Dimethylthallium(III) and methylmercury(II) derivatives of pyridine-2-carbaldehyde thiosemicarbazone: synthesis and structure

Abstract

The reaction of dimethylthallium(III) hydroxide and methylmercury(II) chloride with pyridine-2-carbaldehyde thiosemicarbazone (HL) and its sodium salt, respectively, afforded [TlMe₂(L)] and [HgMe(L)]. The thallium complex crystallizes in the triclinic space group P(no. 2) with a= 11.005(2), b= 12.153(2), c= 10.822(1)Å, α= 110.18(1), β= 99.79(1), γ= 70.39(1)°, and Z= 4 (R= 0.031, R′= 0.035). The unit cell has two independent molecules in each asymmetric unit, both containing an N,N′,S-tridentate ligand but with significant differences in bond distances and angles. The ¹H NMR spectrum of [TlMe₂(L)] in CDCl₃ indicates that the bonding scheme observed in the solid state is retained in solution. Infrared data for [HgMe(L)] in the solid state suggest that the metal is N(hydrazinic), S-co-ordinated; in solution in chloroform, [HgMe(L)] consists of a mixture of (E) and (Z) isomers.