FLUORIDATION INFLUENCE ON UV SPECTRA OF STRUCTURAL FRAGMENTS OF POLYURETHANES
The results of TDDFT calculations of the characteristics for exited singlet states of fluorinated urethanes containing from one to six fluorine atoms are presented. The influence of a number and location of the fluorine atoms in the urethane structure on formation of its absorption UV spectrum has been analyzed. It has been established, that fluoridation of the phenyl group in the ortho-substitutions leads to steric hindrance in the urethane structure and to the urethane group rotation on a significant angle (of about 20°). With the additional fluoridation of the amino group, the rotation angle of the urethane group can reach 60° and more. Such changes in the structure of urethane are accompanied by characteristic significant bathochromic shifts of the long-wavelength absorption bands.