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111.
112.
The formation of transition metal complexes with pivalate and cymantrenecarboxylate ligands in the presence of axial cyclopentadienyl and α-substituted pyridine ligands is discussed. The latter present steric hindrances due to repulsion from the O atoms of the carboxylate bridges. Particular emphasis is placed on the role of outer-sphere ammonium cations: their hydrogen bonding to fluoride bridges limits the growth of cyclic chromium(III) complexes with the pivalate and fluoride ligands that possess the properties of molecular magnets. 相似文献
113.
114.
A. A. Pasynskii I. L. Eremenko B. Orazsakhatov Yu. V. Rakitin V. M. Novotortsev O. G. Ellert V. T. Kalinnikov 《Journal of organometallic chemistry》1981,210(3)
The photochemical reaction between the antiferromagnetic complex (C5H5-CrSCMe3)2S (I) (containing a Cr---Cr bond 2.689 Å long) and Fe(CO)5 results in the elimination of two carbonyl groups and one tert-butyl radical to give (C5H5Cr)2(μ2-SCMe3)(μ3-S)2 · Fe(CO)3 (III). As determined by X-ray diffraction, III contains a Cr---Cr bond of almost the same length as in I (2.707 Å), together with one thiolate and two sulphide bridges. The latter are also linked with the Fe atom of the Fe(CO)3 moiety (average Fe---S bond length 2.300 Å). Fe also forms a direct bond, 2.726 Å long, with one of the Cr atoms, whereas its distance from the other Cr atom (3.110 Å) is characteristic for non-bonded interactions. Complex III is antiferromagnetic, the exchange parameter, −2J, values for Cr---Cr, Cr(1)---Fe and Cr(2)…Fe are 380, 2600 and 170 cm−1, respectively. The magnetic properties of III are discussed in terms of the “exchange channel model”. The contributions from indirect interactions through bridging ligands are shown to be insignificant compared with direct exchange involving metal---metal bonds. The effects of steric factors and of the nature of the M(CO)n fragments on the chemical transformations of (C5H5CrSCMe3)2S · M(CO)n are discussed. 相似文献
115.
Yu.V. Skripkin A.A. Pasynskii V.T. Kalinnikov M.A. Porai-Koshits L.Kh. Minacheva A.S. Antsyshkina V.N. Ostrikova 《Journal of organometallic chemistry》1982,231(3):205-217
The heteronuclear Cp2Nb(CO)(μ-CO)Mn(CO)4 (I), Cp2Nb(CO)(μ-H)Ni(CO)3 (II) and [Cp2Nb(CO)(μ-H)]2M(CO)4 (III, M = Mo;IV, M = W) complexes were prepared by reaction of Cp2NbBH4/Et3N with Mn2(CO)10 in refluxing toluene, direct reaction of Cp2NbBH4 with Ni(CO)4 in ether, and reaction of Cp2NbBH4/Et3N with M(CO)5. THF complexes (M = Mo or W) in THF/benzene mixture. An X-ray investigation of compounds I–III was performed. It is established that in I the bonding between Mn(CO)5 and Cp2Nb(CO) (with the angle (α) between the ring planes being 44.2(5)°) fragments takes place via a direct NbMn bond (3.176(1) Å) and a highly asymmetric carbonyl bridge (MnCco 1.837(5) Å, NbCco 2.781(5) Å). On the other hand, in complex II the sandwich Cp2Nb(CO)H molecule (angle α = 37.8°) is combined with the Ni(CO)3 group generally via a hydride bridge (NbH 1.83 Å, NiH 1.68 Å, NbHNi angle 132.7°) whereas the large Nb?Ni distance, 3.218(1) Å, shows the weakening or even absence of the direct NbNi bond. Similarly, in complex III two Cp2Nb(CO)H molecules (with α angles equal to 41.4 and 43.0°, respectively) are joined to the Mo(CO)4 group via the hydride bridges (NbH 1.83 and 1.75 Å and MoH 2.04 and 2.06 Å) producing a cis-form. The direct NbMo bonds are probably absent, since the Nb?Mo distances are rather long (3.579 and 3.565 Å). The effect of electronic and steric factors on the structure of heteronuclear niobocene carbonyl derivatives is discussed. 相似文献
116.
A.A. Pasynskii I.L. Eremenko G.Sh. Gasanov Yu.T. Struchkov V.E. Shklover 《Journal of organometallic chemistry》1984,276(3):349-362
The reaction of (CH3C5H4CrSCMe3)2S (Ia) with Cp2Mn in boiling toluene (containing some THF) has been used to prepare a pentanuclear cluster, [(CH3C5H4)2Cr2(SCMe3)(μ3-S)2]Mn (II), which is antiferromagnetic and crystallizes into the monoclinic crystal system: space group Cc, a 26.540(10), b 9.208(3), c 21.595(9) Å; β 135.30(2)°, V = 3712.1 Å3, Z = 4. According to X-ray analysis, cluster II contains a metallospirane core, Cr4Mn, which appears to be strongly distorted, compared to its earlier studied cyclopentadienyl analogue [Cp2Cr2SCMe3(μ3-S)2]2Mn, due to the short intramolecular contacts CH3…S (2.9–3.1 Å). The angle between the metal triangle planes of Cr2Mn is 109.60°. Here, the two long CrMn bonds (3.019(3) and 3.104(4) Å) are combined with the shorter Cr Cr bond (2.651(6) Å) in one triangle and, vice versa, the less extended CrMn bonds (2.839(4) and 2.967(3) Å) are combined with a longer CrCr bond (2.726(6) Å) in the other triangle of Cr2Mn. By the reaction of Ia with [CpFe(CO)2]2 (taken in the ratio of ) in boiling toluene, the antiferromagnetic cluster [(CH3C5H4)2Cr2(SCMe3)(μ3-S)2]2Fe (III) has been synthesized in which the same distortions as in cluster II are present, as revealed by X-ray analysis. In the metallospirane core of the molecule of III, the Cr2Fe triangles make an angle of 113.84° with each other. In this cluster, the CrCr distances in the peripheral binuclear fragments (CH3C5H4)2Cr2(μ-SCMe3)(μ3-S)2 are practically equal (2.688(3) and 2.661(3) Å), whereas the FeCr bond lengths are markedly different (2.749(2) and 2.827(2) Å in on triangle and 2.910(2) and 2.969(2) Å in the other). The dependence of the geometries of clusters II and III on the steric effects of the methyl substituents in the cyclopentadienyl ligands and on the electronic effect of the central metal atom (MnII or FeII) is discussed. 相似文献
117.
118.
A. A. Pasynskii A. I. Blokhin S. S. Shapovalov Yu. V. Torubaev 《Russian Journal of Inorganic Chemistry》2007,52(6):871-874
The reaction of CpMn(CO)2(NO)+Cl? with tin dichloride gave a new ionic complex, CpMn(CO)2(NO)+SnCl 3 ? , which was treated with an excess of sodium thiophenoxide. The resulting cyclopentadienyl nitrosyl carbonyl thiolate complex CpMn(CO)(NO)Sn(SPh)3 containing a Sn(SPh)3 ligand linked to manganese by a shortened Mn-Sn bond (2.533(2) Å) was structurally characterized. 相似文献
119.
A. A. Pasynskii I. V. Skabitskii S. S. Shapovalov A. R. Galustyan Yu. V. Torubaev Zh. V. Dobrokhotova V. A. Grinberg E. V. Mutseneck A. R. Kudinov 《Russian Chemical Bulletin》2007,56(9):1731-1735
The reaction of Cb*Co(CO)2I (1) (Cb* is tetramethylcyclobutadiene) with sodium phenyltelluride afforded the mononuclesar complex Cb*Co(CO)2TePh (2). The reaction of the latter with W(CO)5(THF) produced the Cb*Co(CO)2TePh[W(CO)5] compound (4). The reaction of 1 with the Cp2Cr2(SCMe3)2S complex gave the heterometallic cluster Cb*Co(μ3-S)2Cr2Cp2 (μ-SCMe3) (5). Complexes 2, 4, and 5 are diamagnetic. Their structures were determined by X-ray diffraction. Complex 2 contains the Co-Te bond (2.585(1) Å); complex 4, the Co-Te (2.558(8) Å) and W-Te (2.8467(6) Å) bonds. Complex 5 has the stable triangular sulfide-and tert-butylmercaptide-bridged core Cr2Co (Cr-Cr and Cr-Co bond lengths are 2.626(2) and 2.673(2) Å, respectively) with Cp ligands at the chromium atoms and a Cb* ligand at the cobalt atom. Complex 5 was characterized by cyclic voltammetry. The thermolysis of complex 4 was studied. 相似文献
120.
M. V. Tsodikov A. V. Chistyakov M. A. Gubanov P. A. Zharova S. S. Shapovalov A. A. Pasynskii V. V. Kriventsov I. I. Moiseev 《Russian Chemical Bulletin》2015,64(9):2062-2068
We studied deoxygenation of individual fatty esters and fatty acid triglycerides from vegetable oils and lipid extracts from microalgae in the presence of catalysts prepared by deposition of Pt–Sn-containing compounds onto the γ-aluminum oxide surface. Using individual esters as an example, selective reduction of oxygen into water was demonstrated for the first time to proceed on a catalytic system at the 5 : 1 molar ratio of Sn and Pt active components to afford hydrocarbon components of substrates in virtually quantitative yield. Transformation of vegetable oil in the presence of this catalyst affords the C3–C18 hydrocarbon fraction in yield up to 99% at the content of C3 and C18 hydrocarbons up to 90%. The fraction of C1 and C2 hydrocarbons and carbon oxides is not higher than 0.5%. The possibility of carbon weight loss minimization during transformation of lipids was shown for the first time. 相似文献