客体诱导LiCl/FER沸石客/主体材料主体相变行为的研究

用热扩散法将客体LiCl组装进入主体FER沸石孔道生成的客/主体材料中, 客体与主体骨架在一定温度下发生相互作用, 诱导该沸石发生相转变. XRD, FT-IR, TG/DTA/DTG等方法表征该客/主体材料相变过程证明, 相变起始温度500 ℃, 500～600 ℃生成LiAlSi₃O₈, 800 ℃的相变产物主要为β-石英, LiAlSi₃O₈的相对含量随LiCl的组装量增多而增加.     

PEG-沸石固-固相变材料的制备及性能

摘要：采用接枝共聚法合成了以聚乙二醇（PEG）为相变物质,沸石为骨架的PEG沸石固-固相变材料。通过红外光谱（FT—IR）、热失重分析（TGA）和差示扫描量热法（DSC）等测试手段对PEG-沸石固-固相变材料的结构、相变行为及热稳定性进行了研究。结果表明：通过改变PEG的分子量,可以得到不同相变焓和不同相变温度的PEG-沸石固-固相变材料,其相变焓可达105．41J／g,热稳定性良好,起始分解温度高于300℃。     

锂／沸石电池的电化学行为

研究了沸石作为常温非水锂电池阴极材料的放电性能和循环特性。通过库仑滴定，三角波电位扫描，Ｘ－射线分析和红外光谱研究了锂／沸石电池的阴极反应机理，发现在ｘ＜３、４ｍｏｌ时，阴极上发生的是锂的嵌入反应。测得锂嵌入ＮａＡ型沸石生成ＬｉＮａＡ的嵌入自由能为－２３１ｋＪ／ｍｏｌ（２５℃）。用电化学方法测得，常温下锂在ＬｉｘＮａＡ（ｘ＝０．１７～０．６９）中的化学扩散系数为１×１０－９～１×１０－１０ｃｍ２／ｓ数量级。     

用新方法催化合成6-乙酰基-1-甲基环己烯

室温下用HY沸石取代传统催化剂通过1-甲基环己烯与乙酐的酰基化反应合成了6-乙酰基-1-甲基环己烯，考察了HY沸石的SiO2／Al2O2摩尔比、用量和活化时间以及反应时间对该酰化反应的影响．当1-甲基环己烯／乙酐／HY沸石(SiO2／Al2O3摩尔比=29)=1mmol／10mmol／0．200g、反应温度25℃、反应时间3h时，所得酰化产品的产率为60％，HY沸石能够回收和重新使用，显示出与新鲜催化剂几乎相同的催化活性．     

催化裂化USY／ZnO／Al2O3脱硫添加剂的高温水热失活

 对USY／ZnO／Al2O3汽油催化裂化脱硫添加剂经高温水热老化处理前后的脱硫性能进行了考察，发现老化后添加剂的脱硫性能大幅度下降．采用XRD和IR等技术对USY／ZnO／Al2O3添加剂在高温和高温水热条件下失活的原因进行了研究．结果表明，在高温下，ZnO可与USY沸石中的铝发生固相反应生成ZnAl2O4尖晶石，从而造成USY晶体结构崩塌，转变成无定形状态．在ZnO含量较高的条件下，ZnO可继续与USY晶体结构崩塌后生成的无定形的硅和铝的氧化物反应，生成Zn2SiO4硅锌矿和ZnAl2O4尖晶石结构．这一方面使添加剂失去了可形成硫化物吸附中心的ZnO，另一方面破坏了硫化物的裂化活性组分USY，从而造成添加剂脱硫性能下降甚至失去脱硫活性．ZnO对USY的破坏作用主要与温度有关．在USY／ZnO／Al2O3体系中，ZnO被ZnO与Al2O3之间形成的锌铝尖晶石膜固定并与USY隔离，单纯的高温条件对添加剂的破坏不显著，而水蒸气可以促进ZnO的移动，有利于ZnO与USY的接触，因此在高温和有水蒸气存 在的条件下添加剂的结构易遭到破坏．     

催化裂化USY／ZnO／A12O3脱硫添加剂的高温水热失活

对USY／ZnO／A12O3汽油催化裂化脱硫添加剂经高温水热老化处理前后的脱硫性能进行了考察，发现老化后添加剂的脱硫性能大幅度下降．采用XRD和IR等技术对USY／ZnO／A12O3添加剂在高温和高温水热条件下失活的原因进行了研究．结果表明，在高温下，ZnO可与USY沸石中的铝发生因相反应生成ZnAl2O4尖晶石，从而造成USY晶体结构崩塌，转变成无定形状态．在ZnO含量较高的条件下，ZnO可继续与USY晶体结构崩塌后生成的无定形的硅和铝的氧化物反应，生成Zn2SiO4硅锌矿和ZnAl2O4尖晶石结构．这一方面使添加剂失去了可形成硫化物吸附中心的ZnO，另一方面破坏了硫化物的裂化活性组分USY，从而造成添加剂脱硫性能下降甚至失去脱硫活性．ZnO对USY的破坏作用主要与温度有关．在USY／ZnO／Al2O3体系中，ZnO被ZnO与Al2O3之间形成的锌铝尖晶石膜固定并与USY隔离，单纯的高温条件对添加剂的破坏不显著，而水蒸气可以促进ZnO的移动，有利于ZnO与USY的接触，因此在高温和有水蒸气存在的条件下添加剂的结构易遭到破坏．     

人工合成NaX沸石的原位高温X射线衍射研究

对以含铁钾长石粉为原料、人工合成的NaX沸石分子筛,进行原位高温X射线衍射实验,实验结果表明：合成物中含有大量的非品质,受热发生相变,在沸石表面结晶;沸石在800℃以下物相保持稳定,800～1000℃发生相变,生成霞石、赤铁矿。铁对样品的结晶以及结晶后的性能存在影响,铁的存在导致沸石结晶差、非品质增多,含铁多的沸石熔点低。     

用TG/DTG/DTA研究硅沸石与有机分子的主体/客体相互作用

用TG/DTG/DTA法研究无阳离子与Si—OH缺陷、结构完美的硅沸石上烃类、烷基醇、烷基胺的热脱附行为.有机分子从硅沸石上脱附的温度低于300℃其亲和性值A_T=T_d-T_b,式中T_d为有机分子在DTG上的失重峰温,T_b为该有机物在标准压力下的沸点.饱和烷烃的A_T值为60～90,而苯、甲苯、对二甲苯等的A_T值为6～13.电负性较强的羟基使烷基醇与硅沸石的亲和性明显下降.多羟基醇的A_T值为负值.对二甲苯、烷基醇、烷基胺在脱附时有明显吸热效应.A_T值及脱附热效应的不同是硅沸石骨架0~(2-)微孔表面与有机分子C—H基因,其它极性基因之间相互作用不同,以及受到硅沸石骨架空间限制的被吸附分子间缔合情况不同所致,反应了不同类型的主体/客体超分子相互作用.     

钠型斜发沸石Na^＋—K^＋离子交换特性研究（Ⅰ）—离子交换过程热力学特性

测定出斜发沸石的阳离子交换容量为192．18mmol／100g沸石：通过10℃、25℃、50℃、75℃钠型斜发沸石Na^ —K^ 离子交换等温线、温度对选择性校正系数的影响及Kiclland图研究表明：钠型斜发沸石对钠钾混合体系中的钾具有很高的选择性，且随着温度的上升，沸石对钾的选择性下降，并回归出Langmuir模型：依据热力学平衡原理，导出了钠型斜发沸石Na^ —K^ 离子交换过程平衡常数表达式，并计算出该过程的焓、吉布斯自由能和熵变化，进一步验证该过程可自发进行，且为放热反应，低温有利于钾离子吸附。     

Yb2O3对TiO2/(O''+β'')-Sialon复相陶瓷中TiO2相变的影响

以纳米锐钛矿型TiO2粉和（O＇＋β＇）-Sialon粉为原料制备出了TiO2／（O＇＋β＇）-Sialon复相陶瓷，研究了Yb2O3添加剂对材料中锐钛矿型TiO2相变的影响，对其影响机制进行了探讨。采用XRD对材料进行物相组成和晶格参数表征。结果表明，Yb2O3对锐钛矿相变开始温度无明显影响，但对相变有显著的促进作用，随添加量的增加，其作用逐渐减弱。添加的Yb2O3同时以两种形式存在：一部分进入TiO2晶格，一部分堆积在TiO2晶粒表面。Yb^n＋进入TiO2晶格置换Ti^4＋和Yb^3＋与TiO2发生氧化还原反应促进相变，而存在于TiO2表面的Yb^3＋与TiO2相互作用形成Ti-O-Yb键而抑制相变。Yb2O3对锐钛矿相变的影响是这两方面机制共同作用的结果。     

Interaction Study of Guest with Host in Clathrate Hydrate

Lattice dynamical simulations of noble gas hydrate structuresⅠandⅡhave been performed. Potential energies were investigated to study the influence of guest species on the stability of the hydrate structure.Results show that when the diameter of inclusion molecules is between 3(?)and 4.2(?),such as Ar and Kr,the critical role of the 5~(12)cage in the stabilization of hydrates becomes effective.For Xe hydrates SⅠand SⅡ,with the help of lattice dynamical calcnlations,the modes attributions are identified directly.We proposed the resonant effect of the fingerprint frequency at about 7 meV and 10 meV which arise from the coupling of Xe molecules in the 5~(12)cage with the host lattice.     

Host–Guest Complexes of some Stable Free Radicals

Hydrophobic host–guest complexes of some water soluble stable free radicals – potassium nitrosodisulfonate (Fremy's salt), 2-$p$-phenylsulphonic acid-2-phenyl-1-picrylhydrazyl (KSO₃-DPPH^.) and 2,2-p-phenylsulphonic acid-1-picrylhydrazyl ((KSO₃)₂DPPH^.), both of them as potassium salts, with 18-C-6, B18-C-6 and DB18-C-6 crown ethers, were obtained and characterised by elemental analysis, IR, ESR and UV-Vis.     

Host–Guest Chemistry Within Cellulose Nanocrystal Gel Receptors

Cellulose nanocrystals (CNCs) spontaneously assemble into gels when mixed with a polyionic organic or inorganic salt. Here, we have used this ion-induced gelation strategy to create functional CNC gels with a rigid tetracationic macrocycle, cyclobis(paraquat-p-phenylene) ( CBPQT ⁴⁺). Addition of [ CBPQT ]Cl₄ to CNCs causes gelation and embeds an active host inside the material. The fabricated CNC gels can reversibly absorb guest molecules from solution then undergo molecular recognition processes that create colorful host–guest complexes. These materials have been implemented in gel chromatography (for guest exchange and separation), and as elements to encode 2- and 3-dimensional patterns. We anticipate that this concept might be extended to design a set of responsive and selective gel-like materials functioning as, for instance, water-pollutant scavengers, substrates for chiral separations, or molecular flasks.     

Structural Studies on Host + Guest Recognition Sensory Systems

Rhodamine B-ethylenediamine--cyclodextrins (RhB--CDen) and rhodamine B--cyclodextrins (RhB--CD) can form inclusive complexes with many guest molecules, a reaction which can be used as a nucleic acid probe. In this paper, the most stable conformations of RhB--CDen and RhB--CD have been determined by fluorescence experiments and analyzed by molecular modeling simulation. The interaction between RhB--CDen and two guest molecules, 1-borneol and cyclohexanol, has also been investigated. The results showed that RhB--CDen has a stronger interaction with 1-borneol than with cyclohexanol. Borneol could push the three aromatic-rings of rhodamine B out of the CD cavity, while the cyclohexanol could not. The interactive sites of host and guest are also presented.     

Host/Guest Interactions and NMR Spectroscopy. A Computer Program for Association Constant Determination

A computer program is presented for the computation of association constants for host/guest compounds based on experimental data obtained from the NMR spectra of samples with different host/guest ratios of known concentration.     

Structural Studies of Guest–Host Interactions in Dianin's Clathrates

Dianin's compound(4-p-hydroxyphenyl-2,2,4-trimethyl chroman) forms isostructural clathrates and a clathrand which can be systematically studied to determine the microscopic origins of bulk physical properties. Due to the large number of guests that can be enclathrated in the Dianin's system, experiments in which systematic changes of guest size and functionality can be used to probe guest–host interactions. Herein we report the structures for the1,6-hexanediol, 1,5-pentanediol, and 1-heptanol Dianin's clathrates deduced by X-ray crystallography. In the hexanediol, pentanediol, and heptanol clathrates, the guests' hydroxyl groups hydrogen bond with the host cage's hydrogen-bonded hexamer ring.The two terminal alcohol groups in the diols have different spatial orientations within the cage that result from gauche bonds between atoms in the guest's backbone.     

The Host/Guest Type of Excited‐State Proton Transfer; a General Review

Contemporary progress regarding guest/host types of excited‐state double proton transfer has been reviewed, among which are the biprotonic transfer within doubly H‐bonded host/guest complexes, the transfer through a solvent bridge relay, the intramolecular double proton transfer and solvation dynamics coupled proton transfer. Of particular emphases are the photophysical and photochemical properties of excited‐state double proton transfer (ESDPT) in 7‐azaindole and its corresponding analogues. From the chemical aspect, two types of ESDPT reaction, namely the catalytic and non‐catalytic types of ESDPT, have been classified and reviewed separately. For the case of static host/guest hydrogen‐bonded complexes both hydrogen‐bonding strength and configuration (i.e. geometry) play key roles in accounting for the reaction dynamics. In addition to the dynamical concern, excited‐state thermodynamics are of importance to fine‐tune the proton transfer reaction in the non‐catalytic host/guest type of ESDPT. The mechanisms of protic solvent assisted ESDPT, depending on host molecules and proton‐transfer models, have been reviewed where the plausible resolution is deduced. Particular attention has been given to the excited‐state proton transfer dynamics in pure water, aiming at its future perspective in biological applications. Finally, the differentiation in mechanism between solvent diffusive reorganization and solvent relaxation to affect the host/guest ESPT dynamics is made and discussed in de tail.     

基于主客体竞争模式的凝血酶适配体传感器的研究

基于β-环糊精(β-CD)主客体竞争模式,构建了开关型凝血酶适配体电化学传感器.将末端修饰了二茂铁(Fc)的核酸适配体通过与β-CD的主客体识别固定在金电极表面,当凝血酶存在时,适配体由原来的直立线状构型变为"G-四链体",远离电极表面,适配体探针的氧化还原电流强度减小,即"Signal-off".利用此效应对凝血酶进行了灵敏检测,结果表明,在5.0×10-13~5.0×10-9 mol/L浓度范围内,凝血酶的浓度与电化学响应信号呈良好的线性关系,检出限为2.0×10-13 mol/L(3σ).与其它蛋白分子相比,本方法对凝血酶蛋白的检测具有高特异性.本传感器构建简单,再生性好,为生物血清样本中凝血酶的实时高效检测提供了方法.