B. Jagadish, M. Carducci, C. Bosshard
Aug 14, 2003
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Influential Citations
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Journal
Crystal Growth & Design
Abstract
Piperazine-2,5-diones derived from 2-amino-7-cyano-4-methoxyindan-2-carboxylic acid were prepared in meso, racemic, and enantiomerically pure forms, crystallized from dimethyl sulfoxide (DMSO), and the supramolecular organization in the crystals determined by X-ray crystallography. These molecules were designed to bear two strongly polar p-methoxybenzonitrile moieties either aligned or opposed. In contrast with nonpolar or weakly polar piperazinediones of similar size and shape, which exclude DMSO to form ladder-like tapes by reciprocal intermolecular amide-to-amide hydrogen bonding, these more strongly polar piperazinediones participate in hydrogen bonding with included DMSO. In cocrystals of the enantiomerically pure compounds, the p-methoxybenzonitrile dipoles were aligned in the three-dimensional lattice but opposed by the dipoles of included DMSO. These cocrystals exhibited second harmonic properties comparable to urea. A second cocrystal possessing aligned p-methoxybenzonitrile dipoles was observed ...