Syntheses of molecular wires containing redox center:Reversible redox property and good energy level matching with Au electrode

有 tetrathiafulvalene (TTF ) 的分子的电线作为氧化还原作用中心被综合并且描绘。紫外鈥搗i s 系列和周期的 voltammetry 证明这些电线在周围的条件和他们的人精力层次下面有好可逆氧化还原作用行为(? 5.0 eV ) 与 Au 的费密水平匹配很好(? 5.1 eV ) 。

A Rapid Solid-phase Synthesis to Soluble Oligothiophene Molecular Wires

分子的电线经由双向稳固阶段的合成被描述的为 oligothiophene 的准备的一个新奇方法。用 brominationand Stille 偶合反应的一个轮流出现的序列， oligomers 在优秀产量和纯净被获得直到 heptamer。

Cyanopolyynes as Organic Molecular Wires in the Interstellar Medium

Cyanopolyynes (H[C≡C]n-CN or HC2n+1N, where n = 1, 2, 3, …, n) are commonly observed in the interstellar medium (ISM) as well as in the envelopes of carbon-rich stars. These linear molecular structures can be well described with a one-dimensional conduction model, which considers the scattering processes of electrons through the charge transfer conduction bridge of the H[C≡C]n-molecular wire containing the CN group as an electron-acceptor terminal unit. Therefore, our results using this model enable a better understanding of the longest molecules observed in interstellar space and provide new insight into why these particular cyanopolyynes reach a maximum length, such as is observed from astronomical experimental spectral data and cosmological chemical models. Dipole moments and geometrical parameters of these cyanopolyynes were obtained from ab initio molecular orbital calculations using the restricted Hartree-Fock approach and 6-311G* basis set, in order to obtain the inner resistance as a new parameter of chemical reaction feasibility for this molecular series. Using this last molecular parameter, we have been able to analyze the possibility of identifying long molecular species that can be found under local thermodynamic equilibrium in some ISM such us HC25H, HC27H, and HC29N, which have not been observed at present.

The amplified fluorescence quenching of heteroatomic conjugated polymers based on the “molecular wire”effects

Tremendous interest has been evoked in the utility of the fluorescent conjugated polymers towards the creation of ultra-sensitive systems based on the molecular wire effects which can amplify the transduction events. Here, a series of new polymers pyridine substitute poly (phen- ylene ethynylene)s are synthesized by Sonogashira-Hagihara coupling reaction. The impact of structure modification on the physical properties and spectral characteristics of poly-mers has been investigated. The quenching studies are car-ried out and exhibit that recognition site (pyridyle group) highly influences the quenching efficiency. The results show that polymer PI with pyridyl group entrapped in the conju-gated backbone has the specific and sensitive response to Pd(Ⅱ). The fluorescence quenching of PⅠby Pd(Ⅱ) is about 65 times greater than that of model monomer.

DFT Study of the Transport Properties of Molecular Wire at Low Bias

用非平衡格林功能(NEGF ) 和密度功能的理论(DFT ) 方法， Au-di-thiol-benzene (DTB ) 三明治系统的运输性质的计算被执行。结果两个都显示出那在 DTB 分子和增加的 S-Au 表面距离的结束的留下的 H 原子将减少电子运输显著地。应用偏爱将改变系统的对称电子结构。我们的结果是与实验一致的品质上，但是在那里存在三的差距数量级，和这被归因于在理论工作和实验之间的不同联合几何学。

First-principle studies of Ⅰ-Ⅴ properties of a molecular wire

The elastic scattering Green function method has been developed to describe the I-V characteristics of molecular wires. The molecular electronic structure and the interaction between the molecule and the gold surface are two key factors for the charge transport properties of molecular wires in the formulas. An ab initio calculation at the hybrid density functional theory level is carried out to obtain the electronic structure of 4-4′-dimercaptodibenzene molecule. The frontier orbit theory and the perturbation theory are employed to determine the constant of the interaction energy between molecule and surface quantitatively. The numerical results show that the bonding between the sulfur atom and the gold atoms corresponds mainly to the covalent bond. Some molecular orbits are extended over molecule and gold cluster that certainly give channels for the charge transport, other molecular orbits are localized and the charge transport can take place by tunnel mechanism. At zero bias region, there exists a current gap. With the increasing bias, the conductance of the wire takes a shape of plateaus.

Self-assembly of insulated molecular wires of a water-soluble cationic PPV and anionic dendrons

Insulated molecular wires of poly(phenylenevinylene) (PPV) were prepared by wrapping the conjugated backbones with dendrons through a noncovalent approach. It was found that electrostatic interaction between the quaternary ammonium groups of PPV-1 and the carboxylate moieties in dendrons induced the packing of dendrons along PPV-1 conjugated backbones. Absorption and emission spectroscopic examinations in solution and solid film indicated that the PPV-1 backbones adopted a more planar and isolated conformation in the complexes. Furthermore, interchain interactions in the complexes could be greatly reduced, improving the quantum yield of PPV-1.

Fabrication of Two-dimensional Monolayer and One-dimensional Wire of Zn-tetra-[3,5-di-t-butylphenyl]-porphyrin on Cu(100) Surface

We describe in this paper the fabrication of two- and one-dimensional nanostructures with organic molecular beam epitaxy （OMBE） principle based on controlled selfassembly by using adsorbate-substrate and intennolecular interactions that are important in molecular fabrication. Cu（100） single crystal was used as substrate in fabricating molecular nanostructures. Scanning tunneling microscopy （STM） experiments confirmed that Zn-tetra- [3,5-di-t-butylphenyl]porphyrin-molecules can be used to fabricate both monolayer and molecular wire on Cu（100） surface simultaneously, and the latter is arranged on the terrace edges. We herein briefly discuss the selectivity in terms of a mechanism in which the highest occupied and lowest unoccupied molecular orbitals （HOMO and LUMO） of the molecules interact with the surface.

Advances in Molecular Electronics:A Brief Review

The field of molecular electronics,also known as moletronics,deals with the assembly of molecular electronic components using molecules as the building blocks.It is an interdisciplinary field that includes physics,chemistry,materials science,and engineering.Moletronics mainly deals with the reduction of size of silicon components.Novel research has been performed in developing electrical-equivalent molecular components.Moletronics has established its influence in electronic and photonic applications,such as conducting polymers,photochromics,organic superconductors,electrochromics,and many more.Since there is a need to reduce the size of the silicon chip,attaining such technology at the molecular level is essential.Although the experimental verification and modeling of molecular devices present a daunting task,vital breakthroughs have been achieved in this field.This article combines an overview of various molecular components,such as molecular transistors,diodes,capacitors,wires,and insulators,with a discussion of the potential applications of different molecules suitable for such components.We emphasize future developments and provide a brief review of different achievements that have been made regarding graphene-based molecular devices.

Influence of InAs deposition thickness on the structural and optical properties of InAs quantum wires

The influence of InAs deposition thickness on the structural and optical properties of InAs/InA1As quantum wires （QWR） superlattices （SLS） was studied. The transmission electron microscopy （TEM） results show that with increasing the InAs deposited thickness, the size uniformity and spatial ordering of InAs QWR SLS was greatly improved, but threading dislocations initiated from InAs nanowires for the sample with 6 monolayers （MLs） InAs deposition. In addition, the zig-zag features along the extending direc- tion and lateral interlink of InAs nanowires were also observed. The InAs nanowires, especially for the first period, were laterally compact. These structural features may result in easy tunneling and coupling of charge carders between InAs nanowires and will hamper their device applications to some extent. Some suggestions are put forward for further improving the uniformity of the stacked InAs QWRs, and for suppressing the formation of the threading dislocations in InAs QWR SLS.

电场作用下分子导线的理论研究

利用从头计算法分别在HF/6-31G,HF/6-31G*,HF/6-31G**,HF/6-31+G,HF/6-31++G,HF/6-31+G*,HF/6-31+G**,HF/D95+*,B3LYP/6-31G*和B3LYP/6-31+G*水平上计算了5个单体的聚乙炔分子导线,从几何构型、SCF能量和分子轨道能级三个方面讨论了外电场对分子导线的影响,给出了聚乙炔分子导线性质与外电场变化的定量关系.

电场对Ni3(dpa)4Cl2金属串配合物结构影响的理论研究

应用密度泛函UBP86方法对具有分子导线潜在应用性的金属串配合物Ni3(dpa)4Cl2进行研究,分析了外电场对配合物的几何构型和电子结构的影响.结果表明,零电场条件下存在沿着Ni63+轴及轴向配体Cl的Ni—Ni及Ni—Cl离域作用.沿金属轴Cl4→Cl5方向施加外电场,可使高电势端的Ni2—Cl4键长增大而Ni1—Ni2键长减小,低电势端的Ni3—Cl5键长减小而Ni1—Ni3键长增大;分子能量降低,偶极矩线性增大;HOMO与LUMO能隙减小,前线占据轨道分布向低电势方向移动且轨道能升高,空轨道分布则向高电势方向移动且轨道能降低,其中沿着金属轴方向离域的前线轨道分布及其轨道能随电场的变化尤为显著.在电场作用下,电荷分布发生改变,低电势端Cl5的负电荷向高电势端Cl4转移,但金属和桥联配体的电荷变化很小;同样,在电场作用下,配合物存在明显的结构变化和电子转移现象,呈现出类似导电过程中电子定向转移的变化规律.

外电场作用下寡聚苯分子导线的性质

利用Hartree—Fock方法在6-31G^＊水平上对聚苯分子进行了计算研究．分别从几何构型、分子轨道空间分布和分子轨道能级三个方面讨论了外电场对寡聚苯分子导线的影响，给出了分子导线的性质与外电场的关系．进一步，连接硫原子于聚苯分子的两端，并共价结合在金电极上．利用非平衡格林函数方法对其在0—2．0V偏压下电子输运特征进行了深入研究．

分子线电子输运特性的第一性原理研究

从第一性原理出发 ,利用密度泛函理论研究了SH -C8H16-SH分子和金表面的相互作用 ,并利用分子前线轨道理论和微扰理论定量地确定了该相互作用能常数 ,然后 ,利用弹性散射格林函数方法研究了该分子与金表面形成的分子线的伏 安特性 .研究结果表明 ,当含有硫氢官能团的有机分子化学吸附于金表面时 ,硫原子将与金原子形成以共价键为主的混和键 ,此时 ,扩展的分子轨道使分子线的电导呈现出欧姆特性 ,而对于局域的分子轨道 ,电子的输运只能通过隧道效应来实现 .对分子线伏 安特性的计算结果显示 ,在零偏压附近 ,存在一个电流禁区 ,随着偏压的增加 ,分子线的电导呈现出平台特征 .

电场对分子线电子结构的影响

从第一性原理出发 ,利用密度泛函理论计算了分子 2 氨基 5 硝基 1,4 二乙炔基 4 苯硫醇基苯与金原子团形成的分子线的电子结构 ,从轨道、能级及吸附电子三个方面讨论了电场对分子线电子结构的影响。该工作将有利于未来纳米电子学器件的设计。

多巴胺在电沉积石墨烯修饰碳分子线电极上的电化学测定

以分子线二苯乙炔为修饰剂和粘合剂制备了一种新型的碳糊电极-碳分子线电极（CMWE）,并以其为基底电极采用电化学还原法将石墨烯（GR）沉积到CMWE表面得到电沉积石墨烯修饰碳分子线电极（GR/CMWE）。考察了多巴胺（DA）在该修饰电极上的电化学行为。实验结果显示DA在GR/CMWE上出现了1对峰形良好的氧化还原峰,与裸电极相比,该氧化还原峰的电流增大,峰电位差减小,表明修饰电极对DA的电化学反应有催化作用。在最佳实验条件下峰电流与DA浓度在8.0×10-7-2.0×10-3 mol/L范围内呈良好的线性关系,检出限（3σ）为2.55×10-7 mol/L。将该电极用于多巴胺注射液样品的检测,结果满意。

有机分子电子器件的研究进展

随着传统硅基电子器件的发展日趋受限,以原子和分子作为电子元器件的研究受到了越来越多的重视。概述了分子电子器件的概念和基本原理,详细介绍了分子导线、分子二极管、分子开关、分子存储器件和分子场效应晶体管的工作原理及最近的研究进展。具有π-共轭结构的有机分子体系是构造分子导线的理想单元;分子结的电子结构不对称性是分子具有整流特性的根本原因;轮烷和索烃是构造分子开关的理想单元之一;分子场效应晶体管的工作原理是量子隧穿,主要是金属-绝缘体-金属间的隧穿效应。最后阐述了目前分子电子器件研究中存在的主要问题。

分子的电子结构对分子线电子输运性质的影响

分子通过硫氢官能团可以很强地吸附于金表面上 ,从而可作为连接体用于纳米电子学中的分子器件 .利用密度泛函理论计算了分子的电子结构 ,讨论了温度对分子结构的影响 ,并利用轨道的扩展情况讨论了分子电子结构对分子线电导的影响 .

含席夫碱桥联配体的双核金属钌配合物的合成及其性能研究(英文)

合成了3种双核钌配合物[Ru（bpy）2]2{[（PyCHN）-Ph-0-C6H4-12R}（C104）4，bpy=2，2＇-联吡啶，PyCHN=N-2．吡啶亚甲基，R=无（1），-C（CH3）2（2），-SO2（3）并进行了有关表征。电化学研究表明：配合物3的△E和憨值最大，说明苯环和硫原子之间存在着较强的（P（π）-d）丌相互作用，有助于获得较强的金属-金属相互作用。配合物1，2，3都有混合价，通过Hush方程可以得到V女的值大概为320-420cm^-1。这些结果表明：Schiff碱作为桥配体对于调配金属-金属相互作用并将其作为分子导线起着特殊的作用。

聚吡咯/环糊精准聚轮烷分子导线材料的合成

在掺杂了α-环糊精或β-环糊精的情况下,对吡咯单体进行氧化聚合,制备了聚吡咯/环糊精准聚轮烷结构材料。通过傅里叶转换红外光谱、广角X射线衍射、元素分析、扫描电镜、电导率测试和循环伏安曲线等手段,表征了聚吡咯/环糊精准聚轮烷的微观结构与微观形态,研究了其导电性能。结果表明,准聚轮烷中吡咯单元和α-CD、β-CD分子的比值分别约为5∶1和24∶1。与聚吡咯相比,准聚轮烷的电导率明显降低,氧化还原的可逆性也有所降低。这类材料在分子导线领域具有广阔的应用前景。