DFT study of structure, IR and Raman spectra of P0′ and P4′ dendrimers built from octasubstituted metal-free phthalocyanine core

The IR and Raman spectra of P0′ and P4′ dendrimers built from an octasubstituted metal-free phthalocyanine core with oxybenzaldehyde terminal groups have been recorded. The phthalocyanine core was used as a probe for analyzing the properties of the internal structure. The structural optimization and normal mode analysis were performed for P0′ dendrimer on the basis of the density functional theory (DFT). It was found that the P0′ molecule exists in a stable conformation with planar phthalocyanine core. The calculated geometrical parameters and harmonic vibrational frequencies are predicted in a good agreement with the experimental data. The experimental IR spectra of P1 dendrimer were interpreted by means of potential energy distributions. Relying on DFT calculations a complete vibrational assignment is proposed. The difference IR and Raman spectra of molecules built from the thiophosphoryl and phthalocyanine cores with the same repeating units and terminal groups were studied in order to underline the role of the core functionality on the dendrimer architecture.