A main-group metal carbonyl complex: Structure and isomerization to a carbene-stabilized tin atom

In contrast to transition elements, s- and p-block metal compounds that coordinate carbon monoxide (CO) under near-ambient conditions are elusive. Here, we report an isolable, crystalline main-group metal carbonyl complex and its isomerization to a carbene-stabilized metal atom. The stannylene (Boryl)₂Sn [where Boryl is B(NDippCH)₂] coordinates CO reversibly, affording an isolable adduct below 0°C, which was characterized by x-ray crystallography. This complex rearranges at temperatures above 0°C to generate the stannavinylidene, (Boryl)(OBoryl)C=Sn, that is, a complex between the triplet carbene (Boryl)(OBoryl)C and monatomic Sn(0) in its electronic ground state.