Vibrational Spectra and Density Functional Theory Calculations of Metallotriphenylcorroles

The infrared absorption and Raman scattering spectra were measured for the metallotriph-enylcorroles (MTPCs, M=Cu, Co, Ni, Mn). The ground-state structures and vibrational spectra of MTPCs have been calculated with the density functional theory. The observedRaman and IR bands have been assigned based on the calculation results. Due to the symmetry lowering, the vibrational spectra of MTPCs are much more complex than metal-loporphyrins, and several skeletal modes are found strongly coupled to the phenyl vibrations.The relationship between the Raman/IR frequencies and the structures of TPC ring is in-vestigated. It is found that the vibrations involving the C^I_αC^I_α stretch and C_αC_mstretch are sensitive to the size of corrole core. In particular, the frequency of υ₅, which is assigned to C^I_αC^I_α stretch in coupling with the C_αC_m symmetric stretch, increases linearly with the decrease of the corrole core-sizes and may be used as a mark band to evaluate the structural change of the metallocorroles.