Synthesis and characterization of pentagonal-bipyramidal Mercury(II) complexes with 2,6-diacetyl pyridine bis(2'-pyridylhydrazone). X-Ray structure of (2,6-diacetylpyridine bis (2'-pyridylhydrazone)) mercury(II) tetrachloro mercurate(II).

The ligand 2,6-diacetylpyridine bis(2′-pyridylhydrazone) (H<inf>2</inf>dapp) reacts in ethanol with HgCl<inf>2</inf> or Hg(ClO<inf>4</inf>)<inf>2</inf>·3H<inf>2</inf>O to give the charged species [Hg(H<inf>2</inf>dapp)][HgCl<inf>4</inf>] (1) or [Hg(H<inf>2</inf>dapp)(H<inf>2</inf>O)<inf>2</inf>][ClO<inf>4</inf>]<inf>2</inf> (2) respectively. Starting from HgCl<inf>2</inf> in the presence of perchlorate ions the mixed chloro-aqua complex [Hg(H<inf>2</inf>dapp)Cl(H<inf>2</inf>O)][ClO<inf>4</inf>] (3) is obtained. Complexes (1), (2), and (3) can be deprotonated to the neutral species [Hg(dapp)] (4) under basic conditions. The complexes have been characterized by a number of physicochemical measurements including the X-ray analysis of (1). Crystals of (1) are monoclinic, space group P2<inf>1</inf>/n, with unit-cell dimensions a = 12.271(5), b = 15.948(6), c = 12.703(6) Å, β = 109.06(3)°, and Z = 4. The structure has been solved from three dimensional counter data by Patterson and Fourier m...