Complexes of ruthenium(III), rhodium(III) and iridium(III) with ligands bearing 2,6-diacetylpyridine bis(S-alkylisothiosemi- carbazones): Synthesis, spectral studies and structural elucidation

Reactions of the ligands, 2,6-diacetylpyridine bis(Smethylisothiosemicarbazone) and 2,6-diacetylpyridine bis(Sbutylisothiosemicarbazone) with ruthenium(III), rhodium(III) and iridium(III) have been studied and their structures have been proposed based on elemental analyses, molar conductance, magnetic moment, spectral data (IR, H NMR, FAB mass) and thermal investigations. The ligands behave as pentacoordinated and give acyclic complexes of the general formula [M(H2L)Cl2]Cl and macrocyclic complexes, [M(L’)Cl2]Cl·H2O, which are formed by template condensation by using β-diketones. Pentagonal bipyramidal geometries are observed for acyclic and macrocyclic complexes. In both types of complexes, the ligands coordinate in their amino form. The thermal stability and mode of decomposition of the various complexes have been studied by TGA techniques. Conductance measurements reveal 1:1 electrolytic nature of the complexes.