四硫富瓦烯衍生物在有机光电功能材料方面的研究进展

四硫富瓦烯(TTF)及其衍生物不仅是分子导体的有效构筑模块之一, 而且在材料化学的诸多领域显示了广阔的应用前景. 本工作综述了近几年TTF及其衍生物在非线性光学、分子光电器件、光伏器件及光致变色方面的最新研究进展.     

基于四硫富瓦烯衍生物导电LB膜研究概况

四硫富瓦烯(TTF)是具有可逆氧化还原性质的强电子给体, 由其衍生物制备的导电Langmuir-Blodgett (LB)膜可应用于分子材料及分子电子器件方面的研究. 简要综述了近年来具有代表性的基于TTF衍生物的导电LB膜及其可能用途.     

“A-C≡C-TTF-C≡C-A”型四硫富瓦烯衍生物的合成与性质研究

四硫富瓦烯及其衍生物是性能优良的电子给体.本文利用Sonogashira反应将吡啶基团连接在四硫富瓦烯单元上,合成了"A-C≡C-TTF-C≡C-A"型四硫富瓦烯共轭体系衍生物4,4′(5′)-二-(4-吡啶乙炔基)-四硫富瓦烯(TTF4N).吸收光谱、电化学和Pb2+配位键合研究表明,三键作为桥基能够有效实现分子内的电荷转移.金属Pb2+离子与吡啶基团的配位能够引起TTF4N的吸收光谱、核磁氢谱和电化学性质的显著变化.     

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.     

四硫富瓦烯(TTF)衍生物的配位组装

四硫富瓦烯（tetratiafulvalenc,TTF)衍生物和二硫纶（dithiolene)化合行等有机富硫分子作为有机光电磁的功能化合物,一直受到了人们的重视,近年来一类融合了TTF和二硫纶结构的扩展TTF衍生物引起人们很大的兴趣,这类八硫共轭体系具有较好的电子授受特性,展示出潜在的应用价值。有目的地利用它与与金属离子间较强的配位能力对这些化合物进行晶体或分子设计已成为配位化学在富硫有机配合物研究中的一个热点。本文重点介绍这方面的研究的最新进展。主要包括以卤化亚铜基本骨架为基础的四烷基硫取代四硫富瓦烯（[(RS)2TTF(SR)2])的配位组装;二烷基硫取代的TTF融合二硫纶离子（[(RS)2TTF(S2)]^2-)和TTF融合双二硫纶离子（[(S)2TTF(S)]^4-金属配位衍生物的分子设计和空间构筑。通过配位修饰或组装,这类TTF金属衍生物显示了多变的结构,有的已发展具有较好的物理性质。     

配合物Zn(TC-TTF)0.5(bipy)2(CH3OH)的合成与结构表征

在有机导体和超导体领域,四硫富瓦烯(TTF)及其衍生物受到研究者广泛的关注[1,2].由于TTF电荷转移金属配合物具有特殊的结构和性质,它们不仅可以作为分子导体的构成部分,而且可以作为非线性光学材料、传感器、液晶材料以及薄膜材料的构筑模块,在材料化学等诸多领域显示出广阔的应用前景[3～5].     

硫原子桥联芳基取代/稠合四硫富瓦烯

近年来,四硫富瓦烯(Tetrathiafulvalene,TTF)衍生物的设计合成、超分子组装、组装材料的物理性能研究及其在有机电子器件中的应用引起了人们广泛的研究兴趣。在本文中,我们简略综述硫原子桥联芳基取代/稠合四硫富瓦烯衍生物(Ar-S-TTF)的最新研究进展,包括其高效合成、电化学及光学性能研究、分子的结构特征/空间堆积方式,以及此类分子与球形原子簇(富勒烯、杂多酸)之间的超分子组装及组装材料的性能。     

葫环联脲新进展

葫环联脲这类新型主体分子正受到化学家们的广泛关注,并逐渐成为超分子化学研究领域中的一个热点.本文综述了近两-来葫环联脲同系物、衍生物的合成及其在分子识别、分子催化、分子组装等方面的研究进展,并对该领域的研究前景作一展望.     

基于偶氮苯的光开关分子探针与传感芯片研究进展

随着人们对偶氮苯光致异构化反应机制和特性的研究和认识越来越深入透彻,偶氮苯衍生物无论是在理论上还是在实验方面都受到了大量的关注。近年来,偶氮苯衍生物作为光开关响应的功能元件不仅已经用于合成智能聚合物,液晶材料,分子开关和分子机器等,而且正迅速地渗透到化学生物学体系研究和分析的各个方面。因此,本文将着重就基于偶氮苯衍生物功能化的光开关型分子探针与传感芯片及其在化学生物学分析研究方面所取得的最新进展进行总结和综述。引用103篇文献,并对未来的发展前景进行了展望。     

双组分有机低分子凝胶的研究进展

双组分有机低分子凝胶的研究已成为纳米化学新兴研究领域的热点之一, 形成双组分有机低分子凝胶的有机分子具有多种结构, 例如: 巴比妥酸衍生物、氨基酸衍生物、糖类衍生物、金属有机化合物、胆固醇类衍生物和树枝状分子等. 较系统地综述了目前已知的双组分凝胶及其所涉及的有机低分子凝胶因子的主要结构类型, 并展望了双组分有机低分子凝胶的应用前景.     

New Concepts in Tetrathiafulvalene Chemistry

Tetrathiafulvalene (TTF) and its derivatives were originally prepared as strong electron-donor molecules for the development of electrically conducting materials. This Review emphasizes how TTF and its derivatives offer new and in some cases little-exploited possibilities at the molecular to the supramolecular levels, as well as in macromolecular aspects. TTF is a well-established molecule whose interest goes beyond the field of materials chemistry to be considered an important building block in supramolecular chemistry, crystal engineering, and in systems able to operate as machines. At the molecular level, TTF is a readily available molecule which displays a strong electron-donor ability. However, its use as a catalyst for radical-polar crossover reactions, thus mimicking samarium iodide chemistry, has only recently been addressed. Important goals have been achieved in the use of TTF at the macromolecular level where TTF-containing oligomers, polymers, and dendrimers have allowed the preparation of new materials that integrate the unique properties of TTF with the processability and stability that macromolecules display. The TTF molecule has also been successfully used in the construction of redox-active supramolecular systems. Thus, chemical sensors and redox-switchable ligands have been prepared from TTF while molecular shuttles and molecular switches have been prepared from TTF-containing rotaxanes and catenanes. A large synthetic effort has been devoted to the preparation of the so-called organic ferromagnets, many of which are derived from TTF. The main task in these systems is the introduction of ferromagnetic coupling between the conduction electrons and localized electrons. TTF has also played a prominent role in molecular electronics where TTF-containing D-sigma-A molecules have allowed the preparation of the first confirmed unimolecular rectifier. Recently, it has been confirmed that TTF can display efficient nonlinear optic (NLO) responses in the second and third harmonic generation as well as a good thermal stability. These findings can be combined with the redox ability of TTF as an external stimuli to provide a promising strategy for the molecular engineering of switchable NLO materials. Fullerenes endowed with TTF exhibit outstanding photophysical properties leading to charge-separated (CS) states that show remarkable lifetimes.     

Binding studies between tetrathiafulvalene derivatives and cyclobis(paraquat-p-phenylene)

The complexation between a number of different pi-electron donating TTF derivatives and the pi-electron accepting tetracationic cyclophane cyclobis(paraquat-p-phenylene) (CBPQT(4+)) has been studied by (1)H NMR and UV-vis spectroscopy. The results demonstrate that the strength of association between the donors (TTF derivatives) and acceptor (CBPQT(4+)) is strongly dependent on the pi-electron donating properties (measured by the first redox potential ) of the TTF derivatives. However, the first redox potential () is not the only factor of importance. The extended pi-surface of the TTF derivatives also exerts a stabilizing influence upon complexation. The kinetics for the complexation-decomplexation were studied using (1)H NMR spectroscopy and are related to the bulkiness of the TTF derivatives. These effects may serve to improve the design of interlocked molecular systems, especially (bistable) molecular switches, in which CBPQT(4+) and a derivatized TTF unit are incorporated.     

A macrocycle/molecular-clip complex that functions as a quadruply controllable molecular switch

Herein, we report the synthesis of a molecular clip with TTF side-walls and its binding behavior towards electron-deficient guests, namely the formation of macrocycle/molecular-clip supramolecular complexes in solution. Four different sets of external stimuli--the K(+)/[2.2.2]cryptand, NH(4) (+)/Et(3)N and (p-BrPh)(3)NSbCl(6)/Zn pairs, and heating/cooling cycles-control the movement of this molecular switch between its threaded and unthreaded states and provide color changes that are observable by the naked eye. This macrocycle/molecular-clip complex system can be considered not only as a quadruple-use molecular switch, but can also be operated by three of these stimuli as a three-input molecular NOR-functioning logic gate that may be monitored by UV-visible spectroscopy.     

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 multistate switchable [3]rotacatenane

Rotacatenanes are exotic molecular compounds that can be visualized as a unique combination of a [2]catenane and a [2]rotaxane, thereby combining both the circumrotation of the ring component (rotary motion) and the shuttling of the dumbbell component (translational motion) in one structure. Herein, we describe a strategy for the synthesis of a new switchable [3]rotacatenane and the investigation of its switching properties, which rely on the formation of tetrathiafulvalene (TTF) radical π-dimer interactions-namely, the mixed-valence state (TTF(2) )(+.) and the radical-cation dimer state (TTF(+.) )(2) -under ambient conditions. A template-directed approach, based on donor-acceptor interactions, has been developed, resulting in an improved yield of the key precursor [2]catenane, prior to rotacatenation. The nature of the binding between the [2]catenane and selected π-electron-rich templates has been elucidated by using X-ray crystallography and UV/Vis spectroscopy as well as isothermal titration microcalorimetry. The multistate switching mechanism of the [3]rotacatenane has been demonstrated by cyclic voltammetry and EPR spectroscopy. Most notably, the radical-cation dimer state (TTF(+.) )(2) has been shown to enter into an equilibrium by forming the co-conformation in which the two 1,5-dioxynaphthalene (DNP) units co-occupy the cavity of tetracationic cyclophane, thus enforcing the separation of TTF radical-cation dimer (TTF(+.) )(2) . The population ratio of this equilibrium state was found to be 1:1. We believe that this research demonstrates the power of constructing complex molecular machines using template-directed protocols, enabling us to make the transition from simple molecular switches to their multistate variants for enhancing information storage in molecular electronic devices.     

Acid/base controllable molecular recognition

The study of controllable molecular recognition in supramolecular receptors is important for elucidating design strategies that can lead to external control of molecular recognition applications. In this work, we present the design and synthesis of an asymmetric (TTF) tetrathiafulvalene-calix[4]pyrrole receptor and show that its recognition of 1,3,5-trinitrobenzene (TNB) can be controlled by an acid/base input. The new receptor is composed of three identical TTF units and a fourth TTF unit appended with a phenol moiety. Investigation of the host-guest complexation taking place between the TTF-calix[4]pyrrole receptor and the TNB guests was studied by means of absorption and (1)H NMR spectroscopy; this revealed that the conformation of the molecular receptor can be switched between locked and unlocked states by using base and acid as the input. In the unlocked state, the receptor is able to accommodate two TNB guest molecules, whereas the guests are not able to bind to the receptor in the locked state. This work serves to illustrate how external control (acid/base) of a receptor may be used to direct the molecular recognition of guests (TNBs). It has led to a new controllable molecular recognition system that functions as an acid/base switch.     

A neutral redox-switchable [2]rotaxane

A limited range of redox-active, rotaxane-based, molecular switches exist, despite numerous potential applications for them as components of nanoscale devices. We have designed and synthesised a neutral, redox-active [2]rotaxane, which incorporates an electron-deficient pyromellitic diimide (PmI)-containing ring encircling two electron-rich recognition sites in the form of dioxynaphthalene (DNP) and tetrathiafulvalene (TTF) units positioned along the rod section of its dumbbell component. Molecular modeling using MacroModel guided the design of the mechanically interlocked molecular switch. The binding affinities in CH(2)Cl(2) at 298 K between the free ring and two electron-rich guests--one (K(a) = 5.8 × 10(2) M(-1)) containing a DNP unit and the other (K(a) = 6.3 × 10(3) M(-1)) containing a TTF unit--are strong: the one order of magnitude difference in their affinities favouring the TTF unit suggested to us the feasibility of integrating these three building blocks into a bistable [2]rotaxane switch. The [2]rotaxane was obtained in 34% yield by relying on neutral donor-acceptor templation and a double copper-catalysed azide-alkyne cycloaddition (CuAAC). Cyclic voltammetry (CV) and spectroelectrochemistry (SEC) were employed to stimulate and observe switching by this neutral bistable rotaxane in solution at 298 K, while (1)H NMR spectroscopy was enlisted to investigate switching upon chemical oxidation. The neutral [2]rotaxane is a chemically robust and functional switch with potential for applications in device settings.     

Binaphthalene molecules with tetrathiafulvalene units: CD spectrum modulation and new chiral molecular switches by reversible oxidation and reduction of tetrathiafulvalene units

By combining the features of binaphthalene and tetrathiafulvalene (TTF), compounds 1-4 were designed for studies of chiral molecular switches. Absorption and CD spectral studies clearly indicate that the CD spectra resulting from axial chiral binaphthalene units can be modulated through the redox reactions of TTF units, which means new chiral molecular switches can be established on the basis of binaphthalene molecules with TTF units. The reference compound 5, which has one TTF unit rather than two as in the case of compounds 1, 3, and 4, failed to show such property, hinting that the presence of two or more TTF units is required for the realization of CD spectrum modulation. In addition, the manner of the CD spectrum modulation has been found to be dependent on the way TTF units are linked to the binaphthalene skeleton, in terms of the linker length, the positions for substitution, and the number of TTF units.     

Investigating charge transport in molecular switches with neural networks

The control of charge transport on a polymer chain by impurity molecules working as switches is studied. Charge propagation is estimated using a backpropagation neural network approach. The supervised learning is accomplished using theoretical results in which the chain is modeled by a tight-binding Hamiltonian extended to include the effects of an external electric field. The charge transport through the sites that work like a switch is analyzed by the numerical integration of the equations of motion. For a donor–acceptor pair of impurities, we found that the chain offers a wide range of devices, from simple switches to perfect molecular rectifiers. The influence of the parameters of the molecules on the charge transport, the role of the length of separation between the sites where the impurity molecules bond, as well as the changes they must undergo to characterize each kind of molecular switch are determined. ©1999 John Wiley & Sons, Inc. J Comput Chem 20: 1060–1066, 1999