Si-H cleavage

Thus, the metal-catalyzed reactions of several silicon species with acetylenes clearly show evidence for the generation of metal silylene species as well as Si—Si and Si—H cleavage. The nature of the metal catalyst, its ancillary ligands, and the nature of the substrate determine the ultimate product distribution. It is probable that certain silicon species are com-... 

SiH4 binding and Si-H cleavage are exciting because they directly model the binding of CH4 to M and subsequent C-H bond-breaking. By analogy with H-H,... 

Me3SiMn(CO)j has also been obtained from Mn2(CO)io, and HMn(CO)5 was a postulated intermediate 31). Thus, method (a) comprises a formally oxidative M—M cleavage and a subsequent hydrogen elimination between Si—H and H—M moieties. 

This is an intermolecular reaction, so it s going to be a chain process. Initiation has the AIBN-derived radical remove H from Si. In the propagation, the Si radical adds to C9. From there, two pathways are possible. Either we can make C4-C2, then cleave C3-C2, or we can cleave C2-C3, then make C4-C2. Either way, the final steps are the cleavage of C4-C5, then abstraction of H from Si-H to start the propagation again. 

The surface complex [=Si-NH2] can be obtained on siUca by reaction of ammonia on silicajiooo) (Scheme 2.7) [9]. The addition of ammonia on siUca, normally unable to induce N-H cleavage at room temperature, becomes possible in this case because of the drastic dehydroxylation treatment, which produces a few highly strained [=Si-0-Si=] bridges (0.15 nm ) that undergo cleavage by bimolecular oxidative addition of otherwise unreactive bonds [10-13]. 

Various competitive studies have shown that the ease of bond cleavage is in the order Si—H>Si—OR>Si—OH>Si—R Si-Si>Si-R Si-Ar>Si-R Si-Et>Si-Me depending upon the nature of substituents on silicon81. 

Linford and coworkers have shown that the attachment of alkenes to H-terminated silicon surfaces can also be initiated by direct mechanical scribing, in a process termed chemomechanical functionalization [145-147]. The reaction of 1-alkenes (as well as 1-alkynes) leads to attachment of the molecule to the surface through two new Si—C bonds. The proposed mechanism is the mechanical cleavage of Si—H and Si—Si bonds, leading to silicon radicals that then react with the reactive liquid. Interestingly, Linford and coworkers have also extended this work to show that chemomechanical functionalization can be carried out not only on H-terminated Si, but also on sihcon covered with oxide, and have shown that the process works with a variety of halides, alcohols, and epoxides in both the liquid and gas phase [146]. 

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