SPECTROSCOPIC CHARACTERIZATION OF P-QUINONE WITH RUTHENIUM II COMPLEX OF 1,10-PHENANTHROLINE FAMILY OF LIGANDS.

Tridendate polypyridine ligands made of 1,10-phenanthroline ligands substituted at the 4,7 positions with the corresponding homoleptic Ru(II) complex have been synthesized and characterized. The complex is formulated as [Ru(NN)32+], (where N= 1,10 phenanthroline, 4,7-dimethyl 1.10-phenanthroline, 4,7-diphenyl 1,10-phenanthroline). In this work, electron transfer studies of quinone with [Ru(NN)32+] complexes were carried out using absorption spectral technique. The binding efficiency of quinone was also studied using this technique. Intrinsic binding constants (Kb) have been estimated under a similar set of experimental conditions, to probe the details of BQ binding by these complexes. The results indicated that the complex interacted with BQ. The binding efficiency was moderate and similar for all complexes with quinone. The nature of the binding seemed to be mainly an electrostatic interaction between BQ and the Ruthenium(II)complex. The possibility of electron transfer between the ruthenium(II) complex and 1,4-benzoquinone as an electron acceptor was explored by UV/Vis spectroscopy.