Notes. Chemical and structural investigations on bismuth complexes of 2,6-di-acetylpyridine bis(2-thenoylhydrazone) and 2,6-diacetylpyridine bis(thiosemicarbazone)

Abstract

Bismuth complexes with the polydentate ligands 2,6-diacetylpyridine bis(2-thenoylhydrazone)(H₂dapt) and 2,6-diacetylpyridine bis(thiosemicarbazone)(H₂dapts) were synthesized and characterized by means of i.r. spectroscopy and X-ray crystal analysis. In the complex [Bi(dapt)(OH)]·dmso·H₂O (1)(dmso = dimethyl sulphoxide) the co-ordination of the carbonyl and azomethine groups is in agreement with the shift of the amide I and II bands to lower and higher frequencies respectively. For [Bi(dapts)(N₃)]·0.5dmso (2) the strong band at 2 025 cm^–1 is in accord with co-ordination of the azide group, and involvement of the sulphur atom in the co-ordination is evidenced by the negative shift of the band from 1 250 to 1 180 cm^–1. The crystals of (1) and (2) are monoclinic, space group P2₁/n, with lattice constants: (1), a= 14.763(7), b= 10.844(6), c= 16.590(7)Å, β= 105.03(3)°, Z= 4, and R= 0.0483; (2)a= 21.112(9), b= 11.939(7), c= 7.333(6)Å, β= 97.86(6)°, Z= 2 for a double formula, and R= 0.0546. In both compounds the geometry around bismuth is pentagonal pyramidal with the base occupied by the organic ligand and the apical site occupied by the OH^– and N₃^– groups for (1) and (2) respectively.