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TitleGeometry and bond-length alternation in nonlinear optical materials. II. Effects of donor strength in two push-pull mol-ecules
Publication TypeJournal Article
Year of Publication2008
AuthorsGainsford, G.J., Bhuiyan M.D.H., and Kay A.J.
JournalActa Crystallographica Section C: Crystal Structure Communications
Paginationo195 - o198
Date Published2008
ISSN01082701 (ISSN)
KeywordsBond length, Cell packing, Crystal packing, Donor strength, Hydrogen bonds, Molecules, Nonlinear optical chromophores, Optical materials, Organic compounds
AbstractThe compounds N-[2-(4-cyano-5-dicyano-methyl-ene-2,2-dimethyl-2,5-dihydro- furan-3-yl)vin-yl]-N-phenyl-acetamide, C20H16N4O2,(I), and 2-{3-cyano-5,5- dimethyl-4-[2-(piperidin-1-yl)vin-yl]-2,5-dihydro-furan-2-yl-idene} malononitrile 0.376-hydrate, C17H18N4O·0.376H2O, (II), are novel push-pull mol-ecules. The significant bonding changes in the polyene chain compared with the parent mol-ecule 2-dicyano-methyl-ene-4,5,5-trimethyl-2,5- dihyrofuran-3-carbonitrile are consistent with the relative electron-donating properties of the acetanilido and piperidine groups. The packing of (I) utilizes one phen-yl-cyano C - H⋯N and two phenyl-carbonyl C - H⋯O hydrogen bonds. Compound (II) crystallizes with a partial water mol-ecule (0.376H2O), consistent with cell packing that is dominated by attractive C - H⋯N(cyano) inter-actions. These com-pounds are precursors to novel nonlinear optical chromophores, studied to assess the impact of donor strength and the extent of conjugation on bond-length alternation, crystal packing and aggregation. © 2008 International Union of Crystallography.

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