Redox-flow batteries(RFBs)are a promising energy storage technology with remarkable scalability and safety for storing vast amounts of renewable energy and mitigating outputfluctuations of renewable power grids.We demon...Redox-flow batteries(RFBs)are a promising energy storage technology with remarkable scalability and safety for storing vast amounts of renewable energy and mitigating outputfluctuations of renewable power grids.We demonstrate a neutral pH aqueous RFB using a custom-designed 1’,1’’’,1’’’’’-(benzene-1,3,5-triyltris(methylene))tris(1-(3-(trimethyl ammonio)propyl)-[4’’,4’’’-bipyridine]-1,1’-diium)nonachloride(BTTMPB)as a 3 e-storage anolyte.The custom design with the high polarization in charge density has led to the excellent water solubility of 4.0 M in H_(2)O(321.6 A h L^(-1))and 2.4 M in 2.0 M NaCl(192.9 A h L^(-1)).The density functional theory(DFT)calculations and electrochemical experiments have shown 3 e-storage response of BTTMPB with a diffusion coefficient of 3.1×10^(-6)cm^(2) s^(-1)and rate con-stant of 1.6×10^(-2)cm s^(-1) for thefirst reduction process.The synthesized anolyte was paired with(Ferrocenylmethyl)trimethylammonium chloride(FcNCl)as catholyte enabling a 0.92 V aqueous RFB with 125.9 W h L^(-1)theoretical energy density.The aqueous RFB has an excellent cycling performance from 10-30 m A cm^(-2),energy efficiency up to 80%,capacity retention of 99.96%per cycle at 20 m A cm^(-2),and a high demonstrated energy density of 29.1 W h L^(-1).展开更多
A new iodiplumbate/organic hybrid constructed from asymmetric viologen and polyiodides,(PBPY-H_2)_2[PbI_4(I_3)_2](1, PBPY = N-(propionate)-4,4?-bipyridinium), has been synthesized via solvothermal reaction and structu...A new iodiplumbate/organic hybrid constructed from asymmetric viologen and polyiodides,(PBPY-H_2)_2[PbI_4(I_3)_2](1, PBPY = N-(propionate)-4,4?-bipyridinium), has been synthesized via solvothermal reaction and structurally determined by X-ray diffraction method. Compound 1 crystallizes in monoclinic system, space group P21/c with Mr = 1936.72, a = 11.622(2), b = 14.839(3), c = 13.372(2) ?, β = 109.447(3)°, V = 2174.6(7) ?3, Z = 2, Dc = 2.958 g/cm3, F(000) = 1712, μ(Mo Kα) = 11.011 mm–1, the final R = 0.0389 and wR = 0.0854 for 3866 observed reflections with I > 2σ(I). [Pb I4(I3)2]4-mononuclear cluster of 1 features a seldom example of coordinated I-3 donors for the lead center. Intermolecular hydrogen bonds between [Pb I4+4(I3)2]-clusters and(PBPY-H)42 dimmers contribute to the formation of a 2-D layer. Its absorption spectrum was investigated, and lower energy band gap of 1.42 eV was explained by DFT calculation. Interestingly, 1 exhibits photocatalytic activity for the degradation of rhodamine B.展开更多
A series of acrylic ester copolymers with viologen group as pendant were synthesizedthrough the reaction of MMA-EBA （Ethenyl bromoacetate） copolymer with 4-（4’-pyridyl）-N-alkyl （or arylalkyl） pyridiniums. These...A series of acrylic ester copolymers with viologen group as pendant were synthesizedthrough the reaction of MMA-EBA （Ethenyl bromoacetate） copolymer with 4-（4’-pyridyl）-N-alkyl （or arylalkyl） pyridiniums. These viologen copolymers can exchange their anionwith NH<sub>4</sub>PF<sub>6</sub> in methanol to improve their solubility in organic solvents such as DMFand acetone. Compared with the corresponding low molecular viologens, these viologencopolymers have relatively lower color development rate under UV light and fade fasterin air due to less affinity to photo-reductant and deficiency of association between theircation radicals. Their photofatigue resistant ability is also slightly better than that of lowmolecular vinlogens.展开更多
Porphyrins and methyl viologen(MV<sup>2+</sup>) are widely used as a photosensitizer and an electron acceptor respectively in photoinduced electron transfer systems. Literatures covered numerous examples o...Porphyrins and methyl viologen(MV<sup>2+</sup>) are widely used as a photosensitizer and an electron acceptor respectively in photoinduced electron transfer systems. Literatures covered numerous examples of photochemical studies of porphyrins covalently linked to various electron acceptor units, such as viologen, which functioned as both a photosensitizer and an electron acceptor in the same molecule. However, the length of the linked chain between porphyrin and viologen is very important. To improve the rate of photoin-展开更多
Viologens (<i>N,N'</i>-dimethyl-4,4-bipyridinium) are advanced functional materials, found important applications in electrochromic devices, molecular machines, organic batteries, and carbohydrate oxid...Viologens (<i>N,N'</i>-dimethyl-4,4-bipyridinium) are advanced functional materials, found important applications in electrochromic devices, molecular machines, organic batteries, and carbohydrate oxidation catalysts in alkaline fuel. In this article, we investigated the design, synthesis and photophysical properties of <i>N,N'</i>-dimethyl-2,5-Bis(pyridinium)oxadiazole <b>4</b> and its precursor 2,5- Bis(pyridine)oxadiazole<b> 2</b>. The crystal structure and photophysical properties of viologen <b>4</b> and precursor <b>2</b> have been determined. The viologen molecule <b>4</b> crystallized in monoclinic form, space group <i>P</i>2<sub>1</sub>/<i>n</i> with four molecules in unit cell. Precursor molecule <b>2</b> also crystalized in monoclinic form, space group <i>C</i>2/<i>c</i> with four molecules in unit cell. From X-rd data, we found three cations in the molecular structure of viologen molecule <b>4</b>, which is unusual in viologens. In the three-dimensional molecular packing diagram of molecule <b>4</b>, the three cations and iodate anions are stabilized by C···C, C···I, N···I, N···H, H···I, N—H···I and C—H···I. The dihedral angle between planes having oxadiazole and two benzene rings are 5°and 8°, suggesting the molecule <b>4</b> is a slightly strained one. The molecular structure of precursor molecule <b>2</b> stabilized by C···C and N···H short contacts between the molecules. The molecule <b>4</b> displayed strong absorbance at 315 nm and emissions between 390 - 410 nm.展开更多
Methyl viologen(MV) as a bench-mark anolyte material has been frequently applied in aqueous organic redox flow batteries(AORFBs) towards large-scale renewable energy storage. However, only the first reduction of MV wa...Methyl viologen(MV) as a bench-mark anolyte material has been frequently applied in aqueous organic redox flow batteries(AORFBs) towards large-scale renewable energy storage. However, only the first reduction of MV was utilized in aqueous electrolytes because of the insoluble MV^0 generated from the second reduction of MV. Herein, we report that methyl viologen with bis(trifluoromethane)sulfonamide counter anion, MVTFSI, can achieve two reversible reductions in a nonaqueous supporting electrolyte. Paired with(Ferrocenylmethyl)trimethylammonium bis(trifluoromethanesulfonyl)imide, FcNTFSI as catholyte, the MVTFS/FcNTFSI nonaqueous organic redox flow battery(NOARFB) can take advantage of either one electron or two electron storage of the methyl viologen moiety and provide theoretical energy density of 24.9 Wh/L and a cell voltage of up to 1.5 V. Using a highly conductive LiTFSI/CH_3CN supporting electrolyte and a porous Daramic separator, the NOARFB displayed excellent cycling performance, including up to a 68.3% energy efficiency at 40 mA/cm^2, and more than 88% total capacity retention after 100 cycles.展开更多
Two iodoargentate hybrids templated by viologen or viologen-like cations, i.e. [MV(Ag_2I_4)]n(1) and [MBYP(AgI 2)]n(2),(MV^(2+) = methyl viologen, MBYP+ = 1-methyl-2,2?-bipyridine) have been synthesized in polar organ...Two iodoargentate hybrids templated by viologen or viologen-like cations, i.e. [MV(Ag_2I_4)]n(1) and [MBYP(AgI 2)]n(2),(MV^(2+) = methyl viologen, MBYP+ = 1-methyl-2,2?-bipyridine) have been synthesized in polar organic solvents.(Ag_2I_4)2-n and(Ag I2)2- n chains in both compounds were constructed from edge-sharing of normal and distorted Ag I4 tetrahedra, and a 2-D supramolecular layer based on C–H···I hydrogen bond was observed in 1. The band gaps of 1.54 and 2.67 e V indicated their semiconductor nature. Their band gap difference was led by different hydrogen bond donors in MV^(2+) and MBYP+, which result in more diffused p-π* antibonding orbitals in MV^(2+).展开更多
A new copper iodide/organic hybrid incorporated with methyl viologen, [(MV)(Cu_2I_4)·H_2O]_n(1, MV = methyl viologen), has been solvothermally synthesized and structurally determined by X-ray diffraction method. ...A new copper iodide/organic hybrid incorporated with methyl viologen, [(MV)(Cu_2I_4)·H_2O]_n(1, MV = methyl viologen), has been solvothermally synthesized and structurally determined by X-ray diffraction method. 1 crystallizes in tetragonal system, space group P42212 with M_r = 838.95, a = 12.4721(18), c = 6.5892(13 ?, V = 1025.0(3) ?~3, Z = 2, Dc = 2.7125 g/cm^3, F(000) = 756, μ(Mo Kα) = 8.097 mm–1, the final R = 0.0273 and wR = 0.0665 for 1062 observed reflections with I > 2σ(I). In 1, the(Cu_2I_4)_n^(2n-) chain was constructed from edge-sharing of distorted Cu I4 tetrahedra. Its absorption spectrum and photoluminescence were investigated, and energy band gap of 1.76 e V indicates its semiconductor nature. Interestingly, 1 exhibits photocatalytic activity for the degradation of rhodamine B.展开更多
The design and synthesis of catalysts for the oxidation desulfurization and production of hydrogen are extremely important for solving environmental pollution and energy shortage.Herein,a novel bifunctional [α-Mo_(8)...The design and synthesis of catalysts for the oxidation desulfurization and production of hydrogen are extremely important for solving environmental pollution and energy shortage.Herein,a novel bifunctional [α-Mo_(8)O_(26)]^(4-)/[β-Mo_(8)O_(26)]^(4-)-based Cu-viologen complex H_(4)[Cu_(2)~ⅠCl_(2)(Hbcbpy)_(4)] [α-Mo_(8)O_(26)] [β-Mo8O_(26)]·H_(2)O(BHU-2,Hbcbpy=1-(4-carboxybenzyl)-4,4'-bipyridinium) was synthesized and characterized by single-crystal X-ray diffraction(XRD),infrared radiation spectra,powder X-ray diffraction(PXRD) and X-ray photoelectron spectroscopy(XPS) spectra.The structural characteristic of BHU-2 is the presence of two types of octamolybdate clusters [α-Mo_(8)O_(26)]^(4-)/[β-Mo_(8)O_(26)]^(4-)and a new binuclear Cu~Ⅰ-Hbcbpy complex linked by Cl-bridges[Cu_(2)ⅠCl_(2)(Hbcbpy)_(4)]^(4+).BHU-2 as a heterogeneous catalyst exhibits excellent activities to the oxidation desulfurization and photocatalytic hydrogen production.At room temperature,BHU-2 can catalyze 96% conversion of methyl phenyl sulfide with 98% selectivity,and the process obeys the pseudo-first-order reaction kinetic with the half-life of9.6 min.The notorious 2-chloroethyl ethyl sulfide can achieve 99% conversion with 98% selectivity within only1 min at the presence of BHU-2,and the turnover frequency(TOF) is up to 7400 h^(-1).BHU-2 also exhibits high catalytic activity for the oxidation of other aromatic and aliphatic thioethers within short time at room temperature.Furthermore,BHU-2 shows a high catalytic activity for visible-light-driven hydrogen evolution with an H_(2) evolution rate of 1677.85 μmol·g^(-1)·h^(-1) within 10 h.Moreover,the catalytic activities do not decrease evidently after three cycles,revealing the prominent structural stability and recyclability.展开更多
Flexible electronics play a key role in the development of human society and our daily activities.Currently they are expected to revolutionize personal health management.However,it remains challenging to fabricate sma...Flexible electronics play a key role in the development of human society and our daily activities.Currently they are expected to revolutionize personal health management.However,it remains challenging to fabricate smart sensors with high robustness,reliability,and visible readout.Herein,high-performance electrochromic(EC),electro-fluorochromic(EFC),and double-network ionogels with excellent transmissivity,high mechanical robustness,and ultrastable reversibility are prepared by combination of thienoviologen-containing ionic liquids with poly(ethyl acrylate)elastomer.The ionogels exhibit good mechanical properties(1000%stretchability and 3.2 kJ m^(−2) fracture energy).The ionogel-based EC devices have a significantly simplified device fabrication process as well as superior cycling stability in which 88%of the contract ratio is maintained at 88%at 500 cycles,even after being stored for 2 years under ambient atmosphere(relative humidity:30%∼40%,25°C).The conductivity of ionogels showed a fast and reproducible response to strain,and the conductivity decreased with increased strain.By virtue of the EC and EFC properties of the thienoviologen component,the EC and EFC efficiency decreased with the increased strain loaded on the ionogels,and almost no EC or EFC phenomena were observed when the strain was above 300%.This feasible strategy provides an opportunity for the development of visible strain sensors to monitor the body’s movements through color and fluorescence emission.展开更多
Developing efficient photosensitizers for C-P bond construction is highly important and remains a challenge due to the urgently needed for the synthesis of modified nucleosides,nucleotides,and other phosphine-containi...Developing efficient photosensitizers for C-P bond construction is highly important and remains a challenge due to the urgently needed for the synthesis of modified nucleosides,nucleotides,and other phosphine-containing ligands.Herein,two pyrene-tethered bismoviologen derivatives(Py-BiV^(2+))were designed and synthesized for visible-light-induced C-P bonds formation.The photochemical and electrochemical properties of Py-BiV^(2+)were studied systemically,certifying fine-tunable opto-electronic properties through the number of pyrene groups(4,n=1;6,n=2).The prepared Py-BiV^(2+)showed strong light absorption,while retaining good redox features and chromic response features that were inherent to viologens.4 exhibited accelerated photoinduced electron transfer in the presence of the electron donor(pyrene)and the generated 4(radical cation)showed higher stability.Accordingly,Py-BiV^(2+)directly served as photosensitizers for the first time in the visible-light-induced C(sp^(3))-P and C(sp^(2))-P bonds formation.As expected,these novel viologen derivatives exhibited good catalytic performance and good substrate expansibility under ambient conditions.展开更多
In comparison with the developing nano-carbon catalysts,some small organic molecules are also emerging as catalysts with typical features,however,their working mechanism is still unclear.Here,we synthesized a series o...In comparison with the developing nano-carbon catalysts,some small organic molecules are also emerging as catalysts with typical features,however,their working mechanism is still unclear.Here,we synthesized a series of viologen-based heterogeneous catalysts with the same molecular skeleton but different substituent groups through anion exchange engineering.These viologen-based molecules were used as a model catalyst to investigate the underlying structure–function relationship for small molecules-based H_(2)O_(2) electrosynthesis.Differing from the commonly reported carbon-based electrocatalysts,viologens can produce H_(2)O_(2) in a synergistic manner,which means that viologens can not only directly catalyze oxygen reduction but also serve as a redox mediator.We found that the ring current and H_(2)O_(2) selectivity of viologens deliver an increasing trend with the increase of the alkyl chain length of alkyl-substituted viologens and further increase when using benzyl as the substituent group.As a result,a benzyl-substituted viologen(BV)delivers the best electrocatalytic performance among the samples,including the highest H_(2)O_(2) selectivity of 96.9%at 0.6 V and the largest ring current density of about 13.6 mA·mmol-1.Furthermore,density functional theory(DFT)calculations disclose that the carbon atoms bonded with positively charged N are the active sites and the small highest occupied molecular orbital(HOMO)–lowest unoccupied molecular orbital(LUMO)energy gap of BV is beneficial to the synergistic mechanism for H_(2)O_(2) production.This work sheds new insight into the efficient H_(2)O_(2) production in a synergistic manner for small molecules-based electrocatalysts.展开更多
紫精材料在外界刺激(如光、热、电)下会表现出灵敏的变色行为,在光学开关和分子传感识别中具有良好的潜在应用前景.通过一步反应合成了4-氟苯乙酮双取代紫精衍生物(VioF_(2)·2Cl).氟苯乙酮取代基的引入扩大了其共轭体系,起到稳定...紫精材料在外界刺激(如光、热、电)下会表现出灵敏的变色行为,在光学开关和分子传感识别中具有良好的潜在应用前景.通过一步反应合成了4-氟苯乙酮双取代紫精衍生物(VioF_(2)·2Cl).氟苯乙酮取代基的引入扩大了其共轭体系,起到稳定自由基的作用,使着色更稳定持久.VioF_(2)·2Cl在紫外(ultraviolet,UV)灯的照射下可以快速地从白色转变为浅黄色直至黄绿色,显示出了灵敏的光致变色行为.变色后晶体中的VioF_(2)^(2+)分子间具有更短的π···π^(*)作用距离,能够促进光致电子转移(photoinduced electron transfer,PET)过程的发生,并且起到稳定紫精阳离子自由基的作用,使其能够在氧气环境下持续变色3 d而不被氧化褪色.这种新型的紫精衍生物表现出了更为灵敏的光致变色性能及自由基着色稳定性,在光致变色材料领域具有良好的潜在应用可能.展开更多
Electroactive self-assembled monolayers (SAMs) containing viologeu group are formed through the adsorption of thiol-functionalized viologen compound CH3(CH2)9V2+(CH2)8SH,where V2+ is N,N’-diaIkylbipyridinium (i.e.a v...Electroactive self-assembled monolayers (SAMs) containing viologeu group are formed through the adsorption of thiol-functionalized viologen compound CH3(CH2)9V2+(CH2)8SH,where V2+ is N,N’-diaIkylbipyridinium (i.e.a viologen group),onto gold electrodes from methanol/water solution and its electrochemical behavior is investigated by Ac voltammetry and square wave voltam-metry,which have the high sensitivity against background charging.The viologen SAM formed is a sub-monolayer and the normal potentials corresponding to the two successive one-electron transfer processes of the active centers (viologen) are-360 mV and-750 mV (vs.Ag/AgCl) in 0.1mol/L phosphate buffer solutions (pH 6.96) respectively,and the standard electron transfer rate constant is 9.0s-1 The electrochemical behavior of this SAM in various solutions has been preliminarily discussed.展开更多
Photoinduced electron transfer and charge separation processes in zinc phthalocya-nine-viologen linked system have been studied and the distance effect of donor/acceptor on electron transfer reaction is discussed. It ...Photoinduced electron transfer and charge separation processes in zinc phthalocya-nine-viologen linked system have been studied and the distance effect of donor/acceptor on electron transfer reaction is discussed. It is indicated that the fluorescence from the zinc phthalocyanine moiety is appreciably quenched and the life-time of singlet excited state is reduced by the pendant viologen. Time-resolved transient absorption spectra measurements show that intramolecular quenching of the triplet state of zinc phthalocyanine by the attached viologen results in charge separation giving reduced viologen radical alive for a rather long period with hundred microsecond duration. The effect of the carbon chain length on the electron transfer rate constant and charge separation efficiency suggests that upon excitation, the zinc phthalocyanine and viologen groups tend to take closer conformation with the increase of the carbon chain examined. The rate constant for the intramolecular electron transfer ket with n =展开更多
Two highly emissive pyrenoviologen derivatives were synthesized and used to fabricate fluorescent sensors for detection of picric acid(PA)with good sensitivity and selectivity.The sensitivity of the sensor was attribu...Two highly emissive pyrenoviologen derivatives were synthesized and used to fabricate fluorescent sensors for detection of picric acid(PA)with good sensitivity and selectivity.The sensitivity of the sensor was attributed to the specific electrostatic association effect of the cationic pyrenoviologens to the picrate anions,which also gave the sensor special selectivity among other compounds with similar structure.The electron transfer between them was attributed to the fluorescence response.Fluorescence lifetime measurements revealed that the quenching is static in nature.The novel and efficient pyrenoviologen derivatives-based sensors offered a strategy to fabricate real-life PA sensor.展开更多
Electrochromic supercapacitors have drawn enormous attention due to their ability to monitor the charge and discharge processes through color changes of electroactive materials.However,there are few work on small orga...Electrochromic supercapacitors have drawn enormous attention due to their ability to monitor the charge and discharge processes through color changes of electroactive materials.However,there are few work on small organic molecules as active materials for all-solid-state electrochromic supercapacitors.Herein,we reported two novel multifunctional symmetric viologens(TPA-bpy and CZ-bpy),which showed different solvatochromic,electrochromic,electroluminochromic and energy storage behaviors despite their similar chemical structures.The different performances between these two viologens were attributed to the difference in the intramolecular charge transfer capability and the solubility in organic solvents.Devices containing TPA-bpy displayed faster response time and higher coloration efficiency due to the introduction of packing-disruptive and three-dimensional triarylamine groups.Moreover,devices containing TPA-bpy also showed energy storage characteristics with an obvious color change from purple to yellow.It showed a wide voltage window(2.0 V),long discharge time(230.3 s at 0.01 mA cm−2),and excellent cycling stability with 90%capacitance retention after 6,000 cycles.The work provides a new and convenient strategy towards the development of novel electrochromic capacitive materials.展开更多
By introducing a host molecule cucurbit[8]uril(CB[8]) into a charge transfer system containing an amphiphile 1-[11-(naphthalene-2-ylmethoxy)-11-oxoundecyl]pyridinium(NP) and an electron-deficient molecule methyl violo...By introducing a host molecule cucurbit[8]uril(CB[8]) into a charge transfer system containing an amphiphile 1-[11-(naphthalene-2-ylmethoxy)-11-oxoundecyl]pyridinium(NP) and an electron-deficient molecule methyl viologen(MV), a novel and anisotropic ternary building block was constructed by hostguest interactions, thereby leading to the morphology transformation of the final assemblies from thinfilms(NP/MV complexes) into diamond-like structures(NP/MV/CB[8] complexes). These intriguing assemblies were firstly discovered and were similar with the shape of well-known metal organic frameworks(MOFs), but just comprised three small organic molecules without metal ions. This finding can enrich the shape of current supramolecular assemblies and thus contributing to more potential applications in material science.展开更多
This study developed a method on detecting methyl viologen(paraquat)using a CdTe-paper-based visual sensor.The CdTe Qdots were immobilized on the paper using glycerin.The volume percentages of CdTe in glycerin were op...This study developed a method on detecting methyl viologen(paraquat)using a CdTe-paper-based visual sensor.The CdTe Qdots were immobilized on the paper using glycerin.The volume percentages of CdTe in glycerin were optimized to be 50%.The sensing principle is that the methyl viologen quenches the fluorescence intensity of CdTe Qdots in a concentration dependent manner.The sensor is linearly response to the logarithm concentration of the methyl viologen in the range from 0.39μmol/L to 3.89 mmol/L with a detection limit of 0.16μmol/L and the corre-lation coefficient R^(2) of 0.99.Three parallel experiments at the methyl viologen concentration of 38.89μmol/L give a relative error of 2.45%,which indicates a good reproducibility.The sensor is not disturbed by other pestisides in-cluding omethoate,anilofos,machete and glyphosate isopropylamine salt.The advantages of this sensor are dis-posable,stable,convenient,and easy to operate.展开更多
Recently,increasing atte ntion has been paid on extending theπ-conjugation structures ofviologens(1,1’-disubstituted-4,4’-bipyridylium salts)by incorporating planar aromatic units into the bipyridinium backbones.Va...Recently,increasing atte ntion has been paid on extending theπ-conjugation structures ofviologens(1,1’-disubstituted-4,4’-bipyridylium salts)by incorporating planar aromatic units into the bipyridinium backbones.Various viologen derivative s with extendedπ-conjugation structures have been synthesized,including the N-termini aromatic substituted viologens,the extendedπ-conjugated viologens(denoted as ECVs)as well as theπ-conjugated oligomeric viologens(denoted as COVs).These compounds typically exhibit interesting properties distinguished from those of an isolated viologen unit,which make them as new class of electron deficient supra-/molecular building blocks in supramolecular chemistry and materials science.In this review,we would like to highlight the recent advances of viologen derivatives with extendedπ-conjugation structures in versatile applications ranging from electrochromic and energy storage materials,the ECV/COV-based supramolecular self-assembly systems including the linear supramolecular polymers and 2D/3D supramolecular organic frameworks(SOFs),to the viologen-based covalent organic frameworks(COFs)/networks.We hope this review will serve as an in-time summary worthy of referring,more importantly,to provide inspiration in the rational design of novel molecules with unexplored properties and functions.展开更多
基金the Department of Science and Technology(DST),Ministry of Science and Technology,Government of India,for sponsoring this study under project no.DST/TMD/MES/2k18/02CSIR,Gov.of India,for the Senior Research Fellowship。
文摘Redox-flow batteries(RFBs)are a promising energy storage technology with remarkable scalability and safety for storing vast amounts of renewable energy and mitigating outputfluctuations of renewable power grids.We demonstrate a neutral pH aqueous RFB using a custom-designed 1’,1’’’,1’’’’’-(benzene-1,3,5-triyltris(methylene))tris(1-(3-(trimethyl ammonio)propyl)-[4’’,4’’’-bipyridine]-1,1’-diium)nonachloride(BTTMPB)as a 3 e-storage anolyte.The custom design with the high polarization in charge density has led to the excellent water solubility of 4.0 M in H_(2)O(321.6 A h L^(-1))and 2.4 M in 2.0 M NaCl(192.9 A h L^(-1)).The density functional theory(DFT)calculations and electrochemical experiments have shown 3 e-storage response of BTTMPB with a diffusion coefficient of 3.1×10^(-6)cm^(2) s^(-1)and rate con-stant of 1.6×10^(-2)cm s^(-1) for thefirst reduction process.The synthesized anolyte was paired with(Ferrocenylmethyl)trimethylammonium chloride(FcNCl)as catholyte enabling a 0.92 V aqueous RFB with 125.9 W h L^(-1)theoretical energy density.The aqueous RFB has an excellent cycling performance from 10-30 m A cm^(-2),energy efficiency up to 80%,capacity retention of 99.96%per cycle at 20 m A cm^(-2),and a high demonstrated energy density of 29.1 W h L^(-1).
基金Project supported by the National Natural Science Foundation of China(21271043,21771038)Qishan Scholars Program of Fuzhou University(No.XQS-1403)
文摘A new iodiplumbate/organic hybrid constructed from asymmetric viologen and polyiodides,(PBPY-H_2)_2[PbI_4(I_3)_2](1, PBPY = N-(propionate)-4,4?-bipyridinium), has been synthesized via solvothermal reaction and structurally determined by X-ray diffraction method. Compound 1 crystallizes in monoclinic system, space group P21/c with Mr = 1936.72, a = 11.622(2), b = 14.839(3), c = 13.372(2) ?, β = 109.447(3)°, V = 2174.6(7) ?3, Z = 2, Dc = 2.958 g/cm3, F(000) = 1712, μ(Mo Kα) = 11.011 mm–1, the final R = 0.0389 and wR = 0.0854 for 3866 observed reflections with I > 2σ(I). [Pb I4(I3)2]4-mononuclear cluster of 1 features a seldom example of coordinated I-3 donors for the lead center. Intermolecular hydrogen bonds between [Pb I4+4(I3)2]-clusters and(PBPY-H)42 dimmers contribute to the formation of a 2-D layer. Its absorption spectrum was investigated, and lower energy band gap of 1.42 eV was explained by DFT calculation. Interestingly, 1 exhibits photocatalytic activity for the degradation of rhodamine B.
基金This work is supported by the National Natural Science Foundation of China.
文摘A series of acrylic ester copolymers with viologen group as pendant were synthesizedthrough the reaction of MMA-EBA （Ethenyl bromoacetate） copolymer with 4-（4’-pyridyl）-N-alkyl （or arylalkyl） pyridiniums. These viologen copolymers can exchange their anionwith NH<sub>4</sub>PF<sub>6</sub> in methanol to improve their solubility in organic solvents such as DMFand acetone. Compared with the corresponding low molecular viologens, these viologencopolymers have relatively lower color development rate under UV light and fade fasterin air due to less affinity to photo-reductant and deficiency of association between theircation radicals. Their photofatigue resistant ability is also slightly better than that of lowmolecular vinlogens.
基金Supported by the National Natural Science Foundation of China
文摘Porphyrins and methyl viologen(MV<sup>2+</sup>) are widely used as a photosensitizer and an electron acceptor respectively in photoinduced electron transfer systems. Literatures covered numerous examples of photochemical studies of porphyrins covalently linked to various electron acceptor units, such as viologen, which functioned as both a photosensitizer and an electron acceptor in the same molecule. However, the length of the linked chain between porphyrin and viologen is very important. To improve the rate of photoin-
文摘Viologens (<i>N,N'</i>-dimethyl-4,4-bipyridinium) are advanced functional materials, found important applications in electrochromic devices, molecular machines, organic batteries, and carbohydrate oxidation catalysts in alkaline fuel. In this article, we investigated the design, synthesis and photophysical properties of <i>N,N'</i>-dimethyl-2,5-Bis(pyridinium)oxadiazole <b>4</b> and its precursor 2,5- Bis(pyridine)oxadiazole<b> 2</b>. The crystal structure and photophysical properties of viologen <b>4</b> and precursor <b>2</b> have been determined. The viologen molecule <b>4</b> crystallized in monoclinic form, space group <i>P</i>2<sub>1</sub>/<i>n</i> with four molecules in unit cell. Precursor molecule <b>2</b> also crystalized in monoclinic form, space group <i>C</i>2/<i>c</i> with four molecules in unit cell. From X-rd data, we found three cations in the molecular structure of viologen molecule <b>4</b>, which is unusual in viologens. In the three-dimensional molecular packing diagram of molecule <b>4</b>, the three cations and iodate anions are stabilized by C···C, C···I, N···I, N···H, H···I, N—H···I and C—H···I. The dihedral angle between planes having oxadiazole and two benzene rings are 5°and 8°, suggesting the molecule <b>4</b> is a slightly strained one. The molecular structure of precursor molecule <b>2</b> stabilized by C···C and N···H short contacts between the molecules. The molecule <b>4</b> displayed strong absorbance at 315 nm and emissions between 390 - 410 nm.
基金Utah State University for providing faculty startup fundsthe Utah Science Technology and Research initiative (USTAR) UTAG award for supporting this study+1 种基金China CSC Study Abroad programUtah Energy Triangle Student Award for supporting his graduate program
文摘Methyl viologen(MV) as a bench-mark anolyte material has been frequently applied in aqueous organic redox flow batteries(AORFBs) towards large-scale renewable energy storage. However, only the first reduction of MV was utilized in aqueous electrolytes because of the insoluble MV^0 generated from the second reduction of MV. Herein, we report that methyl viologen with bis(trifluoromethane)sulfonamide counter anion, MVTFSI, can achieve two reversible reductions in a nonaqueous supporting electrolyte. Paired with(Ferrocenylmethyl)trimethylammonium bis(trifluoromethanesulfonyl)imide, FcNTFSI as catholyte, the MVTFS/FcNTFSI nonaqueous organic redox flow battery(NOARFB) can take advantage of either one electron or two electron storage of the methyl viologen moiety and provide theoretical energy density of 24.9 Wh/L and a cell voltage of up to 1.5 V. Using a highly conductive LiTFSI/CH_3CN supporting electrolyte and a porous Daramic separator, the NOARFB displayed excellent cycling performance, including up to a 68.3% energy efficiency at 40 mA/cm^2, and more than 88% total capacity retention after 100 cycles.
基金Project supported by the National Natural Science Foundation for Fostering Talents in Basic Research(No.J1103303)National Natural Science Foundation of China(21271043)Qishan Scholars Program of Fuzhou University(No.XQS-1403)
文摘Two iodoargentate hybrids templated by viologen or viologen-like cations, i.e. [MV(Ag_2I_4)]n(1) and [MBYP(AgI 2)]n(2),(MV^(2+) = methyl viologen, MBYP+ = 1-methyl-2,2?-bipyridine) have been synthesized in polar organic solvents.(Ag_2I_4)2-n and(Ag I2)2- n chains in both compounds were constructed from edge-sharing of normal and distorted Ag I4 tetrahedra, and a 2-D supramolecular layer based on C–H···I hydrogen bond was observed in 1. The band gaps of 1.54 and 2.67 e V indicated their semiconductor nature. Their band gap difference was led by different hydrogen bond donors in MV^(2+) and MBYP+, which result in more diffused p-π* antibonding orbitals in MV^(2+).
文摘A new copper iodide/organic hybrid incorporated with methyl viologen, [(MV)(Cu_2I_4)·H_2O]_n(1, MV = methyl viologen), has been solvothermally synthesized and structurally determined by X-ray diffraction method. 1 crystallizes in tetragonal system, space group P42212 with M_r = 838.95, a = 12.4721(18), c = 6.5892(13 ?, V = 1025.0(3) ?~3, Z = 2, Dc = 2.7125 g/cm^3, F(000) = 756, μ(Mo Kα) = 8.097 mm–1, the final R = 0.0273 and wR = 0.0665 for 1062 observed reflections with I > 2σ(I). In 1, the(Cu_2I_4)_n^(2n-) chain was constructed from edge-sharing of distorted Cu I4 tetrahedra. Its absorption spectrum and photoluminescence were investigated, and energy band gap of 1.76 e V indicates its semiconductor nature. Interestingly, 1 exhibits photocatalytic activity for the degradation of rhodamine B.
基金financially supported by the National Natural Science Foundation of China (Nos.22271021,21901018 and 21971024)the Natural Science Foundation of Liaoning Province (No.2022-MS-373)Liaoning Revitalization Talents Program (No.XLYC1902011)。
文摘The design and synthesis of catalysts for the oxidation desulfurization and production of hydrogen are extremely important for solving environmental pollution and energy shortage.Herein,a novel bifunctional [α-Mo_(8)O_(26)]^(4-)/[β-Mo_(8)O_(26)]^(4-)-based Cu-viologen complex H_(4)[Cu_(2)~ⅠCl_(2)(Hbcbpy)_(4)] [α-Mo_(8)O_(26)] [β-Mo8O_(26)]·H_(2)O(BHU-2,Hbcbpy=1-(4-carboxybenzyl)-4,4'-bipyridinium) was synthesized and characterized by single-crystal X-ray diffraction(XRD),infrared radiation spectra,powder X-ray diffraction(PXRD) and X-ray photoelectron spectroscopy(XPS) spectra.The structural characteristic of BHU-2 is the presence of two types of octamolybdate clusters [α-Mo_(8)O_(26)]^(4-)/[β-Mo_(8)O_(26)]^(4-)and a new binuclear Cu~Ⅰ-Hbcbpy complex linked by Cl-bridges[Cu_(2)ⅠCl_(2)(Hbcbpy)_(4)]^(4+).BHU-2 as a heterogeneous catalyst exhibits excellent activities to the oxidation desulfurization and photocatalytic hydrogen production.At room temperature,BHU-2 can catalyze 96% conversion of methyl phenyl sulfide with 98% selectivity,and the process obeys the pseudo-first-order reaction kinetic with the half-life of9.6 min.The notorious 2-chloroethyl ethyl sulfide can achieve 99% conversion with 98% selectivity within only1 min at the presence of BHU-2,and the turnover frequency(TOF) is up to 7400 h^(-1).BHU-2 also exhibits high catalytic activity for the oxidation of other aromatic and aliphatic thioethers within short time at room temperature.Furthermore,BHU-2 shows a high catalytic activity for visible-light-driven hydrogen evolution with an H_(2) evolution rate of 1677.85 μmol·g^(-1)·h^(-1) within 10 h.Moreover,the catalytic activities do not decrease evidently after three cycles,revealing the prominent structural stability and recyclability.
基金research was made possible as a result of generous grants from the National Key Research and Development Program of China(grant no.2021YFB3200700)the Natural Science Foundation of China(grant nos.22175138,21875180,and 52203240)+4 种基金the Independent Innovation Capability Improvement Project of Xi’an Jiaotong University(grant no.PY3A066)the China National Postdoctoral Program for Innovative Talents(grant no.BX2021231)the Fundamental Research Funds for the Central Universities(grant no.sxjh032021099)the China Postdoctoral Science Foundation(grant no.2021M692545)the Natural Science Foundation of Shaanxi Province(grant no.2021JQ-043).
文摘Flexible electronics play a key role in the development of human society and our daily activities.Currently they are expected to revolutionize personal health management.However,it remains challenging to fabricate smart sensors with high robustness,reliability,and visible readout.Herein,high-performance electrochromic(EC),electro-fluorochromic(EFC),and double-network ionogels with excellent transmissivity,high mechanical robustness,and ultrastable reversibility are prepared by combination of thienoviologen-containing ionic liquids with poly(ethyl acrylate)elastomer.The ionogels exhibit good mechanical properties(1000%stretchability and 3.2 kJ m^(−2) fracture energy).The ionogel-based EC devices have a significantly simplified device fabrication process as well as superior cycling stability in which 88%of the contract ratio is maintained at 88%at 500 cycles,even after being stored for 2 years under ambient atmosphere(relative humidity:30%∼40%,25°C).The conductivity of ionogels showed a fast and reproducible response to strain,and the conductivity decreased with increased strain.By virtue of the EC and EFC properties of the thienoviologen component,the EC and EFC efficiency decreased with the increased strain loaded on the ionogels,and almost no EC or EFC phenomena were observed when the strain was above 300%.This feasible strategy provides an opportunity for the development of visible strain sensors to monitor the body’s movements through color and fluorescence emission.
基金supported by the Natural Science Foundation of China(Nos.22175138,21875180)the Key Research and Development Program of Shaanxi(No.2021GXLH-Z023)the Independent Innovation Capability Improvement Project of Xi’an Jiaotong University(No.PY3A066)。
文摘Developing efficient photosensitizers for C-P bond construction is highly important and remains a challenge due to the urgently needed for the synthesis of modified nucleosides,nucleotides,and other phosphine-containing ligands.Herein,two pyrene-tethered bismoviologen derivatives(Py-BiV^(2+))were designed and synthesized for visible-light-induced C-P bonds formation.The photochemical and electrochemical properties of Py-BiV^(2+)were studied systemically,certifying fine-tunable opto-electronic properties through the number of pyrene groups(4,n=1;6,n=2).The prepared Py-BiV^(2+)showed strong light absorption,while retaining good redox features and chromic response features that were inherent to viologens.4 exhibited accelerated photoinduced electron transfer in the presence of the electron donor(pyrene)and the generated 4(radical cation)showed higher stability.Accordingly,Py-BiV^(2+)directly served as photosensitizers for the first time in the visible-light-induced C(sp^(3))-P and C(sp^(2))-P bonds formation.As expected,these novel viologen derivatives exhibited good catalytic performance and good substrate expansibility under ambient conditions.
基金financial support from the National Key R&D Program of China(Nos.2021YFA1202802,2022YFF0712200,and 2022YFE0127400)the National Natural Science Foundation of China(Nos.U20A20131 and 51425302)+1 种基金the China Postdoctoral Science Foundation Funded Project(No.2021M690801)the CAS Pioneer Hundred Talents Program.
文摘In comparison with the developing nano-carbon catalysts,some small organic molecules are also emerging as catalysts with typical features,however,their working mechanism is still unclear.Here,we synthesized a series of viologen-based heterogeneous catalysts with the same molecular skeleton but different substituent groups through anion exchange engineering.These viologen-based molecules were used as a model catalyst to investigate the underlying structure–function relationship for small molecules-based H_(2)O_(2) electrosynthesis.Differing from the commonly reported carbon-based electrocatalysts,viologens can produce H_(2)O_(2) in a synergistic manner,which means that viologens can not only directly catalyze oxygen reduction but also serve as a redox mediator.We found that the ring current and H_(2)O_(2) selectivity of viologens deliver an increasing trend with the increase of the alkyl chain length of alkyl-substituted viologens and further increase when using benzyl as the substituent group.As a result,a benzyl-substituted viologen(BV)delivers the best electrocatalytic performance among the samples,including the highest H_(2)O_(2) selectivity of 96.9%at 0.6 V and the largest ring current density of about 13.6 mA·mmol-1.Furthermore,density functional theory(DFT)calculations disclose that the carbon atoms bonded with positively charged N are the active sites and the small highest occupied molecular orbital(HOMO)–lowest unoccupied molecular orbital(LUMO)energy gap of BV is beneficial to the synergistic mechanism for H_(2)O_(2) production.This work sheds new insight into the efficient H_(2)O_(2) production in a synergistic manner for small molecules-based electrocatalysts.
文摘紫精材料在外界刺激(如光、热、电)下会表现出灵敏的变色行为,在光学开关和分子传感识别中具有良好的潜在应用前景.通过一步反应合成了4-氟苯乙酮双取代紫精衍生物(VioF_(2)·2Cl).氟苯乙酮取代基的引入扩大了其共轭体系,起到稳定自由基的作用,使着色更稳定持久.VioF_(2)·2Cl在紫外(ultraviolet,UV)灯的照射下可以快速地从白色转变为浅黄色直至黄绿色,显示出了灵敏的光致变色行为.变色后晶体中的VioF_(2)^(2+)分子间具有更短的π···π^(*)作用距离,能够促进光致电子转移(photoinduced electron transfer,PET)过程的发生,并且起到稳定紫精阳离子自由基的作用,使其能够在氧气环境下持续变色3 d而不被氧化褪色.这种新型的紫精衍生物表现出了更为灵敏的光致变色性能及自由基着色稳定性,在光致变色材料领域具有良好的潜在应用可能.
基金Project supported by the National Natural Science Foundation of China.
文摘Electroactive self-assembled monolayers (SAMs) containing viologeu group are formed through the adsorption of thiol-functionalized viologen compound CH3(CH2)9V2+(CH2)8SH,where V2+ is N,N’-diaIkylbipyridinium (i.e.a viologen group),onto gold electrodes from methanol/water solution and its electrochemical behavior is investigated by Ac voltammetry and square wave voltam-metry,which have the high sensitivity against background charging.The viologen SAM formed is a sub-monolayer and the normal potentials corresponding to the two successive one-electron transfer processes of the active centers (viologen) are-360 mV and-750 mV (vs.Ag/AgCl) in 0.1mol/L phosphate buffer solutions (pH 6.96) respectively,and the standard electron transfer rate constant is 9.0s-1 The electrochemical behavior of this SAM in various solutions has been preliminarily discussed.
基金supported by the National Natural Science Foundation of China and the Laboratory of Excited State Processes,Changchun Institute of physics,Chinese Academy of Sciences.
文摘Photoinduced electron transfer and charge separation processes in zinc phthalocya-nine-viologen linked system have been studied and the distance effect of donor/acceptor on electron transfer reaction is discussed. It is indicated that the fluorescence from the zinc phthalocyanine moiety is appreciably quenched and the life-time of singlet excited state is reduced by the pendant viologen. Time-resolved transient absorption spectra measurements show that intramolecular quenching of the triplet state of zinc phthalocyanine by the attached viologen results in charge separation giving reduced viologen radical alive for a rather long period with hundred microsecond duration. The effect of the carbon chain length on the electron transfer rate constant and charge separation efficiency suggests that upon excitation, the zinc phthalocyanine and viologen groups tend to take closer conformation with the increase of the carbon chain examined. The rate constant for the intramolecular electron transfer ket with n =
基金supported by the National Natural Science Foundation of China(Nos.21603016,21704081,51603016 and21704005)Shaanxi College Students Innovation and Entrepreneurship Training Program(No.S201910710282)
文摘Two highly emissive pyrenoviologen derivatives were synthesized and used to fabricate fluorescent sensors for detection of picric acid(PA)with good sensitivity and selectivity.The sensitivity of the sensor was attributed to the specific electrostatic association effect of the cationic pyrenoviologens to the picrate anions,which also gave the sensor special selectivity among other compounds with similar structure.The electron transfer between them was attributed to the fluorescence response.Fluorescence lifetime measurements revealed that the quenching is static in nature.The novel and efficient pyrenoviologen derivatives-based sensors offered a strategy to fabricate real-life PA sensor.
基金This work was supported by the National Funds for Distinguished Young Scientists(61825503)the National Natural Science Foundation of China(61775101,61804082)+5 种基金the Priority Academic Program Development of Jiangsu Higher Education Institutions(YX030003)Natural Science Foundation of Jiangsu Higher Education Institutions(18KJB430021)the China Postdoctoral Science Foundation Funded Project(2018M642286)Jiangsu Planned Projects for Postdoctoral Research Funds(2019K047A)Natural Science Foundation of Jiangsu Province of China(BK20180760)Science Foundation of Nanjing University of Posts and Telecommunications(NY217142).
文摘Electrochromic supercapacitors have drawn enormous attention due to their ability to monitor the charge and discharge processes through color changes of electroactive materials.However,there are few work on small organic molecules as active materials for all-solid-state electrochromic supercapacitors.Herein,we reported two novel multifunctional symmetric viologens(TPA-bpy and CZ-bpy),which showed different solvatochromic,electrochromic,electroluminochromic and energy storage behaviors despite their similar chemical structures.The different performances between these two viologens were attributed to the difference in the intramolecular charge transfer capability and the solubility in organic solvents.Devices containing TPA-bpy displayed faster response time and higher coloration efficiency due to the introduction of packing-disruptive and three-dimensional triarylamine groups.Moreover,devices containing TPA-bpy also showed energy storage characteristics with an obvious color change from purple to yellow.It showed a wide voltage window(2.0 V),long discharge time(230.3 s at 0.01 mA cm−2),and excellent cycling stability with 90%capacitance retention after 6,000 cycles.The work provides a new and convenient strategy towards the development of novel electrochromic capacitive materials.
基金the financial supports from the National Natural Science Foundation of China (Nos. 31860516, 21662009, 21702037)Frontiers Science Center for Asymmetric Synthesis and Medicinal Molecules, Department of Education, Guizhou Province [Qianjiaohe KY No. (2020)004]Program of Introducing Talents of Discipline to Universities of China (111 Program, No. D20023)。
文摘By introducing a host molecule cucurbit[8]uril(CB[8]) into a charge transfer system containing an amphiphile 1-[11-(naphthalene-2-ylmethoxy)-11-oxoundecyl]pyridinium(NP) and an electron-deficient molecule methyl viologen(MV), a novel and anisotropic ternary building block was constructed by hostguest interactions, thereby leading to the morphology transformation of the final assemblies from thinfilms(NP/MV complexes) into diamond-like structures(NP/MV/CB[8] complexes). These intriguing assemblies were firstly discovered and were similar with the shape of well-known metal organic frameworks(MOFs), but just comprised three small organic molecules without metal ions. This finding can enrich the shape of current supramolecular assemblies and thus contributing to more potential applications in material science.
基金supported by the National Natural Science Foundation of China(Nos.21273059,21003032)the State Key Laboratory of Urban Water Resource and Environment(Harbin Institute of Tech-nology)(No.2014DX09)+1 种基金the Fundamental Research Funds for the Central Universities(No.HIT.KISTP.201407)Harbin Science and Technology Research Council(No.2014RFXXJ063).
文摘This study developed a method on detecting methyl viologen(paraquat)using a CdTe-paper-based visual sensor.The CdTe Qdots were immobilized on the paper using glycerin.The volume percentages of CdTe in glycerin were optimized to be 50%.The sensing principle is that the methyl viologen quenches the fluorescence intensity of CdTe Qdots in a concentration dependent manner.The sensor is linearly response to the logarithm concentration of the methyl viologen in the range from 0.39μmol/L to 3.89 mmol/L with a detection limit of 0.16μmol/L and the corre-lation coefficient R^(2) of 0.99.Three parallel experiments at the methyl viologen concentration of 38.89μmol/L give a relative error of 2.45%,which indicates a good reproducibility.The sensor is not disturbed by other pestisides in-cluding omethoate,anilofos,machete and glyphosate isopropylamine salt.The advantages of this sensor are dis-posable,stable,convenient,and easy to operate.
基金the Natural Science Foundation of Zhejiang Province(No.LY20B020005)Shanghai Scientific and Technological Innovation Project(No.18JC1410600)for the financial support。
文摘Recently,increasing atte ntion has been paid on extending theπ-conjugation structures ofviologens(1,1’-disubstituted-4,4’-bipyridylium salts)by incorporating planar aromatic units into the bipyridinium backbones.Various viologen derivative s with extendedπ-conjugation structures have been synthesized,including the N-termini aromatic substituted viologens,the extendedπ-conjugated viologens(denoted as ECVs)as well as theπ-conjugated oligomeric viologens(denoted as COVs).These compounds typically exhibit interesting properties distinguished from those of an isolated viologen unit,which make them as new class of electron deficient supra-/molecular building blocks in supramolecular chemistry and materials science.In this review,we would like to highlight the recent advances of viologen derivatives with extendedπ-conjugation structures in versatile applications ranging from electrochromic and energy storage materials,the ECV/COV-based supramolecular self-assembly systems including the linear supramolecular polymers and 2D/3D supramolecular organic frameworks(SOFs),to the viologen-based covalent organic frameworks(COFs)/networks.We hope this review will serve as an in-time summary worthy of referring,more importantly,to provide inspiration in the rational design of novel molecules with unexplored properties and functions.
