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Role of methoxy and C_(α)-based substituents in electrochemical oxidation mechanisms and bond cleavage selectivity of β-O-4 lignin model compounds
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作者 Yang Zhou Qiang Zeng +3 位作者 Hongyan He Kejia Wu Fuqiao Liu Xuehui Li 《Green Energy & Environment》 SCIE EI CAS CSCD 2024年第1期114-125,共12页
In order to better understand the specific substituent effects on the electrochemical oxidation process of β-O-4 bond, a series of methoxyphenyl type β-O-4 dimer model compounds with different localized methoxyl gro... In order to better understand the specific substituent effects on the electrochemical oxidation process of β-O-4 bond, a series of methoxyphenyl type β-O-4 dimer model compounds with different localized methoxyl groups, including 2-(2-methoxyphenoxy)-1-phenylethanone, 2-(2-methoxyphenoxy)-1-phenylethanol, 2-(2-methoxyphenoxy)-1-(4-methoxyphenyl)ethanone, 2-(2-methoxyphenoxy)-1-(4-methoxyphenyl)ethanol, 2-(2,6-dimethoxyphenoxy)-1-(4-methoxyphenyl)ethanone, 2-(2,6-dimethoxyphenoxy)-1-(4-methoxyphenyl)ethanol have been selected and their electrochemical properties have been studied experimentally by cyclic voltammetry, and FT-IR spectroelectrochemistry. Combining with electrolysis products distribution analysis and density functional theory calculations, oxidation mechanisms of all six model dimers have been explored. In particular, a total effect from substituents of both para-methoxy(on the aryl ring closing to Cα) and Cα-OH on the oxidation mechanisms has been clearly observed, showing a significant selectivity on the Cα-Cβbond cleavage induced by electrochemical oxidations. 展开更多
关键词 Lignin model compounds β-O-4 dimers Electrochemical oxidation Oxidation mechanisms Substituent effect
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Synthesis of Calix[4] arene Thia Derivative and Extraction Effect of Substituents on Mercury( Ⅱ) and Lead( Ⅱ) 被引量:2
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作者 陶旭晨 何瑾馨 《Journal of Donghua University(English Edition)》 EI CAS 2017年第1期49-52,共4页
Calix[4]arene derivatives have been reported to possess high selectivity for metal ions.In order to analyze the extraction effect of substituents on Hg^(2+)and Pb^(2+),calix[4]arene derivatives containing hydroxyl,bro... Calix[4]arene derivatives have been reported to possess high selectivity for metal ions.In order to analyze the extraction effect of substituents on Hg^(2+)and Pb^(2+),calix[4]arene derivatives containing hydroxyl,bromoethoxy and 1,11-dioxa-4,8-dithiahendecene were successfully synthesized,with their extraction effectiveness towards Hg^(2+)and Pb^(2+)were evaluated respectively.The results indicated that the phenolic hydroxyl in calix[4]arene improved the extraction ability on Hg^(2+)by promoting the formation of the negative oxygen ions that could bind with Hg^(2+)by coordination and ionic bonds.The extraction ability of 5,17-dinitro-26,28-(1’,11’-dioxa-4’,8’-dithiahendecene)-calix[4]arene(calix[4]arene thia derivative)was improved slightly due to the better coordination capacity for metal ions after introduction of 1,11-dioxa-4,8-dithiahendecene,which was a chelate-binding centre.Regarding to Pb^(2+),only 1,11-dioxa-4,8-dithiahendecene on molecule contributed to extraction due to the coordination bond.Since the metal ion with higher charge-to-radius ratio could coordinate with one ligand more stably,Pb^(2+)with higher charge-to-radius ratio than Hg^(2+)was coordinated and extracted by the calix[4]arene thia derivative more easily.Furthermore,extraction rates of the calix[4]arene thia derivative on both ions(Hg^(2+)and Pb^(2+))increased with the increase of pH value in acidic aqueous system(pH<7). 展开更多
关键词 arene thia derivative substituents coordination charge-to-radius ratio
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THE UNIFORMITY OF DISTRIBUTION OF SUBSTITUENTS ALONG THE CHAIN OF CARBOXYMETHYL CELLULOSE SYNTHESIZED IN TWO-PHASE MEDIUM C_6H_6——C_2H_5OH
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作者 程发 冯建新 +2 位作者 李桂凤 王东华 张镜吾 《Chinese Journal of Polymer Science》 SCIE CAS CSCD 1998年第2期117-125,共9页
Based on the property that carboxymethylcellulose (CMC ) can be de-graded to anhydroglucose residues by cellulase, the rate constant (K) of enzymatic degra-dation of CMC synthesized in the benzene-ethanol medium has b... Based on the property that carboxymethylcellulose (CMC ) can be de-graded to anhydroglucose residues by cellulase, the rate constant (K) of enzymatic degra-dation of CMC synthesized in the benzene-ethanol medium has been determined. Further-morel experimental equation K = 2.71× 10^(-2)(DS)^(-1.2) reflecting the relationship betweenK and the degree of substitution (DS) is correlated and used to describe chemical mi-crostructure uniformity of the distribution of substituents along chains effectively. Chainstructure parameters of enzymatic degradation products of CMC-the number of chainbreaks and the percentage of glucose released have been also measured. Average length ofsubstituted and unsubstituted chain segments are calculated simultaneously. Through thestudy of static and dynamic procedures of enzymatic degradation, the method to charac-terize the distribution of substituents of CMC along the chain has been improved. 展开更多
关键词 CARBOXYMETHYLCELLULOSE Distribution of substituents Anhydroglucose unit Enzymatic degradation
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Synthesis and phosphorescent properties of two novel iridium (Ⅲ) complexes bearing bulky tert-butyl substituents 被引量:1
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作者 Rong Huang Xiao Qiang Wei +2 位作者 Tai Ping Zhang Zhi Yun Lu Ming Gui Xie 《Chinese Chemical Letters》 SCIE CAS CSCD 2007年第9期1119-1123,共5页
The synthesis and phosphorescence properties of two novel Ir(Ⅲ)complexes bearing tert-butyl substituents,bis(4-tert-butyl-2- phenylbenzothiozolato-N,C^(2′))iridium(Ⅲ)(acetylacetonate)[(tbt)_2Ir(acac)]and bis(4-tert... The synthesis and phosphorescence properties of two novel Ir(Ⅲ)complexes bearing tert-butyl substituents,bis(4-tert-butyl-2- phenylbenzothiozolato-N,C^(2′))iridium(Ⅲ)(acetylacetonate)[(tbt)_2Ir(acac)]and bis(4-tert-butyl-1-phenyl-1H-benzimidazolato- N,C^(2′))iridium(Ⅲ)(acetylacetonate)[(tpbi)_2Ir(acac)],are reported,their molecular structures are confirmed by^1H NMR,ESI-MS and elementary analysis.Photoluminescence(PL)studies revealed that they can emit strong green and orange phosphorescence in high quantum yields.Compared to their prototypes lacking of tert-butyl substituents,the two novel iridium(Ⅲ)complexes both have shorter lifetimes and improved or nearly similar PL quantum efficiencies,implying that the exciton quenching is inhibited effectively when molecular steric hindrance increases.The two chelates have great potential to be used as electrophosphorescent materials. 展开更多
关键词 SYNTHESIS tert-Butyl substituent Phosphorescence ELECTROPHOSPHORESCENCE
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Template Syntheses and Crystal Structures of Hexaaza Macrocyclic Complexes with C-Methyl Substituents
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作者 ZHANG Bing KOU Hui-Zhong CUI Ai-Li WANG Ru-Ji 《Chinese Journal of Structural Chemistry》 SCIE CAS CSCD 北大核心 2005年第11期1259-1263,共5页
Two new macrocyclic complexes with C-methyl substituents on the framework, namely, [CuL](ClO4)2 (L = 5,12-dimethyl-1,8-dihydroxyethyl-1,3,6,8,10,13-hexaazacyclotetradecane) 1 and [NiL](ClO4)2 2, have been synthe... Two new macrocyclic complexes with C-methyl substituents on the framework, namely, [CuL](ClO4)2 (L = 5,12-dimethyl-1,8-dihydroxyethyl-1,3,6,8,10,13-hexaazacyclotetradecane) 1 and [NiL](ClO4)2 2, have been synthesized and structurally characterized through X-ray diffraction analysis. Also, crystal structure of [CuL^1](ClO4)2 (L^1 = 1,8-dimethyl- 1,3,6,8, [ 0,13- hexaazacyclotetradecane) 3 has been determined. Crystal data for 1: C14H32C12CuN6O10, Mr = 578.90, monoclinic, P2 1/n, α = 8.3529(11), b = 10.8105(17), c = 13.3709(17) ,A, β = 105.189(10)°, V= 1165.2(3) A3, Z = 2, Dc = 1.650 g/cm^3, F(000) = 602, λ(MoKct) = 0.71073 A,μ = 1.229 mm ^-1, R = 0.0474 and wR = 0.0895 for 2771 observed reflections (I 〉 2σ(Ⅰ)). Crystal data for 2: C14H32C12N6NiO10, Mr = 574.07, monoclinic, P2 1/c, a = 8.3636(12), b = 12.997(2), c = 10.764(2) A, β = 99.31(2)°, V = 1154.7(3) A^3, Z = 2, DC = 1.651 g/cm^3, F(000) = 600, λ(MoKa) = 0.71073 A,μ = 1. 134 mm^-1, R = 0.0380 and wR = 0.0796 for 2670 observed reflections (i 〉 2σ(Ⅰ)). Crystal data for 3: C 10H26Cl2CuN6O8, Mr = 492.81, monoclinic, P2 1/n, a = 8.4860(17), b = 8.6320(17), c = 12.662(3) ,A,β = 103.40(3)°, V = 902.2(3)A^3, Z = 2, Dc = 1.814 g/cm^3, F(000) = 510, λ(MoKa) = 0.71073A, μ = 1.562 mm^-1, R = 0.0505 and wR = 0.1061 for 1967 observed reflections (I〉 2σ(Ⅰ)). Complexes 1 and 2 are isostructural with the metal ions situated at the inversion center/Hydrogen bonds between O atoms of pendant and perchlorate anion give rise to a two-dimensional supramolecular layer. The Cu(Ⅱ) ions of compounds 1 and 3 adopt distorted axially-elongated octahedral coordinate geometry, and the nickel(Ⅱ) ion in complex 2 is four-coordinated with a square-planar configuration. 展开更多
关键词 synthesis crystal structure MACROCYCLE C-methyl substituent COPPER nickel synthesis crystal structure MACROCYCLE C-methyl substituent COPPER NICKEL
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ELECTRONIC EFFECTS OF POLYFLUORINATED SUBSTITUENTS ON THE POLYMERIZATION AND THE PROPERTIES OF POLYTHIOPHENES
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作者 张旭庆 沈学明 +2 位作者 杨士勇 陆伟 张景云 《Chinese Journal of Polymer Science》 SCIE CAS CSCD 1997年第1期15-23,共9页
Three series of polythiophenes containing fluoroalkoxy and fluoroether substituents were prepared by electrochemical polymerization. The effect of substituents with fluoroalkoxy or ether functional groups on the elect... Three series of polythiophenes containing fluoroalkoxy and fluoroether substituents were prepared by electrochemical polymerization. The effect of substituents with fluoroalkoxy or ether functional groups on the electrochemical polymerization of thiophene monomers and properties of the obtained polymers were analyzed. The introduction of a fluoroether functional group at the 3-position of the thiophene ring leads to an increase of the oxidation potential of the monomer and to a decrease of the conductivity of the resulting polymers, even with the use of a CH2 group as spacer. Conversely, the presence of an oxygen atom directly at the 3-position of the thiophene ring, which offsets the negative withdrawing effect of fluoroalkyl groups, facilitates the synthesis of highly conducting polythiophenes. 展开更多
关键词 electronic effect electrochemical polymerization polythiophene polyfluorinated substituent
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Introducing alkoxy groups as outer side chains and substituents ofπ-bridges obtains high-performance medium-bandgap polymerized small molecule acceptors
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作者 Yufei Gong Tianwei Zou +5 位作者 Xiaojun Li Hongmei Zhuo Shucheng Qin Guangpei Sun Lei Meng Yongfang Li 《Science China Chemistry》 SCIE EI CAS CSCD 2023年第10期2912-2920,共9页
The medium-bandgap polymerized small molecule acceptors(PSMAs)have broad application scenarios.However,the effort in the molecular design of the high-performance medium-bandgap PSMAs is limited.In this article,we intr... The medium-bandgap polymerized small molecule acceptors(PSMAs)have broad application scenarios.However,the effort in the molecular design of the high-performance medium-bandgap PSMAs is limited.In this article,we introduce alkoxy groups as outer side chains and as substituents of the thiopheneπ-bridges of the high-performance PSMA PY-IT to synthesize a mediumbandgap PSMA PO-TO.Due to the fact that the non-covalent interaction between the alkoxy groups and the terminal groups of the small molecule acceptor(SMA)unit can weaken the intramolecular charge transfer(ICT)effect,the bandgap of PO-TO is enlarged and its absorption is blue-shifted compared with PY-IT,while the absorbance of PO-TO solution and film is enhanced significantly compared with that of PY-IT.When blended PO-TO with the polymer donor PBQx-TF,the corresponding all-polymer solar cells(all-PSCs)exhibit an open-circuit voltage(V_(oc))exceeding 1.04 V with a power conversion efficiency(PCE)of 13.75%.Furthermore,PO-TO was used as the third component to fabricate ternary all-PSCs with PBQx-TF as the polymer donor and PY-IT as the main polymer acceptor,and the ternary all-PSCs based on PBQx-TF:PY-IT:PO-TO(1:1:0.2,w/w/w)demonstrated a high PCE of 17.71%with simultaneously improved V_(oc)of 0.940 V,short-circuit current density(J_(sc))of 24.60 m A cm^(-2)and fill factor(FF)of76.81%.In comparison,the binary all-PSCs based on PBQx-TF:PY-IT showed a PCE of 16.77%.This result indicates that introducing alkoxy groups is a promising strategy for synthesizing high-performance medium-bandgap PSMAs. 展开更多
关键词 polymerized small molecule acceptors medium bandgap PSMAs all-polymer solar cells ternary all-PSCs alkoxy substituents
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High-Performance D-A Copolymer Donor Based on Difluoroquinoxaline A-Unit with Alkyl-Chlorothiophene Substituents for Polymer Solar Cells
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作者 Can Zhu Ke Hu +9 位作者 Lei Meng Xiaolei Kong Wenbin Lai Shucheng Qin Beibei Qiu Jinyuan Zhang Zhanjun Zhang Yilei Wu Xiaojun Li Yongfang Li 《CCS Chemistry》 CSCD 2023年第10期2378-2388,共11页
Side chain engineering with fluorine substitution is widely used to enhance photovoltaic performance of polymer donors in the research field of polymer solar cells(PSCs).However,fluorine substitution has disadvantages... Side chain engineering with fluorine substitution is widely used to enhance photovoltaic performance of polymer donors in the research field of polymer solar cells(PSCs).However,fluorine substitution has disadvantages of complicated synthesis and high cost.Herein,we synthesized a novel D-A copolymer donor PBQ9 based on difluoroquinoxaline A-unit with chlorine substitution on its alkyl-thiophene side chains instead of fluorine substitution in the polymer donor PBQ6,which greatly shortens the synthetic route and reduces the cost.Interestingly,the optimized binary PSC with PBQ9 as polymer donor and m-TEH as acceptor demonstrated a high power conversion efficiency(PCE)of 18.81%(certified PCE of 18.33%by National Institute of Metrology,China)with a high fill factor of 80.59%,and the photovoltaic performance of the PSCs is insensitive to the different batches of the polymer donor.The results indicate that PBQ9 is a high-performance polymer donor and that chlorine substitution is an effective strategy to improve photovoltaic performance and reduce the cost of polymer donors. 展开更多
关键词 D-A copolymer donors polymer solar cells difluoroquinoxaline A-unit chlorothiophene substituents
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“Substituents optimization”and“push effect”dual strategy for design of cobalt phthalocyanine catalyst on oxygen reduction reaction
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作者 Wenjuan Li Wenmiao Chen +4 位作者 Hongyan Zhuo JinShi Yu Xue Liu Yuexing Zhang Yanli Chen 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2023年第26期80-88,共9页
Molecular metallocycle electrocatalysts like metalloporphyrins and metallophthalocyanines were found to be effective for oxygen reduction reaction(ORR)due to their M-N_(4) active sites and large conjugated elec-tronic... Molecular metallocycle electrocatalysts like metalloporphyrins and metallophthalocyanines were found to be effective for oxygen reduction reaction(ORR)due to their M-N_(4) active sites and large conjugated elec-tronic molecular structures.Herein,the“substituents optimization”strategy combined with“push effect”modification was innovatively employed to target a single Co-N_(4) active site in three substituted phthalo-cyaninato cobalt complexes:tetranitrophthalocyaninato cobalt(CoTNPc),tetra(4-nitrophenoxy)phthalo-cyaninato cobalt(CoTPNPc),and tetraphenoxy phthalocyaninato cobalt(CoTPPc)electrocatalyst,also with 4-phenylpyridine axial coordination on Co-N_(4) unit.Through substituents screening,the half-wave poten-tial(E_(1/2))for ORR increases in the order of CoTPNPc(0.75 V)<CoTPPc(0.80 V)<CoTNPc(0.83 V)along with decreased electron-withdrawing ability of their substituents from-OC_(6) H_(4)-NO_(2),-OC_(6) H_(5) to-NO_(2) in the three cobalt phthalocyanine derivatives.CoTNPc with the weakest electron-withdrawing substituent exhibits the best ORR performance among the three compounds.This is attributed to its higher elec-tron delocalization and lifted HOMO energy level with the lower energy barrier in the rate-determining step relative to the other two compounds,which facilitate the electron transfer and reduction of oxy-gen as evidenced by XPS,UPS,and DRS analysis combined with DFT calculations.Further coordination of 4-phenylpyridine shifts the E_(1/2) up to 0.78,0.82,and 0.85 V for CoTPNPc,CoTPPc,and CoTNPc.DFT calcu-lations demonstrate that the introduction of the electron-donating phenylpyridine ligand into the cobalt phthalocyanines breaks the symmetry of the Co-N_(4) center and also raises the electron density of Co sites,which promotes O_(2) adsorption and improves ORR performance.After comparing the two strategies,the substituents on metallophthalocyanine are more determined by the electroactivity than the axial group,which directly regulates the coordination environment and then the activation barrier of the ORR pro-cess.This work provides theoretical and experimental guidance by two coupling strategies for the design of highly active molecular CoPc-based ORR electrocatalysts in the practical application. 展开更多
关键词 Cobalt phthalocyanine Substituent effect Push effect ORR
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Frontier orbital interactions of electron pushing and drawing substituents with ferrocenyl group 被引量:3
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作者 姜月顺 柴向东 +5 位作者 杨文胜 张东 曹云伟 诸真家 李铁津 Jean-Marie Lehn 《Science China Chemistry》 SCIE EI CAS 1997年第3期236-244,共9页
The frontier orbital interactions of electron pushing and drawing substituents with ferrocenyl group were analyzed based on the electrochemical,UV visible spectral and spectroelectrochemical results of five ferrocene ... The frontier orbital interactions of electron pushing and drawing substituents with ferrocenyl group were analyzed based on the electrochemical,UV visible spectral and spectroelectrochemical results of five ferrocene derivatives,R-Fc-A1(PⅠ),A1-Fc-A1(PⅡ),D-Fc-R (PⅢ),D-Kc-A1(PIV) and D-Fc-A2(PV)(R,CH2OH;A1 CHO;A2,CH=C(CN)2 and D,(C18H37)2N-C6H4-CH=CH) It was found that there are strong interactions of the LUMO (πA) of electron drawing substituents with le2g(dxy,dx2 y2)and e2u of the ferroeenyl group because the energy levels of πA and e2g,C2U of (Cp )2 are close,which lower not only the energy levels of bonded orbits,πA+ and dx2-y2+[πA] of PⅠ,PⅡ,PⅣ and PⅤobviously,but also those of their non-bonded orbu dxy For PⅢ,PⅣ and PⅤ,there are strong interactions of HOMO(πD) of the electron pushing substituent with le of the ferrocenyl group because the levels of πD and e of (Cp)2 are close,which result in the formation of anti-bonded orbit,πD- and bonded 展开更多
关键词 FERROCENE derivatives frontier orbital INTERACTIONS ELECTRON PUSHING and DRAWING substituents electrochemistry spectroscopy
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Tetrathiafulvalene esters with high redox potentials and improved solubilities for non-aqueous redox flow battery applications
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作者 Weikang Hu Jiaqi Xu +3 位作者 Nanjie Chen Zongcai Deng Yuekun Lai Dongyang Chen 《Green Energy & Environment》 SCIE EI CAS CSCD 2024年第5期899-908,共10页
The exploitation of high performance redox-active substances is critically important for the development of non-aqueous redoxflow batteries.Herein,three tetrathiofulvalene(TTF)derivatives with different substitution gr... The exploitation of high performance redox-active substances is critically important for the development of non-aqueous redoxflow batteries.Herein,three tetrathiofulvalene(TTF)derivatives with different substitution groups,namely TTF diethyl ester(TTFDE),TTF tetramethyl ester(TTFTM),and TTF tetraethyl ester(TTFTE),are prepared and their energy storage properties are evaluated.It has been found that the redox potential and solubility of these TTF derivatives in conventional carbonate electrolytes increases with the number of ester groups.The battery with a catholyte of 0.2 mol L^(-1) of TTFTE delivers a specific capacity of more than 10 Ah L^(-1) at the current density of 0.5 C with two discharge voltage platforms locating at as high as 3.85 and 3.60 V vs.Li/Liþ.Its capacity retention can be improved from 2.34 Ah L^(-1) to 3.60 Ah L^(-1) after 100 cycles by the use of an anion exchange membrane to block the crossover of TTF species.The excellent cycling stability of the TIF esters is supported by their well-delocalized electrons,as revealed by the density function theory calculations.Therefore,the introduction of more and larger electron-withdrawing groups is a promising strategy to simultaneously increase the redox-potential and solubility of redox-active ma-terials for non-aqueous redoxflow batteries. 展开更多
关键词 Non-aqueous redox flow batteries Tetrathiofulvarene Redox potential SOLUBILITY Substituent effect
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Synthesis and self-assembly of phthalocyanines bearing sulfur-containing substituents 被引量:1
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作者 Yan Zhao Jie Ding Xue-Bin Huang 《Chinese Chemical Letters》 SCIE CAS CSCD 2014年第1期46-50,共5页
Asymmetrically substituted phthalocyanines with sulfur-containing substituents for fabrication of self- assembled monolayers were synthesized. Phthalocyanine 7, bearing a disulfide group, was synthesized from phthaloc... Asymmetrically substituted phthalocyanines with sulfur-containing substituents for fabrication of self- assembled monolayers were synthesized. Phthalocyanine 7, bearing a disulfide group, was synthesized from phthalocyanine with a hydroxyl group, which was prepared via mixed condensation of the corresponding substituted phthalonitriles. Phthalocyanine 10, bearing an acetyl protected thiol group, was synthesized through the Pd-catalyzed coupling reaction of an iodophthalocyanine. Their self- assembling behavior on gold substrates was further studied by UV-vis spectroscopy. 展开更多
关键词 Phthalocyanine Sulfur-containing substituents Self-assembly
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Influence of terminal substituents on the halide anion binding of foldamer-based receptors 被引量:1
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作者 Ling Yang Wei Zhao +2 位作者 Yan-Ke Che Ying Wang Hua Jiang 《Chinese Chemical Letters》 SCIE CAS CSCD 2017年第8期1659-1662,共4页
Foldamers 1–4 incorporating different terminal substituents have been designed and synthesized for binding halide anions.~1H NMR titration experiments carried out in DMSO-d_6/CDCl_3(15/85, v/v)demonstrated that the... Foldamers 1–4 incorporating different terminal substituents have been designed and synthesized for binding halide anions.~1H NMR titration experiments carried out in DMSO-d_6/CDCl_3(15/85, v/v)demonstrated that the short oligo (aryltriazole)s backbone 1 could not bind halide anions unless that amide H-bond donors were incorporated at the termini of the oligomer. Terminal substituents on oligo(aryltriazoleamide)s foldamers 2–4 display a considerable influence on the binding affinities of the foldamers for halide anions. Large steric hindrance of the terminal substituents was found to be unfavorable for binding halide anions, but aromatic π-π interactions between two terminal substituents are capable of stabilizing the conformation of foldamers thus giving rise to an enhancement in the binding strengths. However, the terminal substituents were found to hardly affect the binding selectivity in the studied cases. 展开更多
关键词 Anion binding Triazole Recognition Receptors Terminal substituents
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Benzosuberyl Substituents as a"Sandwich-like"Function in Olefin Polymerization Catalysis 被引量:1
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作者 Yu-Yin Wang Chao-Qun Wang +4 位作者 Xiao-Qiang Hu Yan Xia Yue Chi Yi-Xin Zhang Zhong-Bao Jian 《Chinese Journal of Polymer Science》 SCIE CAS CSCD 2021年第8期984-993,I0006,共11页
For the rational design of metal catalyst in olefin polymerization catalysis,various strategies were applied to suppress the chain transfer by bulking up the axial positions of the metal center,among which the"sa... For the rational design of metal catalyst in olefin polymerization catalysis,various strategies were applied to suppress the chain transfer by bulking up the axial positions of the metal center,among which the"sandwich"type turned out to be an eficient category in achieving high molecular weight polyolefin.In the a-dimine system,the"sandwich"type catalysts were built using the typical 8-aryl-naphthyI framework.In this contribution,by introducing the rotationally restrained benzosuberyl substituent into the ortho-position of N-aryl rings,a new class of "sandwich-like"a-diimine nickel catalysts was constructed and fully identified.The rotationally restrained benzosuberyl substituents played a"sandwich-like"function by capping the nickel center from two axial sites.Compared to the nickel catalyst Ni1 bearing freely rotated benzhydryl substituent,Ni2 featuring benzosubery|substituent enabled the increase(8 times)of polymer molecular weights from 8 kDa to 65 kDa in the polymerization of ethylene.By further increasing the steric bulk of another ortho-site of the N-aryl ring,the polymer molecular weight even reached an ultrahigh level of 833 kDa(Mw=1857 kDa)using the optimized Ni3.Notably,these nickel catalysts could also mediate the copolymerization of ethylene with methyl 10-undecenoate,with Ni3 giving the highest copolymer molecular weight(88 kDa)and the highest incorporation of comonmer(2.0 mol1%),along with high activity of up to 10^(5)g·mol^(-1)·h^(-1). 展开更多
关键词 Olefin polymerization Benzosuberyl substituent SANDWICH Nickel catalyst Polar monomer
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Effect of substituents in hydroxyl radical-mediated degradation of azo pyridone dyes: Theoretical approaches on the reaction mechanism 被引量:1
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作者 J.Dostanic M.Hus D.Loncarevic 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2020年第12期14-21,共8页
Understanding the degradation behavior of azo dyes in photocatalytic wastewater treatment is of fundamental and practical importance for their application in textile-processing and other coloration industries. In this... Understanding the degradation behavior of azo dyes in photocatalytic wastewater treatment is of fundamental and practical importance for their application in textile-processing and other coloration industries. In this study, quantum chemistry, as density functional theory, was used to elucidate different degradation pathways of azo pyridone dyes in a hydroxyl radical(HO ·)-initiated photocatalytic system. A series of substituted azo pyridone dyes were synthesized by changing the substituent group in the para position of the benzene moiety, ranging from strong electron-donating to strong electron-withdrawing groups. The effect of dye molecular structure on the photocatalytic degradation reaction mechanism was analyzed and quantification of substituent effects on the thermodynamic and kinetics parameters was performed. Potential energy surface analysis revealed the most susceptible reaction site for the HO ·attack. The calculated reaction barriers are found to be strongly affected by the nature of substituent group with a good correlation using Hammett σp constants and experimentally determined reaction rates. The stability of pre-reaction complexes and transition state complexes were analyzed applying the distortion-interaction model. The increased stability of the transition state complexes with the distancing from the substituent group has been established. 展开更多
关键词 Quantum chemical calculation Density functional theory Azo dye Reaction mechanism Photocatalytic degradation Hydroxyl radical Hammett equation Substituent effect
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Rational design of systematic AIEEgens further modified by substituents from a novel chain structure
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作者 Hao Lu Kun Wang +4 位作者 Beibei Liu Meng Wang Mingming Huang Yue Zhang Jiping Yang 《Science China Chemistry》 SCIE EI CAS CSCD 2021年第1期52-60,共9页
The expansion of new structures in aggregation-induced emission/aggregation-induced emission enhancement(AIE/AIEE)systems has attracted persistent attention recently,from which more luminescent functional molecules wi... The expansion of new structures in aggregation-induced emission/aggregation-induced emission enhancement(AIE/AIEE)systems has attracted persistent attention recently,from which more luminescent functional molecules with characteristic skeletons are derived to satisfy specialized applications.In this study,a series of derivatives cored by tetraphenyl enamine with various terminal groups were designed and synthesized based on a novel p-πconjugate chain structure(–C=C–N–).Experimental and theoretical studies reveal that attaching modified groups to enamine core is decisive to achieve successful conversion from non-luminance to AIEE-activity.Moreover,due to different substituent effect on electronic structure,molecular conformation and molecular packing,diverse enamine compounds exhibited prominent substituent tunable emission properties,realizing regulated AIEE effect and multicolor emitting.These results not only offer a new method to design AIEgens/AIEEgens with p-πconjugate chain structures,but also provide in-depth knowledge for functional modifications of more novel AIE/AIEE units and materials. 展开更多
关键词 aggregation-induced emission enhancement chain structure enamine derivatives substituent tunable emission
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Identification of a Reliable DFT Calculation Method to Predict the Ground-and Excited-State Properties of Nickel(Ⅱ) Complexes with Porphyrin in Crude Oil
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作者 Pu Ning Ren Qiang +6 位作者 Hu Dawei Fang Wei Yang Qinghe Wang Zhen Hu Anpeng Xu Lei Ge Xin 《China Petroleum Processing & Petrochemical Technology》 SCIE CAS CSCD 2023年第4期106-116,共11页
Metalloporphyrins have devastating effects on the deep processing and efficient utilization of petroleum resources. Various porphyrins are derived from porphin by substitution at the β, meso, or both positions. Herei... Metalloporphyrins have devastating effects on the deep processing and efficient utilization of petroleum resources. Various porphyrins are derived from porphin by substitution at the β, meso, or both positions. Herein, we focus on the interaction between nickel(Ⅱ) and the porphyrin skeleton. Five different density functionals were selected for determining a reliable approach to simulate porphyrin-nickel(Ⅱ) complexes. At D4h symmetry, the 10b1g, 15a1g, 4e1g and 9b2g were dominated by the 3d character of nickel. Compared with pure density functional, the hybrid functional gave larger highest occupied molecular orbital(HOMO) and lowest unoccupied molecular orbital(LUMO) gap, and the higher HOMO-LUMO gap also corresponded to a higher excitation energy. The characteristic Soret and Q bands modeled by timedependent density functional theory(TDDFT) calculations matched well with experimental results, and the absorption was discussed in detail with natural transition orbitals(NTO) analysis. Furthermore, the binding character of nickel(Ⅱ) with various substituted porphyrins were calculated at perdew-burke-ernzerhof(PBE) level, showed that the geometry and complexation behavior of porphyrin-nickel(Ⅱ) complexes could be significantly tuned by different substituents. The symmetry of the complex was reduced and the skeleton ring get distortion when introducing different substituents. Compared with ETIO porphyrin, the introduction of phenyl on the β position can expand the conjugated system and promote the covalent character of Ni-N bond. 展开更多
关键词 porphyrin-nickel(Ⅱ) DFT/TDDFT binding character spectroscopic properties substituent effect
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A new fluorinated poly(ether amide) bearing xanthene group 被引量:1
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作者 Ting Li Shou Ri Sheng +2 位作者 Mei Hong Wei Cheng Chen Cai Sheng Song 《Chinese Chemical Letters》 SCIE CAS CSCD 2010年第10期1247-1250,共4页
A new fluorinated poly(ether amide) bearing xanthene group was prepared from 9,9-bis[4-(2-trifluoromethyl-4-aminophenox- y)phenyl]xanthene (BTFAPX) with 9,9-bis[4-(4-carboxyphenoxy)phenyl]xanthene (BCAPX) in the prese... A new fluorinated poly(ether amide) bearing xanthene group was prepared from 9,9-bis[4-(2-trifluoromethyl-4-aminophenox- y)phenyl]xanthene (BTFAPX) with 9,9-bis[4-(4-carboxyphenoxy)phenyl]xanthene (BCAPX) in the presence of triphenyl phos- phate and pyridine (Py). The polymer had the weight-average molecular weight (Mw) of 69,000 and number-average molecular weight (Mn) of 39,000, showed the glass transition temperature (Tg) of 267 ℃, 5% weight loss temperature (Tds) over 460 ℃ both in N2 and air, and char yield of 62% at 800 ℃ in N2. This polymer was amorphous and readily soluble in amide-type solvents such as N,N-dimethylacetamide (DMAc), and even in m-cressol, Py and tetrahydrofuran (THF) at room temperature, and exhibited tensile strength of 74 MPa, elongation at break of 6%, tensile moduli of 2.2 GPa. The polymer had low dielectric constant of 3.69 (100 Hz), low moisture absorption of 0.56%, and high transparency with an ultraviolet-visible absorption cut-off wavelength at 334 nm. 展开更多
关键词 Fluorinated polyamide Xanthene group Trifluoromethyl substituents
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The substituent effect on the excited state intramolecular proton transfer of 3-hydroxychromone
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作者 宋玉志 刘松松 +3 位作者 陆佳骏 张慧 张常哲 杜军 《Chinese Physics B》 SCIE EI CAS CSCD 2019年第9期150-156,共7页
The excited state intramolecular proton transfer of four derivatives(FM, BFM, BFBC, CCM) of 3-hydroxychromone is investigated.The geometries of different substituents are optimized to study the substituent effects on ... The excited state intramolecular proton transfer of four derivatives(FM, BFM, BFBC, CCM) of 3-hydroxychromone is investigated.The geometries of different substituents are optimized to study the substituent effects on proton transfer.The mechanism of hydrogen bond enhancement is qualitatively elucidated by comparing the infrared spectra, the reduced density gradient, and the frontier molecular orbitals.The calculated electronic spectra are consistent with the experimental results.To quantify the proton transfer, the potential energy curves(PECs) of the four derivatives in S0 and S1 states are scanned.It is concluded that the ability of proton transfer follows the order: FM > BFM > BFBC > CCM. 展开更多
关键词 EXCITED state INTRAMOLECULAR PROTON transfer(ESIPT) hydrogen BOND reduced density gradient(RDG) substituents
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Optical and Electrochemical Properties of Non-Peripheral Thioaryl-Substituted Subphthalocyanine as Precursors for Dye-Sensitizer to Develop Photovoltaic Cells
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作者 Keiichi Sakamoto Satoru Yoshino +5 位作者 Makoto Takemoto Kazuhiro Sugaya Hitomi Kubo Tomoe Komoriya Shinnosuke Kamei Shigeki Furukawa 《American Journal of Analytical Chemistry》 2014年第15期1037-1045,共9页
Phthalocyanines-related compounds, subphthalocyanines, are the homologues consisting of three isoindole units with boron as the center. The absorption maximum of subphthalocyanines, called the Q band, appears around 5... Phthalocyanines-related compounds, subphthalocyanines, are the homologues consisting of three isoindole units with boron as the center. The absorption maximum of subphthalocyanines, called the Q band, appears around 560 - 630 nm, which is shifted by approximately 100 nm to shorter wavelengths compared to phthalocyanines. Subphthalocyanines are used as precursors to prepare unsymmetric phthalocyanines for ring enlargement reaction. In this decade, phthalocyanines are used for dye-sensitized solar cells (DSSCs), which require strong absorption of far-red light between 700 and 850 nm because of their highly efficiency. Non-peripheral thioaryl-substituted phthalocyanines have been synthesized. They show near-infrared absorption around 780 - 870 nm and have excellent electron transfer properties. However, their lack of affinity to basal plats inhibits their use as DSSC photosensitizer. Therefore, to synthesize unsymmetrical non-peripheral thioaryl-substituted phthalocyanines possessing good affinity to basal plates, the authors prepared subphthalocyanines having thioaryl substituents as precursors. Spectroscopic properties and electron transfer abilities to synthesize non-peripheral thioaryl-substituted subphthalocyanines were estimated using cyclic voltammetry. The Q band of non-peripheral thioaryl-substituted subphthalocyanines shows around 650 nm shifted to longer wavelength by 86 nm in comparison to subphthalocyanine. The compounds show many reduction potentials. They are acceptable electrons in the subphthalocyanine ring, meaning that the compounds have good electron transfer properties. 展开更多
关键词 Thioaryl substituents Phthalocyanines SUBPHTHALOCYANINE Cyclic VOLTAMMETRY Precursor for Dye-Sensitizer
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