three-branched octupolar compound, 2,4,6-tris[2-(4-N,N-diethylamino)phenylethenyl]-1,3,5-s-triazine (compound III), as well as its one-and two-branched analogues (compounds I and II respectively) have been synthesized. The structures of I and II have been determined by X-ray diffraction. The linear and nonlinear spectra of these compounds regularly vary: (1) the spectral positions (lmax values) of the linear absorption, the single-photon excited fluorescence (SPEF) and the two-photon excited fluorescence (TPEF) show regular redshifts when the branch number increases from 1 to 3; (2) the spectral intensities, including the linear absorbance emax and the two-photon absorption cross-section s, the SPEF and the TPEF intensities are all increased significantly when going from I to III. The values of emax/MW and s/MW (of compounds I, II and III) vary with the ratios of 1.0: 1.3: 1.7 and 1.0: 1.4: 1.3, respectively. All the photophysical data indicate that by incorporating more branches into the triazine ring, the linear and nonlinear optical responses have been significantly enhanced, and that the spectral behaviour of II is closer to that of III, while more different from that of I. The single-branched compound I crystallizes in the noncentrosymmetric polar space group Cc. Its crystalline powder sample shows remarkable macro second-order nonlinear response with a SHG intensity of 46.8 times that of urea under a fundamental picosecond Nd: YAG laser beam (1064 nm). An important factor of such a large SHG intensity is that all the molecular dipoles take the same-oriented packing style that makes the crystal maximally polarized, fulfilling the optimization in the sense of crystal engineering.

We have synthesized two new organic salts, trans-4-[p-(N-hydroxyethyl-N-methylamino)styryl]-Nmethylpyridinium toluene-p-sulfonate (abbreviated as HMASPS) and trans-4-[p-(N-hydroxyethyl-Nethylamino) styryl]-N-methylpyridinium toluene-p-sulfonate (abbreviated as HEASPS). X-Ray iffraction analyses reveal that HMASPS crystal belongs to the P21/n space group, with water olecules co-crystallized in the crystal and forming the monohydrate with the formula of C17H21N2Oz?C7H7O3S2?H2O, while HEASPS belongs to the P1

Electrically conductive platelet crystals of Z[Pd(dmit)2]2 [Z = (Me3NEt), (MeNEt3), (NEt4)], as well as their precursors Z2 [Pd (dmit) 2], have been synthesized by a non-electrochemical method and their structures have been determined. The single-crystal conductivities at a direction on the cleavage surface at room temperature were measured to be 58 Ω 1 cm 1 for (Me3NEt)[Pd(dmit)2]2, 5.0 Ω 1 cm 1 for (MeNEt3)[Pd(dmit)2]2 and 2.2 Ω 1 cm 1 for (NEt4)[Pd(dmit)2]2, respectively. This sequence of conductivity is agreement with the sequence of structural twodimensionality of these three complexes. The resistivity–temperature curves reveal the semiconducting behavior of the above complexes, which show very narrow band gaps. The structure analysis results reveals that when the size of cation Z in Z[Pd(dmit)2]2 is finely tuned [(Me4N)+→(Me3NEt)+→(Me2NEt2)+→(MeNEt3)+→(NEt4)], the corresponding complexes belong to the same structural motif and each individual possesses some special structural characteristics. Subtle structural difference in this group of complexes can severely influence their measured conductivities and significantly influence their calculated band structures.

Three compounds with three p-substituted styryls attaching to the central s-triazine have been synthesized and two crystals determined to be in non-centrosymmetric Cmc21 and Pmn21 space groups, respectively. All of them in solid state are second harmonic generation (SHG) active and two of them show powder SHG intensities one order of magnitude that of urea.

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.