New complexes of fullerenes C60 and C70 with organic donor DBTTF:: synthesis, some properties and crystal structure of DBTTF•C60•C6H6 (DBTTF=dibenzotetrathiafulvalene)

New complexes of fullerenes C-60 and C-70 with dibenzotetrathiafulvalene (DBTTF), DBTTF . C-60 . C6H6, DBTTF . C-60 . Py and DBTTF . C-70 . C6H6, were obtained. The crystal structure of DBTTF . C-60 . C6H6 was determined. The arrangement of fullerene molecules is approximately simple cubic packing where each C-60 molecule is located in slightly distorted octahedral surrounding. DBTTF molecules have a concave conformation. Xray photoelectron spectroscopy (XPS) and IR spectroscopy show only weak charge transfer in these compounds. A weak charge transfer band near 900 nm was found in the UV-Vis-NIR absorption spectrum of DBTTF . C-60 . C6H6 single crystals. DBTTF molecules are coordinated on C-60 ones by pi-pi and n-pi interactions. It was shown that the steric discrepancy between DBTTF and C-60 molecules does not provide favourable conditions for charge transfer in the DBTTF . C-60 . C6H6 complex. (C) 1998 Elsevier Science S.A.