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Nonlinear optical properties of dicyanomethylene‐derived heteroaromatic dyes: Semiempirical molecular orbital calculations and experimental investigations
Author(s) -
Zerner Michael C.,
Fabian Walter M. F.,
Dworczak Renate,
Kieslinger Dietmar W.,
Kroner Gert,
Junek Hans,
Lippitsch Max E.
Publication year - 2000
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/1097-461x(2000)79:4<253::aid-qua6>3.0.co;2-k
Subject(s) - chemistry , hyperpolarizability , moiety , molecular orbital , intramolecular force , conformational isomerism , computational chemistry , nitrile , acceptor , hydrogen bond , crystallography , photochemistry , stereochemistry , molecule , organic chemistry , physics , polarizability , condensed matter physics
The effect of conformation ( E / Z isomerism), nature (donor/acceptor) of substituents, and endgroups (indandione, pyrazolone, pyrazoledione) on the molecular hyperpolarizability β vec of dicyanomethylene (hetero)aromatic dyes is investigated by means of semiempirical (AM1, ZINDO) molecular orbital calculations. Unless Z isomers are stabilized by intramolecular hydrogen bonding, generally E conformers have larger β vec 's. Replacement of one nitrile group of the dicyanomethylene moiety by p ‐aminoaryl rather than p ‐R‐arylamino (R=NMe 2 , MeO, H, NO 2 ) is found to be advantageous. Increasing the acceptor strength of 29 by successively replacing the carbonyl with dicyanovinyl groups leads to a maximum of β vec for the derivative with one rather than two C(CN) 2 groups. With respect to endgroups, the indandione moiety generally is the least active group. Solvent effects are treated within the framework of the self‐consistent reaction field approximation. In most cases gas‐phase tendencies are either parallel or even reinforced if solvent effects are taken into account. The calculated results are compared with electric field induced second harmonic generation (EFISH) measurements. © 2000 John Wiley & Sons, Inc. Int J Quant Chem 79: 253–266, 2000