DFT study of structure, IR and Raman spectra of the first generation dendron built from cyclotriphosphazene core

The FTIR and FT-Raman spectra of the first generation dendron built from the cyclotriphosphazene core, five arms OC6H4CHNN(CH3)P(S)< with 10 oxybenzaldehyde terminal groups and one ester function Gv1′ have been recorded. The structural optimization and normal mode analysis were performed for dendron on the basis of the density functional theory (DFT). The calculated geometrical parameters and harmonic vibrational frequencies are predicted in a good agreement with the experimental data. It was found that Gv1′ has a concave lens structure with planar OC6H4CHNN(CH3)P(S)< fragments and slightly non-planar cyclotriphosphazene core. The oxybenzaldehyde groups attached to different arms show significant deviations from a symmetrical arrangement relative to the local planes of repeating units. The experimental IR spectra of Gv1′ dendron was interpreted by means of potential energy distributions. Relying on DFT calculations a complete vibrational assignment is proposed. The strong band 1597 cm−1 show marked changes of the optical density in dependence of the aldehyde (−СНО), ester (−OСO−) or azomethyne (−СНN−) substituents in the aromatic ring.