A mononuclear organoruthenium complex of a polydentate thiosemicarbazone ligand and its utilization as a building block for the synthesis of heterodinuclear Ru-Pd and Ru-Pt complexes

Department of Chemistry, Inorganic Chemistry Section, Jadavpur University, Kolkata-700 032, India

E-mail : samaresh_b@hotmail.com

Manuscript received online 24 May 2013, revised 03 June 2013, accepted 04 June 2013

Reaction of 2,6-diacetylpyridine thiosemicarbazone with [Ru(CO)₂ (PPh₃ )2Cl₂ ] in refluxing ethanol affords a mononuclear ruthenium complex [Ru], in which the thiosemicarbazone is coordinated to ruthenium as dianionic CNS-donor, along with two triphenylphosphines and a carbonyl. Using the unutilized donor atoms in the free wing of the thiosemicarbazone in the [Ru] complex two hetero-bimetallic [Ru-Pd] and [Ru-Pt] complexes have been synthesized via reaction of the [Ru] complex with [Pd(PPh₃ )2Cl₂ ] and [Pt(PPh₃ )2Cl₂ ] respectively. Structures of the [Ru] and [Ru-Pt] complexes have been determined by X-ray crystallography. Structure of the [Ru-Pd] complex has been optimized by DFT method. The free wing of the thiosemicarbazone in the [Ru] complex is utilized in binding to the second metal center in dianionic CNS-mode in the [Ru-Pd] and [Ru-Pt] complexes, and a triphenylphosphine has occupied the fourth coordination site on the second metal center. All the three complexes show characteristic IR and ¹H NMR spectra. They also display intense absorptions in the visible and ultraviolet regions.