三维超分子化合物[H_2(C_4H_(10)N_2)](SO_4)(H_2O)的制备、晶体结构及差热-热重性质研究

用MnSO4H2O和哌嗪在水-甲醇混合溶剂中反应得到了1个超分子化合物[H2(C4H10N2)](SO4)(H2O) (C4H14N2O5S)。 该晶体属单斜晶系, 空间群为P21/n, 晶胞参数为: a = 6.386(1), b = 11.695(2), c = 11.680(2) ? = 101.06(3), V = 856.1(3) 3, Z = 4, Mr =202.23 , Dc = 1.569 g/cm3, F(000) = 432, ?= 0.368 mm-1。 该化合物是由[H2(C4H10N2)]2+、SO42-、H2O通过氢键自组装而形成的。 其中[H2(C4H10N2)]2+存在2种椅式构象:一种[H2(C4H10N2)]2+与4个SO42-、2个H2O通过氢键相连, 另一种[H2(C4H10N2)]2+则与6个SO42-相连。 它们分别沿着b、c方向交替排列展开, 通过SO42-桥联成二维的层状结构;层与层之间在NH…O、CH…O、OH…O氢键的作用下互相连接, 形成了具有网状结构的三维超分子化合物。 差热及热重测试表明:该化合物从92℃开始分解,首先失去1个H2O, 然后再失去[H2(C4H10N2)]2+和SO4 2-。     

热重-差示扫描量热法研究金属铝盐与载体的相互作用

通过浸渍法将相同负载量的不同类型的金属铝盐负载在介孔分子筛HMS内外表面,用热重-差示扫描量热(TG-DSC)法研究了金属铝盐热性质的变化。将负载型金属铝盐干燥、焙烧,得到负载型催化剂Al2O3/HMS样品,用X射线衍射(XRD)、N2吸附-脱附等手段对样品进行了介孔结构表征,并初步考察了催化剂上烷基化反应的活性。实验结果表明:负载金属盐的起始分解温度均高于金属盐,证明了金属盐与载体之间有相互作用。Al2O3/HMS催化剂在对苯二酚烷基化反应中表现出不同的催化活性。这种催化活性的高低与催化剂比表面积、孔容的大小没有相应的顺变关系,与负载金属盐与载体的相互作用有关,相互作用越弱,催化剂在烷基化反应中表现出的催化活性越高。     

石墨烯氧化过程中的热分析-质谱以及脉冲热分析方法研究

本文由氧化石墨烯通过水热法制备直接获得石墨烯。采用热重-差热分析方法检测了石墨烯受热过程中的质量变化和氧化温度。利用热分析-质谱联用技术在400-650 ℃温度区间得到了水和二氧化碳正离子质谱峰,这说明石墨烯氧化过程中的质量损失是由羟基水和二氧化碳脱除造成的。同时,还采用非等温热分析动力学方法,利用5、10、15 ℃·min^-1三种不同升温速率获得了石墨烯材料在空气气氛下的热分析动力学参数。通过Kissinger方法计算出石墨烯氧化过程中的活化能（E_a）和指前因子的对数（lg（A/s^-1））分别为155.11 kJ·mol^-1和6.90。利用Ozawa-Flynn-Wall （FWO）方法还建立了活化能和指前因子与反应转化率之间的关系。基于以上研究结果,本工作将对石墨烯在热界面、导热和先进复合材料等领域的应用提供参考价值。     

N-(1-萘基)-琥珀酰亚胺化合物晶体结构的理论预测

用Materials Studio软件对N-(1-萘基)-琥珀酰亚胺多晶粉末的X射线衍射数据进行衍射峰指标化、晶胞参数优化和空间群搜索等理论计算, 可以确定晶体结构所属的晶系和空间群, 并初步给出和多晶粉末衍射数据相近的晶胞参数; 在已确定空间群范围内, 以密度泛函理论计算得到的最低能量构象作为初始分子结构, 对N-(1-萘基)-琥珀酰亚胺多晶进行晶体结构理论预测, 给出一系列假定的晶胞参数, 从中可以找到和经上述计算给出的晶胞参数一致的晶体结构；对其进行晶胞参数优化后, 得到晶体结构具有和多晶粉末X射线衍射数据相近的衍射曲线, 并与已有的单晶数据相吻合.     

柄型金属有机化合物(Ⅰ)──硅桥联二(1-茚基)和四氢茚基钛化合物的合成及结构

通过1,3-二(1-茚基)四甲基二硅氧烷的双锂盐与TiCl₄·2THF反应制得硅桥联二(1-茚基)钛化合物(Me₂SiOSiMe₂)[Ind]₂TiCl₂(1),对其催化氢化得到相应的四氢茚基化合物(Me₂SiOSiMe₂)[IndH₄]₂TiCl₂(2).对化合物1和2的单晶进行了X射线衍射结构分析,它们的晶体都属单斜晶系,P2₁/n空间群.     

N-对甲基苯基-N′-(2-吡啶基)脲的低温热容及热分析

通过低温量热和热分析方法,测定了N-对甲基苯基-N′-(2-吡啶基)脲(以下简称NPMPN′2PU)的低温热容和热力学性质.通过对NPMPN′2PU进行低温量热,得到了NPMPN′2PU在80～370K温区的热容曲线,热容曲线光滑,没有任何热异常现象,由此实验热容数据计算出NPMPN′2PU在这段温区内的热力学数据.从DSC实验结果发现,NPMPN′2PU熔化峰值出现在173.86℃,熔化焓为204.45kJ·mol-1.紧接熔化峰后NPMPN′2PU开始分解,分解峰只有一个,分解峰值温度为226.11℃.TG和DTG的实验结果表明,NPMPN′2PU失重的峰值为227.2℃,这些结果与DSC实验结果吻合.     

CH/π, CH/O弱氢键在2,6-二(α-苯基苄基)-1,5-萘二酚主体分子包结物构筑中的作用

设计、合成了一种新的主体分子2,6-二(α-苯基苄基)-1,5-萘二酚 (1). 它可与许多有机小分子形成配位包合物. 用IR和¹H NMR表征了配位包结物, 并测定了主客体分子的摩尔比: 1•DMF (1∶1), 1•DMSO (1∶2), 1•吡啶 (1∶1), 1•喹啉(1∶2), 1•N-甲基吡咯烷酮(1∶1). 用单晶X衍射分析了包结物 (1)•DMF的晶体结构, 属三斜晶系, 晶胞参数为P-1, a＝0.9085(9) nm, b＝0.9501(6) nm, c＝2.0995(6) nm, α＝99.59(3)°, β＝90.13(4)°, γ＝96.20(7)°, V＝1.776(2) nm³, D_c＝1.898 g•cm^－3. 结果表明, 主体分子间的CH/π弱氢键在决定主体分子的层状框架结构和客体分子在层间的填充方式中发挥了重要作用; 两种不等效的客体分子与主体分子的作用方式是不同的, 一种客体分子是通过CH/π, CH/O弱氢键与同层的不同主体分子相互作用, 另一种是通过CH/π, CH/O弱氢键与相邻层的不同主体分子相互作用.     

聚酰胺-46的合成和结构研究(Ⅱ)──产物的基本表征和结构研究

用红外光谱、核磁共振和示差扫描量热分析等手段对聚酰胺－46进行了基本表征,并用广角X射线衍射和扫描隧道电子显微镜技术对其聚集态结构进行了分析.     

开环夹心化合物 VII: 二(2,4-二甲基戊二烯)羰基钒的合成及其低温X射线结构分析

The title compound (I) was prepared from 2,4-dimethylpentadienyl potassium and VCl3?THF. The crystal structures of I was determine at -60?     

新的夹层型杂多化合物（Hpy)_4Na_2H_2[Cu(H_2O){WO(H_2O)}(WO)-(AsW_9O_(33))_2·5H_2O的合成、性质和晶体结构

在pH=1.0的水溶液中，吡啶与Na12[Cu3(H2O)3(AsW9O33)2].xH2O反应，得到了 新的夹层型杂多钨酸盐（Hpy)4Na2H2[Cu(H2O){WO(H2O)}(WO)(AsW9O33)2].5H2O单 晶，用X射线单晶衍射法及元素分析确定了其结构，晶胞参数为：空间群P21/c, a=2.4681(5)nm,b=1.7474(3)nm,c=2.4853(5)nm,β=118.723(3)°，V=9.400(3) nm^3,Z=4,R1=0.0491,[Cu(H2O){WO(H2O)}(WO)AsW9O33)2]^8-是由两个a-B- AsW9O33^9-阴离子连接一个Cu^2+,两个W^6+形成的，中心离子的配位数分别为4， 5和6，讨论了标题化合物的形成条件。     

Reaction of the Intermetallic Compound SmFe11Ti with Gaseous Ammonia

The reaction of the intermetallic compound SmFe₁₁Ti with ammonia at the initial NH₃ pressure of 0.6 – 0.8 MPa in the temperature range 150 – 450 °C in the presence of 10 wt % NH₄Cl as activator was studied. Depending on the reaction temperature, SmFe₁₁Ti undergoes both hydrogenation to form a hydride phase of the starting intermetallic compound and disproportionation to form a hydride phase of a new intermetallic compound. The reaction products are finely dispersed powders. The magnetic properties of the products were studied.__________Translated from Zhurnal Obshchei Khimii, Vol. 75, No. 6, 2005, pp. 881–885.Original Russian Text Copyright © 2005 by Fokin, Shul’ga, Tarasov, Fokina, Korobov, Burlakova, Shilkin.     

Plasmon-enabled N2 photofixation on partially reduced Ti3C2 MXene

Benefiting from the superior conductivity, rich surface chemistry and tunable bandgap, Ti₃C₂ MXene has become a frontier cocatalyst material for boosting the efficiency of semiconductor photocatalysts. It has been theoretically predicted to be an ideal material for N₂ fixation. However, the realization of N₂ photofixation with Ti₃C₂ as a host photocatalyst has so far remained experimentally challenging. Herein, we report on a sandwich-like plasmon- and an MXene-based photocatalyst made of Au nanospheres and layered Ti₃C₂, and demonstrate its efficient N₂ photofixation in pure water under ambient conditions. The abundant low-valence Ti (Ti^(4−x)+) sites in partially reduced Ti₃C₂ (r-Ti₃C₂) produced by surface engineering through H₂ thermal reduction effectively capture and activate N₂, while Au nanospheres offer plasmonic hot electrons to reduce the activated N₂ into NH₃. The Ti^(4−x)+ active sites and plasmon-generated hot electrons work in tandem to endow r-Ti₃C₂/Au with remarkably enhanced N₂ photofixation activity. Importantly, r-Ti₃C₂/Au exhibits ultrahigh selectivity without the occurrence of competing H₂ evolution. This work opens up a promising route for the rational design of efficient MXene-based photocatalysts.

N₂ photofixation in water is realized under ambient conditions using partially reduced Ti₃C₂ MXene that is interlaminated with Au nanospheres.     

A new perovskite-type compound: Ca4Fe2Ti2O11

A new perovskite-related oxide with a composition Ca₄Fe₂Ti₂O₁₁ has been found in the Ca₂Fe₂O₅-Ca TiO₃ system. Synthesis and characterization by X-ray diffraction and electron microscopy are reported. A model based on a stacking sequence of … OOOTOOOT′ … along theb axis of this material, corresponding to the structure of a compound withn = 4 in theA_nM_nO_3n−1 series, is proposed.     

Synthetic architectures of TiO2/H2Ti5O11.H2O, ZnO/H2Ti5O11.H2O, ZnO/TiO2/H2Ti5O11.H2O, and ZnO/TiO2 nanocomposites

Although synthetic investigations of inorganic nanomaterials had been carried out extensively over the past decade, few of them have been devoted to fabrication of complex nanostructures that comprise multicomponents/phases (i.e., composite nanobuilding blocks), especially in the area of structural/morphological architecture. In this work, nanobelts of a protonated pentatitanate (H(2)Ti(5)O(11).H(2)O) were synthesized hydrothermally for the first time. Two technologically important transition-metal-oxides TiO(2) and ZnO were then grown respectively or sequentially onto the surface of the as-prepared nanobelts in aqueous mediums. With a main emphasis on organizational manipulation, the present investigation examines general issues of morphological complexity, synthetic interconvertibility, and material combinability related to fabrication of inorganic nanocomposites. Using this model material system, we demonstrate that complex binary and tertiary composite building blocks of TiO(2)/H(2)Ti(5)O(11).H(2)O, ZnO/H(2)Ti(5)O(11).H(2)O, ZnO/TiO(2)/H(2)Ti(5)O(11).H(2)O, and ZnO/TiO(2) can be architected stepwise in solution. Structural features of these nanocomposites have also been addressed.     

Identifying characteristics of the fibrous cesium titanate Cs2Ti5O11

Electron microscopic studies of the fibrous cesium titanate Cs₂Ti₅O₁₁ reveal characteristic features not readily apparent using standard methods of phase analysis (optical microscopy, X-ray diffraction). Its fibrous needle-like laths give characteristic diffuse scattering, complicating the indexing of electron diffraction patterns. The hydrated form Cs₂Ti₅O₁₁ · (1 + x)H₂O (0.5 < x < 1) is typically grossly distorted, resembling pyrolytic graphite. Cs₂Ti₅O₁₁ is unstable when stored under ambient conditions at room temperature for ∼1 year when disproportionation into Cs₂Ti₄O₉ and Cs₂Ti₆O₁₁ · nH₂O occurs. The structure of Cs₂Ti₅O₁₁ and intergrowth defects in the unstable forms have been studied by high-resolution electron microscopy. It is evident that these phases would be undesirable in titanate ceramics such as SYNROC, which are designed for immobilization of radioactive ¹³⁷C_s.     

Das Schwingungsspektrum des Ti[N(CH3)2]4

Zusammenfassung Die Infrarot- und Ramanspektren von Ti[N(CH₃)₂]₄ werden mitgeteilt, zugeordnet und mit den Spektren der analogen Dimethylamino-Verbindungen von Si, Ge und Sn verglichen.

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The IR and Raman spectra of Ti[N(CH₃)₂]₄ are reported, assigned and compared with those of the Si, Ge and Sn analoga.