X-ray crystal structure of bis(4-nitropyrazol-1-yl)methane,and some empirical rules concerning the bond angles in pyrazoles

The crystal structure of bis(4-nitropyrazol-1-yl)methane has been determined by X-ray diffraction. The nitro groups form angles of 16.45(6) and 11.83(7)°, respectively, with the pyrazole ring to which they are attached. The internal and external angles of the pyrazole rings follow a set of empirical rules: (1) N(1)-N(2)-C(3) is smaller than N(2)-N(1)-C(5); (2) N(2)-C(3)-C(4) is larger than N(1)-N(2)-C(3) and at least one chosen between C(3)-C(4)-C(5) and C(4)-C(5)-N(1); (3) C3-C4-C5 is not the largest internal angle; (4) R1-N1-N2 is smaller than R1-N1-C5; (5) N2-C3-R3 is smaller than R3-C3-C4, or R5-C5-N1 is smaller than C4-C5-R5; (6) C3-C4-R4 and R4-C4-C5 are nearly the same. Provided that the angle considered is not part of another ring, the first five rules are valid for all the pyrazoles investigated up to now, while violation of the last rule is good evidence for steric hindrance or marked asymmetry of the 3- and 5-substituents.     

Synthesis and mesomorphic properties of 2,4-bis(4′-n-pentyloxybenzoyloxy)- benzylidine-4″- n-alkoxyaniline

The synthesis and mesomorphic properties of a new series of 2,4-bis(4′-npentyloxybenzoyloxy)- benzylidine-4″ -n-alkoxyaniline (DC5An) are reported. The molecular structure of compounds was confirmed by FTIR, ¹H-NMR, ¹³C-NMR, mass spectroscopy and elemental analysis. The mesomorphic properties were studied by differential scanning calorimetry (DSC) and polarizing optical microscopy (POM) measurements. All compounds of the series exhibit nematic (N) and smectic C (SmC) phases. The first four homologues (DC5A1-DC5A4) display a N mesophase, whereas the highest homologues (DC5A5-DC5A10) exhibit an enantiotropic dimorphism N and SmC phases. The mesomorphic properties of the present series are compared and discussed with other structurally related series.     

燃烧法制备掺杂Y改性LaMgB5O10粉体及表征

以水合硝酸镧(La(NO3)3·nH2O)、六水硝酸镁(Mg(NO3)2·6H2O)为氧化剂,甘氨酸(C2H5NO2)为还原剂,掺杂氧化钇(Y2O3)粉体,通过燃烧法合成掺杂Y改性的硼酸镁镧(LaMgB5O10)粉体.研究了Y的掺杂量、焙烧温度和时间等工艺参数对合成Y改性LaMgB5O10的影响.通过X射线粉末衍射(XRD)、扫描电子显微镜(SEM)、荧光光谱(PL)、紫外-可见漫反射光谱(UV-Vis DRS)等手段对产物进行表征.结果表明,当Y的掺杂量为5;,焙烧温度900 ℃,焙烧时间5 h时,Y改性LaMgB5O10效果最佳.Y改性LaMgB5O10在212~317 nm处出现了很强的紫外吸收峰;在280~355 nm和368~435 nm处有很强的发射宽峰.     

晶核剂P2O5对CaO-Al2O3-SiO2系黄磷炉渣微晶玻璃析晶的影响

采用熔融法以自然冷却黄磷炉渣为主要原料,P2O5为晶核剂,制备了黄磷炉渣微晶玻璃.利用X射线衍射仪(XRD)、差热分析(DTA)和扫描电子显微镜(SEM)等分析技术手段,探究了晶核剂P2O5(以KH2PO4的形式引入)对黄磷炉渣微晶玻璃晶化行为及物化性能的影响规律.结果表明:黄磷炉渣基础玻璃的析晶峰温度Tp及析晶活化能E随着P2O5晶核剂的增加呈现先减小后增大的趋势;当晶核剂P2O5加入量达到4wt;时,黄磷炉渣基础玻璃的析晶峰温度Tp及析晶活化能E最小,析晶效果最优,物化性能最优;主晶相硅灰石(CaSiO3)并不随着晶核剂P2O5加入量的增大而发生改变,同时能够促进晶相氟磷灰石(Ca5(PQ)3F)生成.     

Structure of substituted 2-(phenoxy)benzimidazoles

The synthesis and X-ray diffraction study of 1-benzyl-2-[2-(5-ethyltetrazole-2-yl)-phenoxy]-1H-benzimidazole and 1-benzyl-2-[2-(5-ethyltetrazole-2-yl)-4-nitrophenoxy]-1H-benzimidazole single crystals have been performed. The oxidative splitting of an azo-hydrazone group of 1-(2-hydroxy-(5-nitro)phenyl)-3-ethyl-5-(benzylbenzimidazolyl)formazans, a break in the C2-N1 bond, the interaction of o-hydroxyl group of aryl fragment with oxygen, and the formation of new 2-(phenoxy)benzimidazoles are found to occur in the presence of perchlorate iron(III).     

Synthesis and Characterization of 5′-Hexyl-2,2′-bithiophene Based on Organic Dyes for Dye-Sensitized Solar Cell Applications

A series of new organic dyes, 2-(2,6-bis((E)-2-(5′-hexyl-2,2′-bithiophen-5-yl)vinyl)-pyran-4-ylidene)-2-cyanoacetic acid (OD-1) and 2,2′-(2-((E)-2-(5′-hexyl-2,2′-bithiophen-5-yl)vinyl)-1H-indene-1,3(2H)-diylidene)bis(2-cyanoacetic acid) (OD-2), were synthesized as a sensitizers for the application of dye-sensitized solar cells (DSSCs). The introduction of the 5′-hexyl-2,2′-bithiophene units as an electron donor group and 2,6-dimethyl-pyran-4-one or 1,3-indandione as a π-spacers units increased the conjugation length of the sensitizers and thus improved their molar absorption coefficient and light harvesting efficiency.     

Asymmetric base pairing in the complex 5-fluorocytosinium chloride/5-fluorocytosine monohydrate

The structure of the complex 5-Fluorocytosinium chloride/5-Fluorocytosine monohydrate has been studied by X-ray diffraction methods. It crystallizes in the monoclinic system, space group P 2₁ /n, a = 7.1257 (15), b = 8.351 (3), c = 21.520 (4) ?, β = 92.89 (8)°, V = 1279.0 (6) ?³, Z = 4. The structure consists of triple hydrogen-bonded 5-Fluorocytosine pairs, water molecules and chloride anions. Asymmetric reversed Watson-Crick base pairing occurs between one protonated (5FcytH⁺) and one neutral 5-Fluorocytosine (5Fcyt) molecule.     

(Nb2O5)1-x(TiO2)x陶瓷的制备及其介电性能的研究

我们采用传统固态反应方法烧结制备(Nb2O5)1-x(TiO2)x陶瓷,给出了掺杂量x从0.01到0.13陶瓷的介电性能.在本工艺条件下,所有样品的介电系数均大于120.当样品中TiO2的掺杂量为5mol;时,陶瓷的介电性能最佳:介电系数和损耗分别为217和0.078.XRD测试实验给出,当x≤0.05时,陶瓷的主要相结构为Nb2O5;当x≥0.07时,主相为TiNb24O62.     

Supramolecular structure of 5-methyl-5-phenyl hydantoin and hydrogen-bonding patterns in 5,5′-substituted hydantoins

The crystal structure of heterocyclic compound 5-methyl-5-phenyl hydantoin has been determined from X-ray single crystal structural characterization. This material crystallizes in the orthorhombic system and noncentrosymmetric space group P21 (N°4). The crystal packing is governed by N–H···O hydrogen bond-type intermolecular interactions, forming chains and edge-fused 12-membered rings with graph-set C(4) C(5) C22(8) R33(12) in a similar hydrogen-bonding pattern of another chiral 5,5′-substituted hydantoins.     

The Crystal and Molecular Structure of Mesogenic Malonates (II)

The crystal and molecular structures of three diethyl-2-{n-[4-(4-nitrophenylazo)-phenoxy]alkyl}malonate with n = 5 (5 PhNO₂), 7 (7PhNO₂), 9 (9 PhNO₂) and an analogous diethyl-2-[4(4-cyanophenylazo)phenoxy]pentylmalonate (5 PhCN) have been determined with CuK_a or MoK_a: 5 PhNO₂: a = 8.007(6) Å, b = 11.960(8) Å, c = 13.516(9) Å, α = 77.10(6)°, β = 81.80(5)°, γ = 83.15(5)°; R = 0.053; 7PhNO₂: a = 8.074(4) Å, b = 11.592(5) Å, c = 14.422(7) Å, α = 87.43(3)°, β = 82.46(3)°, γ = 85.43(3)°; R = 0.072; 9 PhNO₂: a = 5.520(5) Å, b = 13.628(9) Å, c = 20.220(11) Å, α = 100.02(4)°, β = 95.49(4)°, γ = 101.02(4)°; R = 0.042; 5 PhCN: a = 8.018(6) Å, b = 11.960(8) Å, c = 13.566(7) Å, α = 77.82(5)°, β = 81.89(5)°, γ = 82.69(5)°; R = 0.067 (isotropically refined). All these structures belong to the triclinic space groups P1 . The arrangements of the molecules in the crystal of the homologous series of nPhNO₂ suggest two different types of packing independent of n even, odd or large, small. 5 PhCN represents an isomorphous structure to 5 PhNO₂. Isomophism between 7 PhNO₂ and 7 PhCN was confirmed by cocrystallization of these two compounds whose crystal structure was also determined.     

X-ray diffraction studies of 5-functionalized substituted 1,2,3,4-tetrahydropyrimidin-2-ones(thiones): I. Molecular structures of 5-acetyl-4-ethyl-6-methyl-1,2,3,4-tetrahydropyrimidine-2-thione, 5-acetyl-6-methyl-4-(4-methylphenyl)-1,2,3,4-tetrahydropyrimidine-2-thione, and 5-acetyl-4-(4-methoxyphenyl)-6-methyl-1,2,3,4-tetrahydropyrimidin-2-one

The structures of three 5-acetyl-1,2,3,4-tetrahydropyrimidin-2-ones(thiones), namely, 5-acetyl-4-ethyl-6-methyl-1,2,3,4-tetrahydropyrimidine-2-thione, 5-acetyl-6-methyl-4-(4-methylphenyl)-1,2,3,4-tetrahy-dropyrimidine-2-thione, and 5-acetyl-4-(4-methoxyphenyl)-6-methyl-1,2,3,4-tetrahydropyrimidin-2-one, which are potential medicinals, are studied by X-ray diffraction. The conformational features of the molecules studied are analyzed. For these compounds, the dependence of the conformation of the tetrahydropyrimidine ring on the orientation of the substituent at the C(4) atom with respect to the heterocycle is found.     

Synthesis and crystal structure of a binuclear maleatocopper(II) complex with phenanthroline

The title copper(II) complex [Cu₂(C₄H₂O₄)₂(phen)₂]⋅4H₂O (phen = 1,10-phenanthroline) was prepared and its crystal structure was determined by X-ray diffraction method. The crystal belongs to space group C2/c with cell of a = 18.136(5), b = 12.505(5), and c = 14.617(5) Å, β = 103.440(5)^∘ and Z = 4. The Cu(II) atom assumes a square pyramidal coordination geometry with a longer Cu–O3 coordination distance [2.308(3) Å] in the apical direction. The carboxyl O3 atoms from two maleate dianion bridges two Cu(II) atoms to form the binuclear complex with a shorter Cu⋅sCu separation of 3.349(1) Å. The separations of 3.39(1) and 3.41(1) Å between parallel phen rings indicate the existence of aromatic stacking.     

Growth of high-quality ZnO single crystals by seeded CVT using the newly designed ampoule

The high-quality ZnO single crystals were grown by seeded chemical vapor transport (CVT) in a newly designed ampoule using carbon as a transport agent. The well-faceted crystal of about 5×5×5 mm³ can be grown reproducibly. Secondary ion mass spectroscopy (SIMS) analysis, X-ray rocking curve (XRC) and photoluminescence (PL) measurements demonstrate that the grown single crystal is of high purity and high crystallinity.     

Co2+,Er3+:Y3Al5O12晶体的生长及其吸收特性

应用中频感应提拉法成功生长出新型的Co2+,Er3+:Y3Al5O12晶体.研究了室温下晶体的吸收光谱性能.结合Er3+:Y3Al5O12晶体的光谱,并利用调Q判据对Co2+,Er3+:Y3Al5O12晶体调Q特性进行了简单的分析.结果表明Co2+,Er3+:YAG晶体是一种很有潜力的自调Q激光晶体.     

The Crystal Structure of a RAS (N–CH3-2-NH2-5-Cl–Py)(TCNQ)(CH3CN) Solvate

Crystallography Reports - The structure of the radical anion salt (RAS) of 7,7,8,8-tetracyanedimethane (TCNQ) with a cation based on 2-amin-5-chloro-pyridine (2-NH2-5-Cl–Py, Am), that is,...     

Palladium(II) and platinum(II) tetrakisthiourea dichloride bis(7-hydroxy-5-methyl[1,2,4]triazolo[1,5a]pyrimidine) dihydrate solvates

The title compounds palladium(II) and platinum(II) tetrakisthiourea dichloride bis(7-hydroxy-5-methyl[1,2,4]triazolo[1,5a]pyrimidine (Hmtpo)) dihydrate solvates, have been synthesized by reacting thecis-[MCl₂(Hmtpo)₂] (where M=Pt(II), Pd(II)) complexes with an excess of thiourea (tu) and the structure of the palladium compound was solved by X-ray diffraction. Crystals of [Pd(tu)₄]Cl₂·2Hmtpo·2H₂O are triclinic with space groupP and unit cell dimensionsa=7.972(1),b=9.049(1),c=11.808(2)Å, =88.20(1), =75.15(1), =76.54(1)^o. The cation [Pd(tu)₄]²⁺ is centrosymmetric involving four sulfur thiourea atoms in a near square planar environment. The triazolopyrimidine molecules, chloride anions and water molecules do not take part in the metal center coordination but interact by hydrogen bonding between them and the thiourea moieties. A comparison between powder diffraction data of palladium(II) and platinum(II) compounds clearly indicates that both compounds are isomorphous.     

硼磷酸盐晶体BaBPO5的非线性光学系数研究

用Maker条纹方法测量了硼磷酸盐晶体BaBPO5的非线性光学系数d11(BaBPO5)=(0.439±O.002)d36(KH2PO4),d12(BaBPO5)=(0.425±0.008)d36(KH2PO4),相应的相干长度为:l11=16.985±0.301μm,l12=16.972±0.304μm.确定了非线性光学系数的相对符号,d11(BaBPO5)和d12(BaBPO5)符号相反.BaBPO5晶体激光损伤阈值大于900 MW/cm2.     

Crystal and molecular structure ofS-methyl(pentafluorosulfanyl)thiocarbamate

The X-ray structure of S-methyl(pentafluorosulfanyl)thiocarbamate, SF₅NHC(O)SCH₃, has been determined from three-dimensional diffractometer data and refined by full-matrix least-squares techniques. The crystals are monoclinic:P2₁/m,a=5.008 (5),b=7.811 (2),c=9.348 (4) Å, =99.08 (7)°, andZ=2; finalR=0.046 for 517 observed reflections. The structure comprises hydrogen-bonded (NHO) chains with the component monomers in thecis, cis-conformation, i.e., the arrangement of the nonhydrogen and nonfluorine atoms is nearly planar, the SF₅ group and the O are in acis position with respect to the C-NH bond, and the O and the CH₃ group are in acis position with respect to the C(O)-S bond. Theoretical methods including MNDO and molecular modeling were used to study the relative stabilities of the four possible conformations of SF₅NHC(O)SCH₃.     

Nb2O5/Co2O3加入量对(Ba,Sr)TiO3基电容器陶瓷介电性能的影响

研究了Nb2O5/Co2O3加入量[质量分数,Nb/Co(摩尔比)=0.8]不同对(Ba,Sr)TiO3(Barium strontiumtitanate,BST)铁电电容器陶瓷介电性能的影响,得到不同Nb2O5/Co2O3加入量与BST陶瓷性能的关系。借助扫描电镜(SEM)和X射线衍射仪(XRD)研究不同Nb2O5/Co2O3加入量对BST陶瓷显微结构和物相的影响,探讨了Nb2O5/Co2O3加入量对BST陶瓷性能影响机理。结果表明:当Nb2O5/Co2O3加入量为1.0%时,可得到满足Y5V特性、介电常数为3934、介质损耗为2.6%综合性能好的BST陶瓷。Nb2O5/Co2O3加入量对BST陶瓷性能的影响是通过细晶化、压抑展宽居里峰、改善介电常数温度特性、减少介电常数、形成杂相、形成“晶核-晶壳”结构等进行。     

Molecular structure of [(C<Subscript>5</Subscript>H<Subscript>5</Subscript>)<Subscript>2</Subscript>(C<Subscript>5</Subscript>H<Subscript>4</Subscript>CH<Subscript>3</Subscript>)(C<Subscript>4</Subscript>H<Subscript>8</Subscript>O)Sm]

The mixed tris-cyclopentadienyl tetrahydrofuranato samarium complex bis-(cyclopentadienyl) methylcyclopentadienyl tetrahydrofuranato samarium (I) was synthesized by reaction of (C₅H₅)₂SmCl with methyl cyclopentadienyl sodium in THF. [(C₅H₅)₂(C₅H₄CH₃)(C₄H₈O)Sm] (I) was characterized by elemental analyses—IR spectra and MS spectra. The structure of [(C₅H₅)₂(C₅H₄CH₃)(C₄H₈O)Sm] (I), which has two slightly different independent molecules per asymmetric unit, has been elucidated through complete X-ray analysis. The crystals are monoclinic, with a = 12.791(3) Å, b = 10.467(2) Å, c = 26.108(5) Å, β = 98.22(2)°, and space group Cc, R = 0.0381 for 2103 observed-reflection with I ≥ 3σ(I).