Investigations on organozinc compounds VIII. The influence of π-bonding on the stability of dialkylzinc-2,2′-bipyridine complexes

Abstract

The stability of a number of complexes of dialkylzinc compounds R2Zn with N,N,N′,N′-tetramethylethylenediamine (TMED) and with the potentially π-bonding ligand 2,2′-bipyridine (Bipy) has been compared using a dielectric constant titration technique. The stability of the R2Zn·TMED complexes decreases in the expected order: Me> Et> iso-Pr> tert-Bu. The reversed stability sequence: Me < Et < iso-Pr < tert-Bu has been observed for the R2Zn·Bipy complexes. It is concluded that π-bonding is the predominant factor determining the stability of the latter type of complexes.