The orientational-ordering transition in single crystals of selected C60 complexes with organic donors followed by infrared spectroscopy

Investigations of infrared spectra of single crystals of the complex of fullerene C-60 With dianthracene (DAN) and C-60 grown from CS2 solution (clathrate) versus temperature, between 4 and ca. 430 K, have been performed. A phase transition for the complex and the clathrate accompanied by a splitting of the F-1u(4) band into at least two components was detected at temperatures higher than 260 K. The line splitting was attributed to C-60 symmetry lowering as a result of suppression of its rotation. Phase transitions at 80, 160 and 305 K have been observed for DAN C-60 (C6H6)(3); the nature of the transitions has been suggested. (C) 1998 Elsevier Science B.V. All rights reserved.