Synthesis and spectroscopic studies of novel mononuclear and binuclear ruthenium(III) complexes with bidentate and tridentate acyclic hydrazones

Abstract

Nine novel acyclic hydrazone ligands, FINH = N-(furylidene)-N′-isonicotinoylhydrazine, FNH = N-(furylidene)-N′-nicotinoylhydrazine, PINH = N-(pyrienylidene)-N′-isonicotinoylhydrazine, PNH = N-(pyrienylidene)-N′-nicotinoylhydrazine, TINH = N-(thienylidene)-N′-isonicotinoylhydrazine, TNH = N-(thienylidene)-N′-nicotinoylhydrazine, FSH = N-(furylidene)-N′-salicyloylhydrazine, PSH = N-(pyrienylidene)-N′-salicyloylhydrazine and TSH = N-(thienylidene)-N′-salicyloylhydrazine, have been synthesized. Their corresponding mononuclear and binuclear ruthenium(III) complexes have been prepared by the reaction of the ligand with RuCl₃·3H₂O in 1 : 2 and 2 : 2 molar ratio and are characterized by elemental analyses, thermogravimetric analyses (TGA and DTG), IR, electronic, magnetic susceptibility and electrical conductance measurements. Electronic spectra and magnetic susceptibility measurements of the solid complexes (both mono- and binuclear) indicate an octahedral geometry around ruthenium(III). Particular emphasis is given to the binuclear complexes in which FSH, PSH and TSH behave as tridentate ligands and chloride bridges the Ru(III) ions. Conductance measurements show the mononuclear complexes are electrolytic and binuclear complexes are of non-electrolytic. The fungicidal activities of the ligands and metal complexes against Fusarium oxysporium and Aspergillus niger are described.

Keywords:

• Hydrazones
• Mononuclear and binuclear complexes
• Thermogravimetry
• Catalytic activity

Acknowledgement

The authors are thankful to the Council of Scientific and Industrial Research, New Delhi, India for financial assistance vide Project No. 01(1860)/03/EMR-II.