Geometry and bond-length alternation in nonlinear optical materials. II. Effects of donor strength in two push-pull molecules.
The compounds N-[2-(4-cyano-5-dicyanomethylene-2,2-dimethyl-2,5-dihydrofuran-3-yl)vinyl]-N-phenylacetamide, C(20)H(16)N(4)O(2), (I), and 2-{3-cyano-5,5-dimethyl-4-[2-(piperidin-1-yl)vinyl]-2,5-dihydrofuran-2-ylidene}malononitrile 0.376-hydrate, C(17)H(18)N(4)O x 0.376 H(2)O, (II), are novel push-pull molecules. The significant bonding changes in the polyene chain compared with the parent molecule 2-dicyanomethylene-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 phenyl-cyano C-H...N and two phenyl-carbonyl C-H...O hydrogen bonds. Compound (II) crystallizes with a partial water molecule (0.376H(2)O), consistent with cell packing that is dominated by attractive C-H...N(cyano) interactions. These compounds 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.
Gainsford
Graeme J
GJ
Industrial Research Limited, PO Box 31-310, Lower Hutt, New Zealand. g.gainsford@irl.cri.nz
Bhuiyan
M Delower H
MD
Kay
Andrew J
AJ