Resonance Raman investigation of the MLCT transition in [Pt(dppm)2(PhC≡C)2] and the MMLCT transition in [Pt2(μ-dppm)2(μ-PhC≡C)(PhC≡C)2]

Abstract

We report resonance Raman spectra including absolute Raman cross section measurements obtained with excitation wavelengths within the MLCT absorption band of [Pt(dppm)2(PhC≡C)2] and the MMLCT absorption band of [Pt2(μ-dppm)2(μ-PhC≡C)(PhC≡C)2]+. We have simultaneously simulated the absolute absorption and resonance Raman intensities in order to estimate the vibrational reorganizational energies associated with the MLCT and MMLCT transitions. We observe a small amount of fluorescence background underneath the resonance Raman spectra of [Pt(dppm)2(PhC≡C)2] which we attribute to emission from the very shortlived initially excited MLCT state. Our quantum yield measurements of this fluorescence yields an excited state lifetime of approximately 80-130 fs.