The Crystal Structures of Two Binuclear Copper Complexes and Some Organic Molecules of Biological and Stereochemical Interest

by Bear, Cedric Allen

The crystal and molecular structure of a complex between riboflavin dihydrobromide and hydroquinone has been determined. The crystals are monoclinic, a = 20.55(5)A, b = 13.69(4)A, c = 10.18(4)A, b = 91.1599), Z = 4 and the space group is P21. The intensity data were collected photographically and the atomic parameters were refined by the block-diagonal matrix method with the final R-factor at 0.145.

The complex between riboflavin and hydroquinone is of a charge-transfer type but the interaction does not appear to involve a specific site on the flavin, it being inferred that the association nevertheless influences the N(S) “active” site of the acceptor.