Direct Conversion of a Si–C(aryl) Bond to Si–Heteroatom Bonds in the Reactions of η3‑α-Silabenzyl Molybdenum and Tungsten Complexes with 2‑Substituted Pyridines

η3-α-Silabenzyl complexes Cp*M­(CO)2{η3(Si,C,C)-Si­(p-Tol)3} (M = Mo (1-Mo), W (1-W)) reacted with 2-substituted pyridines NC5H4(2-EHn) (E = O, S (n = 1); N (n = 2)) under mild conditions to give M–Si–E–C–N (E = O, N), W–Si–N–C–S, and M–E–C–N (E = S, N) metallacycles depending on the metal M or heteroatom E. These three kinds of metallacycles were characterized by spectroscopy, elemental analysis, and X-ray crystallography. The first two silametallacycles take on some silylene complex character and are considered to form via (aryl)­silylene complex intermediates generated by cleavage of the Si–C­(aryl) bond in the η3-α-silabenzyl ligand of 1-Mo and 1-W.

η³-α-硅苄基配合物Cp*M(CO)₂{η³(Si,C,C)-三(对甲苯基)硅基}（其中M为钼（Mo，记为1-Mo）、钨（W，记为1-W））与2-取代吡啶NC₅H₄(2-EHₙ)（E为O、S时n=1，E为N时n=2）在温和条件下发生反应，根据金属M或杂原子E的种类不同，生成M–Si–E–C–N（E=O、N）、W–Si–N–C–S及M–E–C–N（E=S、N）型金属杂环。上述三类金属杂环均通过光谱学、元素分析及X射线晶体学完成表征。前两类硅基金属杂环表现出一定的硅烯配合物特性，其形成被认为是经由1-Mo与1-W的η³-α-硅苄基配体中Si–C(芳基)键断裂产生的（芳基）硅烯配合物中间体实现的。