Synthesis and characterization of Mercury(II) complexes with 2,6-diacetylpyridine bis [N-methyl-N-(2'-pyridyl)hydrazone]. X-ray structure of chloro-2,6-diacetylpyridine-bis[N-methyl-N- (2'-pyridyl)hydrazone]-mercury(II)-hexachloro dimercurate (II) (2/1).

The quinquedentate ligand 2,6-diacetylpyridine bis[N-methyl-N-(2′-pyridyl)hydrazone], (dapmp) reacts in ethanol with Hg(NO3)2·H2O in the presence of perchlorate ions to give the seven-co-ordinate diaqua complex [Hg (dapmp) (H2O)2][ClO4]2 (1), while starting from HgCl2 the species [Hg(dapmp)Cl]·0.5[Hg2Cl6] (2) is obtained. The complexes have been characterized by a number of physicochemical measurements including the X-ray analysis of (2). Crystals of (2) are monoclinic, space group P21/c, with unit-cell dimensions a = 12.081 (2), b = 10.295(2), c = 21.480(2) Å, β = 93.00(1)°, and Z = 4. The structure has been solved from three-dimensional counter data by Patterson and Fourier methods and refined by full-matrix least squares to R 0.037 for 3 350 observed reflections. The crystal consists of a packing of discrete units of [Hg(dapmp)Cl]+ cations and [Hg2Cl6]2- anions in the ratio 2: 1. The co-ordination in the cation is approximately pentagonal pyramidal; the five basal positions are occu...