Microwave assisted synthesis, spectroscopic, thermal, and antifungal studies of some lanthanide(III) complexes with a heterocyclic bishydrazone

A bishydrazone formed by the condensation of isatinmonohydrazone and salicylaldehyde reacted with lanthanide(III) chloride to form complexes of the type [Ln(HISA)2Cl3], where, Ln=La(III), Ce(III), Pr(III), Nd(III), Sm(III), Eu(III), or Gd(III) and HISA=[(2-hydroxybenzaldehyde)-3-isatin]bishydrazone. Both reactions were carried out under microwave conditions. The ligand and the metal complexes were characterized on the basis of elemental analysis, molar conductance, magnetic susceptibility measurements, UV visible, infrared, far infrared, and proton NMR spectral data. The ligand acted as neutral tridentate, coordinating through the carbonyl oxygen, azomethine nitrogen, and phenolic oxygen without deprotonation. The ligand and lanthanum(III) complex were subjected to X ray diffraction studies. The X-ray diffraction pattern of ligand exhibited its crystalline nature and that of the lanthanum(III) complex indicated its amorphous character. The thermal decomposition behaviour of the complex, [La(HISA)2Cl3], was examined in the temperature range of 40-800 °C using TG, DTG, and DTA. The ligand and the metal complexes were screened for their antifungal activities.