Vibrational spectroscopy studies of dendrimers built from cyclophosphazene core with terminal oxybenzaldehyde groups

Abstract

The FTIR and FT Raman spectra of four generations of phosphorus dendrimers built from cyclotriphosphazene core with terminal oxybenzaldehyde groups have been recorded and analyzed. Their spectral pattern is determined by the ratio T n/R n ( T n – the number of terminal groups, R n – the number of repeating units). This ratio tends to r − 1 (r – branching functionality of repeating unit), and becomes constant, when the generation number is higher than 3–5. Experimental IR and Raman spectra of different generations of dendrimers built of thiophosphoryl and cyclophosphazene cores are very close similar, according theoretical approach. The dependence of band full width at half height in the IR and Raman spectra on generation number and on the number of dendrons is established. Bands assigned to the core, repeating units and terminal groups of dendrimers were separated by the difference spectroscopy method. The rather rigid repeating units with little conformational flexibility define the perfect microstructure of phosphorus-containing dendrimers. FTIR and FT Raman spectroscopies provide the unique detailed information about the structure of technologically relevant materials, which could not be obtained before with any other technique.