Table of Contents
Laser Chemistry
Volume 19, Issue 1-4, Pages 237-243
http://dx.doi.org/10.1155/1999/74587

Transient Resonance Raman Studies of Ru(II) Complexes in DNA and in Homogeneous Media

1School of Chemistry, The Queen's University of Belfast, Belfast BT9 5AG, Ireland
2Department of Chemistry, Trinity College, Dublin 2, Ireland
3School of Chemical Sciences, Dublin City University, Dublin 9, Ireland

Received 23 April 1997

Copyright © 1999 Hindawi Publishing Corporation. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Transient resonance Raman (TR2) spectroscopy has been used to investigate the metalligand charge-transfer (MLCT) excited states of Ru(II) polypyridyl complexes inDNAand in homogeneous solution. In DNA, complexes of the type [Ru(L)2(L′)]2+ were studied, where L=2, 2-bipyridyl (bpy), 1,4, 5, 8-tetraazaphenanthrene (tap), and L′ dipyrido [3,2:a-2′ ,3′:c]-phenazine (dppz) or 1,4,5,8,9,12-hexaazatriphenylene (HAT). For [Ru(bpy)2(HAT)]2+, the enhancement pattern of vibrational modes in the TR2 spectra attributable to reduced HAT in the triplet MLCT state suggest perturbations to the intraligand transition of HAT in the presence of DNA. Transient RR spectra for [Ru(tap)2(dppz)]2+ are indicative of formation of the species RunII(tap)(tap)(dppz) by electron transfer from DNA to the triplet MLCT state of the complex.

TR2 spectra for complexes of the type, [(Ru(bpy)2)n(L)]2+ , n=1, 2 where L=a triazole bridging ligand, illustrate the use of the technique as a probe of the response of MLCT states to the electronic environment.