Hydrogen bonds and π–π stacking interaction in 4′, 7-dimethoxylisoflavone and 4′,7-diacetyl-O-isoflavone

4′,7-dimethoxylisoflavone, C₁₇H₁₄O₄, (I), is linked into a supramolecular structure by a variety of weak but direction-specific intermolecular forces, the molecules are linked into chains through C–H⋅sO hydrogen bonds, these chains are further linked by face-to-face (F-tape) π–π stacking into a one-dimensional bi-chain, another type π–π stacking, edge-to-face (T-tape), assemble the bi-chain into framework together with C–H⋅sO hydrogen bonds. 4′,7-diacetyl-O-isoflavone, C₁₉H₁₅O₆, (II), shows some discrepancies with I and the molecules are assembled into framework all by C–H⋅sO hydrogen bonds. The molecules are linked into centrosymmetric dimers built from classic R₂² (8) rings by pairs of C–H⋅sO hydrogen bonds, the dimers are linked into (011) sheets by combination of the R₂² (8) ring and C–H⋅sO hydrogen bonds, another C–H⋅sO hydrogen bond assemble the sheets into three-dimensional network.     

Structure of tetrazole steroid analogues,IV: Structure of 7a-aza-B-homocholest-5-eno [7a, 7-d]tetrazol-3β-yl-acetate (HS503)

The crystal and molecular structure of the steroidal tetrazole 7a-aza-B-homocholest-5-eno[7a,7-d]tetrazol-3-yl acetate (C₂₉H₄₆N₄O₂) has been determined by vector verification, and refined to a finalR of 0.087 for 3454 observed reflections. The compound crystallizes in space groupP2₁ with cell dimensionsa=7.352(3),b=25.950(8),c=15.408(6) Å,=91.22(3)°;Z=4,D _x=1.33 g cm^–3, (CuK)=4.87 cm^–1. The two independent molecules exhibit similar overall topography, ringsA, B, C, andD adopting chair, butterfly (Husainet al., 1981), sofa, and distorted envelope conformations respectively in both molecules.Steroids and Related Studies, Part 74.     

β-Zn3BPO7晶体的生长研究

采用泡生法生长β-Zn3BPO7(简称ZBP)晶体.用不同方向的籽晶进行晶体生长,分别得到了大尺寸的ZBP单晶.采取了适当措施有效地抑制了ZBP相变的发生,对生长得到的单晶进行X射线衍射分析,确定其为β-Zn3BPO7晶体.对得到的大尺寸单晶进行了形貌研究,并研究了ZBP晶体的生长习性.     

Zn3BPO7晶体的THz和红外吸收光谱

本文研究了Zn3BPO7(ZBP)晶体的THz时域光谱以及从中红外到远红外的吸收光谱,以及6.6 cm-1 (0.2 THz)～4000 cm-1宽频段的红外光谱光学性质.THz吸收光谱表明晶体在0.5～1.2 THz有较好的透射性质,在1.7 THz和2.5 THz分别存在一个泛频共振峰和基频共振峰,并且折射率稳定.在远红外区(100～2700 cm-1)晶体的透射率极小,几乎接近于零.在中红外波段(2700～4000 cm-1)晶体具有较好的透射性质.50～4000 cm-1波段的吸收规律表明ZBP晶体具有做成特定波段滤波器的潜力.     

Ga3PO7晶体的非弹性振动特性

采用拉曼散射技术,从声子角度研究了Ga3PO7晶体的非弹性振动特性,主要内容为:采用位置对称性法从理论上计算了晶体的晶格振动模式,判定了晶体共有27个拉曼活性模,其振动模式为Γ=7Al+10E,可看作由PO43-集团形成的晶体的内振动模和由PO43-集团、O和Ga原子形成的晶体的外振动模组成;通过室温拉曼光谱实验观测到了晶体的16个拉曼活性模,包括8个外振动模和6个内振动模,并对各模进行了指认,其中高波段的声子模主要为PO4四面体的内振动模.由于晶体结构缺陷和某些内、外振动模的耦合等原因,观测到的振动模数量明显少于理论预测值.     

Synthesis and crystal structure of 7-ethoxyl-4′-hydroxyisoflavone

7-Ethoxyl-4-hydroxyisoflavone was prepared and its crystal structure was examined by X-ray diffraction. Crystallization of the title compound occurs in the monoclinic, space group P2(1)/c with a = 11.144(2) Å, b = 10.209(1) Å, c = 13.191(2) Å, = 113.43(1) and Z = 4. The molecular structure of title compound consists of a benzopyranone moiety, a phenyl moiety, a hydroxyl and an ethoxyl group. The benzopyranone ring is not coplanar with the phenyl ring, the dihedral angle being 46.75. The ethoxyl group is nearly coplanar with its corresponding ring with the torsion angle 175.23(2). Three kinds of hydrogen bond and two kinds of aromatic stacking interaction link the title compounds into a three-dimensional networking structure.     

Te2HPO7晶体的非线性光学特性研究

采用水热法合成了一种具有非中心对称结构的已知化合物Te2HPO7,并用波长为1064 nm的激光测试了其粉末倍频效应,发现相同颗粒尺寸下其倍频效应近似为KH2PO4的0.27倍,并且满足相位匹配条件.偶极矩计算表明,该化合物倍频效应主要源于含有孤立电子的TeO4多面体非对称单元.另外,本文用高温差示扫描量热法研究了晶体的热稳定性,在紫外-可见-近红外分光光度计上测量了它的透过光谱.     

β-Zn3BPO7晶体的提拉法生长研究

采用提拉法生长β-Zn3BPO7(简称ZBP)晶体.研究了生长工艺,用[210]方向的籽晶,获得了尺寸为35mm×20mm×10mm的单晶,该晶体无色透明,不开裂,呈现发育完好的{001}板面.通过设计特殊的温场以及在生长结束后采用适当的热条件有效地抑制了相变的发生.生长过程中靠近液面的温度梯度为30～60℃/cm,晶体转速为15～25r/min,提拉速度不大于1mm/h.ZBP晶体有宽的透光范围,它的紫外吸收边为240nm.ZBP晶体不潮解,其莫氏硬度为5Mohs.     

Ga3PO7晶体结构及声表面波特性研究

本文采用第一性原理方法研究了磷酸三镓(Ga3PO7)晶体的几何结构和电子结构.计算了该晶体X,Y,Z切型传播角度为0～180°的声表面波速度,机电耦合系数和能流角.第一性原理研究表明该晶体具有较强的共价键结构特征,其带隙为3.646 eV,属于直接带隙材料.计算结果表明其声表面波速度范围为3620 ～3850m/s,与石英晶体相当,但其Y切型的机电耦合系数最高可达1.075;,是石英晶体的三倍.     

Li吸附对石墨烯、BC7、C7N电学性质影响的第一性原理研究

基于密度泛函理论(DFT)的第一性原理方法,对Li在本征石墨烯、BC7和C7N表面最稳定位置的吸附进行了结构优化,计算了本征石墨烯、BC7和C7N吸附Li前后的能带结构,态密度,电荷转移,差分电荷密度和结合能。结果表明,B掺杂浓度为12.5%(原子分数)时可显著提高石墨烯的Li吸附能,N掺杂浓度为12.5%(原子分数)时减弱了石墨烯的Li吸附能。吸附Li后的graphene-Li、BC7-Li和C7N-Li体系均显示出金属性,且Li与石墨烯、BC7和C7N体系间存在离子键和共价键的混合。     

GO/Tb4 O7复合材料的光催化性能研究

以氧化石墨烯(GO)和氧化铽(Tb4 O7)为原材料,采用水热法制备了GO/Tb4 O7复合粉体.通过SEM、XRD和分光光度计等手段对复合材料粉体进行了分析.用罗丹明B溶液作为模拟污染物,在光催化反应仪中采用紫外光照射不同时间后,利用分光光度计测试其光催化性能.实验结果表明:复合材料粉体中,氧化铽颗粒基本可以均匀的分布在GO表面;随着GO含量(6;,8;,10;)的增加,复合材料粉体和罗丹明B的反应速率逐渐加快;在60 min时三种复合材料粉体的降解率分别为98.40;、98.64;、98.94;.     

Li在石墨烯、BC7及C7N表面吸附与迁移的第一性原理研究

基于密度泛函理论的第一性原理方法,本文系统研究了Li在本征石墨烯及BC7、C7N表面的吸附和迁移行为。与本征石墨烯相比,硼含量为12.5at%时提高了Li的吸附能,而氮含量为12.5at%时减弱了Li的吸附能,这归因于掺杂物种具有不同的电子结构。通过NEB方法计算了Li在本征石墨烯、BC7、C7N表面的迁移。结果表明,相比于本征石墨烯,硼含量为12.5at%的石墨烯减弱了Li的扩散,而氮含量为12.5at%的石墨烯促进了Li的扩散,有助于提高石墨烯负极材料的充放电性能。     

三维(C2H7N4S)+·(C7H5O4)——超分子氢键网格的构筑

利用脒基硫脲和3,5-二羟基苯甲酸制备出了一种新型的加合物(C2H7N4S)+·(C7H5O4)-,用X射线单晶衍射试验方法测定其晶体结构.结果表明,晶体属单斜晶系,P21/n空间群,其中a=0.72303(1)nm,b=1.42970(3) nm,c=1.07991(2)nm,β=91.591(2)°,Z=4,R1=0.0303, wR=0.0823(I>2σ(I)).在标题化合物的晶体结构中,3,5-二羟基苯甲酸通过羧基和羟基的O-H…O氢键头尾相连形成了沿b轴无限延伸的"Z"型链,脒基硫脲通过氢键的缔合和静电相互作用连接3,5-二羟基苯甲酸的"Z"型链构成了3D超分子氢键网络结构.     

The crystal and molecule structure of three 2,4,6-trinitrobenzene derivatives:α,α,α-trifluoro-2,4,6-trinitrotoluene (C7H2F3N3O6), 2,4,6-trinitrobenzamide (C7H4N4O7), 2,4,6-trinitrobenzoic acid (C7H3N3O8)

The crystal and molecular structures of three 2,4,6-trinitrobenzene derivatives have been determined. Forα,α,α-trifluoro-2,4,6-trinitrotoluene (1): monoclinic,P2₁/n,a=7.510(2),b=9.273(2),c=14.984(0) Å,β=99.02(2)°,V=1028.1(4)° ų,Z=4,D=1.816 g cm^?3,R(F)=0.051, andR(wF)=0.055. For 2,4,6-trinitrobenzamide (2): orthorhombic,Pbca,a=9.248(3),b=14.377(6),c=17.729(4) Å,V=1958(1) ų,Z=8,D=1.737 g cm^?3,R(F)=0.073, andR(wF)=0.077. For 2,4,6-trinitrobenzoic acid (3): orthorhombic,P2₁2₁2₁,a=6.553(1),b=11.405(2),c=12.796(2) Å,V=956.3(3) ų,Z=4,D=1.785 g cm^?3,R(F)=0.045, andR(wF)=0.046.1 crystallizes as discrete molecules,2 as weakly hydrogen-bonded dimers and3 as a chiral polymer of hydrogen-bonded helices. In1, the presence of the nonplanar CF₃ substituent causes a large twisting of theα-nitro groups out of the plane of the benzene ring, whereas the nearly planar C(O)NH₂ and C(O)OH substituents in2 and3 are perpendicular to the benzene plane and do not cause a significant rotation of theα-nitro groups.