(ETA-5-CYCLOPENTADIENYL)TRIALKYLPLATINUM PHOTOHYDROSILYLATION CATALYSTS - MECHANISM OF ACTIVE CATALYST FORMATION AND PREPARATION OF A NOVEL BIS(SILYL)PLATINUM HYDRIDE
(ETA-5-CYCLOPENTADIENYL)TRIALKYLPLATINUM PHOTOHYDROSILYLATION CATALYSTS - MECHANISM OF ACTIVE CATALYST FORMATION AND PREPARATION OF A NOVEL BIS(SILYL)PLATINUM HYDRIDE
复制标题
DOI：
10.1021/om00060a042
复制
发表时间：
1992-12-01
期刊：
影响因子：
2.8
通讯作者：
BOARDMAN, LD
中科院分区：
文献类型：
--
作者：
BOARDMAN, LD
描述了（η 5-β）三烷基铂络合物作为光氢化硅烷化催化剂的用途。CpPtMe3在硅烷存在下的光解导致活性硅氢加成催化剂的形成，证据表明该催化剂是非均相铂胶体。该催化剂被元素汞中毒，但不被二苯并[a，e]环辛四烯抑制。在某些反应性硅烷如HMe2SiOSiMe3的存在下，新的双（甲硅烷基）铂化合物CpPt（SiR3）2H作为可分离的物质形成，然而，其不是活性氢化硅烷化催化剂的主要途径上的中间体。实验结果表明，硅基甲基氢化物配合物CpPtMe（SiR3）H是关键中间体，在反应条件下，CpPt（SiR3）2H与胶体铂发生配位反应。当它们用第二反应性硅烷处理时，双（甲硅烷基）铂氢化物络合物可以通过在铂上的顺序还原-消除/氧化-加成反应进行容易的硅烷交换，得到其它双（甲硅烷基）铂CpPt（SiR3 '）2H。提出并讨论了连接CpPtMe3、CpPt（SiR3）2H和胶体铂的机理。
The use of (eta5-cyclopentadienyl)trialkylplatinum complexes as photohydrosilylation catalysts is described. Photolysis of CpPtMe3 in the presence of a silane leads to the formation of an active hydrosilylation catalyst that evidence suggests is a heterogeneous platinum colloid. The catalyst is poisoned by elemental mercury but is not inhibited by dibenzo[a,e]cyclooctatetraene. In the presence of certain reactive silanes such as HMe2SiOSiMe3 the novel bis(silyl)platinum hydrides CpPt(SiR3)2H are formed as isolable species, which are not, however, intermediates on the primary pathway to the active hydrosilylation catalyst. The evidence suggests that the silyl methyl hydride complex CpPtMe(SiR3)H is the critical intermediate which is partitioned under the reaction conditions between colloidal platinum and CpPt(SiR3)2H. When they are treated with a second reactive silane, bis(silyl)platinum hydride complexes may undergo facile silane exchange via sequential reductive-elimination/oxidative-addition reactions at platinum to give other bis(silyl)platinum hydrides CpPt(SiR3')2H. A mechanism connecting CpPtMe3, CpPt(SiR3)2H, and colloidal platinum is proposed and discussed.