基于水合碳酸镁结晶过程的化学键分析

基于晶体学结构,将化学键理论定量地应用到水合碳酸镁Mg5(CO3)4(OH)2·4H2O和MgOgO3·3H2O的结晶行为研究中,以此指导和控制实际晶体的生长行为.根据所选晶面的化学键数目和强度,可以计算出该晶面的垂直生长速率,从而方便地预测出Mg5(CO3)4(OH)2·4H2O和MMgO3·3H2O晶体的理想形貌.Mg5(CO3)4(OH)2·4H2O晶体表现出六方片状的结晶习性,MgCO3·3H2O则具有六方柱的理想形貌.在实验中,六方片状的Mg5(CO3)4(OH)2-114心O和MgO3·3H2O六方柱可以通过简单的液相反应获得,证明我们的理论计算与实验结果完全相符.目前研究结果表明,单晶生长可以通过热力学意义上调整组成原子或离子的成键方式获得本质上的改进,这一过程为我们从动力学角度优化实验策略提供了更广阔的空间.     

Hydrogen-Bond Character of 2,2′-Bi-1H-Imidazole Systems

Abstract

The characters of hydrogen-bond of 2,2′-bi-1H-imidazole (H2BIM) system were examined from a viewpoint of the proton-transfer (PT) and electron-transfer (CT) interactions. To make the effects of the dibenzo substitution of H2BIM molecule clear, we prepared the charge-transfer complexes of dibenzo-2,2′-bi-1H-imidazole (H2BBIM) and H2BIM systems with 7,7,8,8- tetracyanoquinodimethane(TCNQ). The one-dimensional column of TCNQ was confirmed by the crystal structural analysis, however, the packing forms of the H2BIM and H2BBIM systems were entirely different to each other. The H2BBIM system in the TCNQ complex formed the one-dimensional column which is parallel to the TCNQ stack, while the H2BIM system was constructed by the hydrogen-bonded dimer unit along the perpendicular direction to the TCNQ column.     

UV-vis辐照下H2Fe2Ti3O10/TiO2插层材料光催化活性的研究

在高压汞灯辐照下,通过插入反应将H2Fe2Ti3O10与n-C3H7NH2/C2H5OH和TiO2溶胶制备出H2Fe2Ti3O10/TiO2插层复合物.插入TiO2的层状钙钛矿化合物H2Fe2Ti3O10在UV-vis辐照下表现出高活性.实验结果表明H2Fe2Ti3O10/TiO2作为光催化剂在可见光(λ＞420nm)下辐照24h,降解甲基橙的速率为59.0;.与相同条件下降解率只有24;的商用光催化剂TiO2(Degussa P-25)相比,H2Fe2Ti3O10/TiO2表现出了更高的光催化活性.     

[Co(H2O)6](C18H15O4SO3)2·4H2O的合成和晶体结构

以芒柄花素为先导化合物,合成了水溶性的[Co(H2O)6](C18H15O4SO3)2·4H2O,并采用IR, 1H NMR, TG-DTA, XRD和单晶X射线衍射法对其结构进行了表征.单晶X射线衍射结果表明:[Co(H2O)6]2+、C18H15O4SO 3和H2O之间存在多种氢键,形成晶体结构中的亲水区.异黄酮骨架间反平行排列,面对面和边对面芳香堆积作用同时存在于其中,构成晶体结构中的疏水区.磺酸根是连接亲水区和疏水区的桥梁.氢键、芳香堆积作用以及阴阳离子之间的静电引力共同将标题化合物组装成具有三维网络结构的超分子.     

单一基质白光荧光粉Sr3Bi1-x（PO4）3∶Dy3+的制备与发光性能研究

本文采用高温固相法合成了Sr3Bi1-x(PO4)3∶xDy3+荧光粉。XRD图谱表明合成物质为纯相Sr3Bi(PO4)3晶体结构。主激发峰位于323 nm,348 nm,362 nm,385 nm,423 nm,451 nm和471 nm,分别对应Dy3+的6H15/2到4L19/2,6P7/2,6P5/2,4I13/2,4G11/2,4I15/2,4F9/2的跃迁。主发射峰位于482 nm(4F9/2→6H15/2),575 nm(4F9/2→6H13/2),分别对应于黄光和蓝光发射,其中以348 nm激发得到的峰值最强。研究了不同Dy3+掺杂浓度对发光性能的影响。随着Dy3+浓度的增大,样品的发光强度先增大后减小。当掺杂浓度x=0.08时,发光强度最好。并测试了样品的色坐标,为x=0.33,y=0.35,属于白光区域。     

Syntheses,Crystal Structures and Fluorescence Properties of Three Complexes Based on 2,2'-Quinoline-4,4'-dicarboxylic Ligands

Crystallography Reports - Three new coordination complexes, [Mn(L)(H2O)4⋅(H2O)3]2 (1), [Mg(L)(H2O)4⋅(H2O)3]2 (2), and [Cu(L)(phen)⋅(H2O)4]2 (3) (H2L =...     

不同晶相WO3的热分解法制备及其光催化性能

以钨酸铵为钨源,硝酸为沉淀剂,首先通过沉淀法制备前驱体H2 WO4,随后采用热分解H2 WO4法合成六方及单斜晶相WO3催化剂.利用X射线衍射(XRD)、拉曼光谱、差热-热重(TG-DTA)、扫描电子显微镜(SEM)、X射线光电子能谱(XPS)及紫外-可见漫反射光谱(UV-Vis DRS)对H2 WO4向WO3转变过程中结构、形貌、组成及光学性质的变化进行研究.结果表明,热处理后前驱体发生如下相变过程:H2 WO4→六方相WO3→六方/单斜相WO3→单斜相WO3.此外,以罗丹明B为模拟污染物,考察不同晶相WO3的光催化活性,结果表明,六方相WO3具有更高的光催化性能,单斜相WO3的活性较低.     

Synthesis,Crystal Structure,and DNA Binding Studies of the 3-(2-(2-Hydroxybenzylidene)Hydrazinyl)Quinoxalin-2(1H)-One

Crystallography Reports - The Schiff base, 3-(2-(2-hydroxybenzylidene)hydrazinyl)quinoxalin-2(1H)-one has been synthesized by condensation of 3-hydrazinyl quinoxalin-2(1H)-one and salicylaldehyde...     

Study of the Fracture Toughness of K2NixCo(1 – x)(SO4)2 · 6H2O Crystals in Dependence of the Growth Direction and Rate

Crystallography Reports - K2Ni(SO4)2 · 6H2O (KNSH), K2Co(SO4)2 · 6H2O (KCSH), and K2NixCo(1 – x)(SO4)2 · 6H2O (KCNSH) crystals have been grown by traditional...     

Synthesis and Structural Characterization of a Di-nuclear Uranyl Complex with Quinoline-6-carboxylate

Crystallography Reports - A di-nuclear uranyl complex with the formula of [(UO2)2(L)4(H2O)2]?4H2O (1) (HL = quinoline-6-carboxylic acid) was synthesized hydrothermally and characterized by...     

Synthesis and Structure of Uranyl Succinate Complexes with Cyanoguanidine and Diethylacetamide

Crystallography Reports - [UO2(suc)(C2N4H4)2] · 2H2O (I) and [UO2(Deaa)4(H2О)][(UO2)2(C4H4O4)3] · 2Deaa (II) crystals (suc2– is succinate ion, C2N4H4 is cyanoguanidine, and...     

热丝CVD法制备a-Si1-xCx薄膜的光电性能研究

本文以硅烷、乙炔和氢气为气源,采用热丝CVD法制备了非晶碳化硅薄膜.通过FITR、紫外-可见光分光光度计、四探针仪、台阶仪和霍尔效应测试仪对薄膜的光学和电学性能进行了系统的研究.结果表明,随着乙炔气体流量的增加,薄膜中碳含量和薄膜光学带隙呈现逐渐递增的趋势,其中光学带隙由1.7 eV上升到2.1 eV.同时还发现B掺杂薄膜的空穴浓度随着B2H6与硅烷流量比的增大而显著增大,而霍尔迁移率的变化趋势则与空穴浓度的变化趋势相反,与二者对应的总体效果是薄膜的电阻率首先显著下降,然后缓慢下降至最小值1.94Ω·cm,此后电阻率略有上升.     

[Co(dmg)2Cl2]3·[Co(dmg)2Cl(OH)]·[Co(dmg)(phen)]·(H2O)4的合成和晶体结构

本文合成了一个复杂的单核配合物 [Co(H2dmg)2Cl2]3·[Co(H2dmg)2Cl(OH)]·[Co(Hdmg)(phen)]·(H2O)4 (H2dmg＝dimethylglyoxime, phen＝1,10-Phenanthroline).通过X射线衍射技术获得其单晶结构.在单晶结构中,每五个单核钴(II)的配位结构形成一个重复单元,是一个较为复杂的单晶.其空间群为P-1,晶胞参数为a＝1.3738nm;b＝1.4396nm;c＝1.8656nm.本文中我们将讨论该化合物的分子结构及相关光谱性质.     

Hydrothermal Synthesis,Characterization, and Property of a Thulium Dinuclear Complex Based on Sulfonate-Phenol Ligand and 1,10-Phenanthroline

Crystallography Reports - A new lanthanide metal complex [Tm2(H2L)3(phen)2] (1) (Na2H2L = 4,5-dihydroxy-1,3-benzenedisulfonic acid disodium salt, phen = 1,10-phenanthroline) was synthesized by...     

气体介质对电弧离子镀沉积类金刚石膜的影响

采用电弧离子镀方法,在Si(100)基底上分别在高纯Ar、高纯H2和C2H2的气氛下沉积类金刚石膜,利用激光Raman谱和X射线光电子能谱(XPS)对沉积膜的结构进行了分析.结果表明与在高纯H2和C2H2气氛下相比,在高纯Ar中沉积类金刚石膜Raman谱的ID/IG值最小,膜中sp3C含量最高为35.55;.纳米压痕仪测量结果表明不同气氛下沉积膜的硬度和弹性模量分别在16.7～34.8GPa和143.2～236.9GPa之间变化.在高纯Ar气氛下沉积膜的硬度和弹性模量最大分别为34.8GPa和236.9GPa.     

[Gd(BMBCP)(H2O)4][PMo12O40]·2.75H2O配位聚合物的合成及表征

以-Keggin型多金属氧酸盐[PMo12O40]3-作为模板,采用水热法成功合成一例新型二维Gd(Ⅲ)配位聚合物[Gd(BMBCP)(H2O)4][PMo12O40]·2.75H2O (HNU-13) (H2BMBCP·Cl2=1,4-双(3-羧酸吡啶基-1-亚甲基)苯二氯).通过单晶X-射线衍射仪确定其结构,并通过X-射线粉末衍射 (PXRD),傅里叶红外光谱 (IR)和热重分析仪(TG)对其进行表征.结果表明,化合物结构结晶于单斜晶系,P2(1)/n空间群,晶胞参数为a =1.4291 nm ,b=1.3772 nm,c=2.8430 nm,α=90.00°,β =91.154°, γ=90.00°,Z =4.值得注意的是,由于[PMo12O40]3-与H2BMBCP·Cl2配体的静电作用,从而形成左右手螺旋链,进一步的构筑为层状4,4-网格结构.     

Mechanism of the 2H → 6H solid state transformation in SiC

Single crystals of 2H SiC transform directly into the 6H (ABCACB) structure when the transformation nucleates at temperatures above 2000°C. The 2H close-packed structure may be transformed to the 6H structure by displacing every third layer. The theory of X-ray diffraction from one-dimensionally disordered crystals undergoing the 2H to 6H structural transformation by such a layer displacement mechanism has been developed. The fact that all the observed solid state transformations in SiC crystals commence with the random insertion of stacking faults and then proceed further to create a statistically ordered structure, permits such a theory to be developed. Exact expressions for the diffracted intensity from such crystals have been obtained and the different diffraction effects observable on single crystal X-ray photographs predicted. A comparison of the theoretically predicted diffraction effects with those visible on the X-ray photographs of SiC crystals undergoing the 2H to 6H transformation shows that the structural transformations in SiC occur by the layer displacement mechanism.     

Synthesis and Crystal Structure of a 3D Cd(II) Coordination Polymer Assembled with Itaconate and 1,2-Bis(4-pyridyl)ethane

Crystallography Reports - The three-dimensional cadmium coordination polymer {[Cd4(H2O)2(ita)4(bpe)6]⋅(H2O)26}n (1) (ita = itaconate; bpe = 1,2-bis(4-pyridyl)ethane) was obtained by...     

溶胶-凝胶法制备Zn3Ga2Ge2O10:Cr3+0.01,Pr3+0.03,Yb3+0.3纳米长余辉材料及其表面修饰的研究

以Ga(NO3)3·8H2O、Zn(NO3)2·6H2O、Pr(NO3)2·6H2O、GeO2、Yb(NO3)3·5H2O、Cr(NO3)2·9H2O为原料,采用溶胶-凝胶法合成了Cr3+,Pr3+,Yb3+共掺杂的Zn3Ga2Ge2O10长余辉纳米材料(PLNPs).利用XRD,SEM,激发发射图谱,余辉曲线测试确定1000℃煅烧,保温3 h时,基质Zn3 Ga2 Ge2 O10已形成.Yb3+掺杂百分比为0.3时,样品的发光性能最好.Zn3 Ga2 Ge2 O10:Cr3+0.01,Pr3+0.03,Yb3+0.3纳米长余辉材料在波长为267 nm的紫外线激发下发射出中心波长为745 nm的深樱桃红色光,此时晶粒粒径约为150 nm;随着Yb3+掺杂百分比的增加,晶粒粒径逐渐变小.通过FT-IR,Zeta电势,激光粒度测试,TEM及悬浮实验测试表明,PEG修饰PLNPs后,可观察到明显的核壳结构,水合粒径约为155 nm;水溶性大大增加,0.3 mg/mL的浓度下其悬浮时间超过48 h,这表明PEG包裹PLNPs成功.     

氨水浓度对化学浴沉积的Zn(O,S)薄膜形貌、结构和性能的影响

采用化学浴法,以ZnSO4·7H2O和SC( NH2)2作为反应前驱物,C6H5O7 Na3·2H2O作为络合剂,NH3·H2O 作为辅助络合剂和缓冲剂制备Zn(O,S)薄膜.采用SEM、EDS、XPS、XRD和透射光谱分析方法,研究氨水浓度对化学浴法制备的Zn(O,S)薄膜形貌、成分、结构和光学性能的影响以及Zn(O,S)薄膜的形成机理.结果表明:Zn(O,S)薄膜是由ZnO和ZnS纳米颗粒混合组成的,ZnO具有纤锌矿结构,ZnS是以非晶相存在.随着反应溶液中氨水浓度的降低,薄膜中所包含的ZnO逐渐减少,ZnS逐渐增加,S/Zn原子比逐渐增加,透射率和光学带隙也逐渐增大.