fe-III-NHase from R. erythropolis N-771. Potential energy curves and optimized transition states are presented. The computed barriers for the two models are a few kcal/mol above the experimental value, indicating that the conserved second-shell tyrosine could function as the catalytic base of NHase. To further evaluate the likelihood of this mechanism, we estimated the pK(a) value of the second-shell tyrosine in each model. We also provide estimates of the energy involved in the exchange of a metal-bound water molecule with a nitrile substrate.

  • 24.
    Hopmann, Kathrin H.
    et al.
    KTH, School of Biotechnology (BIO), Theoretical Chemistry.
    Himo, Fahmi
    KTH, School of Biotechnology (BIO), Theoretical Chemistry.
    Theoretical Investigation of the Second-Shell Mechanism of Nitrile Hydratase2008In: European Journal of Inorganic Chemistry, ISSN 1434-1948, E-ISSN 1099-1948, no 9, p. 1406-1412Article in journal (Refereed)
    Abstract [en]

    Nitrile hydratases (NHases) are biocatalytically important enzymes that are utilized in the industrial production of acrylamide and nicotinamide. There are two different classes of NHases, harbouring either a low-spin Fe-III or a low-spin Co-III ion in the active site, in each case with the same peculiar set of ligands, involving deprotonated backbone amides and oxidized cysteine residues. The detailed reaction mechanism of NHase has not been established yet, but different proposals have been put forward. Depending on the binding site of the substrate, these can be divided into first-shell and second-shell mechanisms, respectively, Recently, we have investigated different first-shell mechanisms using quantum-chemical active-site models based on the iron-dependent NHase (Inorg. Chem. 2007, 46, 4850). Here we continue our investigation of the NHase reaction by exploring two different variations of the second-shell mechanism of the iron-dependent NHase. In the first, a metal-bound hydroxide ion performs a nucleophilic attack on the nitrile substrate, while in the second investigated mechanism, the oxidized cysteine, Cys114-SO-, acts as the nucleophile. We report energies, optimized transition state, and intermediate geometries for both investigated mechanisms. The calculated barriers are similar to the previously reported first-shell mechanism involving Cys114-SO- as catalytic base.

  • 25. Huang, D. G.
    et al.
    Wang, W. G.
    Zhang, X. F.
    Chen, C. N.
    Chen, F.
    Liu, Q. T.
    Liao, D. Z.
    Li, L. C.
    Sun, Licheng C.
    Synthesis, structural characterizations and magnetic properties of a series of mono-, di- and polynuclear manganese pyridinecarboxylate compounds2004In: European Journal of Inorganic Chemistry, ISSN 1434-1948, E-ISSN 1099-1948, no 7, p. 1454-1464Article in journal (Refereed)
    Abstract [en]

    Seven new manganese(II, III, IV) pyridinecarboxylate compounds (Et4N)[MnCl2(pic)(2)] (1, Hpic = picolinic acid) [MnCl(Pic)(2)(H2O)].H2O (2), [MnCl(pic)(H2O)2](n) (3), [Mn(Pic)(2)](n) (4), [MnCl(pic)](n) (5), [MnCl2(4-C5H4NHCOO)](n) (6) and [Mn2O2(pic)(4)] (7) were synthesized and structurally characterized. The picolinate ligand coordinates to the Mn ion forming a chelating five-membered ring which constructs diverse architectures by various bridging modes, such as mu-Cl, mu(1,1)(-) and mu(1,3)-carboxylate bridges (syn-syn and syn-anti modes). The interaction between the pyridyl rings is discussed, displaying a face-to-face pi-pi stacking for complex 6 and a T-shaped C-H...pi attraction for complex 4. Complex 3 has an infinite zigzag chain structure in which two neighboring Mn ions are linked by a carboxylate bridge in a syn-anti mode. In complex 4, the Mn(pic)(2) fragments are joined to each other by double mu(1,1)-carboxylate bridges, forming a 2D layer structure. Complex 5 contains Mn4O4 square subunits which are connected by double mu-Cl bridges to form a grid-like 2D structure. The isonicotinate complex 6 has a zigzag chain structure containing mixed double mu-Cl and mu(1,3)-carboxylate bridges in a syn-syn mode. Protonation at the pyridyl-N position was found and identified by the IR and magnetic properties of 6. The participation of an oxidizing agent like MnO4- leads to complexes containing higher valent manganese (1, 2 and 7). The IR spectra of these complexes are discussed and found to be consistent with the structural features. The magnetic properties of complexes 4, 5 and 6 have been investigated. Antiferromagnetic coupling interactions were observed and satisfactory fitting results were obtained with J values ranging from -0.63 cm(-1) to -2.35 cm(-1). The magnetic parameters of these complexes, together with the parameters of other Mn complexes with comparable structures, are compared and discussed based on the bridging modes. ((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004).

  • 26. Huang, Yong
    et al.
    Gao, Weiming
    Åkermark, Torbjörn
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Applied Electrochemistry.
    Li, Mingrun
    Akermark, Bjorn
    An Air-Stable Fe3S4 Complex with Properties Similar to Those of the HOXair State of the Diiron Hydrogenases2012In: European Journal of Inorganic Chemistry, ISSN 1434-1948, E-ISSN 1099-1948, no 27, p. 4259-4263Article in journal (Refereed)
    Abstract [en]

    A Fe3S4 complex bridged by azapropanedithiolate (adt), complex 6, was prepared as a potential model of the HOXair state of [FeFe]-hydrogenases. Complex 6 was characterized by IR and 1H NMR spectroscopy, and its structure was determined by X-ray crystallography. The electrochemical studies show that complex 6 is redox-active under acidic conditions, which provides insight into the catalytic mechanism. Hydrogen evolution, driven by visible light, was observed in CH3CN/D2O solution by online mass spectroscopy.

  • 27. Huang, Yong
    et al.
    Gao, Weiming
    Åkermark, Torbjörn
    Li, Mingrun
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK), Inorganic and Structural Chemistry.
    Åkermark, Björn
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    An Air-Stable Fe3S4 Complex with Properties Similar to Those of the HOXair State of the Diiron Hydrogenases2012In: European Journal of Inorganic Chemistry, ISSN 1434-1948, E-ISSN 1099-1948, no 27, p. 4259-4263Article in journal (Refereed)
    Abstract [en]

    A Fe3S4 complex bridged by azapropanedithiolate (adt), complex 6, was prepared as a potential model of the HOXair state of [FeFe]-hydrogenases. Complex 6 was characterized by IR and 1H NMR spectroscopy, and its structure was determined by X-ray crystallography. The electrochemical studies show that complex 6 is redox-active under acidic conditions, which provides insight into the catalytic mechanism. Hydrogen evolution, driven by visible light, was observed in CH3CN/D2O solution by online mass spectroscopy.

  • 28.
    Hutchinson, Daniel J.
    et al.
    Institut für Anorganische Chemie, Universität Leipzig.
    Hey-Hawkins, Evamarie
    Institut für Anorganische Chemie, Universität Leipzig.
    The Self-Assembly of AgI -Containing Heterobimetallic Complexes with a Discriminatory N,P-Based Heteroditopic Ligand2018In: European Journal of Inorganic Chemistry, ISSN 1434-1948, E-ISSN 1099-1948, Vol. 2018, no 44, p. 4790-4796Article in journal (Refereed)
    Abstract [en]

    Pyrimidine-hydrazone and phosphole architectures have been combined to create a new heteroditopic ligand capable of forming heterobimetallic ZnII/PdII,PbII/PdII and CuII/PdII complexes in high yielding stepwise or one pot reactions. The catalytic activity of these complexes in Heck coupling and Miyaura borylation reactions was investigated.

  • 29.
    Höglund, Carina
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Birch, Jens
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Beckers, Manfred
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Alling, Björn
    Linköping University, Department of Physics, Chemistry and Biology, Computational Physics . Linköping University, The Institute of Technology.
    Czigany, Zsolt
    Research Institute for Technical Physics and Materials Science, Hungarian Academy of Sciences, P.O. Box 49, H-1525 Budapest, Hungary .
    Mücklich, Arndt
    Institute of Ion Beam Physics and Materials Research, Forschungszentrum Dresden-Rossendorf.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Sc3AlN: A New Perovskite2008In: European Journal of Inorganic Chemistry, ISSN 1434-1948, E-ISSN 1099-1948, Vol. 2008, no 8, p. 1193-1195Article in journal (Refereed)
    Abstract [en]

    Sc3AlN with perovskite structure has been synthesized as the first ternary phase in the Sc–Al–N system. Magnetron sputter epitaxy at 650 °C was used to grow single-crystal, stoichiometric Sc3AlN(111) thin films onto MgO(111) substrates with ScN(111) seed layers as shown by elastic recoil detection analysis, X-ray diffraction, and transmission electron microscopy. The Sc3AlN phase has a lattice parameter of 4.40 Å, which is in good agreement with the theoretically predicted 4.42 Å. Comparisons of total formation energies show that Sc3AlN is thermodynamically stable with respect to all known binary compounds. Sc3AlN(111) films of 1.75 μm thickness exhibit a nanoindentation hardness of 14.2 GPa, an elastic modulus of 249 GPa, and a roomtemperature electrical resistivity of 41.2 μΩ cm.

  • 30.
    Ivanov, Sergey
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Structural Chemistry.
    Nordblad, Per
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Mathieu, Roland
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Tellgren, Roland
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Materials Chemistry, Structural Chemistry.
    Politova, Ekaterina
    Dept of Inorganic Materials, Karpov' Institute of Physical Chemistry, Moskva, Ryssland.
    Andre, Gilles
    Laboratoire Leon Brillouin, Commissariat à l'Ènergie Atomique et aux Ènergies Alternative (CEA), Saclay, Frankrike.
    Short-Range Spin Order and Frustrated Magnetism in Mn(2)InSbO(6) and Mn(2)ScSbO(6)2011In: European Journal of Inorganic Chemistry, ISSN 1434-1948, E-ISSN 1099-1948, no 30, p. 4691-4699Article in journal (Refereed)
    Abstract [en]

    The complex metal oxides Mn(2)ASbO(6) (A = In, Sc) with a corundum-related structure A(3)BO(6) were prepared as polycrystalline powders by a solid-state reaction route. Their crystal structure and magnetic properties were investigated by using a combination of X-ray and neutron powder diffraction, electron microscopy, calorimetric, and magnetic measurements. At room temperature, these compounds adopt a trigonal structure, space group R (3) over bar, with a = 8.9313(1) angstrom, c = 10.7071(2) angstrom (for In) and a = 8.8836(1) angstrom, c = 10.6168(2) angstrom (for Sc), which persists down to 1.6 K. The Mn and A cations were found to be randomly distributed over the A sites. The overall behavior of the magnetization of Mn(2)InSbO(6) and that of Mn(2)ScSbO(6) are quite similar. In spite of the relatively large amount of Mn ions on the A site, only short-range magnetism is observed. Neutron diffraction patterns of Mn(2)InSbO(6) showed no evidence of a long-range magnetic ordering at 1.6 K, instead only a weak diffuse magnetic peak was observed at low temperatures. The factors governing the observed structural and magnetic properties of Mn(2)ASbO(6) are discussed and compared with those of other Mn-containing complex metal oxides with a corundum-related structure. The influence of the A cation sublattice on the magnetic properties is also considered.

  • 31.
    Kloo, Lars
    et al.
    KTH, Superseded Departments, Chemistry.
    Rosdahl, Jan
    KTH, Superseded Departments, Chemistry.
    Svensson, Per H.
    KTH, Superseded Departments, Chemistry.
    On the Intra- and Intermolecular Bonding in Polyiodides2002In: European Journal of Inorganic Chemistry, ISSN 1434-1948, E-ISSN 1099-1948, no 5, p. 1203-1209Article in journal (Refereed)
    Abstract [en]

    The nature of intra- and intermolecular interactions of poly-iodides has been investigated by means of quantum chemical methods and structural statistical data. In the region of "secondary bonds" the interaction is adequately described in terms of covalent bonding accompanied by dispersion. At greater distances the interaction is dominated by ion-quadrupole interactions between ionic and neutral iodine building blocks of the polyiodide structures.

  • 32.
    Koeppen, Milan
    et al.
    Christian Albrechts Univ Kiel, Inst Anorgan Chem, Max Eyth Str 2, D-24118 Kiel, Germany.
    Dhakshinamoorthy, Amarajothi
    Christian Albrechts Univ Kiel, Inst Anorgan Chem, Max Eyth Str 2, D-24118 Kiel, Germany;Madurai Kamaraj Univ, Sch Chem, Madurai 625021, Tamil Nadu, India.
    Inge, A. Ken
    Christian Albrechts Univ Kiel, Inst Anorgan Chem, Max Eyth Str 2, D-24118 Kiel, Germany;Stockholm Univ, Dept Mat & Environm Chem, S-10691 Stockholm, Sweden.
    Cheung, Ocean
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Nanotechnology and Functional Materials.
    Angstrom, Jonas
    Stockholm Univ, Dept Mat & Environm Chem, S-10691 Stockholm, Sweden.
    Mayer, Peter
    Ludwig Maximilians Univ Munchen, Dept Chem, Butenandtstr 5-13,Haus D, D-81377 Munich, Germany.
    Stock, Norbert
    Christian Albrechts Univ Kiel, Inst Anorgan Chem, Max Eyth Str 2, D-24118 Kiel, Germany.
    Synthesis, Transformation, Catalysis, and Gas Sorption Investigations on the Bismuth Metal-Organic Framework CAU-172018In: European Journal of Inorganic Chemistry, ISSN 1434-1948, E-ISSN 1099-1948, no 30, p. 3496-3503Article in journal (Refereed)
    Abstract [en]

    Very few microporous bismuth metal-organic frameworks have been discovered to date. Of these, no detailed experimental characterization of the synthesis and properties have been reported until now for the only one which can be prepared from inexpensive starting materials: CAU-17 [Bi(BTC)(H2O)], with H3BTC = trimesic acid. In-situ powder X-ray diffraction during solvothermal synthesis of CAU-17 revealed that it crystallizes rapidly within 2 minutes, and if the reaction is not stopped, the MOF transforms into a nonporous dense purely inorganic material within one hour, revealing that CAU-17 is a crystalline intermediate phase. Synthesis scale-up employing more concentrated reaction mixtures resulted in another Bi trimesate of composition [Bi(HBTC)(NO3)(MeOH)]MeOH, which structurally decomposes upon storage under ambient conditions. Sorption experiments showed that CAU-17 is microporous with a BET surface area of 530 m(2)/g. As a potential greenhouse gas sorbent, CAU-17 showed high SF6/N-2 and CO2/N-2 selectivity > 31 and 29, respectively. Furthermore, the catalytic activity of CAU-17 was studied in the regioselective ring-opening of styrene oxide by methanol to obtain 2-methoxy-2-phenylethanol, thus demonstrating the existence of coordinatively unsaturated sites in the crystal structure of CAU-17.

  • 33.
    Krassen, Henning
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science, Molecular Biomimetics.
    Stripp, Sven T.
    Boehm, Nadine
    Berkessel, Albrecht
    Happe, Thomas
    Ataka, Kenichi
    Heberle, Joachim
    Tailor-Made Modification of a Gold Surface for the Chemical Binding of a High-Activity [FeFe] Hydrogenase2011In: European Journal of Inorganic Chemistry, ISSN 1434-1948, E-ISSN 1099-1948, no 7, p. 1138-1146Article in journal (Refereed)
    Abstract [en]

    Hydrogenases are iron-sulfur proteins that catalyze hydrogen turnover in a wide range of microorganisms. Three different classes have been described, and among these [FeFe] hydrogenases are the most active in H-2 evolution. Hydrogenases are redox enzymes that have been shown to exchange electrons with graphite and modified noble metal electrodes. Making use of the latter, diffusible electron carriers are required to enable redox catalysis, as proteins do not specifically bind to the electrode surface. Diffusion-limited electron transfer can be replaced by electron injection into immobilized hydrogenase by binding the redox mediator to the electrode surface. Here, we present the synthesis and spectroelectrochemical characterization of 1-( 10-mercaptodecyl)-1'-benzyl-4,4'-bipyridinium dibromide (MBBP), which is used as redox-active linker. CrHydA1, the high-activity [FeFe] hydrogenase from Chlamydomonas reinhardtii, is immobilized on the linker-modified gold electrode. Each surface modification step is controlled in situ by surface-enhanced infrared absorption spectroscopy (SEIRAS). Functionality of the electrode-protein hybrid is demonstrated by recording the linker-supported current. The specific catalytic rate of hydrogen evolution by CrHydA1 (2.9 mu molH(2)min(-1)mg(-1) hydrogenase) promises a valuable approach for further optimization of this novel bioelectrical interface.

  • 34. Kravchenko, Ekaterina
    et al.
    Neagu, Alexandra
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Zakharchuk, Kiryl
    Grins, Jekabs
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Svensson, Gunnar
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Pankov, Vladimir
    Yaremchenko, Aleksey A.
    High-Temperature Structural and Electrical Characterization of Reduced Oxygen-Deficient Ruddlesden-Popper Nickelates2018In: European Journal of Inorganic Chemistry, ISSN 1434-1948, E-ISSN 1099-1948, no 28, p. 3320-3329Article in journal (Refereed)
    Abstract [en]

    High-temperature characterization of oxygen-deficient Sr-rich (La1-xSrx)(2)NiO4-delta (x = 0.5-0.8) solid solutions under mildly reducing conditions with p(O-2) approximate to 5x10(-5) atm was performed by employing structural and thermal analysis, TEM, and electrical conductivity measurements. Oxygen losses from the crystal lattice on reduction were found to result in a reversible transition from the tetragonal (I4/mmm) to the orthorhombic (Immm) structure and shrinkage of the crystal lattice for the compositions with x > 0.5. TEM and thermogravimetric analysis evidenced slow kinetics of the structural transition. The increase in oxygen deficiency under reducing conditions is accompanied by localization of the electronic charge carriers, a drop of the p-type electronic conductivity, and a transition from metallic-like to semiconducting behavior. The extent of changes in oxygen nonstoichiometry, unit--cell dimensions, average Ni oxidation state, electron-hole concentration, and electronic conductivity on reduction is interrelated with the strontium content. The results suggest that the electrical conductivity of (La1-xSrx)(2)NiO4-delta ceramics depends mainly on the average Ni oxidation state.

  • 35.
    Kurz, Philipp
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science.
    Anderlund, Magnus F.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science.
    Shaikh, Nizamuddin
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science.
    Styring, Stenbjorn
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science.
    Huang, Ping
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science.
    Redox reactions of a dinuclear manganese complex: the influence of water2008In: European Journal of Inorganic Chemistry, ISSN 1434-1948, E-ISSN 1099-1948, no 5, p. 762-770Article in journal (Refereed)
    Abstract [en]

    The redox properties of the dinuclear manganese complex [(Mn2L)-L-III,III(mu-OAC)(2)](+) (1) (where L is the trianion of the heptadentate ligand 2,6-bis{[(3,5-di-tert-butyl-2-hydroxybenzyl)(2-pyridylmethyl)amino]methy l)-4-methylphenol) were studied in acetonitrile solutions containing different concentrations of water. Electrochemical reactions as well as reactions with different chemical and photochemical redox reagents were monitored, using a variety of analytical techniques, namely cyclic voltammetry, UV/Vis spectroelectrochemistry, and EPR spectroscopy. We found that even small concentrations of water influence the compound's redox behaviour significantly, especially the oxidation reactions. As a consequence, the presence of water reduces the overall potential span needed to reach the highest oxidation state observed for 1 (M-2(III,IV)) from its most reduced state (Mn-2(II,II)) to about 1.1 V Higher oxidation states of I are stabilized, most likely by water coordination and the formation of mu-oxido bridge(s) between the two manganese atoms. For reducing conditions, an unprecedented 25-line EPR signal was observed, which might originate from reduced 1 in its Mn-2(II,II) or Mn-2(II,II) state after considerable ligand rearrangement. As complexes like I have been designed to act as potential water oxidation catalysts, the complicated redox- and ligand-exchange chemistry found for 1 in the presence of water, its intended substrate, might be exemplary for many of the dinuclear manganese compounds currently under investigation.

  • 36.
    Kurz, Philipp
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Photochemistry and Molecular Science.
    Probst, Benjamin
    Spingler, Bernhard
    Alberto, Roger
    Ligand variations in [ReX(diimine)(CO)(3)] complexes: Effects on photocatalytic CO2 reduction2006In: European Journal of Inorganic Chemistry, ISSN 1434-1948, E-ISSN 1099-1948, no 15, p. 2966-2974Article in journal (Refereed)
    Abstract [en]

    Two series of complexes [MX(diimine)(CO)(3)] (M = Tc, Re) have been prepared, fully characterised and investigated for their ability to act as photocatalysts for the reduction of CO2 to CO. One series consists of complexes with different aromatic diimine ligands while keeping X = Br- constant. The second series describes complexes with diimine = 2,2-bipyridine and variations in the anionic ligand X-. Although numerous complexes of this type have been prepared and investigated before, a systematic study of their photocatalytic activity has not yet been carried out. Electrochemical and spectroscopic characterisation of these complexes has been performed with the objective of better understanding their respective activity in the photocatalytic CO2 reduction. Despite various modifications, catalytic activity is retained for all compounds exhibiting fluorescence, including [(TcCl)-Tc-99(bipy)(CO)(3)], whereas nonfluorescing compounds did not convert CO2 to CO. The correlation of catalytic activity and spectroscopic or electrochemical properties such as absorption or emission wavelengths, redox potentials or Stern-Volmer constants for the reductive quenching of the excited complexes is difficult. Nevertheless, the study emphasises the possibility to obtain [ReX(CO)(3)(diimine)] complexes with a wide range of physicochemical properties by ligand variations and the great potential of compounds of this class of complexes as inorganic photosensitisers.

  • 37. Kuznetsov, Alexei N.
    et al.
    Popovkin, Boris A.
    Ståhl, Kenny
    Lindsjö, Martin
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Inorganic Chemistry.
    Kloo, Lars
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Inorganic Chemistry.
    Synthesis of main group polycations in molten and pseudo-molten GaBr3 media2005In: European Journal of Inorganic Chemistry, ISSN 1434-1948, E-ISSN 1099-1948, no 24, p. 4907-4913Article in journal (Refereed)
    Abstract [en]

     The prospects of synthesizing polycationic species using GaBr3 in benzene solution at room temperature have been investigated. The salts Bi-8[GaBr4](2), Sb-8[GaBr4](2) and Te-4- [Ga2Br7](2) have been isolated and characterized. The first two compounds are isotypic with Sb-8[GaCl4](2), crystallize in the space group Pna2(1), and feature square anti-prismatic E-8(2+) polycations (E = Sb, Bi). Unit-cell parameters for Bi-8[GaBr4](2) are a = 18.3014(10) angstrom, b = 10.3391(6) angstrom and c = 13.5763(7) angstrom, and for Sb-8[GaBr4](2); a = 18.096(2) angstrom, b = 10.1572(9) angstrom and c = 13.2168(10) angstrom. Te-4[Ga2Br7](2) crystallizes in the space group P2(1)/c with a = 10.1600(9) angstrom, b = 10.8314(9) angstrom, c = 13.8922(10) angstrom and beta = 99.182(7)degrees, and features a square-planar Te-4(2+) polycation. The compound Bi-5[GaBr4](3) has been synthesized from molten GaBr3 and characterized by using powder diffractometry in space group Fm-3c; a = 17.6263(8) angstrom. The structure model for this compound suggests the included Bi-5(3+) cations to be practically freely oriented within its cavities in the solid phase.

  • 38. Köppen, Milan
    et al.
    Dhakshinamoorthy, Amarajothi
    Inge, A. Ken
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK). Christian‐Albrechts‐Universität zu Kiel, Germany.
    Cheung, Ocean
    Ångström, Jonas
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Mayer, Peter
    Stock, Norbert
    Synthesis, Transformation, Catalysis, and Gas Sorption Investigations on the Bismuth Metal-Organic Framework CAU-172018In: European Journal of Inorganic Chemistry, ISSN 1434-1948, E-ISSN 1099-1948, no 30, p. 3496-3503Article in journal (Refereed)
    Abstract [en]

    Very few microporous bismuth metal-organic frameworks have been discovered to date. Of these, no detailed experimental characterization of the synthesis and properties have been reported until now for the only one which can be prepared from inexpensive starting materials: CAU-17 [Bi(BTC)(H2O)], with H3BTC = trimesic acid. In-situ powder X-ray diffraction during solvothermal synthesis of CAU-17 revealed that it crystallizes rapidly within 2 minutes, and if the reaction is not stopped, the MOF transforms into a nonporous dense purely inorganic material within one hour, revealing that CAU-17 is a crystalline intermediate phase. Synthesis scale-up employing more concentrated reaction mixtures resulted in another Bi trimesate of composition [Bi(HBTC)(NO3)(MeOH)]MeOH, which structurally decomposes upon storage under ambient conditions. Sorption experiments showed that CAU-17 is microporous with a BET surface area of 530 m(2)/g. As a potential greenhouse gas sorbent, CAU-17 showed high SF6/N-2 and CO2/N-2 selectivity > 31 and 29, respectively. Furthermore, the catalytic activity of CAU-17 was studied in the regioselective ring-opening of styrene oxide by methanol to obtain 2-methoxy-2-phenylethanol, thus demonstrating the existence of coordinatively unsaturated sites in the crystal structure of CAU-17.

  • 39. Lee, Bao-Lin
    et al.
    Karkas, Markus D.
    Johnston, Eric V.
    Inge, Andrew K.
    Tran, Lien-Hoa
    Xu, Yunhua
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Hansson, Örjan
    Zou, Xiaodong
    Åkermark, Björn
    Synthesis and Characterization of Oligonuclear Ru, Co and Cu Oxidation Catalysts2010In: European Journal of Inorganic Chemistry, ISSN 1434-1948, E-ISSN 1099-1948, no 34, p. 5462-5470Article in journal (Refereed)
    Abstract [en]

    In this work, we report the preparation and crystal structures of three new oligonuclear complexes, Ru-2(bbpmp)(mu-OAc)(3) (4), [Co-2(bbpmp)(mu-OAc)(mu-OMe)](PF6) (5), [Cu-4(Hbbpmp)(2)(mu-OAc)(H2O)(2)](OAc)(PF6)(2) (6) {H(3)bbpmp = 2,6-bis[(2-hydroxybenzyl)-(2-pyridylmethyl)aminomethyl]-4-methylphenol (3)}. The structures of the complexes were determined by single-crystal X-ray diffraction. The oxidation states of ruthenium, cobalt and copper in the complexes are +3, +3 and +2, respectively. In 4 and 5, Ru-III and Co-III are coordinated to four oxygen and two nitrogen atoms in an octahedral geometry, while in 6, Cu-II adopts both octahedral (CuN2O4) and square-pyramidal (CuN2O3) geometry. The potential of the three complexes as oxidation catalysts has been investigated.

  • 40.
    Lee, Bao-Lin
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Kärkäs, Markus D.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Johnston, Eric V.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Inge, Andrew K.
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Tran, Lien-Hoa
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Xu, Yunhua
    Hansson, Örjan
    Zou, Xiaodong
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Åkermark, Björn
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Synthesis and characterization of oligonuclear Ru, Co, and Cu oxidation catalysts2010In: European Journal of Inorganic Chemistry, ISSN 1434-1948, E-ISSN 1099-1948, no 34, p. 5462-5470Article in journal (Refereed)
    Abstract [en]

    In this work, we report the preparation and crystal structures of three new oligonuclear complexes, Ru-2(bbpmp)(mu-OAc)(3) (4), [Co-2(bbpmp)(mu-OAc)(mu-OMe)](PF6) (5), [Cu-4(Hbbpmp)(2)(mu-OAc)(H2O)(2)](OAc)(PF6)(2) (6) {H(3)bbpmp = 2,6-bis[(2-hydroxybenzyl)-(2-pyridylmethyl)aminomethyl]-4-methylphenol (3)}. The structures of the complexes were determined by single-crystal X-ray diffraction. The oxidation states of ruthenium, cobalt and copper in the complexes are +3, +3 and +2, respectively. In 4 and 5, Ru-III and Co-III are coordinated to four oxygen and two nitrogen atoms in an octahedral geometry, while in 6, Cu-II adopts both octahedral (CuN2O4) and square-pyramidal (CuN2O3) geometry. The potential of the three complexes as oxidation catalysts has been investigated.

  • 41. Li, P.
    et al.
    Wang, M.
    He, C. J.
    Li, G. H.
    Liu, X. Y.
    Chen, C. N.
    Akermark, B.
    Sun, Licheng C.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Influence of tertiary phosphanes on the coordination configurations and electrochemical properties of iron hydrogenase model complexes: Crystal structures of (mu-S2C3H6)Fe-2(CO)(6-n)L-n (L = PMe2Ph, n=1, 2; PPh3 P(OEt)(3), n=1)2005In: European Journal of Inorganic Chemistry, ISSN 1434-1948, E-ISSN 1099-1948, no 12, p. 2506-2513Article in journal (Refereed)
    Abstract [en]

    A series of mono- and disubstituted diiron complexes [(mu-pdt)-Fe-2(CO)(5)L] [pdt = 1,3-propanedithiolato; L = PMe3 (2), PMe2Ph (3), PPh3 (4), P(OEt)(3) (5)] and [(mu-pdt)Fe-2(CO)(4)L-2] [L = PMe2Ph (6), PPh3 (7), P(OEt)3 (8)] were prepared as Fe-only hydrogenase-active-site models by controllable CO displacement of [(mu-pdt)Fe-2(CO)(6)] by tertiary phosphanes. The coordination configurations of 3-6 were characterized by X-ray crystallography. Disubstituted diiron complex 6 features an apical/apical coordination mode, instead of the typical transoid basal/basal configuration. The electrochemistry of 2-6 and 8 was studied by cyclic voltammetry to evaluate the effects of different tertiary phosphane ligands on the redox properties of the iron atoms of model complexes.

  • 42. Li, Ping
    et al.
    Wang, Mei
    He, Chengjiang
    Liu, Xiaoyang
    Jin, Kun
    Sun, Licheng
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry.
    Phosphane and phosphite unsymmetrically disubstituted diiron complexes related to the Fe-only hydrogenase active site2007In: European Journal of Inorganic Chemistry, ISSN 1434-1948, E-ISSN 1099-1948, no 23, p. 3718-3727Article in journal (Refereed)
    Abstract [en]

    A series of unsymmetrically disubstituted diiron complexes [(mu-pdt){Fe(CO)(2)L-1]{Fe(CO)(2)L-2}] [pdt = 1,3-propanedithiolato; L-1 = PMe3, L-2 = PMe2Ph, 4; PPh3, 5; PCy3, 6; P(OEt)(3), 7; L-1= PMe2Ph, L-2 = PPh3, 8; P(OEt)(3), 9; L-1 = P(OEt)(3), L-2 = PPh3, 10; PCy3, 11] and [(mu-edt){Fe(CO)(2)PMe3)}{Fe(CO)(2)PPh3}] (edt = 1, 2-ethane dithiolato, 12) were prepared by means of step-wise CO displacements of [(mu-pdt)Fe-2(CO)(6)] and [(mu-edt)-Fe-2(CO)(6)] by different tertiary phosphane and phosphite ligands. The interconversion of the irondithiacyclohexane ring and the rotation of the [Fe(CO)(2)PR3] subunit were studied using by variable-temperature P-31{H-1} NMR spectroscopy of 4, 6 and 12 in solution. The molecular structures of 4-6, 8-10 and 12 show that complexes 4-6, 8, 9 and 12 possess an apical/basal coordination mode and complex 10 has an apical/apical conformation. The X-ray analyses indicate that the PMe2Ph ligand in the apical position of the starting complex [(mu-pdt){Fe(CO)(3)}{FeCO2(PMe2Ph)}] rotates to the basal position on conversion to the products 8 and 9. Cyclic voltammograms of 4-11 were studied both under argon and CO. The influences of the phosphane and phosphite ligands on the redox properties of the unsymmetrically disubstituted diiron complexes are discussed. ((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)

  • 43. Liao, Rong-Zhen
    et al.
    Himo, Fahmi
    Yu, Jian-Guo
    Liu, Ruo-Zhuang
    Theoretical study of the RNA hydrolysis mechanism of the dinuclear zinc enzyme RNase Z2009In: European Journal of Inorganic Chemistry, ISSN 1434-1948, E-ISSN 1099-1948, no 20, p. 2967-2972Article in journal (Refereed)
    Abstract [en]

     RNase Z is a dinuclear zinc enzyme that catalyzes the removal of the tRNA 3'-end trailer. Density functional theory is used to investigate the phosphodiester hydrolysis mechanism of this enzyme with a model of the active site constructed on the basis of the crystal structure. The calculations imply that the reaction proceeds through two steps. The first step is a nucleophihc attack by a bridging hydroxide coupled with protonation of the leaving group by a Glu-His diad. Subsequently, a water molecule activated by the same Glu-His diad makes a reverse attack, regenerating the bridging hydroxide. The second step is calculated to be the rate-limiting step with a barrier of 18 kcal/mol, in good agreement with experimental kinetic studies. Both zinc ions participate in substrate binding and orientation, facilitating nucleophilic attack. In addition, they act as electrophilic catalysts to stabilize the pentacoordinate trigonal-bipyramidal transition states.

  • 44.
    Liao, Rong-Zhen
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Himo, Fahmi
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Yu, Jian-Guo
    Liu, Ruo-Zhuang
    Theoretical study of the RNA hydrolysis mechanism of the dinuclear zinc enzyme RNase Z2009In: European Journal of Inorganic Chemistry, ISSN 1434-1948, E-ISSN 1099-1948, Vol. 2009, no 20, p. 2967-2972Article in journal (Refereed)
    Abstract [en]

    RNase Z is a dinuclear zinc enzyme that catalyzes the removal of the tRNA 3'-end trailer. Density functional theory is used to investigate the phosphodiester hydrolysis mechanism of this enzyme with a model of the active site constructed on the basis of the crystal structure. The calculations imply that the reaction proceeds through two steps. The first step is a nucleophihc attack by a bridging hydroxide coupled with protonation of the leaving group by a Glu-His diad. Subsequently, a water molecule activated by the same Glu-His diad makes a reverse attack, regenerating the bridging hydroxide. The second step is calculated to be the rate-limiting step with a barrier of 18 kcal/mol, in good agreement with experimental kinetic studies. Both zinc ions participate in substrate binding and orientation, facilitating nucleophilic attack. In addition, they act as electrophilic catalysts to stabilize the pentacoordinate trigonal-bipyramidal transition states.

  • 45.
    Liao, Rong-Zhen
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Li, Xi-Chen
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Siegbahn, Per E. M.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Reaction Mechanism of Water Oxidation Catalyzed by Iron Tetraamido Macrocyclic Ligand Complexes - A DFT Study2014In: European Journal of Inorganic Chemistry, ISSN 1434-1948, E-ISSN 1099-1948, no 4, p. 728-741Article in journal (Refereed)
    Abstract [en]

    Density functional calculations are used to elucidate the reaction mechanism of water oxidation catalyzed by iron tetra-amido macrocyclic ligand (TAML) complexes. The oxidation of the starting TAML-Fe3+-OH2 complex by removing three electrons and two protons leads to the formation of a key intermediate, TAML-Fe5+=O, which can undergo nucleophilic attack by either a water molecule or a nitrate ion. Both pathways involve attack on the oxo group and lead to the production of O-2. The water attack is more favoured and has a total barrier of 15.4 kcal/mol. The alternative nitrate attack pathway has a barrier of 19.5 kcal/mol. Nitrate functions as a cocatalyst by first donating an oxygen atom to the oxo group to form O-2 and a nitrite ion, which can then be reoxidized to regenerate a nitrate ion. Three possible competing pathways result in ligand modification, namely, water and nitrate attack on the ligand, as well as ligand amide oxidation. The water attack on the ligand has a low barrier of only 10.9 kcal/mol and leads to the opening of the benzene ring, which explains the observation of fast catalyst degradation. The lack of activity or lower activity of other catalysts with different substituents is also rationalized.

  • 46. Lindsjo, Martin
    et al.
    Kloo, Lars A.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Inorganic Chemistry.
    Kuznetzov, Alexei
    Popovkin, Boris
    Bi16I4 - A New Bismuth Subiodide: An Analysis of Molecular Packing and Electronic Structures of the Compounds in the BimI4 (m=14, 16, 18) Family2008In: European Journal of Inorganic Chemistry, ISSN 1434-1948, E-ISSN 1099-1948, no 33, p. 5196-5202Article in journal (Refereed)
    Abstract [en]

    A new bismuth subiodide Bi16I4 was synthesized by hightemperature synthesis. Its structure was determined by single-crystal X-ray diffraction analysis [C2/m (No. 12), a = 25.948(6) angstrom, b = 4.354(1) angstrom, c = 13.259(3) angstrom, beta = 104.48(2)circle, Z = 2, R-1 = 0.041, wR(all)(F-2) = 0.109]. The compound belongs to the BimI4 (m = 14, 16, 18) family of low-dimensional subhalides that feature one-dimensional bismuth stripes of varying width, terminated by iodine atoms. Ab initio calculations at the I)FT level were performed on 31) structures of all three BimI4 compounds of the family. According to the computational data all three compounds are expected to exhibit metallic behavior and Pauli paramagnetism, with a directional anisotropy of the properties indicated by the calculated band structures. The molecular packing in bismuth subiodides has been analyzed in detail and two homologous series - Bi8+4nI4 and Bi10+4nI4 (n = 0, 1, 2, ...) - are suggested to describe existing and possible structures of the compounds of the BimI4 family. ((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)

  • 47.
    Lindsjö, Martin
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Fischer, Andreas
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Kloo, Lars
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Improvements of and insights into the isolation of bismuth polycations from benzene solution - Single-crystal structure determinations of Bi-8[GaCl4](2) and Bi-5[GaCl4](3)2005In: European Journal of Inorganic Chemistry, ISSN 1434-1948, E-ISSN 1099-1948, Vol. 2005, no 4, p. 670-675Article in journal (Refereed)
    Abstract [en]

    The synthesis, crystal growth and structure are reported for the two salts Bi-5[GaCl4](3) and Bi-8[GaCl4](2). The compounds are prepared from a solution of BiCl3 and GaCl3 in benzene, using gallium metal as reducing agent. Bi-8[GaCl4](2) contains a Bi-8(2+) polycation that, essentially, adopts an ideal square antiprismatic geometry. The compound crystallizes in the P6(3) space group; a = 17.760(2) Angstrom and c = 12.979(3) Angstrom. Bi-5[GaCl4](3) crystallizes in the R3c space group, a = 11.814(2) Angstrom, c = 29.974(3) Angstrom, and contains a Bi-5(3+) cation adopting a trigonalbipyramidal geometry. The cation is slightly distorted from the ideal D-3h symmetry.

  • 48. Lomoth, R.
    et al.
    Huang, P.
    Zheng, J. T.
    Sun, Licheng C.
    Hammarstrom, L.
    Akermark, B.
    Styring, S.
    Synthesis and characterization of a dinuclear manganese(III,III) complex with three phenolate ligands2002In: European Journal of Inorganic Chemistry, ISSN 1434-1948, E-ISSN 1099-1948, no 11, p. 2965-2974Article in journal (Refereed)
    Abstract [en]

    A dinuclear manganese complex ([Mn2L(mu-OAc)(2)]PF6) has been synthesized, where L is the trianion of 2,6-bis{[(2-hydroxy-3,5-di- tert-butylbenzyl) (2-pyridylmethyl) amino] methyl)-4-methylphenol, a ligand with three phenolate groups. The two pseudo-octahedrally coordinated Mn ions are bridged via the two bidentate acetate ligands and the 4-methylphenolate group of the ligand. We have characterized the complex with electrochemistry, spectroelectrochemistry and EPR spectroscopy. Electrochemically the Mn-2(III,III) complex undergoes two metal-centered quasi-reversible one-electron reduction steps (E-1/2 = 0.04 and -0.32 V vs. SCE). Reduction to the Mn-2(II,III) state results in transformation into a modified complex with slightly different redox properties. One-electron oxidation (E-1/2 = 0.96 V vs. SCE) affords the Mn-2(III,IV) state while further one-electron oxidation (E-1/2 = 1.13 V vs. SCE) presumably involves ligand oxidation. High valent Mn complexes involving Mn-IV or Mn-V centers are of particular interest as intermediates in catalytic water oxidation. The redox potentials of [Mn2L(mu-OAC)(2)](+) show the expected stabilization of higher manganese oxidation states compared with the related complex, [Mn-2(bpmp)(mu-OAc)(2)](+).

  • 49.
    Lomoth, Reiner
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical Chemistry.
    Huang, Ping
    Zheng, Jiutian
    Sun, Licheng
    Hammarström, Leif
    Åkermark, Björn
    Styring, Stenbjörn
    Synthesis and Characterization of a Dinuclear Manganese(III,III) Complex with Three Phenolate Ligands2002In: European Journal of Inorganic Chemistry, ISSN 1434-1948, E-ISSN 1099-1948, p. 2965-2974Article in journal (Refereed)
  • 50. Ma, C. B.
    et al.
    Chen, C. N.
    Liu, Q. T.
    Chen, F.
    Liao, D. Z.
    Li, L. C.
    Sun, Licheng C.
    Great framework variation of polymers in the manganese(II) maleate/alpha,alpha' - Diimine system: Syntheses, structures, and magneto-structural correlation2003In: European Journal of Inorganic Chemistry, ISSN 1434-1948, E-ISSN 1099-1948, no 15, p. 2872-2879Article in journal (Refereed)
    Abstract [en]

    Three novel manganese(II) coordination polymers, [Mn (maleate)(phen)](n) (1; phen = 1,10-phenanthroline), [Mn-(maleate)(phen)](n).nH(2)O (2), and [Mn(maleate)(bpy)](n) (3; bpy = 2,2'-bipyridine), have been synthesized by treatment of Mn2+ with maleic acid with participation of chelate diimine ligands, and have been identified by single-crystal, X-ray diffraction to have either one-dimensional (1D) zigzag chain structures (1 and 2) or a two-dimensional (2D) sinuous layer structure (3). Each maleate dianion coordinates to three Mn centers, in different bridging modes (syn-anti in 1 and 2, syn-syn and anti-anti in 3). These compounds represent an interesting example of structural topology variation from 1D to 2D mediated by chemically similar auxiliary chelate ligands. Variable-temperature magnetic susceptibility measurements show weak anti-ferromagnetic exchange interactions between the adjacent Mn-II ions, with J = -0.06 cm(-1) (2) and J = -1.3 cm(-1), zJ' = -0.27 cm(-1) (3). The differences in the magnitudes of these coupling interactions agree well with the nature of the carb oxylate-bridging coordination of maleate.

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