离子液体的分子模拟与量化计算

分子模拟方法是研究离子液体结构与性质关系非常有效的方法,可以从分子间相互作用出发研究离子液体的微观结构、热力学和动力学性质;量子化学计算则在分子、电子水平上对离子液体的结构、性能及催化机理进行理论研究。本文综述了分子模拟方法应用于离子液体体系的研究进展,重点介绍了利用分子动力学模拟和量子化学计算方法对不同离子液体进行研究,获得离子液体的结构性质、光谱性质(红外光谱、拉曼光谱)及离子液体催化反应机理等,为探讨离子液体结构-性质的关系、离子对的作用方式、催化反应活性中心、反应途径、反应活化能、振动模式和频率以及设计功能性离子液体提供理论导向。     

分子磁性的量子化学研究进展

本文概述了研究分子磁性的量子化学方法和研究进展。首先介绍分子磁性研究中的量子化学原理和所使用计算方法,总结了有代表性的自由基、自由基-金属配合物、桥联多核过渡金属配合物等分子磁性的研究情况,并对今后研究分子磁性的量子化学方法作了展望。     

金衬底上阴、阳离子型硫醇分子的量子化学计算

采用量子化学程序Gaussian98从头计算方法，对用做金衬底离子化的2—巯基乙基—二甲基氯化铵和3—巯基丙磺酸钠两种硫醇分子进行了全优化计算，得到了这两种化合物的平衡几何构型、基态能量、分子轨道组成和电荷分布等，并分析讨论了其分子轨道作用性质以及自由硫醇分子和金表面的相互作用．研究发现，表面分子基团带有大部分的净电荷，说明利用金与硫醇分子的自组装可实现金衬底的离子化。     

一种具有规则结构的蛋白单体之间相互识别的分子力学模拟和量子化学计算

使用分子力学、分子动态学以及量子化学计算方法, 对天然的昆虫抗冻蛋白质分子(TmAFP)以长轴平行的方式发生二体相互作用的可能模式进行了系统研究. 分子模拟的结果表明, 在可能的相互作用模式中, 其相互作用区域必须至少包含一个β-面, 并且当蛋白单体均取β-面靠近时, 其侧链上的羟基在空间的分布满足结构上的二维匹配; 利用分子力学与量子化学相结合的方法得到的结果表明两单体的β-面之间具有相对最强的相互作用, 同时, 高级别的DFT计算以及van der Waals键电荷密度分析进一步证实β-面的相互识别主要表现为β-面的一个苏氨酸侧链的羟基对另一个的苏氨酸羟基氧的识别, 即它们之间能形成较强的氢键. 因此, 分子力学以及量子化学的计算结果都说明蛋白单体在相互识别的过程中, 均以β-面相互作用的可能性最大.     

AlPO4-5分子筛模板剂的量子化学计算

以23种有机分子作为模板剂用于AlPO4-5分子筛的合成。利用分子图形技术研究这些有机分子的形状的尺寸，采用量子化学PM3方法研究这些有机分子的电子性质，它们与AlPO4-5分子筛骨架模型簇之间的相互作用能。结果表明，量子化学计算数据可以作为寻找合成AlPO4-5分子筛新型模板剂时的重要参考依据。     

量子化学奠基人之一——查尔斯.阿尔弗雷德.库尔森

查尔斯·阿尔弗雷德·库尔森是量子化学领域的杰出研究者,也是“英国量子化学学派”的领导者。他将分子轨道理论应用于化学键、分子电子结构和分数价概念,并发展了许多数学技术来解决化学和物理问题;他的著作《原子价》被认为是用于量子化学教学的杰作。库尔森无疑为提升量子化学在当今化学中的作用做出了巨大贡献。本文就库尔森的生平、求学经历及其对量子化学的贡献进行了论述。     

分子的酸碱性质与氢键强度之间关系的探讨*——介绍一个计算化学实验

介绍一个面向高年级本科生的计算化学实验。通过利用量子化学计算,确定嘧啶碱基的酸碱性质以及它们与水分子之间的相互作用能,构建氢键复合物分子间相互作用与分子酸碱性之间的定量关系,使学生对分子的酸碱性、分子间相互作用、分子识别之间的关系有一定的直观认识。该实验有助于学生梳理课堂学到的碎片化知识,提升学生逻辑分析及创新能力。     

乙酸离子与血红蛋白相互作用的可极化力场及分子片方法研究

本文应用传统的FF03力场、基于分子片的可极化力场模型以及基于能量的分子片量子化学方法,在B3LYP／6-31G（d）计算水平下,研究了乙酸负离子（CH3COO^-）与血红蛋白α亚基在4个作用靶点位（Lys16、Lys90、Arg92和Lys127）的相互作用．可极化力场模型得到的相互作用能大小顺序为：Arg92〉Lys127〉Lys90〉Lys16．通过分析每个分项对结合能的贡献发现,长程静电作用及立体效应共同控制CH3COO^-与血红蛋白的结合．     

配体间相互作用研究: 氨基酸与二肽配体形成 质子复合物的稳定性

用pH电位滴定法测定了苯丙氨酰亮氨酸(PL)与甘氨酸(Gly)、丙氨酸(Ala)、缬氨酸(Val)、亮氨酸(Leu)、异亮氨酸(Ile)、苯丙氨酸(Phe)在离子强度为0.1mol/L(NaNO~3),(25.0±0.1)℃时形成质子复合物的稳定常数,并对苯丙氨酰亮氨酸与六种氨基酸相互作用体系进行了量子化学和分子力学计算。从配体间弱相互作用的观点,讨论了二肽配体对氨基酸分子的识别。结果表明,二肽与氨基酸配体间的结合主要受到配体间静电、氢键作用的控制,同时受到范德华力和键间排斥能等弱相互作用的影响。     

配体间相互作用研究: 氨基酸与二肽配体形成 质子复合物的稳定性

用pH电位滴定法测定了苯丙氨酰亮氨酸(PL)与甘氨酸(Gly)、丙氨酸(Ala)、缬氨酸(Val)、亮氨酸(Leu)、异亮氨酸(Ile)、苯丙氨酸(Phe)在离子强度为0.1mol/L(NaNO~3),(25.0±0.1)℃时形成质子复合物的稳定常数,并对苯丙氨酰亮氨酸与六种氨基酸相互作用体系进行了量子化学和分子力学计算。从配体间弱相互作用的观点,讨论了二肽配体对氨基酸分子的识别。结果表明,二肽与氨基酸配体间的结合主要受到配体间静电、氢键作用的控制,同时受到范德华力和键间排斥能等弱相互作用的影响。     

基于分子间侧向氢键作用的电光材料制备及性能

通过重氮耦合和酯化等反应制备了一系列侧向含有酰胺基团的偶氮苯类非线性光学生色团, 并将其与聚合物进行掺杂或通过分子间的侧向氢键作用制备了主客体型及超分子型的电光薄膜材料. 生色团的结构通过核磁共振谱(¹H NMR, NMR)、 红外光谱(IR)、 质谱(MS)和元素分析(EA)等进行了表征, 结果表明, 生色团形成了分子间的氢键作用. 通过紫外-可见(UV-Vis) 光谱研究了材料的极化性能. 相比主客体型电光薄膜材料, 由分子间侧向氢键作用形成的超分子型电光薄膜材料无需与聚合物基体材料复合, 更有利于提高材料的生色团含量、 极化取向度及稳定性. 通过Teng-Man简单反射法研究了主客体型和超分子型电光材料的二阶非线性光学性质, 结果表明, 基于分子间侧向氢键作用形成的超分子体系具有更大的电光系数.     

均聚物/共聚物共混体系的相行为研究进展

通过控制均聚物与共聚物共混过程中的相行为，能够得到许多性能优异的材料。本文从理论和实验两方面总结了影响均聚物／共聚物共混体系相容性和形态结构的因素，主要包括均聚物的分子量、浓度，共聚物的组成、结构、浓度，与均聚物相应的共聚物组分的分子量，共聚物分子内的相互作用，均聚物与共聚物分子间的相互作用等。     

Structure-fluorescence relationships in pyrrole appended o-carborane crystalline materials

Based on three rationally designed pyrrole-appended o-carborane derivatives, we present that fluorescence properties of crystalline materials are highly dependent on intermolecular interaction and steric hinderance. Though the three molecules are similar in structure, single crystals of the three compounds showed obvious difference in molecular stacking and fluorescence behavior. Systematic studies indicate that fluorescence quantum yields, thermo-response as well as mechano-response are highly ...     

Interactions modes and physical properties in transition metal chalcogenolene-based molecular materials

Molecule-based materials are extremely versatile materials as they can be built from specifically designed building blocks with the desired size, shape, charge and electronic properties which determine their intermolecular interactions and, thus, their organization in the solid. The intermolecular interactions, therefore, in particular van der Waals interactions, π–π and π–d interactions, H-bonding, etc., play a crucial role in self-assembling these pre-designed molecular units and may provide a powerful way to afford layered mono- and multifunctional molecular materials with new or unknown physical properties. In this review the relationship between interaction modes and physical properties of organic/inorganic hybrids based on transition metal complexes with chalcogenolene ligands will be examined and an outlook will be proposed. With this goal, magnetic materials, highly conducting and metallic single-component materials containing dithiolene complex building blocks, multifunctional materials where the dithiolene complex is the magnetic or conducting component in addition to more complex systems involving other types of building block such as the metal oxalate complexes, will be discussed.     

Halogen bonding in supramolecular chemistry

Halogen bonding is the noncovalent interaction where halogen atoms function as electrophilic species. The energetic and geometrical features of the interaction are described along with the atomic characteristics that confer molecules with the specific ability to interact through this interaction. Halogen bonding has an impact on all research fields where the control of intermolecular recognition and self-assembly processes plays a key role. Some principles are presented for crystal engineering based on halogen-bonding interactions. The potential of the interaction is also shown by applications in liquid crystals, magnetic and conducting materials, and biological systems.     

Tris(Znsalen) cryptand minimizes Znsalen aggregation arising from intermolecular Zn…O interaction

Exploring the factors to control Znsalen aggregation is of importance to design functional materials in catalysis, optical materials and biological imaging. In this work, we synthesized and characterized four cryptand type triZnsalen complexes and found that cryptand structure could efficiently minimize intermolecular Zn···O interaction. More importantly, encapsulated by PLGA nanoparticles, cryptand triZnsalen 1 displayed visible intracellular fluorescence whereas monomeric Znsalen 5 could not. These results provide a new access to design new luminescent materials with the potential application in optics and biological studies.     

Investigation on two triphenylene based electron transport materials

Promoting electron mobility is the key to designing high performance electron transport materials(ETMs). Formation of intermolecular interaction can be helpful to enhance their electron mobilities as a result of more ordered molecular stacking.Here, to reveal the inherent influence of intermolecular π-π stacking on the electron mobilities, we designed two ETMs, namely,2,4-diphenyl-6-[3-(2-triphenylenyl)phenyl]-1,3,5-triazine(TPTRZ) and 2,4-diphenyl-6-[4′-(2-triphenylenyl)[1,1′-biphenyl]-3-yl]-1,3,5-triazine(TPPTRZ). Thermal, photophysical and electrochemical measurement results indicate they are good ETM candidates. Additionally, TPTRZ and TPPTRZ exhibit high electron mobilities of 3.60×10~(-5) and 3.58×10~(-5) cm~2V-1 s~(-1), respectively, at an electric field of 7×10~5 V cm~(-1). By taking X-ray single crystal structure, theoretical calculation and time of flight(TOF) results into consideration, it is revealed that strong intermolecular π-π stacking induced by planar triphenylene and triphenyltriazine units renders TPTRZ and TPPTRZ small energetic and positional disorder parameters, and results in their high electron mobilities thereby. By further enhancing intermolecular π-π stacking, ETMs with even higher electron mobilities can thus be anticipated.     

Dithienophosphole‐Based Phosphinamides with Intriguing Self‐Assembly Behavior

A new, highly adaptable type of phosphinamide‐based hydrogen bonding is representatively demonstrated in π‐conjugated phosphole materials. The rotational flexibility of these intermolecular P=O?H?N hydrogen bonds is demonstrated by X‐ray crystallography and variable‐concentration NMR spectroscopy. In addition to crystalline compounds, phosphinamide hydrogen bonding was successfully introduced into the self‐assembly of soft crystals, liquid crystals, and organogels, thus highlighting the high general value of this type of interaction for the formation of organic soft materials.     

The role of CH-π interaction in the charge transfer properties in tris(8-hydroxyquinolinato)aluminium(III)

The charge mobility is a key property in many electro-optical materials, with charge transfer (CT) taking place in a solid matrix of molecules. Large intermolecular electronic interaction is one of the key factors for a good CT rate, which is dependent on both intra- and intermolecular structures. The connection of the molecular structure with the intermolecular CT property would facilitate the search for a new material with desirable CT property, but currently it is still quite limited by the lack of knowledge for intermolecular configurations. In the present work, we study factors influencing the intermolecular configurations, and subsequently the CT property, in tris(8-hydroxyquinolinato) aluminium(III) (AlQ(3)) from all currently available crystal structures. We found that there exists a pair of CH-π interactions in a good majority of the π-π stacked bimolecular configurations. Such CH-π and π-π interacting structures are also seen in the crystal structures of many other similar molecules. With both experimental and simulated structures, we show that the CH-π interaction stabilizes the bimolecular configurations, and drives the structure towards a region with a higher electron transfer coupling and lower hole transfer coupling. This effect likely affects the electron transport property of AlQ(3), since it is consistent with recent experimental results, where AlQ(3) analogs with their CH-π interaction blocked either require a higher operating voltage in light-emitting devices [Sapochak et al., J. Am. Chem. Soc., 2001, 123, 6300], or become bipolar in their charge mobilities [Liao et al., J. Am. Chem. Soc., 2009, 131, 763]. CH-π interaction is commonly seen in aromatic molecules, which are frequently used as building blocks in molecules for electro-optical applications. Our work points out a possible way to enhance the desired CT property in the design of new materials.     

共晶含能材料研究进展

共晶是不同种类的分子(两种或两种以上)通过氢键等分子间相互作用,形成具有特定结构和性能的多组分分子晶体,不同含能材料形成共晶可以有效改善炸药的感度、安全性等性能。针对目前高能炸药的改性需求,共晶在含能材料领域中的应用具有巨大的潜力。综述了共晶的形成原理及生长特性,总结了常见共晶的制备方法和表征方法,评述了含能材料共晶的研究现状和发展前景。