Journal of Physical Chemistry A, Vol.106, No.41, 9533-9537, 2002
Lithium-benzene sandwich compounds: A quantum chemical study
The structures and dissociation energies of Li-n.(C6H6)(n+1) sandwich complexes (n = 1-6) have been investigated using quantum chemical techniques. At the G3(MP2) level of theory, the Li.(C6H6)(2) complex exhibits a JahnTeller distortion, forming a D-2h charge-separated species [C6H6-1/2-Li+-C6H6-1/2] with a surprisingly large dissociation energy of 0.85 eV, and a short benzene-benzene distance of 3.54 Angstrom. Comparisons are made with the Li.C6H6, Li+.C6H6, and Li+.(C6H6)(2) complexes. The larger (n > 1) complexes were studied at the B3LYP/6-31G(d) level and were also found to have large dissociation energies, ca. 0.85 eV per Li atom, and short benzene-benzene distances (3.70 Angstrom).