Quantum Chemical Study of the Structure and Stability of the Adducts of Zn(II) Pivalate with N-Heterocyclic Carbenes

Geometric characteristics and the thermodynamic stability of zinc(II) pivalate derivatives with functionalized N-heterocyclic carbenes R–NHC–X (R= Dipp, t-Bu, Mes, i-Pr; X = OMe, H, Br, CN) are studied using the density functional theory (DFT B3LYP/Def2-TZVP). It is shown that formation of coordination compounds ([Zn(Piv)₂(R–NHC–X)] or [Zn(Piv)₂(R–NHC–X)₂]) of various compositions is mainly determined by steric hindrances created by the bulky groups R at the nitrogen atoms in carbenes. The introduction of electron-active groups X into carbene positions 4 and 5 slightly diminishes the stability of the resulting adducts.