Comparison of the LMCT resonance Raman spectra of PdCl2(PCy3)2 and PdCl2(PPh3)2: Effect of the phenyl versus cyclohexyl substituents on the LMCT excited state

Abstract

Resonance Raman spectra have been obtained at four excitation wavelengths within the A-band ligand to metal charge transfer (LMCT) absorption of trans-dichloro-bis(tricyclo-hexylphosphine) palladium(II) and a resonance Raman intensity analysis was done to elucidate the excited state structure relative to the ground state. Comparison of the present results for trans-dichlorobis(tricyclohexylphosphine) palladium(II) with those previously reported for trans-dichlorobis(triphenylphosphine) palladium(II) shows that the phenyl ligand appears to primarily affect the adjacent P-C vibrational reorganizational energy and does not significantly perturb the Pd-Cl or Pd-P vibrational reorganizational energies.