Electronic Origin of the Thermochromic Effect in 2, 2', 5, 5': Tetramethyldistibolyl

T. Hughbanks, R. Hoffmann, M.-H. Whangbo, K. A. Stewart, O. Eisenstein and E. Canadell, J. Amer. Chem. Soc., 104, 3876-3879 (1982).