Ligands derived from tetrathiafulvalene: building blocks for multifunctional materials

The last decade has witnessed many advances in the coordination chemistry of tetrathiafulvalene (TTF). Various ligands, in which a metal-binding functionality is attached to the TTF unit, have been synthesized and used for the preparation of metal complexes. This Perspective summarizes the main types of TTF-containing ligands and their metal complexes and outlines the potential for the use of these building blocks in the design and assembly of multifunctional molecular materials.     

Tetrathiafulvalene: A Paradigmatic Electron Donor Molecule

Abstract

Tetrathiafulvalene (TTF) and its derivatives are exceptional building blocks in many areas of organic, supramolecular, and materials chemistry. Since the discovery ca. 30 years ago of the first “organic metal” tetrathiafulvalene-tetracyano-p-quinodimethane (TTF-TCNQ), a huge number of TTF derivatives have been synthetized.

Although initial efforts were directed to enhance the electron-donating ability of TTF analogues to improve the conductivities of salts and charge-transfer (CT) complexes derived from them, the developments in synthetic TTF chemistry have made it possible to incorporate TTF into more sophisticated structures such as materials exhibiting intramolecular charge-transfer and nonlinear optical properties, sensors, molecular shuttles and devices.

Compounds in which TTF and electron-accepting molecules, especially C ₆₀ , are covalently tethered exhibit outstanding photophysical properties leading, upon photoexcitation, to charge-separated (CS) states showing remarkable lifetimes. In these systems, the gain of aromaticity upon oxidation of the TTF moiety has been used as a new concept for improving the stability of the charge-separated state, and, therefore, are of interest for the preparation of artificial photosynthetic systems as well as photovoltaic devices.     

A novel class of nonlinear optical materials based on host-guest composites: zeolites as inorganic crystalline hosts

The demand for nonlinear optical (NLO) materials with exceptional NLO properties is very large, and hence the search for such materials should be continued not only to enhance their functions in current applications but also to help expedite the materialization of photonics in which photons instead of electrons are used for signal processing, transmission, and storage. This article summarizes the preparation, characteristics, and the future perspectives of novel second order nonlinear optical (2NLO) materials prepared by orientation-controlled incorporation of 2NLO molecules into zeolite channels and third order nonlinear optical (3NLO) materials prepared by compartmentalization of very small (<1.3 nm) PbS QDs within zeolite nanopores under different environments, and the novel chemistry newly unveiled during the preparation of novel zeolite based NLO materials.     

含卤素取代基四硫富瓦烯的合成与研究进展

简要概括了含卤素取代基四硫富瓦烯(TTF)衍生物的主要合成方法, 即TTF及其衍生物的直接卤化法以及卤代1,3-二硫杂环戊烯-2-(硫)酮在亚磷酸三烷基酯参与下的偶合反应. 介绍了含卤素TTF衍生物的电化学、结晶和成膜性能, 及其作为重要的合成中间体在构筑给体-受体二元体、低聚TTF体系、含TTF单元的环蕃、含TTF单元的聚合物以及各种官能化TTF衍生物中的应用. 提出了含卤素TTF衍生物的研究发展趋势.     

Macromolecules containing bipyridine and terpyridine metal complexes: towards metallosupramolecular polymers

The ability of a broad range of N-heterocycles to act as very effective and stable complexation agents for several transition metal ions, such as cobalt(II), copper(II), nickel(II), and ruthenium(II), has long been known in analytical chemistry. This behavior was later utilized in supramolecular chemistry for the construction of highly sophisticated architectures, such as helicates, racks, and grids. The discovery of macromolecules by Staudinger in 1922 opened up avenues towards sophisticated materials with properties hitherto completely unknown. In the last few decades, the combination of macromolecular and supramolecular chemistry has been attempted by developing metal-complexing and metal-containing polymers for a wide variety of applications that range from filtration to catalysis. The stability of the polymer-metal complex is a fundamental requirement for such applications. In this respect, the use of bi- and terpyridines as chelating ligands is highly promising, since these molecules are known to form highly stable complexes with interesting physical properties with transition-metal ions. A large number of different structures have been designed for many different applications, but polymers based on the application of coordinative forces have been prepared in a few cases only. Furthermore, the synthetic procedures applied frequently resulted in low yields. During the last few years, strong efforts have been made in the direction of self-assembling and supramolecular polymers as novel materials with "intelligent" and tunable properties. In this review, an overview of this active area at the interface of supramolecular and macromolecular chemistry is given.     

Redox responsive molecular tweezers with tetrathiafulvalene units: synthesis, electrochemistry, and binding properties

Several new molecular tweezers with tetrathiafulvalene (TTF) arms as well as mono-TTF derivatives bearing 3,5-di-tert-butylbenzylthio groups to provide enhanced solubility were prepared starting from a bis-cyanoethyl-protected tetrathiafulvalene derivative. The X-ray crystallographic analysis of 3 and 7a showed highly distorted TTF groups and absence of close TTF-TTF contacts in the crystalline state. Comparative cyclic voltammetry (CV) measurements demonstrated that through space distance-dependent TTF-TTF interactions take place in the TTF-containing molecular tweezers, leading to electronic pairing with formation of mixed valence [TTF]₂⁺ species and splitting of the first oxidation wave. TTF-containing molecular tweezers were successfully tested as receptors for several electron-deficient substances.     

基于环糊精和偶氮化合物的光控可逆超分子体系

超分子化学是当前化学领域的研究热点之一。基于环糊精和偶氮化合物的光控超分子可逆体系是近几年在超分子化学基础上发展起来的活跃领域。二者的复合物具有的优秀光学性质使其在光敏型自组装、催化、分子机器设计和智能材料领域受到极大的关注。本文综述了基于环糊精和偶氮化合物的光控超分子可逆体系的研究进展。介绍了该体系的研究背景、优势与原理; 根据该体系控制组装体的不同进行了分类总结,包括囊泡、凝胶、轮烷、催化体系、分子触手等; 最后结合现阶段的研究情况,对其前景与发展方向进行了展望。     

The Halogen Bond: An Emerging Supramolecular Tool in the Design of Functional Mesomorphic Materials

Owing to their dynamic attributes, non-covalent supramolecular interactions have enabled a new paradigm in the design and fabrication of multifunctional material systems with programmable properties, performances, and reconfigurable traits. Recently, the “halogen bond” has become an enticing supramolecular synthetic tool that displays a plethora of promising and advantageous characteristics. Consequently, this versatile and dynamic non-covalent interaction has been extensively harnessed in various fields such as crystal engineering, self-assembly, materials science, polymer chemistry, biochemistry, medicinal chemistry and nanotechnology. In recent years, halogen bonding has emerged as a tunable supramolecular synthetic tool in the design of functional liquid-crystalline materials with adjustable phases and properties. In this Concept article, the use of halogen bond in the field of stimuli-responsive smart soft materials, that is, liquid crystals is discussed. The design, synthesis and characterization of molecular and macromolecular liquid crystalline materials are described and the modulation of their properties has been emphasized. The power of halogen bonding in offering a large variety of functional liquid crystalline materials from readily accessible mesomorphic and non-mesomorphic complementary building blocks is highlighted. The article concludes with a perspective on the challenges and opportunities in this emerging endeavor towards the realization of enabling and elegant dynamic functional materials.     

Cyclodextrin-based inclusion complexation bridging supramolecular chemistry and macromolecular self-assembly

Research into macromolecular self-assembly has been progressively developing since the 1970s but with a little affect from the achievements of supramolecular chemistry. In recent years, this situation has changed as more and more factors and concepts in supramolecular chemistry have been introduced into studies of the self-assembly of polymers. In this respect, inclusion complexation based on cyclodextrins plays a remarkable role. In this tutorial review, we address how inclusion complexation has been employed and used to promote the recent developments in macromolecular self-assembly. These include the amphiphilicity adjustment of macromolecules, non-covalent linkages for forming pseudo block copolymers and micelles, surface modification and functionalization of polymeric micelles and vesicles, and the combination of synthetic polymeric assemblies with biological moieties. Furthermore, the realization of the reversible stimuli-responsiveness of polymeric assemblies and materials, particularly hydrogels by means of controllable inclusion complexation is discussed as well.     

液晶的超分子系统及生物膜模拟

本文评述了自组织产生功能的原理及溶致性液晶对生命科学的重要意义。这些是生命发展及细胞产生功能的先决条件。在高分子材料科学中, 通过自组织作用产生功能的原理导致了新的液晶材料。分子的自组织作用形成超分子体系从而产生相应的功能。从高分子材料科学的观点出发, 我们尝试将这两个领域结合在一起, 并希望能促进它们之间的相互作用和联合处理。同时评述了液晶的超分子体系、生物膜模型, 高分子脂质体及其在化学与生物医学方面的应用。如果双分子层的组装概念能更一般地延伸到有机介质, 那么一种全新的化学分支将会产生。     

葫芦[n]脲超分子水凝胶的研究进展

超分子化学的发展一直是众多研究者所关注的一大热点,葫芦[n]脲作为第四代大环主体分子,拓宽了超分子化学领域的发展。水凝胶是一种具有可拉伸性、生物相容性、环境响应性等多种优异性能的软材料。人们充分利用葫芦[n]脲优异的分子识别能力和配位能力,研究出了一系列具有特殊功能的超分子水凝胶材料。本文在结合葫芦[n]脲特点的基础上,着重论述了葫芦[n]脲水凝胶在(刺激响应性、粘附性、自愈合性)功能性材料、(药物传递、伤口敷料、仿生)生物医学材料、超分子发光材料等领域的研究前沿和动态,并且对葫芦[n]脲水凝胶的主要设计思路进行了讨论。最后,针对当前存在的问题以及未来可能的发展方向对葫芦[n]脲水凝胶的研究前景作出了展望。     

Noncovalent interactions in inorganic supramolecular chemistry based in heavy metals. Quantum chemistry point of view

Complexity is a concept that is being considered in chemistry as it has shown potential to reveal interesting phenomena. Thus, it is possible to study chemical phenomena in a new approach called systems chemistry. The systems chemistry has an organization and function, which are regulated by the interactions among its components. At the simplest level, noncovalent interactions between molecules can lead to the emergence of large structures. Consequently, it is possible to go from the molecular to the supramolecular systems chemistry, which aims to develop chemical systems highly complex through intra- and intermolecular forces. Proper use of the interactions previously mentioned allow a glimpse of supramolecular system chemistry in many tasks such as structural properties reflecting certain behaviors in the chemistry of materials, for example, electrical and optical, processes of molecular recognition and among others. In the last time, within this area, inorganic supramolecular systems chemistry has been developed. Those systems have a structural orientation which is defined by certain forces that predominate in the associations among molecules. It is possible to recognize these forces as hydrogen bonding, π-π stacking, halogen bonding, electrostatic, hydrophobic, charge transfer, metal coordination, and metallophilic interactions. The presence of these forces in supramolecular system yields certain properties such as light absorption and luminescence. The quantum theoretical modeling plays an important role in the designing of the supramolecular system. The goal is to apply supramolecular principles in order to understand the associated forces in many inorganic molecules that include heavy metals for instance gold, platinum, and mercury. Relevant systems will be studied in detail, considering functional aspects such as enhanced coordination of functionalized molecular self-assembly, electronic and optoelectronic properties.     

Design,Synthesis, and Properties of Molecule-Based Assemblies with Large Second-Order Optical Nonlinearities

The design, synthesis, characterization, and understanding of new molecular and macromolecular assemblies with large macroscopic optical nonlinearities represents an active field of research at the interface of modern chemistry, physics, and materials science. Challenges in this area of photonic materials typify an important theme in contemporary chemistry: to create new types of functional materials by the rational construction of supramolecular assemblies exhibiting preordained collective phenomena by virtue of “engineered” molecule–molecule interactions and spatial relationships. This review surveys several approaches to, and the microstructural and optical properties of, second-order nonlinear optical materials built from noncentrosymmetric assemblies of chromophores having large molecular hyperpolarizabilities. Such types of materials can efficiently double the frequency of incident light, exhibit other second-order nonlinear optical effects, and contribute to the knowledge base needed for new photonic device technologies. Systems described include chromophore macromolecule guesthost matrices, chromophore-functionalized glassy macromolecules, thermally crosslinked chromophore-macromolecule matrices, and intrinsically acentric self-assembled chromophoric superlattices.     

Covalent Organic Frameworks as Emerging Nonlinear Optical Materials

The vastness of organic synthetic strategies and knowledge of reticular chemistry have made covalent organic frameworks (COFs) one of the most chemically and structurally diverse class of materials with potential applications ranging from gas storage, molecular separation, and catalysis to energy storage and magnetism. Recently, this class of porous materials has garnered increasing interest as potential nonlinear optical (NLO) materials. Traditionally, inorganic crystals, small-molecule organic chromophores, and oligomers have been studied for their NLO response. Nevertheless, COFs offer significant advantages over existing NLO materials in terms of higher mechanical strength, thermochemical stability, and extended conjugation. Herein, we discuss crucial aspects, terminology, and measurement techniques related to NLO, followed by a critical analysis of the design principles for COFs with NLO response. Furthermore, we touch on selected potential applications of these NLO materials. Finally, future prospects and challenges of COFs as NLO materials are discussed.     

超分子构筑调控合成结构规整的梯形聚合物及其应用研究

综述了"超分子构筑调控的逐步偶联/聚合法",该方法将高分子化学与超分子化学相结合,利用多种类型的超分子弱键协同作用首先构筑预期的梯形超分子结构,再经聚合得到共价键梯形高分子.利用该方法合成了一系列结构规整的氧桥基和有机桥基梯形聚硅氧烷以及碳基梯形聚酯,并利用侧基间π-π叠加作用实现了对聚合物立体构型控制.扼要介绍了梯形聚合物在先进材料方面的应用,例如梯形聚硅氧烷液晶光致取向膜;由梯形聚硅氧烷合成的管状聚硅氧烷在高室温储存期微电子环氧塑封料方面的应用;以及基于梯形聚硅氧烷的拟筛板聚合物在二阶非线性光学材料方面的应用等.     

Recent progress on pure organic room temperature phosphorescence materials based on host-guest interactions

The inclusion of specific organic phosphorescent guest molecules by the host molecules can reduce the nonradiative transitions and engender room temperature phosphorescence emission.     

Recent progress on pure organic room temperature phosphorescence materials based on host-guest interactions

Pure organic room temperature phosphorescence (RTP) has been attracting a lot interest recently. So far, many strategies have succeeded in achieving efficient organic RTP materials by increasing the rate of intersystem crossing (ISC) and suppressing non-radiative transitions. In supramolecular chemistry, the control and regulation of molecular recognition based on the role of the host and guest in supramolecular polymers matrix, has attracted much attention. Recently, researchers have successfully achieved room temperature phosphorescence of pure organic complexes through host-guest interactions. The host molecule specifically includes the phosphorescent guest to reduce non-radiative transitions and enhance room temperature phosphorescence emission. This review aims to describe the developments and achievements of pure organic room temperature phosphorescence systems through the mechanism of host-guest interactions in recent years, and demonstrates the exploration and pursuit of phosphorescent materials of researchers in different fields.     

超分子化学发展简介

本文综述了超分子化学的定义 , 范围及内容. 着重介绍了分子识别, 分子自组装, 超分子催化, 超分子器件及超分子材料等概念. 对由此可能形成的新的前沿科学如分子电子学, 分子离子学, 分子光子学及超分子工艺学等作了扼要介绍 .     

Synthesis and Supramolecular Structure of a Novel :r-Extended TTF Derivative

A novel x-extended TTF derivative (C24H20N6S8, Mr=649.02) has been synthesized and characterized by IR,1H NMR and MS. The crystal structure was prepared by crystallization from CH2Cl2-MeOH. The crystal belongs to the monoclinic system, space group P21/c with a=5.465(5), b=26.835(5), c=10.180(5) A, β=101.929(5)°, V=1460.7(15) A3, Z=2, Dc=1.476 g/cm3,F(000)=668,μ=0.638 mm-1, the final R=0.0390 and wR=0.0586 for 1694 observed reflections with I > 2σ(I). The structure reveals planarity of the two dithiole tings, different from the boat-shaped structure usually found in neutral derivatives of TTF. The central ring of the benzene also adopts a planar conformation, while it is twisted from planarity of the two dithiole rings and forms a dihedral angle of 61.8°. The molecule exhibits a three-dimensional supramolecular architecture constructed through hydrogen bonds. In the molecular structure a noticeable feature can be found that there exist S…S interactions which further reinforce the 3D supramolecular framework.     

Hierarchical Co‐Assembly Enhanced Direct Ink Writing

Integrating intelligent molecular systems into 3D printing materials and transforming their molecular functions to the macroscale with controlled superstructures will unleash great potential for the development of smart materials. Compared to macromolecular 3D printing materials, self‐assembled small‐molecule‐based 3D printing materials are very rare owing to the difficulties of facilitating 3D printability as well as preserving their molecular functions macroscopically. Herein, we report a general approach for the integration of functional small molecules into 3D printing materials for direct ink writing through the introduction of a supramolecular template. A variety of inorganic and organic small‐molecule‐based inks were 3D‐printed, and their superstructures were refined by post‐printing hierarchical co‐assembly. Through spatial and temporal control of individual molecular events from the nano‐ to the macroscale, fine‐tuned macroscale features were successfully installed in the monoliths.