Crystal and molecular structure of bis(2-amino-5-methyl-1,3,4-thiadiazole-N3)dibromomercury(II). A spectroscopic study and INDO calculations

The crystal structure of the compound Hg(amtz)2Br2(amtz= 2-amino-5-methyl-1,3,4-thiadiazole) was determined by X-ray crystallography. The compound crystallizes in the triclinic space group P1̄ with cell dimensions a = 9.133(2), b = 11.002(2), c = 8.404(2) Å, α = 102.65(2), β = 116.80(2), γ = 93.87(2)°, and Z = 2. The structure was solved by the heavy-atom method and refined by least-squares calculations. The structure consists of monomeric discrete molecules, in which the Hg atom is co-ordinated in a distorted tetrahedral geometry by two bromine ions and by two nitrogens of the 2-amino-5-methyl-1,3,4-thiadiazole ligands. Infrared bands are assigned, the 1H, 13C, and 199Hg n.m.r. spectra of the complex have been recorded, and INDO calculations are discussed.