A structural and infrared study of the charge states of tetrakis (dimethylamino)ethylene (TDAE) in TDAE-C-60 and (TDAE)(Cl)(2)

The molecular structure and vibrational spectra of the different oxidation states of tetrakis(dimethylamino)ethylene (TDAE) are calculated using struc tural optimization and normal-mode calculations. The predictions are compar ed with x-ray structural data and infrared spectra of TDAE, TDAE-C-60 and ( TDAE)(Cl)(2). The C-N stretch vibration frequency and axial torsional angle are shown to be sensitive indicators of the charge state of the molecule. TDAE(+), which occurs in TDAE-C-60 is found to have a near-degenerate confi gurational ground state. (C) 1999 American Institute of Physics. [S0021-960 6(98)70840-2].