Computational studies dehydrogenation

A computational study of ethane dehydrogenation by the 14-electron complex Ir(PH3)2H has been carried out [72]. The first step of the reaction is the formation of the ethane adduct... 

When the same reaction was carried out with the nickel analogue, complete decomposition to compound 43, in which one of the NHC rings had opened, took place (Scheme 3.15). ° A similar migratory insertion of a ligand on nickel to the NHC was proposed by Hall et al. based on computational studies of the dehydrogenation of ammonia borane by NHC-Ni-NHC based catalysts. 

Computational and catalytic studies of the hydrosilylation of terminal alkynes have been very recently reported, with the use of [ Ir( r-Cl)(Cl)(Cp ) 2] catalyst to afford highly stereoselectively P-Z-vinylsilanes with high yields (>90%) [35]. B-isomers can be also found among the products, due to subsequent Z —> E isomerization under the conditions employed. The catalytic cycle is based on an lr(lll)-lr(V) oxidahve addition and direct reductive elimination of the P-Z-vinylsilane. Other iridium complexes have been found to be active in the hydrosilylation of phenylacetylene and 1-alkynes for example, when phenylacetylene is used as a substrate, dehydrogenative silylation products are also formed (see Scheme 14.5 and Table 14.3). 

Zhang D-D, Chen X-K, Liu H-L, Huang X-R. A computational mechanistic study of pH-dependent alcohol dehydrogenation catalyzed by a novel [C, N] or [C, C] cyclometalated Cp Ir complex in aqueous solution. New J Chem. 2014 38 3862—3873. 

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