Correlation of Reactivities of Organocuprate(I) and Zincate(II) with d-Orbital Energies of Ate Complexes

Kohn–Sham orbital analysis of MeCu, Me2Cu−, Me2Zn, Me3Zn− and Me4Zn2−, as well as the bent structures of Me2Cu−, has been performed with the density functional (B3LYP) method. It has been shown that the organozincates possess high-lying methyl carbon orbitals and low-lying d-orbitals, and hence are expected to behave as alkyl nucleophiles. On the other hand, the d-orbitals of the cuprate are at the same energy levels as the methyl carbon orbitals, and hence the cupretes react as metal-centered nucleophiles. The correlation between the bent geometry and the orbital energies of d-orbitals (z2 and xz) was also found and has been related to the mechanistic difference between SN2 alkylation reaction and conjugate addition reaction.