REACTIONS OF MERCURY(II) WITH 2-PYRIDINECARBOXYLIC AND 6-METHYL-2-PYRIDINECARBOXYLIC ACIDS AND CORRESPONDING ESTERS - CRYSTAL-STRUCTURES OF[HG(C5H4NCOO)(2)], [HGX2(C5H4NCOOPRI)], X=BR OR I AND [HGCL2(MEC5H3NCOOET)]

Several mercury(II) complexes with 2-pyridinecarboxylic and 6-methyl-2 -pyridinecarboxylic acids as well as with corresponding esters have be en obtained and some of them structurally characterized by X-ray diffr action. [HgC5H4NCOO)(2)] consists of one-dimensional chains of octahed rally coordinated mercury atoms linked by means of the oxygen atoms of the carboxylate groups. The structure of the isomorphous complexes [H gX2(C5H4NCOOPri)], X = Br or I, consists of isolated centrosymmetric d imers with unsymmetrical mu-X bridges, where mercury atoms are in a di storted square pyramidal coordination. Complex [Hg(Cl-2(MeC2H3NCOOEt)] has a polymeric chain structure formed by loosely bound formula units through a unique non-planar bis(chloride) asymmetric Hg(mu-Cl)(2)Hg b ridge. In all cases picolinate ligands behave as chelates. The crystal structures are compared with those found for the related family [HgCl 2(C5H4NCOOR)], R = Me,Et, Pr-n or Pr-i. (C) 1998 Published by Elsevier Science Ltd. All rights reserved.