Isolation and Diverse Reactivity of an Unsymmetrical 1,2-Bis(silylene)-Stabilized Pentacarbonyl Chromium(0) Species

The construction of the unsymmetrical 1,2-bis(silylene) pentacarbonyl chromium(0) complex 1 was achieved through the reaction of chlorosilylene with half an equivalent of K₂Cr(CO)₅. X-ray diffraction analysis of 1 confirms the formation of the Si-Si bond and the coordination of one of the silicon atoms to the Cr center. Density functional theory (DFT) calculations disclose that highest occupied molecular orbital (HOMO) mainly corresponds to the lone pair of electrons on the silicon atom and the σ-bonding interaction between two Si atoms. Based on its unique electronic structure, its diverse reactivity toward the transition metal compounds and small molecules was investigated in detail. The reactions of 1 with Fe₂(CO)₉ or CuCl yielded the 1,2-bis(silylene)-stabilized heterobimetallic complex 2 or oxidized product 3, respectively. Additionally, treatments of 1 with selenium, CO₂, or Me₃SiN₃ led to the formation of the corresponding selenium-, oxo-, and nitrogen-bridged complexes 4-7. All compounds were characterized by multinuclear NMR spectroscopy and X-ray crystallography.