Tetrathiafulvalene-Inserted Diphenoquinone: Synthesis,Structure, and Dynamic Redox Property

A new tetrathiafulvalene (TTF) derivative is synthesized, which is substituted with two phenoxy radicals on one 1,3-dithiole ring, and may have either open-shell diradical or closed-shell extended-quinoidal ground states. X-ray single crystal analysis and NMR measurements prove that this molecule has a closed-shell extended quinoidal structure both in the solid state and in solution. DFT calculations show the donor–acceptor electronic properties of this molecule with a well-separated HOMO–LUMO distribution and a small HOMO–LUMO energy gap. Because of this donor–acceptor character, this molecule gives both the dication and the dianion species by electrochemical oxidation and reduction. Furthermore, during the redox process between the neutral and dication states, this molecule exhibits unique changes in the cyclic voltammogram upon repeating the cycles or varying the scan rate. The observed electrochemical behavior is explained by the conformational changes in the electrochemically generated species, thus indicating that this molecule is classified as a dynamic redox system.     

Thermodynamically Stable o-Quinodimethane: Synthesis,Structure, and Reactivity

Thermal isomerization of cyclobutaphenanthrene to o-quinodimethane was investigated. Sterically congested substituents or electron-donating substituents on the four-membered ring promoted the ring-opening, affording o-quinodimethane in a relatively stable form. Isolation of the newly prepared o-quinodimethane allowed its structural elucidation and investigation of its potential reactivities. Dual [4+2] cycloaddition of an aryne and o-quinodimethane afforded tetrabenzopentacene, demonstrating the synthetic application of the isolated compound.     

Flavin Derivatives with Tailored Redox Properties: Synthesis,Characterization, and Electrochemical Behavior

This study establishes structure–property relationships for four synthetic flavin molecules as bioinspired redox mediators in electro‐ and photocatalysis applications. The studied flavin compounds were disubstituted with polar substituents at the N1 and N3 positions (alloxazine) or at the N3 and N10 positions (isoalloxazines). The electrochemical behavior of one such synthetic flavin analogue was examined in detail in aqueous solutions of varying pH in the range from 1 to 10. Cyclic voltammetry, used in conjunction with hydrodynamic (rotating disk electrode) voltammetry, showed quasi‐reversible behavior consistent with freely diffusing molecules and an overall global 2e^?, 2H⁺ proton‐coupled electron transfer scheme. UV/Vis spectroelectrochemical data was also employed to study the pH‐dependent electrochemical behavior of this derivative. Substituent effects on the redox behavior were compared and contrasted for all the four compounds, and visualized within a scatter plot framework to afford comparison with prior knowledge on mostly natural flavins in aqueous media. Finally, a preliminary assessment of one of the synthetic flavins was performed of its electrocatalytic activity toward dioxygen reduction as a prelude to further (quantitative) studies of both freely diffusing and tethered molecules on various electrode surfaces.     

Synthesis,Structure, and One-electron Redox Reactions of Novel Benzodithiolium Salts

Abstract

Novel stable benzodithiolium salts have been synthesized and characterized by X-ray crystallographic analysis, which have been readily converted to the first isolable dithiolyl radicals by one-electron reduction.     

齐聚苯胺修饰的三联吡啶铁配合物的合成及其光谱和电化学性质

合成了一系列齐聚苯胺修饰的三联吡啶铁配合物,研究了齐聚苯胺链长、不同取代基等对配合物光谱性质和氧化还原性质的影响。 结果表明,相对于配合物[Fe(TPY)₂]²⁺(TPY:三联吡啶),供电子齐聚苯胺单元的引入,使得修饰基团与配合物中心核[Fe(TPY)₂]²⁺之间形成了强的D-A体系,导致配合物¹MLCT吸收波长显著红移至594 nm,且摩尔吸光系数增加近5倍。 配合物同时具有基于金属中心、三联吡啶配体和齐聚苯胺单元的多个氧化还原过程,强拉电子取代基使齐聚苯胺单元氧化还原峰简并且峰电势明显正移,而正丁基取代基对氧化还原峰电势的影响较小。     

基于金属氧簇和铜-四氮唑配合物构建的空旷骨架:合成、结构及性能

在水热条件下,通过CuCl2 6H2O、5-(2-吡啶基)-四唑与不同的金属氧簇阴离子反应,合成了3个基于金属氧簇与铜-四氮唑构建的空旷骨架:Cu4(2-ptz)4(H2O)7SiW12O40 4H2O(1),Cu5(2-ptz)6(OH)(H2O)3PW12O40 H2O(2),Cu9(μ-O)6(2-ptz)6(H2O)9(H6P2W18O62)3H2O(3)(2-ptz=5-(2-吡啶基)-四唑),并通过元素分析、红外光谱、热失重曲线、紫外-可见光谱、粉末衍射和单晶X射线衍射等手段进行了表征.结构分析表明:它们均为三维结构.化合物1是由分立的Z字形的Cu-(2-ptz)配合物单元与412 40SiW O-簇阴离子连接而成;化合物2是由二维的Cu-(2-ptz)网络与312 40PW O-簇单元桥连形成的;化合物3则是一个不常见的基于一维Cu-(2-ptz)链与62 18 62P W O-簇单元构建的.磁性研究结果表明:化合物1和2表现出反铁磁性,而化合物3表现出不常见的亚铁磁性.     

Synthesis,Redox Behavior,Sensitizer Activity,and Oxygen Transfer of Covalently Bound Polymeric Porphyrins

Metal complexes of covalently bound porphyrins are used as sensitive probes for several investigations. Substituted derivatives of tetraphenyl-porphin, phthalocyanine, and naphthalocyanine are synthesized at positively and negatively charged as well as uncharged polymers. The photo-redox activities were studied under irradiation with visible light in the presence of a donor and an acceptor. The triplet life times of covalently bound porphyrin moieties are strongly enhanced compared with the analogous monomeric porphyrins. In addition, the polymer binding results in higher photocatalytic activity. The electron-transfer reactions of Mn(III)-containing porphyrins using the reducing agent dithionite are strongly influenced by the polymer environment. In contrast to monomeric Mn(III)-porphyrins, the porphyrins containing polymers exhibit a two-step reduction which may be due to the change of the conformation of the polymer coil. The catalytic epoxidation of 2,5-dihydrofuran with hypochlorite with formation of 3,4-epoxytetrahydrofuran occurs with water-soluble porphyrins in water. No influence of the polymer environment exists. The different reactions require reaction times from milliseconds up to hours.     

也谈有机化合物的同系列

关于同系列通式的推导贵刊有2次报道,现介绍一种利用数学等差公式的简单方法。等差公式为：an=a1 (n-1)a其中a．为第n项,d为公差,a1为首项,将之用于有机化学同系列通式的推导如下：     

Metal-Bonded Redox-Active Triarylamines and Their Interactions: Synthesis,Structure, and Redox Properties of Paddle-Wheel Copper Complexes

Four new triphenylamine ligands with different substituents in the para position and their corresponding copper(II) complexes are reported. This study includes their structural, spectroscopic, magnetic, and electrochemical properties. The complexes possess a dinuclear copper(II) paddle-wheel core, a building unit that is also common in metal-organic frameworks. Electrochemical measurements demonstrate that the triphenylamine ligands and the corresponding complexes are susceptible to oxidation, resulting in the formation of stable radical cations. The square-wave voltammograms observed for the complexes are similar to those of the ligands, except for a slight shift in potential. Square-wave voltammetry data show that, in the complexes, these oxidations can be described as individual one-electron processes centered on the coordinated ligands. Spectroelectrochemistry reveals that, during the oxidation of the complexes, no difference can be detected for the spectra of successively oxidized species. For the absorption bands of the oxidized species of the ligands and complexes, only a slight shift is observed. ESR spectra for the chemically oxidized complexes indicate ligand-centered radicals. The copper ions of the paddle-wheel core are strongly antiferromagnetic coupled. DFT calculations for the fully oxidized complexes indicate a very weak ferromagnetic coupling between the copper ions and the ligand radicals, whereas a very weak antiferromagnetic coupling is found among the ligand radicals.     

基于四硫富瓦烯新型弯曲电子给体的合成、结构与氧化还原性质

四硫富瓦烯(TTF)和其衍生物是优良的电子给体.利用TTF的衍生物在甲醇钠的条件下,和氯化锌以及四丁基溴化铵生成锌盐,再和二硒唑的四氟化硼化合物在低温下生成化合物1.化合物1经元素分析、核磁共振氢谱、质谱和X衍射单晶结构确定.化合物为正交晶系,空间群Pna21,晶胞参数:a=1.8011(7) nm,b=2.0351(7) nm,c=0.4067(2) nm,Z=4,V=1.4907(10)nm3,Dc=2.176 g·cm-3,F(000)=944,μ=5.655 mm-1,2762个可观测点[I＞2o( I)],精修的最终残余因子为:R=0.0773,wR=0.1779.循环伏安结果表明化合物1有两对可逆氧化还原峰.     

基于四硫富瓦烯新型大环化合物的合成、结构与氧化还原性质

以四硫富瓦烯(TTF)和氯甲基噻吩为原料, 在碱性条件下合成了一个新的基于TTF大环分子1. 化合物1的结构经元素分析、核磁共振氢谱、质谱和X衍射单晶结构确认. 化合物1属单斜晶系, 空间群P2(1)/n, 晶胞参数: a＝0.97220(19) nm, b＝1.2366(3) nm, c＝1.6051(3) nm, β＝95.41(3)°, V＝1.9211(7) nm3, Z＝2, Dc＝1.621g/cm3, F(000)＝960, μ＝1.032 mm－1, R＝0.0333, wR＝0.1000 [I＞2σ(I)]. 循环伏安结果显示化合物1有两对氧化还原峰, 氧化还原过程不可逆.     

Synthesis and Redox Behavior of Novel 9,10‐Diphenylphenanthrenes

The synthesis and electrochemical investigations of 9,10‐diphenylphenanthrene 2a and its derivatives 2b – 2e are reported. The cyclic voltammetry of derivatives 2a – 2c and 2e in different solvent/Bu₄NPF₆ electrolyte systems reveals that the redox properties are dependent on solvent, temperature, and sweep rate. The oxidation of 9,10‐diphenylphenanthrene 2a occurred as an irreversible process, while two fully reversible oxidation waves were observed for dimethoxy derivative 2c . The room‐temperature oxidation of brominated compound 2b is reversible, whereas AcO‐substituted phenanthrene 2e displayed a reversible oxidation peak only at low temperature. Furthermore, the electronic nature of the substituent affects the oxidation potentials. In the CH₂Cl₂‐based electrolyte system, the first oxidation potentials increase in the order 2c < 2e < 2b .     

CoC60(OH)的合成及氧化还原性能

富勒烯独特的电子及空间结构 ,使富勒烯及其衍生物具有特殊的物理化学性能[1 ,2 ] 。在富勒烯金属化合物方面 ,如碱金属原子可以与C60 键合成类“离子型”化合物而表现出十分良好的超导特性[3] 。过渡金属也能与富勒烯形成稳定的过渡金属富勒烯化合物[4] ,此类化合物可能具有与碱金属富勒烯化合物不同的性能 ,如Pd和C60 形成C60 Pdn后具有良好的催化性能[5] 。最近Chi等[6] 合成出稀土富勒烯化合物Sm3C70 ,并且认为Sm与C70 是以共价键的形式结合。研究的主要目的是通过研究富勒烯衍生物结构与性能之间的内在联系规律 ,以期在开发应用方…     

Three Bis‐BODIPY Analogous Diruthenium Redox Series: Characterization and Electronic Structure Analysis

The dianion derived from (2Z,6Z)‐3,7‐diphenyl‐N2,N6‐di(pyridin‐2‐yl)pyrrolo[2,3‐f]indole‐2,6(1H,5H)‐diimine (H₂BL), a modified BODIPY ligand precursor, is shown to be capable of bridging two metal complex fragments RuL₂, L=2,4‐pentanedionato (acac^?), 2,2’‐bipyridine (bpy) or 2‐phenylazopyridine (pap) in [Ru(acac)₂Ru(μ‐BL)Ru(acac)₂] ( 1 / 2 ), [Ru(bpy)₂Ru(μ‐BL)Ru(bpy)₂](ClO₄)₂ ([ 3 ](ClO₄)₂) and [Ru(pap)₂Ru(μ‐BL)Ru(pap)₂](ClO₄)₂ ([ 4 ](ClO₄)₂). The compounds, including a diastereoisomeric pair 1 (meso) and 2 (rac) were spectroscopically and structurally characterized. Reversible electron transfers as revealed by cyclic and differential pulse voltammetry allowed for an EPR and UV‐vis‐NIR spectroelectrochemical investigation of several neighboring charge states. Together with susceptibility measurements and TD‐DFT calculations the assignment of oxidation states reveals that 1 , 2 are diruthenium(III) species which can be oxidized or reduced by one electron whereas 3 ²⁺ and 4 ²⁺ contain ruthenium(II) and get reduced or oxidized mainly at the dianionic bridge ( 3 ²⁺) or are reduced at the ancillary ligands pap ( 4 ²⁺).