651743-53-2Relevant academic research and scientific papers
Steric influence on the reactivity of silyl-o-carboranes: Oxidative-addition reactions involving Si-H and B-H activation
Lee, Young-Joo,Lee, Jong-Dae,Kim, Sung-Joon,Ko, Jaejung,Suh, Il-Hwan,Cheong, Minserk,Kang, Sang Ook
, p. 135 - 143 (2004)
The reactivity of mono(silyl)- and bis(silyl)-o-carboranes (HSiR2)n(C2B10H12-n) (n = 1, R = Me, 1a; n = 1, R = Et, 1b; n = 2, R = Me, 3a; n = 2, R = Et, 3b) toward six-coordinate iridium [(Cp*IrCl2)2] and nine-coordinate rhenium [ReH7(PPh3)2] complexes has been investigated. Reactions between the mono(silyl)-o-carboranes (1a,b) and (Cp*IrCl2)2 resulted in the formation of four-membered, cyclic seven-coordinate iridium complexes Cp*IrH2[η1: η1-(SiR2)BC2B9H10-Si, B] (R = Me, 2a; R = Et, 2b), where Si-H activation in the mono-(silyl)-o-carborane (1) is accompanied by the concomitant B-H activation of a neighboring boron hydride. The X-ray structure of 2a reveals that the iridium center is coordinated to both silicon and boron in a four-legged piano-stool arrangement. In the reaction between the bis(silyl)-o-carboranes (3a,b) and (Cp*IrCl2)2, silylation occurs at both Si-H sites, giving rise to the complexes Cp*IrH2[η1:η1- (SiR2)2C2B10H10- Si,Si′] (R = Me, 4a; R = Et, 4b), in which the metal center forms part of a five-membered metallacycle (Ir-Si-C-C-Si). Interestingly, the reaction of 3a with ReH7(PPh3)2 afforded the kinetically stabilized intermediate (PPh3)2ReH5[η1-SiMe2C 2B10H10(SiMe2H)-Si] (8), in which only one of the Si-H groups is coordinated, as determined by X-ray crystallography.
