Abstract

The preparation and characterization of mono and binuclear complexes of Ru(II) with a newly synthesized derivate of the terpyridine ligand, 4 ?-(5-bromothiophene)-2,2?,6 ?,2?-terpyridine, are communicated. In the binuclear complex, 2,5-bis(2,2?,6?,2?-terpyridine- 4?yl)thiophene was used as a bridge between two Ru(II) centers. The new compounds were characterized by H NMR, UV-Vis and IR spectroscopies. Bands at ?500 nm for the Ru(II) to terpyridine charge transfer transition and absorption bands at ?<400 nm assigned to intraligand transitions, ?*??, centered in the tpy moiety were observed in the UV-Vis spectra of the complexes. Irradiation of the complexes in CH 3CN at 337 or 500 nm induced luminescence with maxima at ?670 nm and lifetimes ??102 ns. Time-resolved absorption spectroscopy revealed the formation of long-lived species during the decay of the metal to ligand charge transfer excited states. The intermediates were tentatively assigned as unstable products of ligand-substitution or orthometalation excited state reactions. © 2004 Elsevier B.V. All rights reserved.