Unprecedented Alkene Complex of Zinc(II):  Structures and Bonding of Divinylzinc Complexes

This report describes the solid-state structures of a series of divinylzinc complexes, one of which represents the only structurally characterized zinc(II) π-complex. Vinylzinc reagents, Zn[C(Me)CH₂]₂ (1) and Zn[C(H)CMe₂]₂ (2), have been synthesized and isolated as white crystalline solids in 66 and 72% yield, respectively. Each compound exhibits an infinite polymeric architecture in the solid state via a series of zinc-π (1) and zinc-σ-bonded (2) bridging interactions. Addition of chelating ligands to these divinylzinc compounds allowed isolation of the monomeric adducts (bipy)Zn[C(Me)CH₂]₂ (1•bipy), (tmeda)Zn[C(Me)CH₂]₂ (1•tmeda), (bipy)Zn[C(H)CMe₂]₂ (2•bipy), and (tmeda)Zn[C(H)CMe₂]₂ (2•tmeda), of which 1•bipy, 2•bipy, and 2•tmeda have been characterized crystallographically.