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