title: Three solvates of a bis-mesoionic fluorescent yellow pigment.
abstract: p-Phenylenebis(2-oxo-3-phenyl-1,2-dihydropyrido[1,2-a]pyrimidin-5-ium-4-olate), C(34)H(22)N(4)O(4), is a bis-mesoionic yellow pigment that shows fluorescence in the solid state. During a polymorph screening, single crystals of three solvates were grown and their crystal structures determined. Solvent-free crystals were not obtained. A solvate with N-methylpyrrolidone (NMP) and propan-2-ol, C(34)H(22)N(4)O(4).2C(5)H(9)NO.C(3)H(8)O, (Ia), and an NMP trisolvate, C(34)H(22)N(4)O(4).3C(5)H(9)NO, (Ib), crystallize with pigment molecules on inversion centres. The NMP/propan-2-ol mixed solvate (Ia) forms O-H...O hydrogen bonds between the different solvent molecules. In both structures, at least one of the solvent molecules is disordered. A third solvate structure, C(34)H(22)N(4)O(4).0.5C(5)H(9)NO.C(4)H(10)O, (Ic), was obtained by crystallization from NMP and butan-1-ol. In this case, there are two symmetry-independent pigment molecules, both situated on inversion centres. The solvent molecules are heavily disordered and their contribution to the scattering was suppressed. This solvate displays a channel structure, whereas the other two solvates form layer structures.
authors: Institute of Inorganic and Analytical Chemistry, Goethe-University Frankfurt, Max-von-Laue-Strasse 7, 60438 Frankfurt am Main, Germany.
authors: Jürgen
authors: J
authors: Brüning
authors: Michael
authors: M
authors: Bolte
authors: Martin U
authors: MU
authors: Schmidt