Synthesis and X-ray structure of zinc(II) derivatives of esters of 2-pyridinecarboxylic acid

Zinc(II) halides form a series of 1:1 and 1:2 complexes with neutral 2-pyridinecarboxylate esters, which act as bidentate nitrogen-oxygen donors, via reaction in alcohol solution. Compounds of formula [ZnX(2)(C(5)H(4)NCOOR)(n)] with n = 1 (X = Cl, R = Me, Et, Pr-i and X = Br, R = Et) and the whole series with n = 2 (X = Cl, Br, I and R = Me, Et, Pr-i) have been obtained. The crystal structures of five complexes, [ZnX, (C5H4NCOOPri)(2)] (X = Cl, Br or I) and [ZnX(2)(C(5)H(4)NCOOMe)(2)] (X - Br or I), have been determined. In all cases the structure consists of discrete neutral monomeric units where the zinc atom has a distorted octahedral coordination to two halides, in cis disposition, and to two 2-pyridinecarboxylate ester ligands by means of the pyridine nitrogen and the carbonyl oxygen atoms. The degree of distortion from regular octahedral geometry is compared to closely related structures. Copyright (C) 1996 Elsevier Science Ltd