Late Transition-Metal Sulfido Complexes: Reactivity Studies and Mechanistic Analysis of Their Conversion into Metal-Sulfur Cubane Complexes
Late Transition-Metal Sulfido Complexes: Reactivity Studies and Mechanistic Analysis of Their Conversion into Metal-Sulfur Cubane Complexes
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后过渡金属硫配合物：反应性研究及其转化为金属硫古巴烷配合物的机理分析
DOI：
10.1021/ic00101a027
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发表时间：
1994
影响因子：
4.6
通讯作者：
R. Bergman
中科院分区：
文献类型：
--
作者：
Daniel A. Dobbs;R. Bergman
R= Me， M= Rh；15， R= p- toyl， M= Ir)已制备。将这些化合物加热可得到金属-硫立方烷配合物（Cp* MS） 2 (Cp* IrS) 2 （10， M= Ir; 13， M= Rh）。观察到diiridium/ dihodium配合物13是从12的热裂解中定量获得的唯一产物，这证明了二聚体单元在形成立方烷的途径上保持完整，而不是解离成单体单元，然后重新组装成四聚体。利用配合物15对古巴烷组装反应进行了机理研究。当膦浓度较低时，[15]为一级反应，[PR3]为零级反应。在高（淹水）[PR3]时，[15]的速率为二阶，磷化氢浓度的速率为反二阶。这些数据与双重不饱和中间体Cp* MS2-IrCp*的机理一致，该中间体由磷化氢的可逆损失产生，然后在第二个双分子步骤中二聚形成立方烷。还叙述了3与甲基溴、一氧化碳和异氰酸叔丁酯的反应。测定了Cp* Ir (PMe3) S2lrCp*(3)、Cp* Ir (CN-f-Bu)（«-S） 2lr (CN-f-Bu) Cp*(9)和（Cp* IrS） 4（10）的单晶x射线结构。配合物3在单斜晶系中结晶，空间群P2i为a= 8.556 (1) a, b= 14.093 (2) a, c= 10.977 (2) a,/3= 103.28 (1)， Z= 2。通过标准最小二乘技术进行细化，最终残差R= 0.039和7？w = 0.046。配合物9在单斜晶系中结晶，空间群C2lc， a= 18.798 (5) a, b= 9.554 (2) a, c= 18.219 (3) a,/？= 90.34， Z= 8。通过标准最小二乘技术进行细化，最终残差R= 0.034和7？w = 0.040。配合物10在正交体系中结晶，空间群为74，a= 12.026 (3) k, b= 12.026 (3) a, c= 14.844 (3) a， Z= 2。通过标准最小二乘技术进行细化，最终残差R= 0.031, Rv= 0.039。
R= Me, M= Rh; 15, R= p-tolyl, M= Ir) have been prepared. Heating these compounds leads to the metalla—sulfur cubane complexes (Cp* MS) 2 (Cp* IrS) 2 (10, M= Ir; 13, M= Rh). The observation that diiridium/dirhodium complex 13 is the only product obtained quantitatively from the thermolysis of 12 provides evidence that the dimeric units remain intact on the pathway to cubane formation rather than dissociatingto monomeric units followed byreassembly into the tetramer. A mechanistic study of the cubane-assembly reaction was undertaken using complex 15. The reaction is first-orderin [15] and zero-order in [PR3] when the concentration of phosphine is low. At high (flooding)[PR3], the rate is second-order in [15] and inverse second-order in phosphine concentration. These data are consistent with a mechanism in which a doubly unsaturated intermediate, Cp* MS2-IrCp*, is generated by reversible loss of phosphine and then in a second bimolecular step dimerizes to form the cubane. The reactions of 3 with methyl bromide, carbon monoxide, and tert-butyl isocyanide are also described. The single crystal X-ray structures of Cp* Ir (PMe3) S2lrCp*(3), Cp* Ir (CN-f-Bu)(«-S) 2lr (CN-f-Bu) Cp*(9), and (Cp* IrS) 4 (10) have been determined. Complex 3 crystallized in the monoclinic system, space group P2i with a= 8.556 (1) A, b= 14.093 (2) A, c= 10.977 (2) A,/3= 103.28 (1), and Z= 2. Refinement by standard least-squares techniques gave final residuals R= 0.039 and 7? w= 0.046. Complex 9 crystallizedin the monoclinic system, space group C2lc with a= 18.798 (5) A, b= 9.554 (2) A, c= 18.219 (3) A,/?= 90.34, and Z= 8. Refinement by standard least-squares techniques gave final residuals R= 0.034 and 7? w= 0.040. Complex 10 crystallized in the orthorhombic system, space group 74 with a= 12.026 (3) k, b= 12.026 (3) A, c= 14.844 (3) A, and Z= 2. Refinement by standard least squares techniques gave final residuals R= 0.031 and Rv= 0.039.