Studies on macrocyclic complexes derived from vic-dioximes. XII. The crystal structure of the π-sandwich compound formed between anthracene and bis(difluoroboronmethylglyoximato)nickel(II)

The 1:1 adduct of anthracene with bis(difluoroboronmethylglyoximato)nickel(II) is triclinic, space group P1, a = 7.448(6), b = 7.780(7), c = 9.366(8) Å, α = 91.4(1), β = 92.5(1), γ = 92.1(1)°, Z = 1. The structure was refined to R = 0.075 for 1250 photographic reflexions by full-matrix least-squares methods. The planar macrocycle [average NiN 1.850(10) Å and NNiN 82.4(3)°] and the anthracene molecule each have a space group imposed centre of symmetry. The planes of the macrocycle and anthracene molecule are nearly parallel and close intermolecular contacts indicate ππ interactions between the molecules which give rise to chains of alternately stacked molecules aligned along a. The stacking is such that molecules lie approximately in the (211) series of planes with an interplanar spacing of 3.17 Å. The reduction of this separation compared with that previously reported for the adduct of the analogous dimethylglyoximato compound results from a diminished steric influence of the substituent methyl groups.