苝酰亚胺和大环化合物的超分子组装(英文)

苝酰亚胺及其衍生物是一类具有良好的π…π堆积能力和优良的光电性能的n型半导体材料,通过该类化合物与大环化合物构筑纳米超分子组装体是近年来化学、材料科学和纳米科学等领域备受关注的研究之一。本文主要论述了近年来以共价或非共价的方法将超分子大环化合物引入到苝酰亚胺体系构筑出各种纳米功能超分子组装体的研究进展,可以认为超分子大环化合物与苝酰亚胺的组装不仅可以调节苝酰亚胺的光物理行为,而且还可以赋予超分子组装体很多新颖的物理化学特性,使其在传感材料和光电器件等方面展现出很大的潜在应用价值。这些研究极大地拓展了构筑新颖苝酰亚胺纳米超分子组装体的方法。我们相信本文对于进一步构筑具有特定结构和功能的苝酰亚胺-大环化合物超分子组装体将起到积极的促进作用。     

基于Schiff-Base反应的成环策略及应用

基于Schiff-base反应的大环化合物是近些年来超分子领域研究的热点.这些大环化合物不但在传感器、功能材料等领域发挥着重要的作用,而且在自组装研究领域具有重要的意义.从模板法和非模板法两方面分析了一些具有代表性Schiff-base大环的合成,发现,不但具有合适半径和构型的离子可以作为成环反应的模板,而且强烈的分子内氢键也能有效地驱动成环反应.同时,对于该类大环分子合成所面临的问题及发展方向进行了评述和预测.     

含有氢键供体大环化合物的构筑及其功能研究进展

含有氢键供体基团构筑的大环化合物因其结构中具有可以提供氢键供体的N—H基团,可以为大环化合物的主客体化学提供额外的分子间作用力,在分子识别、自组装以及超分子催化等领域被广泛应用.综述了近十年基于(硫)脲键、酰胺键构筑的大环化合物的合成方法及其在分子识别中的最新研究进展.为今后此类大环化合物的合成及应用提供参考.     

芳香聚芳醚酮大环化合物结构分析

大环化合物因其特有的环状结构,近些年来引起了人们的强烈关注.氮杂大环化合物[1]、二联苯和氨基酸构建的大环化合物[2]、赖氨酸衍生氮杂大环化合物[3]、酞菁、类酞菁类大环化合物[4]以及含吡啶大环化合物[5]相继报道.     

吡啶氮氧化衍生物与酰胺大环化合物络合性能与结构的关系

介绍了3,5-吡啶二甲酸氮氧衍生物作为客体分子与主体分子酰胺大环的相互作用.通过质谱和核磁共振氢谱等实验技术研究了吡啶氮氧化物和酰胺大环化合物的结构特点对两者络合作用的影响.实验结果表明,3,5-吡啶二甲酰苄胺氮氧化物与酰胺大环化合物的络合能力最强,3,5-吡啶二甲酰丁胺氮氧化物次之,3,5-吡啶二甲酸苄酯氮氧化物最弱.酰胺大环分子的空腔越大其络合吡啶氮氧化物的能力越弱,酰胺大环上是否含有吡啶环结构对其络合氮氧化物的能力影响较小.并通过核磁实验进一步验证吡啶酰胺氮氧化合物与酰胺大环形成的[2]准轮烷分子在三氟乙酸/三乙胺的作用下能够发生解离/再组装行为.     

葫芦[8]脲的环套环分子组装

以4,4'-联吡啶鎓、 2,6-萘二酚和2,7-萘二酚为基本结构单元, 设计合成了2种带有分子内给受体相互作用的大环化合物, 并采用紫外光谱和核磁共振等手段研究了其与葫芦[8]脲的键合行为. 研究结果表明, 在水溶液中大环的2,6-萘二酚和2,7-萘二酚与4,4'-联吡啶鎓之间存在分子内的电荷转移相互作用, 而葫芦[8]脲可以键合这2种大环化合物, 导致电荷转移吸收峰增强并红移, 表明葫芦[8]脲能增强这种分子内的电荷转移相互作用, 形成稳定的环套环分子组装体. 这种结构是基于葫芦[8]脲的新型拓扑结构.     

芳炔大环的结构与超分子性质

芳炔大环是由芳(杂)环和炔键构成的具有规整多边形环状分子结构的化合物,自问世以来即受到化学家和材料学家的广泛关注。芳炔大环具有不会坍塌的刚性骨架,环上特定位置可带有柔性侧链或取代官能团,环平面上大的π电子共轭体系和环上灵活的结合点赋予芳炔大环独特而有趣的超分子性质。本文对芳炔大环的超分子性质作了综述,从大环在溶液中的缔合、热致液晶性质、一维超分子自组装及在基底表面或固-液界面二维自组装4个方面展开评述,介绍了研究方法,着重讨论了分子结构与物质性质的关系,并对芳炔大环的应用前景做了展望,为通过合理设计分子结构来制备满足尺寸、形状及功能要求的新型材料提供借鉴。     

基于分子内旋转受限原理的线性共轭小分子的AIE性能研究

研究了6个线性共轭化合物4-丁基联苯(L1)、4,4’-二异丙基联苯(L2)、5,5’-二甲基-2,2’-联吡啶(L3)、2-([1,1’-联苯]-4-)噻吩(L4)、1,1’-联萘(L5)和5-苯基-2,2’-联噻吩(L6)的紫外-可见光谱和荧光发射光谱。结果表明,化合物L1、L2和L3均具有聚集诱导发光(AIE)性能,化合物L4、L5和L6则不具有AIE性能。该研究结果表明,二联苯(或两个简单芳杂环相连)系列化合物具有AIE性能,分子内旋转受限(RIR)是该系化合物产生AIE现象的机理。但是在二联苯的结构基础上继续增加链的长度,或者引入体积更大的芳环(萘环),化合物不再具有AIE性能。     

聚(杯芳烃-哌嗪)酰胺与2,2'-联吡啶超分子泡沫网络结构的构筑

大环番衍生物单体5,11,17,23-四叔丁基-25,27-二酰氯基-26,28-二羟基杯[4]芳烃(DC)与哌嗪通过界面聚合,制备了聚(杯芳烃-哌嗪)酰胺(D).化合物D在乙酸乙酯溶液中形成平均直径为28和164 nm的双分布囊泡形聚集体. 2,2'-联吡啶(bpy)对化合物D的交联作用可将囊泡转变为实心无规则交联网.水将交联网转变为两相界面处存在的泡沫.这个变化过程表明,化合物D在不同的诱导条件下可调整聚集状态,多重诱因使其最终形成宏观泡沫状自组装构筑.化合物D是一个集合芳香大环-小杂环,疏水-亲水、氢键供体受体、刚性-柔性及富π空腔等多种结构及自组装于一体的高分子结构,其分子链在不同诱因下改变扭曲和取向导致超分子交联网络的形成.这种可逆宏观自组装现象为自组装机理的理解及刺激-响应材料的开发提供了一种有价值的试材.     

基于分子间卤键的超分子平面大环自组装

本工作报道了含卤键供体和受体片段的三种芳酰胺分子(化合物1~3)的设计和合成, 并对固相中卤键的不同作用模式进行了探索和分析. 化合物1的晶体数据显示, 由于没有分子内氢键, 组成分子的三个芳环相互扭转一定角度, 并且在分子间交替排列的N···I和O···I卤键的控制下, 组装成了一条线型的超分子组装体. 由于酰胺羰基和两个紧邻的氟原子之间的排斥作用, 化合物2未能形成分子内三中心氢键. 在此基础上, 将三氟碘代苯作为卤键供体片段引入到化合物3中, 并且在折叠体骨架中嵌入了嘧啶单元. 化合物3的晶体数据显示, 基于多组有效的分子内三中心氢键和分子间较强的卤键作用, 双分子间形成了[1+1]的超分子大环. 另外, 由于嘧啶环的引入, 使得该超分子大环接近共平面.     

Structure of liquid formic acid investigated by first principle and classical molecular dynamics simulations

The structure of liquid formic acid has been investigated by Car-Parrinello and classical molecular dynamics simulations, focusing on the characterization of the H-bond network and on the mutual arrangement of pairs of bonded molecules. In agreement with previous computational studies, two levels of H-bonded structures have been found. Small clusters, characterized by O-H...O bonds, are held together by weak C-H...O bonds to form large branched structures. From the ab initio simulation we infer the importance of cyclic H-bond dimer configurations, typical of the gas phase. Most of these dimer structures are however found to be embedded into H-bonded chains. When only O-H...O bonds are taken into account, linear H-bond chains are detected as basic structures of the liquid. More branched structures occur when C-H...O bonds are also considered. Regarding the arrangement of molecular pairs, we observed that O-H...O bonds favor the occurrence of configurations with parallel molecular planes, whereas no preferential orientation is observed for molecules forming C-H...O bonds.     

Facile preparation of [4.4]metacyclophane- and [5.5]paracyclophane-type macrocycles from arylboronic acids and salicylideneaminoaryl alcohols

Four different salicylideneaminoaryl alcohols have been treated with arylboronic acids in order to prepare air-stable cyclophane-type macrocyclic systems. In two cases, this objective could be realized with the high-yield formation of [4.4]metacyclophane and [5.5]paracyclophane derivatives. The skeleton in these macrocycles is held together by two chiral boron atoms. In the other two cases, monomeric boronates or polymeric material were obtained. The title structures were characterized by spectroscopic techniques and X-ray crystallography. They show transannular C-H...O hydrogen bonding, but no intramolecular pi-pi interactions. A synthetic strategy for the preparation of further boron macrocycles is presented.     

Substituent effects control the self-association of molecular clips in the crystalline state

We report the X-ray crystal structure of 11 molecular clips and analyze the influence of substituents (e.g., OMe, Me, and NO2) and their location on the observed crystal packing. Molecular clips 3a and 3b form tapelike structures in the crystal due to pi-pi interactions between the aromatic walls. Compounds 3d, 3eC, and 3fC form dimers driven by critical C-H...O interactions and then form tapes driven by pi-pi interactions in the crystal. These two building motifs, pi-pi and C-H...O interactions, can be used to rationalize the enantio- and diastereoselectivity observed in the X-ray crystal structures of the remaining five molecular clips. For example, the C-H...O interactions are found to dictate the formation of homochiral dimers in the structures of (+/-)-3eT and (+/-)-3fT and to control the diastereoselective formation of 6a2-6c2 dimeric motifs with internal p-dimethoxy-o-xylylene walls. Overall, the results suggest that substituent effects that induce even weak intermolecular interactions (e.g., C-H...O) can be used to reliably control crystal packing within glycoluril-based systems.     

Self-assembly of dialkyltin moieties and mercaptobenzoic acid into macrocyclic complexes with hydrophobic "pseudo-cage" or double-cavity structures: supramolecular infrastructures involving intermolecular C-H...S weak hydrogen bonds and pi-pi interactions

Four novel organotin complexes of two types--[R2Sn(o-SC6H4CO2)]6 (R = Me, 1 x H2O; nBu, 2) and {[R2Sn(m-CO2C6H4S)R2Sn(m-SC6H4CO2)SnR2]O}2 (R = Me, 3; nBu, 4)--have been prepared by treatment of o- or m-mercaptobenzoic acid and the corresponding R2SnCl2 (R = Me, nBu) with sodium ethoxide in ethanol (95%). All the complexes were characterized by elemental analysis, FT-IR and NMR (1H, (3C, 119Sn) spectroscopy, TGA, and X-ray crystallography diffraction analysis. The molecular structure analyses reveal that both 1 and 2 are hexanuclear macrocycles with hydrophobic "pseudo-cage" structures, while 3 and 4 are hexanuclear macrocycles with double-cavity structures. Furthermore, the supramolecular structure analyses show that looser and more intriguing supramolecular infrastructures were also found in complexes 1-4, which exist either as one-dimensional chains of rings or as two-dimensional networks assembled from the organometallic subunits through intermolecular C-H...S weak hydrogen bonds (WHBs) and pi-pi interactions.     

Macrocyclization and molecular interlocking via Mitsunobu alkylation: highlighting the role of C-H...O interactions in templating

[reaction: see text] A series of diimide-based macrocycles have been prepared using Mitsunobu-mediated alkylation as the macrocyclization step. These macrocycles could not be incorporated into [2]catenanes using previously established building blocks and coupling methodology. However, when one of the macrocycle syntheses was conducted in the presence of a dinaphtho crown ether, catenane formation was achieved. This result is discussed in terms of the ability of the components to establish intermolecular C-H...O hydrogen-bonding contacts.     

Recurrence of carboxylic acid-pyridine supramolecular synthon in the crystal structures of some pyrazinecarboxylic acids.

X-ray crystal structures of pyrazinic acid 1 and isomeric methylpyrazine carboxylic acids 2-4 are analyzed to examine the occurrence of carboxylic acid-pyridine supramolecular synthon V in these heterocyclic acids. Synthon V, assembled by (carboxyl)O-H...N(pyridine) and (pyridine)C-H...O(carbonyl) hydrogen bonds, controls self-assembly in the crystal structures of pyridine and pyrazine monocarboxylic acids. The recurrence of acid-pyridine heterodimer V compared to the more common acid-acid homodimer I in the crystal structures of pyridine and pyrazine monocarboxylic acids is explained by energy computations in the RHF 6-31G* basis set. Both the O-H.N and the C-H...O hydrogen bonds in synthon V result from activated acidic donor and basic acceptor atoms in 1-4. Pyrazine 2,3- and 2,5-dicarboxylic acids 10 and 11 crystallize as dihydrates with a (carboxyl)O-H...O(water) hydrogen bond in synthon VII, a recurring pattern in the diacid structures. In summary, the carboxylic acid group forms an O-H...N hydrogen bond in pyrazine monocarboxylic acids and an O-H...O hydrogen bond in pyrazine dicarboxylic acids. This structural analysis correlates molecular features with supramolecular synthons in pyridine and pyrazine carboxylic acids for future crystal engineering strategies.     

Structure and matrix isolation infrared spectrum of formyl fluoride dimer: blue-shift of the C-H stretching frequency

Infrared spectroscopy (IR) of formyl fluoride (HCOF) dimer is studied in low-temperature argon and krypton matrixes. New IR absorptions, ca. 17 cm(-1) blue shifted from the monomer C-H stretching fundamental, are assigned to the HCOF dimer. The MP2/6-311++G calculations were utilized to define structures and harmonic frequencies of various HCOF dimers. Among the four optimized structures, the dimer having two C-H...O hydrogen bonds possesses strongest intermolecular bonding. The calculated harmonic frequencies of this dimer structure are shifted from the monomer similarly as observed in the experiment. Thus, we suggest that the experimentally observed blue shifted C-H bands belong to the dimer with two C-H...O hydrogen bonds. This observation includes the HCOF dimer to the class of hydrogen bonded complexes showing blue shift in their vibrational energies.     

Understanding the structural properties of a homologous series of bis-diphenylphosphine oxides

A homologous series of bis-diphenylphosphine oxides (C6H5)2PO(CH2)(n)PO(C6H5)2 (with n = 2-8; denoted 2-8] have been investigated to explore the effects of a range of competing and cooperative intermolecular and intramolecular interactions on the structural properties in the solid state. The important factors influencing the structural properties include intramolecular aspects such as the conformation of the aliphatic chain and the intramolecular interaction between the two P=O dipoles in the molecule, and intermolecular aspects such as long-range electrostatic interactions (dominated by the arrangement of the P=O dipoles), C-H...O interactions, C-H...pi interactions and pi...pi interactions. Compounds 3 and 5 could be crystallized only as solvate co-crystals (3 water and 5 x (toluene)2], whereas the crystal structures of all the other compounds contain only the bis-diphenylphosphine oxide molecule. The crystal structures have been determined from single-crystal X-ray diffraction data, with the exception of 7 (which has been determined here from powder X-ray diffraction data) and 4 (which was known previously). The compounds with even n represent a systematic structural series, exhibiting characteristic, essentially linear P=O...P=O...P=O dipolar arrays, together with C-H...O and C-H...pi interactions. For the compounds with odd n, on the other hand, uniform structural behaviour is not observed across the series, although certain aspects of these crystal structures contribute in a general sense to our understanding of the structural properties of bis-diphenylphosphine oxides. Importantly, for the compounds with odd n, there is "frustration" with regard to the molecular conformation, as the preferred all-anti conformation of the aliphatic chain gives rise to an unfavourable parallel alignment of the two P=O dipoles within the molecule. Clearly the importance of avoiding a parallel alignment of the P=O dipoles becomes greater as n decreases. Local structural aspects (investigated by high-resolution solid-state 31P NMR spectroscopy) and thermal properties of the bis-diphenylphosphine oxide materials are also reported.     

Molecular beam rotational spectrum of cyclobutanone-trifluoromethane: nature of weak CH...O=C and CH...F hydrogen bonds

The molecular beam Fourier transform microwave spectrum of cyclobutanone-trifluoromethane has been assigned and measured. The carbon atom of trifluoromethane lies in the plane of the heavy atoms of cyclobutanone. The complex is stabilized by one C-H...O=C and two C-H...F-C weak hydrogen bonds. The C-H...O=C interaction, involving one carbonylic oxygen, is studied for the first time in detail with rotationally resolved spectroscopy. The two C-H...F-C weak hydrogen bonds involve two fluorine atoms of trifluoromethane and two hydrogens of the same methylenic group in the alpha position.     

All-atom molecular dynamic simulations and relative NMR spectra study of weak C-H...O contacts in amide-water systems

Amide-water mixtures are studied by all-atom molecular dynamics (MD) simulations and the relative temperature-dependent NMR experiment. The weak C-H...O contacts are found in the amide-water systems theoretically and experimentally. The statistical results of the average numbers of hydrogen bonds indicate that the methyl groups in amide molecules represent different capabilities in forming the weak C-H...O contacts. The statistics also imply that the C-H...O contacts are more obvious in the amide-rich region than those in the water-rich region. The temperature-dependent NMR spectra are also adopted to investigate the weak C-H...O contacts in the amide-water systems. The relative chemical shifts of the methyl groups are in good agreement with the MD simulations.