三角对称晶场中 4 A2(3d3 )态离子EPR参量的SS和SOO机制

A CDM/ EPR program has been developed using Visual Basic 6. 0. The spin-spin（SS）and spin-otherorbit（SOO）interactions omitted in published works have also been included in the Hamiltonian. The CDM/EPR program can study not only the EPR parameters but also the CF energy levels and wavefunctions for 4A2 （3d3）states ions in crystals. Utilizing the CDM/ EPR program,the EPR parameters and fine spectra for Ruby and Emerald have been investigated. The theoretical results are in good agreement with the experimental findings. The contributions to the EPR parameters and fine spectra arising from SS and SOO interactions have been studied. The investigation shows:① The EPR parameters are mainly induced by SO coupling interaction;② The contribution to the zerofield-splitting（ZFS）arising from SS interaction is appreciable and cannot be omitted,whereas the contributions to the ZFS parameter D arising from SOO interaction are smaller;③ The contribution to the Zeeman g-factors and spectra arising from SS and SOO interactions is slight.     

三角晶场中4A2(3d3)态离子全组态EPR理论研究

在中间场耦合图像中,建立了4A2(3d3)态离子全组态EPR理论;研究了EPR参量随三角晶场参量V、V′及立方晶场参量Dq变化关系;用完全对角化方法验证了MacfarlaneEPR参量的三阶微扰公式,结果表明,在较大的晶场范围内微扰公式的收敛性很好;研究了EPR参量的微观起源及自旋二重态对EPR参量的贡献,指出自旋二重态对零场分裂参量的贡献不可忽略,二重态对g因子的贡献甚微.     

多中心d-pπ键与高氧化态钼簇合物的几何构型——(Ⅱ)簇价电子数规则与构型畸变

本文提出了不同的d-p π作用类型的正常构型及畸变构型的簇价电子数规则,并用以讨论Mo_3S_4(dtp)_4(YX_n)型簇合物中的Mo—Y键松散的机理,以及某些三核和四核钼簇合物构型的畸变现象。     

Synthesis,Crystal Structure and Magnetism of A 1-D Polymeric Manganese(II) Complex with 2-Hydroxyl-2-Hydroxylate-Malonate as Bridging Ligand

A one-dimensional chain complex {Na[MnL(H₂O)₂]} _n (L = 2-hydroxyl-2-hydroxylate-malonate trivalent anion) has been synthesized and its crystal structure determined by X-ray crystallography. In the complex each Mn ion is located in a distorted octahedral environment with two oxygen atoms O(7) and O(8) from terminal ligands of two H₂O molecules, and four other coordinating oxygen atoms O(1), O(5), O(3A) and O(6A) from two bridging ligands, respectively. Each bridging ligand provides four coordinating oxygen atoms, in which O(6) comes from the hydroxylate, O(5) from the hydroxyl, and O(1) and O(3) from two carboxylate groups, respectively. The O(1) and O(5) atoms coordinate to one Mn ion and the O(3) and O(6) atoms coordinate to another Mn ion; a one-dimensional chain is thereby constructed. The variable-temperature magnetic susceptibility of the complex was measured in the 4–300 K range. The magnetic coupling parameter is consistent with an antiferromagnetic exchange and generates the antiferromagnetic coupling parameter, 2J=–0.0544 cm^–1.     

Highly Active and Selective Manganese C=O Bond Hydrogenation Catalysts: The Importance of the Multidentate Ligand,the Ancillary Ligands,and the Oxidation State

The replacement of expensive noble metals by earth‐abundant transition metals is a central topic in catalysis. Herein, we introduce a highly active and selective homogeneous manganese‐based C=O bond hydrogenation catalyst. Our catalyst has a broad substrate scope, it is able to hydrogenate aryl–alkyl, diaryl, dialkyl, and cycloalkyl ketones as well as aldehydes. A very good functional group tolerance including the quantitative and selective hydrogenation of a ketone in the presence of a non‐shielded olefin is observed. In Mn hydrogenation catalysis, the combination of the multidentate ligand, the oxidation state of the metal, and the choice of the right ancillary ligand is crucial for high activity. This observation emphasizes an advantage and the importance of homogeneous catalysts in 3d‐metal catalysis. For coordination compounds, fine‐tuning of a complex coordination environment is easily accomplished in comparison to enzyme and/or heterogeneous catalysts.     

含N4O2配体的铁(Ⅱ)配合物的合成、结构及催化烷烃氧化反应

Two iron(Ⅱ) complexes [Fe(tpdoen)](FeCl₄)Cl (2, tpdoen=N,N-bis(2-pyridylmethoxyethyl)-N-(2-pyridylmethyl)amine) and [Fe(tpdoen)](ClO₄)₂ (3) with an N₄O₂ ligand containing two potentially π-coordinate oxygen atoms were synthesized as functional models of non-heme iron oxygenases. The X-ray crystal structure analysis corroborated that complex 3 possesses a significantly distorted six-coordinate pseudooctahedral configuration, in which all six heteroatoms (N₄O₂) coordinate to the iron center. The catalytic property of complex 3 for alkane oxidation were explored using H₂O₂, TBHP and mCPBA as oxidants in the presence of excess substrates under mild conditions. When cyclohexane oxidation process was monitored by UV-Vis spectra using H₂O₂ as oxidant at 0 ℃, a short-life band appeared at ca. 550 nm, which is attributed to the in-situ Fe(Ⅲ)-OOH species. CCDC: 607630.     

多中心d-pπ键与高氧化态钼簇合物的几何构型——(Ⅰ)“碎片结构”模型及分子轨道研究

本文通过对不同构型的二核钼簇合物簇胳结构的分子轨道计算,揭示了Mo—B(T)原子间的多中心d-p π键与该结构的稳定性及结构参数α、θ和R之间的内在联系,提出了2～6核高氧化态钼簇合物的簇胳由“碎片结构”组合而成的设想,该模型对以μ_2-S_2为桥的三核钼簇合物中的“共面—异面”规则和簇胳为[Mo_4S_3O]~(6+)的钼簇中的反常Mo—Mo键距给出合理解释,确认了桥原子对Mo—Mo键长和键强的决定作用。     

Synthetic, X-ray Structure, Electron Paramagnetic Resonance, and Magnetic Studies of the Manganese(II) Complex of 1-Thia-4,7-diazacyclononane ([9]aneN(2)S)

Reaction of manganese(II) perchlorate hexahydrate with a methanol solution of 1-thia-4,7-diazacyclononane ([9]aneN(2)S) resulted in the isolation of the manganese(II) complex [Mn([9]aneN(2)S)(2)](ClO(4))(2). The X-ray structure of this complex is reported: crystal system orthorhombic, space group Pbam, No. 55, a = 7.937(2) ?,b = 8.811(2) ?, c = 15.531(3) ?, Z = 2, R = 0.0579. The complex is high spin (S = (5)/(2)) with an effective magnetic moment (&mgr;(eff)) 5.82 &mgr;(B) at 298 K and 5.65 &mgr;(B) at 4.2 K. Computer simulation of the Q-band EPR spectrum of [Mn([9]aneN(2)S)(2)](ClO(4))(2) yields g = 1.99 +/- 0.01, |D| = 0.19 +/- 0.005 cm(-)(1), and E/D = 0.04 +/- 0.02. For the analogous hexaamine complex [Mn([9]aneN(3))(2)](ClO(4))(2) ([9]aneN(3) = 1,4,7-triazacyclononane) analysis of the EPR spectra produced the following values: g = 1.98 +/- 0.01, |D| = 0.09 +/- 0.003 cm(-)(1), and E/D = 0.1 +/- 0.01. The spin Hamiltonian parameters for [Mn([9]aneN(2)S)(2)](ClO(4))(2) derived from the EPR spectra produced a good fit to the magnetic susceptibility data.     

A Novel Mixed‐Ligand Manganese(II) Complex Containing a V‐shape Water Trimer: Synthesis,Structure and Magnetic Properties of {[Mn(azpy)2(dca)(H2O)2](ClO4)(azpy)(H2O)2}n

A novel mixed‐ligand complex {[Mn(azpy)₂(dca)(H₂O)₂](ClO₄)(azpy)(H₂O)₂}_n ( 1 ) has been synthesized and characterized by single crystal X‐ray analysis, elemental analysis, IR spectroscopy and variable temperature magnetic measurement. The 4,4′‐azopyridine and dicyanamide ligands are abbreviated as azpy and dca, respectively. The crystal structure of 1 revealed that the 1D covalent bonding chains constructed by μ_1,5‐dca bridging the Mn^II ions are linked together via O–H···N and O–H···O hydrogen bonds and π‐π stacking interactions into a 3D supramolecular structure. V‐shape (bent) water trimers were also found in the structure. The water clusters play an important role in the formation of the 3D supramolecular structure. The determination of the variable temperature magnetic susceptibilities (2–300 K) shows the existence of a very weak antiferromagnetic interaction with a J value of ?0.16 cm^?1.     

N,N'-二茂铁甲基-(1S,2S)-1,2-二苯基乙二胺的合成及其在烯烃的不对称双羟基化反应中的应用

(1S,2S)-1,2-二苯基乙二胺和甲酰基二茂铁经缩合和还原两步反应,以90%的产率合成了N,N'-二茂铁甲基-(1S,2S)-1,2-二苯基乙二胺,并以其为配体催化烯烃的不对称双羟基化反应,获得了较高的对映选择性(71%～86?).     

Electron Spin Resonance (ESR) Spectroscopy of the Transition metal Complexes and Clusters I. Systematic Investigations of Real and Complex Orbital Methods for Calculating the d Orbital Energies of a Low spin( S =1/2) nd 5(t 5 2

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Determination of the Absolute Configuration of Dimethyl (2S,3S)-2-Allyl-3-hydroxyglutarate: A Chiral Building Block for Preparing Branched-Chain Nucleoside Analogues

A yeast-catalyzed reduction of dimethyl (2S,3S)-2-allyl-3-hydroxyglutarate is the key step in the preparation of bis-homo, branched-chain nucleoside analogues. To establish unambiguously the stereochemical course of the microbial reaction, the product has been converted to a derivative esterified with camphanoyl chloride, and a crystal structure of the derivative solved.     

The Valence States of Nickel,Tin, and Sulfur in the Ternary Chalcogenide Ni3Sn2S2—XPS, 61Ni and 119Sn Mössbauer Investigations,and Band Structure Calculations

The hitherto controversial valence states of nickel and tin in the ternary chalcogenide Ni₃Sn₂S₂ (see structure) have been determined by photoelectron and Mössbauer spectroscopy (⁶¹Ni, ¹¹⁹Sn). Results from band structure calculations confirmed that this shandite phase is a metal and that the approximate distribution of the valence electrons is (Ni⁰)₃(Sn(1)^II)(Sn(2)^II)(S^II−)₂.     

Determination of the g-tensors and their orientations for cis,trans-(L-N2S2)Mo(V)OX (X = Cl, SCH2Ph) by single-crystal EPR spectroscopy and molecular orbital calculations

A single-crystal study of cis,trans-(L-N2S2)MoVOCl (1) doped into cis,trans-(N2S2)MoVIO2 (3) has enabled the g-tensor of 1 and its orientation with respect to the molecular structure to be determined. The EPR parameters (g1, 2.004; g2, 1.960; g3, 1.946; A1, 71.7 x 10(-4) cm(-1); A2, 11.7 x 10(-4) cm(-1); A3, 32.0 x 10(-4) cm(-1)) of cis,trans-(L-N2S2)MoVOCl [L-N2S2H2 = N,N'-dimethyl-N,N'-bis(mercaptophenyl)ethylenediamine] mimic those of the low-pH form of sulfite oxidase and the "very rapid" species of xanthine oxidase. The principal axis that corresponds to g1 is rotated approximately 10 degrees from the Mo[triple bond]O vector, while the principal axis that corresponds to g3 is located in the equatorial plane and approximately 38 degrees from the Mo-Cl vector. Independent theoretical calculations of the g-tensor of 1 were performed using two types of techniques: (1) the spectroscopically parametrized intermediate neglect of differential overlap technique (INDO/S) combined with single-excitation configuration interaction (CIS); (2) a scalar relativistic DFT (BP86 and B3LYP functionals) treatment using the zeroth order regular approximation to relativistic effects (ZORA) in combination with recently developed accurate multicenter mean field spin-orbit operators (RI-SOMF) and the estimation of solvent effects using dielectric continuum theory at the conductor-like screening model (COSMO) level. The excellent agreement between experiment and theory, as well as the high consistency between the INDO/S and BP86/ZORA results, provides a sound basis for analysis of the calculated orientation of the g-tensor for cis,trans-(L-N2S2)MoVO(SCH2Ph) (2), for which single-crystal EPR data are not available but which contains three equatorial sulfur donor atoms, as occurs in sulfite oxidase and xanthine oxidase. The implications of these results for the EPR spectra of the Mo(V) centers of enzymes are discussed.