CHARACTERIZATION OF BIS(BETA-DIIMINO-TETRACYANOPYRROLIZINIDO)COPPER(II) COMPLEX - X-RAY CRYSTAL-STRUCTURE OF THE ACETONITRILE ADDUCT AND STRUCTURAL COMPARISON WITH THE TETRAHYDROFURAN DERIVATIVE

The X-ray crystal structure of the bis(1,2,6,7-tetracyano-3,5-diimino-3,5-dihydro-pyrrolizinido)copper(II) complex, as an adduct with acetonitrile, CuL2 . 2CH3CN (1a), is described and compared with that of the analogous tetrahydrofuran derivative Cu L2 . 2THF (1b), previously reported. The molecular structure of both complexes is almost the same (the copper atom is centrosymmetrically surrounded by four chelating imino groups in a square planar configuration), whereas the spatial arrangement is totally different: in 1a the molecular units are slipped stacked, while in 1b they are mutually orthogonal. The results of a number of physical measurements on both 1a and 1b are reported and correlated with the structures. The solution electronic spectrum is also reported and compared with that, extraordinarily similar, of copper-phthalocyanine.