THE VIBRATIONAL SPECTROSCOPY OF C60H36 - AN EXPERIMENTAL AND THEORETICAL-STUDY

Several samples of C60H36 have been prepared by the transfer hydrogena tion method and studied by infrared and Raman spectroscopy. The result s are compared with published infrared spectra of C60H36 samples synth esized by other techniques such as high pressure hydrogenation and zin c reduction of C-60. Raman spectra of C(60)H(36 )have not previously b een reported. Based on previous data in the literature, five isomers o f low-energy were selected for semiempirical quantum chemical calculat ions. They are one each of S-6, T and T-h symmetry and two isomers of D-3d symmetry. The calculations predict that very few LR lines will be coincident with Raman bands, even in the case of the T isomer for whi ch t symmetry vibrations can be both infrared and Raman active, and fo r which the few coincident lines should be extremely weak. The interpl ay between theory and experiment places some strong constraints on the possible symmetries and structures of the various samples of the C60H 36 molecule. The results indicate that each of two samples prepared by transfer hydrogenation contains a mixture of two principal isomers, o f D-3d and S-6 symmetries, the former being the major component in one , and the latter in the other, sample. The analysis also confirms a D- 3d isomer as being the major component of a sample of C60H36 prepared by high pressure hydrogenation and proposes the S-6 isomer as the majo r component of a sample prepared by zinc reduction of C-60 in aromatic solvents. (C) 1998 Elsevier Science B,V. All rights reserved.