DFT study of structure, IR and Raman spectra of phosphorus-containing dendron with azide functional group

Abstract

The Fourier transform IR and Raman spectra of the first generation dendron G1 built from thiophosphoryl core with terminal PCl groups and azide functional group have been recorded. The optimized geometries of low energy isomers of G1 have been calculated by density functional (DFT) method at the PBE/TZ2P level of theory. DFT is used for analyzing the properties of each structural part (core, branches, surface). It was found that the repeated branching units of G1 contain planar OC6H4CHNN(CH3)P< fragments. DFT results for the structure of G1 are in good agreement with recent X-ray diffraction measurements. A complete vibrational assignment is proposed for different parts of G1. The global and local reactivity descriptors have been used to characterize the reactivity pattern of the core function and terminal group. Natural bond orbital (NBO) analysis has been applied to comparative study of charge delocalization. Our study reveals why azide group linked to phosphorus has a different reactivity when compared to organic azides.