• A L Verma

      Articles written in Journal of Chemical Sciences

    • Resonance Raman studies of tetraphenylporphinato manganese(III) chloride

      M Sarkar A L Verma

      More Details Abstract Fulltext PDF

      Resonance Raman spectra of Mn(III)TPPCl in different solvents as well as in KBr pellets have been obtained with laser excitations in different regions of the atypical absorption spectrum of the system. The selective enhancement of vibrational modes arising from different parts of the molecule under excitation in different absorption regions has been used to assign the electronic transitions of Mn(III)TPPCl. The strong absorption band at ∼ 476 nm originates from a charge transfer transition porphyrin and metal orbitals, while a weaker band at ∼ 530 nm has been identified due to singlet-triplet (π, π*) transitions. The present data do not provide distinct evidence for activation of the phenyl group modes under resonance Raman conditions indicating thereby that the phenyl groups may not be conjugated with the porphyrin macrocycle. Depolarization ratios for some isolated bands show dispersion with excitation wavelengths due to reduction of the chromophore symmetry.

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