Conformation of a Fluorochrome from Aniline Blue

The solid-state conformation of the fluorochrome sodium 4,4′-[carbonylbis(benzene-4,1-diyl)bis(imino)]-bisbenzenesulfonate has been defined by single-crystal X-ray crystallography. Monoclinic crystals belong to the space group C 2/c with a 11·732(1), b 6·185(1), c 37·179(3) A, β 94·40(1)° and Z 8. The structure was refined to a final R0·042 for all 2271 unique terms. In the crystal six oxygen atoms form an octahedral grouping around the sodium ion and these octahedra are linked into layers sandwiched between the layers of organic anions which adopt an extended conformation. The n.m.r. spectra indicate that in solution the fluorochrome is flexible and averages to an extended structure that maintains symmetry about its longitudinal and carbonyl axes. Chemical shifts have been measured in water, deuterium oxide and (D6)dimethyl sulfoxide