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The morphology evolution and phase transformation of Al9(Mn,Ni)2 eutectic phase in an Al-4Ni-2Mn alloy during heat treatment at 600 °C were studied by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Results show that nearly all of the eutectic fibers change into prolate ellipsoid and spherical particles in the process of heat treatment, and Ostwald ripening phenomenon occurs in the eutectic region with the increase of the heat treatment time. Besides, a phase transformation from Al9(Mn,Ni)2 to O-phase is confirmed. The morphologies of the transformed particles indicate that the O-phase preferentially nucleates on the specific crystal plane of the Al9(Mn,Ni)2 eutectic phase and grows in a certain direction. During the phase transformation, the (010)[001] slip system in O-phase is activated, and the resultant slip traces appear on the surface of some O-phase particles.

Three undescribed cis -clerodane lactones, scapanialides A–C ( 1–3 ), and a new cis -clerodane furano-diterpenoid, scaparvin F ( 4 ), were isolated from the Chinese liverwort Scapania parva Steph. Scapanialide B ( 2 ) is the first cis -clerodane diterpenoid with a bicyclo[5.4.0]undecane skeleton from liverworts. Their structures including the absolute configurations were determined by extensive analysis of multidimensional NMR spectroscopy and TDDFT CD calculations, together with crystal X-ray diffraction measurements. The cytotoxicity of compounds 1–4 was preliminary tested against the Hela and MCF-7 cell lines.

A new BEDT-TTF-based radical salt, β-(BEDT-TTF)(HSO4) [BEDT-TTF = bis(ethylenedithio)tetrathiafulvalene], has been synthesized by oxidative electrocrystallization. The crystal structure was determined by four-circle X-ray diffraction. The crystal belongs to monoclinic system, C2/c space group with the unit cell parameters of: a = 1.5996(2) nm, b = 1.06173(10) nm, c = 1.15083(11) nm, β = 120.534(8)°, V = 1.6834(3) nm3, and R = 0.0611. In the title crystal, the BEDT-TTF radicals are stacked to form columns along the [1 0 1] axis and the molecular planes of BEDT-TTFs in adjacent columns are parallel to each other. The inter-stack side-by-side S…S short contacts along the b-axis help to form a kind of cationic conducting sheet parallel to (1 0 1) plane. The room temperature conductivity at certain direction on (1 0 1) plane of β-(BEDT-TTF)(HSO4) single crystal was measured to be 11.7 S cm−1. From 100 K to 290 K, the resistivity–temperature curve demonstrates its typical semiconductivity with an excitation energy of 0.26 eV.

A new molecular conductor ( n -Bu 4 N)[Ni(dmit) 2 ] 4 ·MeCN (dmit = 2-thioxo-1,3-dithiole-4,5-dithiolato) has been synthesized and its X-ray structure has been determined. The crystal exhibits conductivity 0.1 Ω −1 cm −1 at room temperature and a semi-conducting behavior with small activation energy of 0.170 eV (at 295 K) and 0.065 eV (at 95 K). The coordination anions are arranged in a parallel fashion in the crystal forming two-dimensional networks, in which the face-to-face π – π longitudinal intermolecular interactions are stronger than the side-by-side S⋯S transverse interactions. The anionic stacks along the b -direction exhibit a type of tetrad structure. Infrared spectra suggest that the tetrad {4[Ni(dmit) 2 ]} − may consist of one mono-anion [Ni(dmit) 2 ] − and three neutral [Ni(dmit) 2 ] units. The bond analysis further suggests that the single electron in the HOMO of [Ni(dmit) 2 ] − can delocalize to its two neighboring [Ni(dmit) 2 ] molecules to some extent.

Structures and nonlinear optical properties of dimethylcroconate (DMCC) and dibenzoylcroconate (DBCC) are reported. The SHG active DMCC crystal packed in non-centrosymmetric P212121 space group. The DBCC crystal has a host–guest structure and crystallized in centrosymmetric P21/n space group. In DBCC crystal, the host DBCC molecules build channels along the b direction with the guest benzene molecules trapped in the channels. DSC, XRD, SHG and structural studies reveal that these benzene molecules can be removed at 90 °C, accompanying the loss of the centro-symmetry and resulting in the SHG active new crystalline phase.

Two donor-π-acceptor (D-π-A) type 2,2′: 6′,2″-terpyridyl-based organic heterocyclic molecules have been efficiently synthesized via solvent-free Wittig reactions in good yields. One crystal structure of them was determined by single crystal X-ray diffraction determination. The two compounds exhibit sensitive single-photon-excited fluorescence (SPEF) emission with high fluorescence quantum yields and long lifetimes. The two-photon-excited fluorescence (TPEF), two-photon absorption (TPA) cross-sections and two-photon initiation polymerization (TPIP) microfabrication experiments have been investigated. Experimental results confirm that they are effective organic two-photon photopolymerization initiators.

Growth mechanisms on the {1 1 0} and {3 1 0} faces of KLu(WO4)2 crystals for the case of top-seeded solution growth technique have been investigated using ex situ atomic force microscopy (AFM). Both 2D nuclei and spiral hillocks are imaged simultaneously on the {1 1 0} surfaces. A special dislocation sources structure with the Burgers vectors perpendicular to the {1 1 0} crystal face of b = 8 are discussed. The 2D nuclei with elementary-step height are distributed in the direction of the strong PBC [1 0 1], indicative of anisotropic surface diffusion or step edge energy. Straight step trains are observed on the {3 1 0} surfaces of KLuW and they move towards to [0 0 1] directions. It was confirmed that the growth proceeds by both screw dislocation sources and 2D nucleus on the {1 1 0} surfaces and by simple flow of steps on {3 1 0} surfaces.

A novel isophorone-based yellow emitting compound 2-(3-(2-(4-(9H-carbazol-9-yl)phenyl)vinyl)-5,5-dimethylcyclohex-2-enylidene)malononitrile with donor-π-acceptor structure for application in organic light-emitting diodes has been designed and synthesized. By researching the crystal structure of the compound, we found it had a big torsion angle between carbazole moiety and neighboring benzene groups, which was likely to prevent the concentration quenching in solid state. The carbazole group has powerful influence on optical properties of the compound in solution or solid state. As a non-doping emitting layer, the dye has bright orange-yellow emission (chromaticity coordinates: x = 0.531, y = 0.462) and a brightness of 748 cd/m2 at the voltage of 18.25 V.

The crystals of Sm3+-doped KLu(WO4)2 with large dimensions up to 40 mm × 33 mm × 13 mm have been grown by the top-seeded solution growth (TSSG) method. The spectral and luminescent properties have been investigated. Based on the Judd–Ofelt theory, the following spectral parameters have been obtained: the phenomenological intensity parameters Ωt, Ω2 = 15.728 × 10−20 cm2, Ω4 = 4.223 × 10−20 cm2 and Ω6 = 2.839 × 10−20 cm2, radiative transition probabilities A J , J ′ and oscillator strengths P J , J ′ . The radiative lifetime of levels 4G5/2 is 748 μs. However, the measured emission lifetime is τem = 569 μs. The quantum efficiency is very low because of the excited state absorption. In addition, the values of integrated emission cross-sections are also calculated.

KLu(WO4)2 (KLuW) crystals with sizes up to 42×32×12 mm3 have been grown from the K2W2O7 solvent system by the top-seeded solution growth (TSSG) slow-cooling method. The crystal structure of monoclinic KLuW crystals has been refined in space group C2/c at room temperature by using single-crystal X-ray diffraction data and the KLuW morphology was studied from the Hartman–Perdok theory. Crystal shapes vary greatly with the seed orientations, whereas {1 1 0}, {1¯ 1 1}, {0 2 0} and {3 1 0} faces are more developed than the others.

A new free-radical photonpolymerization initiator Tris-[4-(2-pyridin-4-yl-vinyl)-phenyl]-amine (TPPA) has been synthesized and characterized by 1H NMR spectra,13C NMR spectra and elemental analyses. X-ray diffraction analyses reveal that TPPA belongs to monoclinic system, P21/n space group with a=15.851 (3), b=9.7932 (18), c=20.084 (6) A, α=90, β=107.241 (12), γ=90°, V=2977.6 (12) A3, Z=4, T=293 (2) K, Dc=1.237 g cm−3, R1=0.0569, wR=0.1245. The calculated two-photon absorption cross-section is 33.6×10−50 cm4 s photon−1. The experimental results confirm that TPPA is a good two-photon absorbing chromophore and operative two-photon photopolymerization initiator. When pumped with 820 nm laser irradiation, TPPA shows strong two-photon induced fluorescence. A microstructure has been fabricated under irradiation using a 200 fs, 76 MHz Ti: sapphire femtosecond laser at 820 nm. The possible photopolymerization mechanism is discussed.

A conjugated and symmetric multi-branched compound, 1,2,4,5-tetrakis(4-pyridylvinyl)benzene (TKPVB), has been synthesized and the crystal structures of TKPVB and its intermediate, 1,2,4,5-tetrakis(dimethoxyphosphorylmethyl)benzene, were determined by diffraction method. TKPVB with four units of 4-vinylpyridine moieties attached to the central benzene core presents an A-π-A general framework, where A is a π-deficient pyridine ring. The single-photon and two-photon absorption and fluorescence properties in different solvents of varying polarity have been investigated. It is also found that the one- and two-photon-induced fluorescence spectra are quite similar, which indicate that the one- and two-photon allowed-excited states are the same.

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

Three zinc(II) halide complexes ZnL2X2 (X=Cl, Br, I; L=4-methoxylbenzaldehyde thiosemicarbazone) have been synthesized and characterized by spectroscopic techniques. The complexes exhibit powder SHG efficiency approximately ten times higher than that of urea. The molecular hyperpolarizabilities are calculated to be −2.6×10−30 esu for the free ligand L, and −4.6×10−30, −6.2×10−30, −10.1×10−30 esu for the three zinc complexes, respectively. The former two complexes crystallize in the noncentrosymmetric space group Aba2, whilst ZnL2I2 crystallizes in the centrosymmetric space group P21/c and does not exhibit any SHG efficiency. The zinc(II) atom in these complexes is tetrahedrally coordinated by two neutral sulfur atoms from the corresponding thiosemicarbazones and two halide anions. The relationships between the molecular structures and nonlinear optical properties were studied based on theoretical calculation and experimental determination methods.

A new BEDT-TTF (BEDT-TTF=Bis(ethylenedithio)tetrathiafulvalene)-based cation radical salt (BEDT-TTF)2HgCl3·TCE (TCE=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 a=39.236(5) A, b=6.676(1) A, c=14.881(3) A, β=95.58(2)0, V=3879.4(12) A3, Z=4. 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)nn−, together with neutral TCE molecules, is also along the b-axis. Cationic BEDT-TTF sheets and anionic HgCl3− sheets are sandwiched along the a-axis. The room temperature resistivity of the single crystal was measured to be 3.33 Ω·m on the bc-plane. Its resistivity–temperature curve demonstrates a semiconductor behavior with an activation energy of 0.308 eV.

Monoclinic rubidium gadolinium bis(tungstate) single crystals, RbGd(WO 4 ) 2 (RGW), have been grown by the spontaneous nucleation from high-temperature solutions. The thermal properties were firstly studied by measuring DSC, TG and specific heat. The melting point was determined to be 1089 °C. The measured specific heat ranges from 0.141 J g − 1 K − 1 to 0.564 J g − 1 K − 1 in the temperature range from 60 °C to 700 °C, a value that is slightly smaller than that of KGd(WO 4 ) 2 . An infrared spectrum of the crystal was recorded in the frequency range of 50 to 1000 cm − 1 and all vibration frequency peaks were assigned.

A new molecular conductor (PyMe)[Ni(dmit) 2 ] 2 (PyMe = N -methylpyridinium, dmit = 2-thioxo-1,3-dithiole-4,5-dithiolato) has been synthesized and its structure been determined. The temperature-dependent conductivities in the range of 290–20 K reveal a semi-conducting behavior of the crystal with a small activation energy of 0.067 eV and a quite high room temperature conductivity of 2 S cm −1 .

Crystallographic, thermal expansion and specific heat data obtained for a single crystal of a new organometallic nonlinear optical material, triallylthiourea mercury bromide (ATMB), are reported. It is trigonal (space and point groups are R3c and C3v respectively) with lattice parameters a = b = 11.580 A , c= 28.939 A , V = 3375 A 3 . There are six formula units per cell and the density is 2.10 g/cm3. The second harmonic generation intensity, obtained on a powder sample, is 2.5 times greater than that of urea.

Electrochemical oxidation of 3,4,3',4'-bis(ethylenedithio)-2,2',5,5'-tetrathiafulvalene (abbr. ET) in the presence of allylsulfonate affords a new charge-transfer salt (ET) 2 (CH 2 =CH-CH 2 -SO 3 ).H 2 O. The crystal structure has been determined to be in orthorhombic crystal system, Pma2 space group. In the crystal of the title compound, ET cations adopt a α'-type packing pattern and organic counter anions form infinite chains by hydrogen bonds along the c-axis. This salt is a semiconductor and its room-temperature conductivity is 0.0489 Ω -1 m -1 .