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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.

Single crystals of monoclinic Nd:LaVO4with dimensions up to Ø28 × 21 mm have been grown from the near-stoichiometric melt by the Czochralski method, making use of various seed orientations that are perpendicular to the (010), (10{\overline 1}), (001) and (00{\overline 1}) crystal planes. A sample was also prepared with the seed orientation in an arbitrary direction relative to the crystal. The anisotropic properties of the crystal are manifested in the growth morphology of the as-grown crystals, where different degrees of bulk spiral growth were observed. It was also found that employing the (001) or (00{\overline 1}) seed faces severely suppressed the bulk spiral growth, and thus high quality and large-scale Nd:LaVO4crystals were obtained. The constituent segregation coefficients and high-temperature stability, including the melting point, were determined and evaluated. Based on the attachment energy model of Hartman–Perdok theory, morphology predictions were made for monoclinic LaVO4and tetragonal YVO4orthovanadate single crystals. Correlating with the as-grown morphology of both crystals developed along different seed orientations, a theoretical explanation is provided for the influences of seed crystals on bulk spiral formation, crystal quality and utilization ratio. It suggests that breaking the axial symmetry of the ideal atomic level interface between crystal and melt plays a crucial triggering role in bulk spiral formation in the Czochralski growth of lanthanide orthovanadate single crystals. Selecting a proper seed orientation that yields such a highly axially symmetric surface structure consisting of a series of large-area facets with similar growth velocities can greatly reduce bulk spiral formation and thus is preferable in the Czochralski growth of large-sized low-symmetry oxide crystals.

Three novel fernane-type triterpenoids, lobarialides A-C (1-3, resp.), together with two known ones were isolated by antifungal bioassay-guided fractionation of the lichen Lobaria kurokawae. Their structures including configurations were established on the basis of extensive spectroscopic analyses, and that of 1 was confirmed by a single-crystal X-ray diffraction analysis. Antifungal tests of the five triterpenoids showed that the activity increased with the increment of the number of COO groups.

The crystal structure of monoclinic Lu2SiO5(LSO) crystals, grown by the Czochralski method, was determined at room temperature by X-ray diffraction. The unit-cell parameters area= 10.2550 (2),b= 6.6465 (2),c= 12.3626 (4) Å, β = 102.422 (1)° in space groupI2/a. The linear thermal expansion tensor was determined along thea,b,candc* directions over the temperature range from 303.15 to 768.15 K, and the principal coefficients of the thermal expansion tensor are found to be αI= −1.0235 × 10−6 K, αII= 4.9119 × 10−6 K and αIII= 10.1105 × 10−6 K. The temperature dependence of the cell volume and monoclinic angle were also evaluated. In addition, the specific heat and the thermal diffusivity were measured over the temperature ranges from 293.15 to 673.15 K and from 303.15 to 572.45 K, respectively. As a result, the anisotropic thermal conductivity could be calculated and is reported for the first time, to the best of the authors' knowledge. The specific heat capacity of LSO is 139.54 J mol−1 K−1, and the principal components of the thermal conductivity arekI= 2.26 W m−1 K−1,kII= 3.14 W m−1 K−1andkII= 3.67 W m−1 K−1at 303.15 K. A new structure model was proposed to better understand the relationships between the crystal structure and anisotropic thermal properties. In comparison with other laser matrix crystals, it is found that LSO possesses relatively large anisotropic thermal properties, and owing to its small heat capacity it has a moderate thermal conductivity, which is similar to those of the tungstates but lower than those of the vanadates.

Three new rearranged ent-kaurane-type diterpenoids (1-3) and seven new ent-kaurane-type diterpenoids (4-10) have been isolated from the liverwort Jungermannia atrobrunnea. Their structures were determined by extensive spectroscopic techniques and X-ray crystallographic analysis. The absolute configurations of these compounds were clarified by CD spectroscopic studies. Compound 1 is the first example of a rearranged ent-kaurane diterpenoid possessing a peroxide bridge.

A transparent Yb3+:NaY(WO4)2single crystal with dimensions of 30 mm (diameter) × 40 mm has been grown by the Czochralski method. The high crystalline quality of the as-grown Yb3+:NaY(WO4)2crystals was confirmed by high-resolution X-ray diffraction. The effective segregation coefficients of elemental Yb, Na, Y and W in Yb3+:NaY(WO4)2were measured using the X-ray fluorescence method. Powder and single-crystal X-ray diffraction data of NaYb0.05Y0.95(WO4)2are reported. The structure refinement shows that NaYb0.05Y0.95(WO4)2crystallizes in the tetragonal space groupI41/a, witha=b= 5.2039 (2),c= 11.2838 (9) Å, α = β = γ = 90°,V= 305.57 (3) Å3andZ= 2. A series of possible growth faces (hkl) were determined from the crystal lattice and symmetry according to the Bravais–Friedel Donnay–Harker theory, and the relationship among crystal structure, growth habits and crystal morphology is discussed. In addition, the thermal properties of the crystal, including the specific heat, thermal expansion, thermal diffusion and thermal conductivity, were carefully investigated. The anisotropy of the crystal thermal conductivities is explained from the point of view of the crystal structure.

A new copper complex of dmit, hexadecyltrimethylammonium bis(2-thioxo-1,3-dithiole-4,5-dithiolato)-copper([C16H33(CH3)3N][Cu(dmit)2], abbreviated as CTCU, C16H33(CH3)3N = hexadecyltrimethylammonium, dmit = 2-thioxo-1,3-dithiole-4,5-dithiolate) has been synthesized and its structure determined by X-ray diffraction. The saturable absorption of CTCU at 1053 nm shows promise as a Q-switch dye in the near IR regions.

In the two title complexes, (C24H20P)[Au(C3S5)2] x C3H6O, (I), and (C20H20P)[Au(C3S5)2], (II), the Au(III) atoms exhibit square-planar coordinations involving four S atoms from two 2-thioxo-1,3-dithiole-4,5-dithiolate (dmit) ligands. The Au-S bond lengths, ranging from 2.3057 (8) to 2.3233 (7) A in (I) and from 2.3119 (8) to 2.3291 (10) A in (II), are slightly smaller than the sum of the single-bond covalent radii. In (I), there are two halves of independent Ph4P+ cations, in which the two P atoms lie on twofold rotation axis sites. The Ph4P+ cations and [Au(C3S5)2]- anions are interspersed as columns in the packing. Layers composed of Ph4P+ and [Au(C3S5)2]- are separated by layers of acetone molecules. In (II), the [Au(C3S5)2]- anions and EtPh3P+ counter-cations form a layered arrangement, and the [Au(C3S5)2]- anions form discrete pairs with a long intermolecular Au...S interaction for each Au atom in the crystal structure.

By combining a new, large π-conjugated bidentate ligand, 2,8-bis[2-(2-pyridyl)vinyl]-5,11-di(2-ethylhexyl)-indolo[3,2-b]carbazole (BPVIC) with a [Cd(NCS)2]∞ polymer chain, a novel supramolecular coordination polymer, [Cd2(BPVIC)2(SCN)4]∞, with network structure has been prepared. The crystal structures of the ligand and the coordination polymer were determined by X-ray crystallography. The crystallographic analyses revealed that “drums” formed by the ligands, Cd2+ cations, and SCN− anions are interconnected, leading to the formation of infinite three-dimensional networks. The π−π and C−H···π interactions among the free ligands, acting as energy traps and increasing nonradiative decay, are eliminated effectively in the metal coordination polymer. The metal coordination polymer exhibits strong luminescence in the yellow region and therefore is a potential luminescent material.

A new nonlinear optical crystal BaTeMo2O9 was grown from the TeO2−MoO3 flux system with sufficient size (30 × 23 × 18 mm3) and optical quality that allowed the characterization of its properties. It crystallizes in the noncentrosymmetrical system, space group P21 (no. 4), with a = 5.5346 A, b = 7.4562 A, c = 8.8342 A, and β = 90.897°. The as-grown BaTeMo2O9 crystal has well-developed faces with the major forms {100}, {001}, {011}, and {011}. The transmission spectra results suggest that it can transmit well from 0.5 to 5.0 µm. The refractive indices were also measured. The smaller refractive indices nx and ny are in the ac-plane, and the largest refractive index nz polarization direction is parallel to the crystallographic b-axis.

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.

Both the title multi-sulfur molecules C5H2S5 (1) and C5H2OS4 (2) have a chair conformation, while molecule 1 has a higher degree of π-conjugation. Both the crystals are characterized by short S···S intermolecular contacts and by face-to-face column-like packing style, but crystal 1 has been more stabilized which may be the result of its stronger π–π intermolecular interactions. Compound 1 crystallizes in non-centrosymmetric polar space group Pmn21 with a = 10.6826(17), b = 9.3633(11), c = 4.0764(6) A, V = 407.74(10) A3, and Z = 2. The molecular dipole moment of 1 is ±62.5(1)° away from the macro-polarization direction along the c-axis. Consequently, the crystalline powder of crystal 1 exhibit a second harmonic generating (SHG) intensity 0.5 time strong as that of urea standard powder crystals when irradiated by a 1,080 nm of Nd:YAP laser beam. Compound 2 shows no SHG effect because it crystallizes in centrosymmtric space group Pbca with a = 11.4208(8), b = 7.8843(9), c = 33.587(3) A, V = 3024.3(5) A3, and Z = 16. Structures and Non-linear Optical Properties of Multi-Sulfur π-Conjugated Compounds 4,5-Vinylenedithio-1,3-dithiole-2-thione (C5H2S5) and 4,5-Vinylenedithio-1,3-dithiole-2-one (C5H2OS4) Gang Xue, Qi Fang,* Wen-Tao Yu, Xia Chen, and Hong Lei Compound C5H2S5 crystallizes in the polar space group Pmn21 and its crystalline powder exhibits a second harmonic generating (SHG) intensity 0.5 times that of urea standard (1080 nm → 540 nm), while the similar compound C5H2OS4 has no SHG effect because of its centrosymmetric space group Pbca.

A novel Λ-shaped pyridinium salt 2,8-(6H,12H-5,11-methanodibenzo[b,f]diazocineylene)-di(p-ethenyl-N-methyl-pyridinium) ditosylate (abbreviated as DMDPS) based on Troger's base was designed, synthesized and characterized. DMDPS exhibits a typical aggregation-induced emission (AIE) behavior that is virtually nonemissive in solution but highly luminescent in solid state. The difference between the structure and the optical properties of DMDPS and 1,4-phenyl-di(p-ethenyl-N-methyl-pyridinium) ditosylate (abbreviated as DPPS) are analyzed and compared. It is concluded that the loose stacking caused by twisted molecular configuration could reduce the distance-dependent intermolecular quenching effect to produce intense fluorescence in the aggregation state while the enantiomerization and/or the intramolecular vibrational motion which induce the nonradiative deactivation process could cause fluorescence quenching in the solution. As a water-soluble AIE-active material, DMDPS would have potential application in th...

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.

Efficient aqueous-phase aldol condensation, Michael addition, and solvent-free Wittig reactions were successfully employed to synthesize two two-photon initiators 9-ethyl-3-[4-(2,2′:6′,2″-terpyridi...

Aggregation induced emission (AIE) is an amazing property for light emitting materials and has attracted much attention. Here, we report a new kind of AIE materials: fluorenone derivates 2,7-dip-tolyl-fluorenone (DTFO) and 2,7-bis(4-(tert-butylthio)phenyl)-fluorenone (DSFO). Strong light emissions with a large Stokes shift and long lifetime in the solid state originate from the formation of excimers. The crystal structure of DSFO shows that every two molecules are bound together even in the ground state by intermolecular hydrogen bonds and form a particular dimer. When this dimer is excited, it turns into an excimer without arrangement adjustment and likewise without repulsive interactions when the excimer decays back to the dimer; so, the nonradiative decay pathways that exist in common excimers are greatly reduced and thus induce a strongly enhanced luminescence in the solid state. OLED devices employing DTFO as light emitting layers are fabricated and evaluated.

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.

The known 7,8-secolabdane type diterpenoids neopallavicinin (1), pallavicinin (2), and 18-hydroxypallavicinin (3) were isolated from Pallavicinia ambigua, and their structures were determined. The X-ray crystal structure of 1 was solved, and, in combination with CD and NMR studies, the absolute configurations of 1–3 were established. A possible biogenetic pathway for 1 and 2 from a single labdane precursor is proposed.

The target compound, Trans-4-(N-2-hydroxyethyl-N-ethyl amino)-4′-(diethyl amino)stilbene, has been synthesized and characterized. The one-photon fluorescence and its lifetimes, two-photon fluorescence and solvent effects have been studied in detail. X-ray diffraction analyses reveal that it is a highly delocalized π -electron system structure. It belongs to monoclinic system, P21/n space group. A two-photon initiating polymerization microfabrication experiment has been carried out and the possible photopolymerization mechanism is also discussed.

Two new two-photon photopolymerization initiators, diphenyl-(4-{2-[4-(2-pyridin-4-ylvinyl)phenyl]vinyl}phenyl)amine 3 and 9-(4-{2-[4-(2-pyridin-4-ylvinyl)phenyl]vinyl}phenyl)-9H-carbazole 4, have b...

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.

Bioautographic assay on TLC plates was adopted to guide the fractionation of the Et2O extract of Homalia trichomanoides (Hedw.) B. S. G., which led to the isolation of the novel p-terphenyl derivative trichomanin (= 4,4''-dihydroxy-1,1':4',1''-terphenyl-2',3',5',6'-tetrayl tetrakis(phenylacetate); 1), together with five known compounds: 3alpha-methoxyserrat-14-en-21beta-ol (2), 3beta-methoxyserrat-14-en-21beta-ol (3), 3beta-methoxyserrat-14-en-21-one (4), atranorin (5), and methyl 2,4-dihydroxy-3,6-dimethylbenzoate (6). Their structures were determined on the basis of spectral data (1D- and 2D-NMR, MS), X-ray crystallographic analysis, and chemical transformation. Compounds 3, 5, and 6 exhibited antifungal activity against Candida albicans, with minimum inhibitory doses (MID) of 2.0, 2.0, and 0.6 microg, respectively.

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.

From Peucedanum praeruptorum, one new khellactone ester (3'R)-O-acetyl-(4'S)-O-angeloylkhellactone (3), as well as four known angular dihydropyranocoumarins (1, 2, 4, 5) have been isolated. On the basis of NMR spectra and X-ray crystallography, their structures were determined. We have elucidated their absolute configuration by either chiral separation of their alkaline hydrolysis products with Rp-18 HPLC eluted with 5% hydroxypropyl-beta-cyclodextrin (beta-HCD) or by measurement of their CD spectra. A general rule relating the position and absolute streochemistry of the khellactone esters to the sign of their Cotton effects in CD curves is proposed.

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.

Two one-dimensional chain complexes, {[Cu(cda)2H2O]·H2O}n (1) and {[Cu(cda)(H2O)2]·(ClO4)·3H2O}n (2) (cda = carbamyldicyanomethanide anion) have been synthesized and their crystal structures determined by X-ray crystallography. The copper(II) ions in 1 are bridged by two µ1,5-cda bridging ligands, whereas in 2 the copper(II) ions are connected by a single µ1,5-cda ligand. Complex 1 is red while 2 is green. Variable-temperature magnetic susceptibility data indicate that there is a very weak antiferromagnetic interaction between the bridged copper(II) ions in both 1 and 2.Key words: synthesis, crystal structure, copper complex, polynitrile ligand, magnetism.

C38H42N2, monoclinic, P21/c (no. 14), a = 5.1381(4) Å, b = 14.238(1) Å, c = 21.372(2) Å, β = 92.359(4)°, V = 1562.2 Å3, Z = 2, Rgt(F) = 0.0863, wRref(F2) = 0.2868, T = 130(2) K.

A complex with a three-dimensional structure {[Na3Co(pyz)3(H2O)4(ClO4)2]} n (pyz = pyrazine-2-carboxylate anion) has been synthesized and its crystal structure determined by X-ray crystallography. The complex crystallizes in a triclinic system with a space group Pī and a = 8.598(11), b = 11.382(15), c = 14.496(19) A, α = 87.79(2), β = 88.21(2), γ = 82.08(2)°. The Co(II) ion is located in a distorted octahedral environment with three oxygen atoms and three nitrogen atoms, from the three pyr ligands. Na(1) ion is coordinated by four oxygen atoms and two nitrogen atoms, in which O(1), O(2), O(2A), N(4A) and N(6A) come from ligand pyr while O(15) comes from H2O. Na(2) and Na(3) ions are each coordinated by six oxygen atoms. Through coordination of the bridging ligand pyr with Co(II) and Na(I) a three-dimensional net structure is formed.

We have synthesized a series of new D−π−A compounds that feature various electron donors and a fixed benzothiazolyl unit as an electron acceptor. The crystal structure of compound 3 [trans,trans-2-{4-[(4-N-carbazolyl)styryl]styryl}-1,3benzothiazole, CSSB] was determined. All these compounds show high fluorescence quantum yields and 3 in toluene gives the most intense blue emission around 450 nm with a quantum yield of Φ = 0.69. When excited at 800 nm by a Ti:sapphire femtosecond laser, these compounds exhibit strong two-photon-excited fluorescence (TPEF) in the blue-to-orange region. The measured TPEF cross-section of compound 2 [trans,trans-2-{4-[4-(N,N-diphenylamino)styryl]styryl}-1,3-benzothiazole, DPSSB], for example, is about 6.1 times that of Coumarin 307. Photophysical data indicate that these compounds are polar in the ground state and have an enhanced polarity in the excited state, and that the electron donating ability of a dialkylamino group is much stronger than that of a diarylamino group. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)

A one-dimensional chain complex {[Mn(pyz)(SCN)(H2O)2] · H2O}∞ (pyz = pyrazine-2-carboxylic anion) has been synthesized and its crystal structure determined by X-ray crystallography. In the complex each Mn ion is located in a distorted octahedral environment with two oxygen atoms O(3), O(4) from terminal ligands of two water molecules, another oxygen atom O(1) from the carboxylate group of pyz, and three nitrogen atoms N(1), N(2A) from two different pyz units and N(3) from the terminal ligand thiocyanate anion, in which a chelated five-membered ring is formed by coordination of O(1) and N(1) to the Mn(1) atom. Thus, an infinite zigzag chain consisting of Mn and pyz is constructed and the chains are linked together by hydrogen bonding from coordinated and uncoordinated water molecules, the sulfur atom of thiocyanate and the carboxylate oxygen of pyz. The variable-temperature magnetic susceptibility of the complex was measured in the 4–300 K range. The magnetic coupling parameter is consistent with an antiferromagnetic exchange between the two manganese(II) centers and the data fit a binuclear magnetic exchange model based on the Hamiltonian operator (H = −2JS 1 S 2, S 1 = S 2 = 5/2), giving the antiferromagnetic coupling parameter of 2J = −0.17 cm−1. This is the first pyrazine-2-carboxylic anion bridging complex dealing with the magnetic interaction study.

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.

Calcium modification of both alumina and MgO·Al2O3 inclusions during protective gas electroslag remelting (P-ESR) of 8Cr17MoV stainless steel and its effect on nitrides and primary carbides were studied by analyzing the transient evolution of oxide and sulfide inclusions in the P-ESR process. The oxide inclusions that were not removed during P-ESR without calcium treatment were found to retain their original state until in as-cast ingot. Calcium treatment modified all MgO·Al2O3 and alumina inclusions that had not been removed in the P-ESR process to liquid/partially liquid CaO-Al2O3-(MgO) with uniformly distributed elements, in addition to a small proportion of partially modified inclusions of a CaO-MgO-Al2O3 core surrounded by a liquid CaO-Al2O3. The modification of low-MgO-containing MgO·Al2O3 inclusions involves the preferential reduction of MgO from the MgO·Al2O3 inclusion by calcium and the reaction of calcium with Al2O3 in the inclusion. It is the incomplete/complete reduction of MgO from the spinel by calcium that contributes to the modification of spinels. Alumina inclusions were liquefied by direct reaction with calcium. Calcium treatment during P-ESR refining also provided an effective approach to prevent the formation of nitrides and primary carbides in stainless steel through modifying their preferred nucleation sites (alumina and MgO·Al2O3 inclusions) to calcium aluminates, which made no contribution to improving the steel cleanliness.

A series of new chromophores, styryl-parent end-capped with various donors, and with barbituric acid, methyl-pyridinium, and methyl-quinolinium as the acceptors, have been synthesized and characterized by element analysis or X-ray diffraction. Using the Z-scan system, their two-photon absorption (TPA) cross-section values (δ) have been determined under excitation with 10 Hz, and 1064 nm, 35 ps mode-locked Nd:YAG laser pulse in DMF with do= 0.05 M. The effective δ value is as high as 10.9 × 10–48 cm4 s per photon for trans-4-(4'-N,N-diphenyl amino) styryl-N-methyl quinolinium iodide (DPASQI). The δ value increases from barbituric acid- to pyridinium- to quinolinium-derivatives apparently due to the increase in both the conjugated degree and planarity; however, when the acceptor is fixed, the δ value increases from dialkyl amino groups to diphenyl amino groups even though the latter is a weaker donor than the dialkyl amino groups. Theoretical calculations confirm that the increased distortion from planarity for the barbituric acid derivative makes its δ value decrease. The relatively large δ value for quinolinium- or pyridinium-derivatives originates from larger intramolecular charge transfer, which can be characterized by the difference of dipole moment (Δµge) between the S0 and S1, and the transition dipole moment (Mee') between S1 and S2.Key words: two-photon absorption, intramolecular charge transfer, styryl-quinolinium, styryl-pyridinium, styryl-barbituric acid.

Two-photon absorption properties of a series of symmetrically substituted stilbenes and asymmetrically substituted stilbene-type derivatives with the same conjugated length have been investigated. The effective two-photon absorption cross sections, δTPA, as large as 62.0 × 10−48 cm4 s photon−1 for D-π-D molecules and 48.5 × 10−48 cm4 s photon−1 for D-π-A counterparts have been observed. The effect of these two types of chromophores on the peak position of the linear absorption, one-photon fluorescence as well as two-photon absorptivity is reported. Dipole moment change between the ground and the first excited states (Δµge), and the transition dipole moment between the first and second excited states (Mee′) have also been calculated. It was found that the asymmetrically substituted derivatives possess relatively large Δµge, whereas the symmetrical counterparts show an increase in Mee′. Although a large two-photon absorption resonance is due to the simultaneously high values of Mee′ and Δµge, correlated to intramolecular charge transfer, the former function is larger. These results obtained have demonstrated that the magnitude and the peak position of two-photon absorption depend not only on the amount but also on the direction of the intramolecular charge transfer.

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.

A series of new two-photon pumped (TPP) up-conversion lasing dyes, named as CSPI, DPASPI, PSPI, DEASPI and HEASPI respectively, have been synthesized. These dyes are stilbene-type chromophores end-capped with the same acceptor group but with varied donor groups, whose different electron-donating abilities can be ordered by 1H NMR chemical shift data. PM3 calculations show that attaching different donors changes the bond length alternation (BLA) and charge density distribution of the styrylpyridine skeleton. These chromophores exhibit different two-photon up-conversion emission behavior. Pumped by a 1064 nm, ∼40 ps mode-locked Nd ∶ YAG laser pulses, all chromophores showed two-photon pumped (TPP) up-conversion laser emission, but the efficiencies showed a difference of about two orders of magnitude, ranging from an up-conversion efficiency of 10.7% for DEASPI to 0.13% for CSPI under the same experimental conditions. The results show that the efficiency of two-photon pumped emission is related to the intramolecular charge transfer character of the chromophore. The two-photon pumped lasing efficiency increases both with decreasing BLA and with increasing intramolecular charge transfer character, measured by the parameter Δρ1,2.

We have synthesized two new organic salts, trans-4-[p-(N-hydroxyethyl-N-methylamino)styryl]-N-methylpyridinium toluene-p-sulfonate (abbreviated as HMASPS) and trans-4-[p-(N-hydroxyethyl-N-ethylamino)styryl]-N-methylpyridinium toluene-p-sulfonate (abbreviated as HEASPS). X-Ray diffraction analyses reveal that HMASPS crystal belongs to the P21/n space group, with water molecules co-crystallized in the crystal and forming the monohydrate with the formula of C17H21N2O+·C7H7O3S−·H2O, while HEASPS belongs to the Pspace group, with no solvent molecules. Pumped by a 1064 nm, 50 ps laser pulse at 2.02 mJ input energy, an up-conversion lasing of 0.169 mJ output energy can be obtained with 0.05 M HMASPS–DMF solution, and the output/input efficiency is 8.4%. A 0.05 M HEASPS–DMF solution exhibits a lasing efficiency of 9.1% with input and output energy of 1.90 mJ and 0.173 mJ respectively.

Nd:YVO 4 crystal has been grown by Czochralski method. The data of thermal expansion and specific heat have been measured. The thermal expansion coefficients along a- and c-axis are α 1 = 2.2 × 10 -6 /K, and α 3 = 8.4 × 10 -6 /K respectively. The specific heat is 24.6 cal/mol K at 330 K. The large anisotropy along c- and a-axis of thermal expansion coefficients is explained by the structure of YVO 4 crystal. 921 mW output laser at 1.06 μm has been obtained with a 3 mm × 3 mm × 1 mm crystal sample when pumped by 1840 mW cw laser diode, and the slope efficiency is 55.5%.

The title complex, C6H15N4O2+·C4H3O4−·2H2O, contains a planar ring formed by sharing one H atom between the O atoms in the carboxyl groups of the maleate anion. This hydrogen bond is slightly asymmetric. In the l-argininium(+) cation, both the α-amino and the guanidyl groups are protonated. The nonlinear optical response of the compound is derived from the intrinsic hyperpolarizabilities of the l-argininium cations, maleate anions and inter­molecular hydrogen bonds.

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.

The mol­ecule of the title compound, C36H28N2, adopts a propeller-like shape and possesses crystallographically imposed twofold rotation symmetry. The N atom has an almost ideal trigonal geometry, indicating that the lone electron pair is involved in conjugation with the system of aromatic rings.

The title polymeric compound, {[MnHg(SCN)4(H2O)]·C4H8O2S}n, consists of slightly distorted MnN4O2 octa­hedra and HgS4 tetra­hedra. Each MnII ion is bound to N atoms belonging to the thio­cyanate (SCN) groups and to two O atoms of adjacent water ligands. The sulfolane mol­ecule connects with the coordinated water mol­ecule through hydrogen bonding. Each HgII atom is coordinated by four SCN S atoms. The two adjacent MnII atoms and two O atoms of bridging water mol­ecules connect with one another and form a parallelogram. Each pair of MnII and HgII atoms is connected by an –SCN– bridge, forming an infinite three-dimensional structure.

In the title complex, (C22H24P)[Ni(C3S5)2] or (BuPh3P)[Ni(dmit)2] (where BuPh3P is the butyl­triphenyl­phospho­nium cation and dmit is the 2-thioxo-1,3-dithiole-4,5-dithiol­ate anion), each Ni atom is tetra­coordinated by four dmit S atoms, forming a nearly square-planar arrangement. The average Ni—S bond length is 2.16A, much smaller than 2.21A for the Ni2+ ion in [Ni(dmit)2]2−. The other bond distances are also shorter, close to the corresponding double-bond value. The [Ni(dmit)2]− anions and butyl­triphenyl­phospho­nium counter-cations form a layered arrangement in the crystal structure.