Transition Metal Silyl Complexes. 60.^,1 Enhanced Reactivity of a Platinum Dimethyl Complex toward Trimethoxysilane Due to a P,N-Chelating Co Ligand

Abstract

[(κ2-P,N)-Me2NCH2CH2PPh2]PtMe2 reacts with trimethoxysilane to yield the methyl trimethoxysilyl complex [(κ2-P,N)-Me2NCH2CH2PPh2]Pt[Si(OMe)3]Me, the bis(trimethoxysilyl) complex [(κ2-P,N)-Me2NCH2CH2PPh2]Pt[Si(OMe)3]2, methyltrimethoxysilane, tetramethoxysilane, and small amounts of pentamethoxydisiloxane and hexamethoxydisiloxane. The formation of these compounds can be explained by Si−H oxidative addition/reductive elimination as well as Si−O activation and scrambling reactions of the silicon substituents.

C−Cl and Si−Cl Activation byP,N-Chelated PtII Complexes

“…[2] In previous studies on the oxidative addition of organosilanes to Pt II complexes, we found that the reactivity the complexes is strongly enhanced by hemilabile P,N-chelating ligands. [3,4] In this paper, we report that this is also true for reactions with chlorocarbons. The presence of the hemilabile ligands allows the thermal reactions of chloromethane derivatives with Pt II complexes.…”

“…Since 3 contains no methyl ligands, the remaining three signals with equal intensity must belong to a single complex. This complex is spectroscopically identified as (P ʝ N)Pt(Me) 3 Cl (4) by comparison with an authentic sample of 4 obtained by another route (see below). An X-ray structure analysis of 4 was performed.…”

“…CCl 4 Ͼ CHCl 3 Ͼ CH 2 Cl 2 , is related to the CϪCl bond strength in these compounds (CCl 4 Ϫ248 kJ·mol Ϫ1 , CHCl 3 Ϫ280 kJ·mol Ϫ1 , CH 2 Cl 2 Ϫ304 kJ·mol Ϫ1 , CH 3 Cl Ϫ328 kJ·mol Ϫ1 ).…”

“…CH 3 Cl does not fit into the sequence as it reacted with (P ʝ N)PtMe 2 in a hot C 6 D 6 solution to form complex 4 and traces of 2. The reaction was complete within 12 h. The amount of 2 increased on further heating, indicating reductive elimination of ethane from 4.…”

SiSi and SiO Bond Activation at Platinum: Stepwise Formation of a SiH3 Complex

“…Note that a hydrogenolysis of disilanes with dihydrogen is rarely investigated; most of the conversions involve rather harsh conditions. [14,15] The hydrogenolysis of Si 2 (OEt) 6 [17] As an intermediate, a methyl silyl complex was identified.…”