Reactions of 'pincer' pyridine dicarbene complexes of Fe(0) with silanes

摘要

Reactions of Fe(C-N-C)(N-2)(2), 1a, or Fe(C-N-Me-C)(N-2)(2), 1b, C-N-C = 2,6-bis(arylimidazol-2-ylidene) pyridine, C-N-Me-C = 2,6-bis(arylimidazol-2-ylidene)-3,5-dimethylpyridine, aryl = 2,6-(Pr2C6H3)-Pr-i, with silanes are described. Complex 1a with excess SiPhH3 and complex 1b with excess Si(tol)H-3, Ph = phenyl, C6H5, tol = 2-methylphenyl, gave the complexes [Fe(C-N-C)(SiH2Ph)(2)(eta(2)-H-SiH2Ph)], 2a, and [Fe(C-N-Me-C)(SiH(2)tol)(2)(eta(2)-H-SiH(2)tol)], 2b, respectively. Complex 1b with excess SiPhH3 gave [Fe(C-N-Me-C)(SiH2Ph)(2)(H)(2)], 3, which was formulated as a dihydride based on the relaxation time T-1(min) in the H-1-NMR spectra. Reaction of 1a with SiPh2H2 gave complex [Fe(C-N-C)(SiHPh2)(2)(eta(2)-H-2)], 4, while reaction with Si(mes)H-3 gave complex [Fe(C-N-C)(SiH(2)mes)(2)(N-2)], 5, mes = mesityl, 2,4,6-trimethylphenyl. The comparison of the reactivity with other 'pincer' complexes of iron and the mechanism leading to 2a-5 are discussed.