INCORPORATION OF A STILBAZOLE DERIVATIVE IN THE HYDROGEN-BONDED CHAINOF L-TARTRATE - TOWARD A ONE-STEP OPTIMIZATION OF MOLECULAR AND BULK 2ND-ORDER NONLINEARITIES

The syntheses and crystal structures of dimethylaminostilbazole (DAS) and dimethylamino-N-methyl stilbazolium hydrogen L-tartrate (DAS-H+Ta- ) are described. Crystal data for DAS: monoclinic, P2(1)/c, a = 6.0443 (9) Angstrom, b = 7.6616(8) Angstrom, c = 26.376(4) Angstrom, beta = 9 3.66(1)degrees, Z = 4. Crystal data for DAS-H+Ta-: monoclinic, P2(1), a = 7.518(1) Angstrom, b = 7.528(1) Angstrom, c = 16.376(2) Angstrom, beta = 92.67(1)degrees, Z = 2. In the latter compound, the anions crea te infinite chains through intermolecular O-H ... O hydrogen bonds, wh ereas the stilbazolium cations are hydrogen bonded to the chains. INDO calculations and spectroscopic studies show that hydrogen bonding gre atly enhances the molecular hyperpolarizability of the stilbazole deri vative, while crystal engineering with tartaric acid is achieved into the acentric space group. Therefore, an efficiency of 8 times that of urea in second-harmonic generation has been measured at 1.907 mu m for this material.