Organozinc ligands in transition metal chemistry

Synthetic strategies and mechanistic pathways for the formation of transition metal-organozinc compounds and their structural properties are reviewed. Herein, two groups of zinc sources are taken into account. Firstly, Zn(II) compounds ZnR ₂ (R=organic group) which includes the discussion of structural features and quantum chemical results of the recently reported zinc-rich and highly coordinated [M(ZnR) _n] molecules (n≥8; M=Mo, Ru, Rh, Ni, Pd, Pt; R=Me, Et, Cp*). Secondly, the recently discovered stable Zn(I) derivative [Zn ₂Cp* ₂] (Cp*=pentamethylcyclopentadienyl) leads to coordination compounds with TM-Zn bonds (TM=transition metal) on reaction with suitable transition metal complexes. The different concepts in the formation of TM-Zn bonds are oxidative addition of Zn-C and Zn-Zn bonds, the use of bis(transition metal)zinc compounds, hydride abstraction, the use of substitution labile transition metal compounds, salt elimination reactions, radical mechanisms, alkane elimination, dissociation/association mechanisms and finally ZnR/GaR exchange reactions.