The crystal packing of a strongly dipolar piperazinedione

A strongly dipolar piperazine-2,5-dione was synthesized in enantiomerically pure form, crystallized from DMSO, and the supramolecular organization of the crystals determined by X-ray crystallography. In contrast with non-pola r or weakly polar piperazinediones of similar molecular topography, which f orm tapes by reciprocal intermolecular amide-to-amide hydrogen bonding, the strongly dipolar piperazinedione participated in hydrogen bonding with occ luded DMSO. The dipoles of the piperazinedione molecules were aligned and w ere opposed by the dipoles of the DMSO molecules. The cocrystals exhibited second harmonic generation when subjected to pulsed irradiation. (C) 2000 E lsevier Science Ltd. All rights reserved.