Os3(CO)10(N,N'-dineopentyl-1,4-diaza-1,3-butadiene) | 221192-58-1

• 英文名称: Os3(CO)10(N,N'-dineopentyl-1,4-diaza-1,3-butadiene)
• 英文别名: decacarbonyl(1,4-dineopentyl-1,4-diaza-1,3-butadiene)triosmium
• CAS: 221192-58-1
• 化学式: C₂₂H₂₄N₂O₁₀Os₃
• 分子量: 1047.04
• InChiKey: VJYXQKXFFOVJEL-UHFFFAOYSA-N

计算性质

• 辛醇/水分配系数(LogP)：
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• 重原子数：
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• 可旋转键数：
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• 环数：
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• sp3杂化的碳原子比例：
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• 拓扑面积：
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• 氢给体数：
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• 氢受体数：
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反应信息

• 作为反应物：
  描述：

  Os3(CO)10(N,N'-dineopentyl-1,4-diaza-1,3-butadiene) 以 乙腈 为溶剂， 生成
  参考文献：
  名称：

  Mechanistic study of the photoisomerization of Os3(CO)10(L) in which L (L=1,4-di-R-1,4-diazabutadiene (R-DAB) or pyridine-2-carbaldehyde N-R-imine (R-PyCa)) changes its coordination from σ, σ-N,N′ into σ-N, μ2-N′, η2-CN′

  摘要：

  The triangular clusters Os-3(CO)(10)(alpha-diimine) photoisomerize to give the imine-bridged clusters Os-3(CO)(10)(sigma-N, mu(2)-N', eta(2)-C=N'-alpha-diimine) if the alpha-diimine has a reactive imine bond as in the case of R-DAB (1,4-di-R-1,4-diazabutadiene) or R-PyCa (pyridine-2-carbaldehyde N-R-imine). The products are identified by comparing their spectroscopic (IR, UV-vis,H-1-NMR) data with those of compounds reported in the literature. The quantum yield of the photoreaction decreases with an increase of the steric bulk of the alpha-diimine. Upon irradiation at low temperature the clusters produce unstable species? which transform into the final products on raising the temperature. The R-PyCa clusters produce a single intermediate, the R-DAB clusters three different ones. Some intermediates are assigned by comparing their IR and W-vis spectra with those of known species. A reaction mechanism is proposed for the photoisomerization, in which visible excitation causes the homolytic cleavage of an Os-Os bond with formation of a biradical. This biradical undergoes an intramolecular radical coupling reaction of the Os+(CO)(2)(alpha-diimine(.-)) and Os-.(CO)(4) radical sites with formation of an imine-bridged species, which is unstable because of a mismatch between the coordination of the two Os atoms. This mismatch is lifted by transfer of a CO ligand from one Os to the other via two CO-bridged (Os-CO-N) intermediates, which are detected at low temperature. This mechanism depicts a route along which the CO ligands of a cluster may move to compensate for an unbalance in metal-coordination. (C) 1999 Elsevier Science S.A. All rights reserved.

  DOI：

  10.1016/s0022-328x(98)00955-3

文献信息

• Photochemistry of the Triangular Clusters Os₃(CO)₁₀(α-diimine): Homolysis of an Os−Os Bond and Solvent-Dependent Formation of Biradicals and Zwitterions
  作者：Jos Nijhoff、Maarten J. Bakker、František Hartl、Derk J. Stufkens、Fu、Rudi van Eldik

  DOI：10.1021/ic9707319

  日期：1998.2.23

  Several clusters Os-3(CO)(10)(alpha-diimine) (alpha-diimine = pyridine-2-carbaldehyde N-R-imine or 1,4-di-R-1,4-diazabutadiene) were synthesized and studied with respect to their spectroscopic and photochemical properties. According to the resonance Raman spectra the visible absorption band of these clusters belongs to electronic transitions having Os-to-a-diimine charge transfer (MLCT) character with a variable degree of pi-delocalization within the Os(alpha-diimine) moiety. Upon irradiation into these transitions zwitterions Os-(CO)(4)-Os(CO)(4)-Os+-(S)(CO)(2)(alpha-diimine) are formed in coordinating solvents (S) and biradicals *Os(CO)(4)-Os(CO)(4)-Os+(CO)(2)(alpha-diamine(.-)) in noncoordinating solvents and in THF at ambient temperature. The zwitterions live seconds in nitrile solvents and minutes in pyridine, and they largely regenerate the parent clusters. Quantum yields of zwitterion formation are wavelength independent and range from 10(-2) to 3 x 10(-2) with an activation energy varying from 440 to 720 cm(-1). For one of the clusters the quantum yield of zwitterion formation in pyridine was studied in dependence of applied pressure. The activation volume Delta V-double dagger = +7.0 +/- 0.5 cm(3) mol(-1) derived from these measurements indicates that the effect of bond cleavage is partially offset by coordination of the solvent. In apolar solvents biradicals are formed instead of zwitterions, which could be detected with nanosecond time-resolved absorption spectroscopy, while their adducts with nitrosodurene were observed with EPR spectroscopy. Their lifetimes vary from 5 ns to 1 mu s depending on the solvent and the alpha-diimine. The biradicals transform into zwitterions in the presence of a Lewis base. in addition, they produce with low efficiency an isomeric product in which the cr-diimine bridges between two Os atoms. The formation of very similar photoproducts (biradicals, cr-diimine-bridged isomeric products, charge-separated species) as in the case of binuclear metal-metal-bonded complexes such as (CO)(5)MnMn(CO)(3)(alpha-diimine) points to the occurrence of a primary photoprocess in which an Os-Os bond is broken homolytically. This reaction most likely occurs from a reactive (3) sigma pi* state after surface crossing from the unreactive but optically accessible MLCT states.