Steric conditions for donor-acceptor interactions in C60 complexes with planar organic donors

Charge transfer complexes of fullerene C-60 With planar donors of tetrathiafulvalene, dithiadiazafulvalene and pyranylidene family were investigated by IR- and W-VIS-NIR spectroscopy. The analysis of IR and X-ray data shows that the charge transfer complexes of fullerene with the planar donors are involved in polarization interactions of van der Waals type. Charge transfer is very weak in these compounds and is hindered by unfavourable steric factors. As a result, the CT rate does not correlate with the ionization potential of the donor; the charge transfer absorption bands are very weak too. (C) 1998 Elsevier Science B.V. All rights reserved.