Three s-triazine derivatives have been synthesized and their structures been de-termined. These are Compound I: 2,4-Dimethyl-6-(p-N, N-dimethylaminostyryl)-s-triazine (ab-breviated to NMe-1), Compound II: 2, 4-Dimethyl-6-(p-N, N-diethylaminostyryl)-s-triazine (to NEt-1), and Compound III: 2-Methyl-4, 6-bis(p-N, N-dimethylaminostyryl)-s-triazine (NMe-2). NMe-1 and NEt-1 molecules belong to the D-π-A type with a one-dimensional charge-transfer character. NMe-1 crystallize to centrosymmetric 1P space group, while NEt-1 to non-centro- sym- metric polar Cc space group with all of the molecular charge-transfer axes taking the same orientation. Under the irradiation of 1064 nm fundamental laser, NEt-1 powder crystals radiate a 2-order harmonic light with an intensity 46.8 times that of urea. The Λ typed NMe-2 molecule, which has a two-dimensional charge-transfer character, crystallize to polar P21 space group. Its powder crystals exhibit a 2-order harmonic intensity 46.2 times that of urea. The quantum chemical calculations and tensor analyses have been carried out to reveal the dependence of the macro 2-order nonlinear optical (NLO) efficiency on the micro 2-order NLO coefficients (β) and on the crystalline packing styles.

A new BEDT-TTF BEDT-TTFsBis ethylenedithio.tetrathiafulvalene.-based cation radical salt BEDT-TTF.2HgCl3PTCE TCEs 1,1,2-trichloroethane.was synthesized by using oxidative electro-crystallization at a constant current. Its structure was determined by four-circle X-ray diffraction method. The crystal belongs to monoclinic system, C2 space group with the unit cell parameters of as39.236 (5). A°, bs6.676 (1) A°, cs14.881 (3). A°, bs95.58 2.0, Vs3879.4 12. A°(3), Zs4. The structure shows that the BEDT-TTF radicals are stacked to form columns along the c-axis and arranged side-by-side to form one-dimensional uniform chains along the b-axis. The one-dimensional polymer HgCl3.nny, together with neutral TCE molecules, is also along the b-axis. Cationic BEDT-TTF sheets and anionic HgCly3 sheets are sandwiched along the a-axis. The room temperature resistivity of the single crystal was measured to be 3.33 VPm on the bc-plane. Its resistivity–temperature curve demonstrates a semiconductor behavior with an activation energy of 0.308 eV.

Two series of multibranched compounds with vinylenes attaching to the s-triazine core have been synthesized. The twophoton absorption cross section σ increases significantly as the branch number increases, with the ratios of between one-, two-, and three-branched compounds being 1.0:3.3:7.0 for series A and 1.0:3.7:7.0 for series B respectively, indicating remarkable cooperative enhancement.

Several donor-p-donor (D-p-D), acceptor-p-acceptor (A-p-A), and donor-p-acceptor (D-p-A) types of organic compounds with fluorene as p bridge and dimesitylboryl group as electron acceptor, which show strong two-photon excited blue fluorescence, have been synthesized and structurally investigated. The symmetric A-p-A type of compound exhibits the shortest wavelength of twophoton excited fluorescence (TPEF) at λem=405 nm under the excitation of λex=730nm; the unsymmetric D-p-A type of compound with diphenylamino as donor exhibits the most intense TPEF at blue region (λem=484 nm) with a two-photon absorption cross-section of 425GM under λex=800nm.