RESONANCE RAMAN AND TIME-RESOLVED RESONANCE RAMAN STUDIES OF TRIS(4-METHYL-2,2'-BIPYRIDINE)RUTHENIUM(II) - POLARIZATION OF THE RADICAL FRAGMENT OF THE (3)MLCT STATES

The resonance Raman (RR) and time-resolved resonance Raman (TR3) spect ra are reported for the tris(4-methyl-2,2'-bipyridine)ruthenium(II) co mplex, Ru(mmb)3(2+), and its methyl-deuteriated analogue, Ru(d3-mmb)3( 2+). The spectra are compared to those of tris(2,2'-bipyridine)rutheni um(II), Ru(bpy)3(2+), and tris(4,4-dimethyl-2,2'-bipyridine)ruthenium( II), Ru(dmb)3(2+), and its methyl-deuteriated analogue Ru(d6-dmb)3(2+) . The Spectra of the ground state of the complex with the asymmetric l igand, mmb, are readily interpretable in terms of vibrationally isolat ed fragments (pyridine and 4-methylpyridine) with the exception of a f ew modes which are assignable to stretches of the inter-ring and adjac ent bands. The TR3 spectra are shown to be consistent with slight pola rization of the 3MLCT excited-state charge distribution toward the pyr idine fragment of the chelated anion.