Herein,an oxygen-doped porous g-C_(3)N_(4)photocatalyst modified with atomically dispersed Fe(Fe_(1)/OPCN)issuccessfully prepared and exhibits significant superiority in removing refractory sulfonic azo contaminants f...Herein,an oxygen-doped porous g-C_(3)N_(4)photocatalyst modified with atomically dispersed Fe(Fe_(1)/OPCN)issuccessfully prepared and exhibits significant superiority in removing refractory sulfonic azo contaminants fromwater via catalyst-contaminant interaction.The elimination performance of Fe_(1)/OPCN towards acid red 9,acidred 13 and amaranth containing similar azonaphthalene structure and increasing sulfonic acid groups increasesgradually.The amaranth degradation rate of Fe_(1)/OPCN is 17.7 and 6.1 times as that of homogeneous Fenton andOPCN,respectively.In addition,Fe_(1)/OPCN also has more outstanding removal activities towards other con-taminantswith sulfonic acid and azo groups alone.The considerable enhancement for removing sulfonic azocontaminants of Fe_(1)/OPCN is mainly ascribed to the following aspects:(1)The modified Fe could enhance theadsorption towards sulfonic azo compounds to accelerate the mass transfer,act as e^(-)acceptor to promoteinterfacial charge separation,and trigger the self-Fenton reaction to convert in-situ generated H_(2)O_(2)into·OH.(2)Fe(Ⅲ)could coordinate with-N=N-to form d-πconjugation,which could attract e^(-)transfer to attack-N=N-bond.Meanwhile,the inhibited charge recombination could release more free h^(þ)to oxidize sulfonicacid groups into SO4^(-)·.(3)Under the cooperation of abundant multiple active species(·O_(2)^(-),h^(þ),e^(-),·OH,SO4^(-)·)formed during the degradation reaction,sulfonic azo compounds could be completely mineralized into harmlesssmall molecules(CO_(2),H_(2)O,etc.)by means of-N=N-cleavage,hydroxyl substitution,and aromatic ringopening.This work offers a novel approach for effectively eliminating refractory sulfonic azo compounds fromwastewater.展开更多
Chlorosulfonyl-containing pyrazolone azo compounds (2a, 2b) have been prepared by reaction of the corresponding sodium sulfonate (1a, 1b) with thionyl chloride in the presence of a catalytic quantity of N,Ndimethylfor...Chlorosulfonyl-containing pyrazolone azo compounds (2a, 2b) have been prepared by reaction of the corresponding sodium sulfonate (1a, 1b) with thionyl chloride in the presence of a catalytic quantity of N,Ndimethylformamide in dry benzene. The effects of reaction temperature, time, catalyst and solvent amount on the yield of 2a and 2b were investigated. The results show that chlorination of 1a and 1b under optimal conditions gives 2a and 2b in 95.5% and 99.2% yield respectively. The given method is facile and suitable for large-scale synthesis.展开更多
Amides can be obtained in good to excellent yield by Sm/TiCl4 mediated reductive cleavage of N=N bond in azo compounds and successive acylation in one pot. It offers an alternative method for the synthesis of amides f...Amides can be obtained in good to excellent yield by Sm/TiCl4 mediated reductive cleavage of N=N bond in azo compounds and successive acylation in one pot. It offers an alternative method for the synthesis of amides from very simple starting materials directly.展开更多
Eleven new-typed azo compounds were synthesized in good yields by dehydrogenating the corresponding aryl substituted semicarbazides using potassium ferricyanide and sodium hydroxide system under solid-state conditions.
The abnormal metabolic activity of the tumor can increase the oxygen consumption in tumor cells,and the poor blood perfusion often happens in tumor regions as well,which are the main reasons that result in a hypoxic s...The abnormal metabolic activity of the tumor can increase the oxygen consumption in tumor cells,and the poor blood perfusion often happens in tumor regions as well,which are the main reasons that result in a hypoxic situation in the tumor.A fluorescence probe,AQD,with selective response toward hypoxia was designed for the detection of hypoxic tumor cells,which was obtained by the covalent connection of a large planar conjugated fluorophore with good fluorescence stability and a N,N-dimethylaniline moiety via the azo bond.The introduction of the azo bond in AQD caused significant fluorescence emission quenching,and the probe was reduced under hypoxic conditions to release the fluorophore via breaking the azo bond,resulting in the gradual recovery of fluorescence emission.Probe AQD exhibited a remarkable fluorescence response in hypoxic conditions,high selectivity,and good biocompatibility,which was successfully used for the imaging of hypoxic tumor cells and realized the detection of hypoxic A549 cells.展开更多
Asymmetric synthesis of enantioenriched azo compounds bearing tetrasubstituted stereocenter was achieved through chiral N,N′-dioxide/metal Lewis acid promoted interrupted Japp-Klingemann reaction of aryldiazonium tet...Asymmetric synthesis of enantioenriched azo compounds bearing tetrasubstituted stereocenter was achieved through chiral N,N′-dioxide/metal Lewis acid promoted interrupted Japp-Klingemann reaction of aryldiazonium tetrafluoroborate salts with nucleophiles under mild conditions. This protocol features wide substrate scope and good functional group compatibility.Azaarene-containing chiral azo compounds were stable enough in Japp-Klingemann reaction condition. The key to success of the reaction was the employment of metal salt/N,N′-dioxide ligand and the dual-task roles of the base. Moreover, the X-ray crystal structure of Ni(II)/N,N′-dioxide/substrate complex confirmed that the substrate was activated by bidentate coordination, which shed light on the origin of chiral control of the reaction.展开更多
A new series of aromatic azo compounds with one, two, three and five azobenzene units were facilely constructed by dehydrochlorination reaction between p-hydroxyazobenzene, 4,4＇-dihydroxyazobenzene and cyanuric chlor...A new series of aromatic azo compounds with one, two, three and five azobenzene units were facilely constructed by dehydrochlorination reaction between p-hydroxyazobenzene, 4,4＇-dihydroxyazobenzene and cyanuric chloride under very mild conditions. Their solubility, crystallinity, thermostability, UV-vis absorption properties and photoisomerization behaviors were carefully examined. When the number of azobenzene unit grew, the solubility of the synthesized compounds basically decreased, the crystallinity of the synthesized compounds firstly rose then dropped, while the thermostability and UV-vis absorption ability of the synthesized compounds greatly im- proved. All the aromatic azo compounds exhibited typical reversible photoisomerization behaviors and were expected to be applied in photosensitive material areas.展开更多
Fully conjugated Schiff base macrocycle has been prepared through a simple and mild condition,a one-pot cyclization procedure of four-component without using a template.The condensation reaction of related bis（hydrox...Fully conjugated Schiff base macrocycle has been prepared through a simple and mild condition,a one-pot cyclization procedure of four-component without using a template.The condensation reaction of related bis（hydroxybenzaldehyde） with phenylenediamines to prepare a conjugated[2 ＋ 2]Schiff base macrocycle has been investigated and fluorescent[2 ＋ 2]Schiff base macrocycles with N_2O_2 binding pockets has been prepared and characterized by elemental analysis,^1H NMR,IR,fluorescent,UV-visible and MALDI mass spectroscopies.展开更多
Potassium 5,5＇-azobis（1-nitraminotetrazolate）,（K2ABNAT）, a new green primary explosive, was synthesized via a safe and convenient synthetic procedure based on methylcarbazate and cyanogen azide. The compound was ...Potassium 5,5＇-azobis（1-nitraminotetrazolate）,（K2ABNAT）, a new green primary explosive, was synthesized via a safe and convenient synthetic procedure based on methylcarbazate and cyanogen azide. The compound was characterized by single-crystal X-ray diffraction, IR spectroscopy, Raman spectroscopy, multinuclear NMR spectroscopy, elemental analysis, and differential scanning calorimetry（DSC）. With the calculated（CBS-4M） heat of formation（617.0 kJ/mol） and the room temperature X-ray density（2.11 g/cm^3）, impressive values for the detonation parameters such as detonation velocity（8367 m/s） and pressure（31.5 GPa） were computed using the EXPLO5 program. The superior calculated energetic performance show it could serve as a green replacement for the widely used primary explosive,lead（II） azide, which contains toxic ingredient.展开更多
A novel palladium-coordinating Azo-type liquid crystalline polysiloxane （Pd-AZLCP） has been synthesized by chelation reaction of polymeric ligand, Azo-type liquid crystalline polysiloxane（AZLCP）, with palladium di...A novel palladium-coordinating Azo-type liquid crystalline polysiloxane （Pd-AZLCP） has been synthesized by chelation reaction of polymeric ligand, Azo-type liquid crystalline polysiloxane（AZLCP）, with palladium dichloride and potassium chloride in the presence of tetrahydrofuran （THF） as reaction medium instead of dioxane/water system, which has been used since Cope first reported the synthesis of palladium-azobenzene in 1965 . The mesogenic behaviors examined by DSC, temperature-variable X-ray diffraction and polarizing microscopy indicate that the incorporation of Pd ions into the liquid crystal polymer can play a positive effect on the mesogenic property of the parent polymeric ligand. It is exhibited that the isotropization temperature T;is increased and the mesophase range ΔT has been widened, too.展开更多
The visible light-driven photoswitches are attracting widespread attention,but it is challenging to leverage their phototriggered structural changes to regulate dynamic bonds,assemblies,and materials.Herein,we incorpo...The visible light-driven photoswitches are attracting widespread attention,but it is challenging to leverage their phototriggered structural changes to regulate dynamic bonds,assemblies,and materials.Herein,we incorporated reversible covalent sites of aldehyde ring-chain tautomers into all-visible-light azobenzenes toward a versatile platform for light-controlled formation/exchange of dynamic C—N bonds from secondary amines.The movement of ring-chain equilibrium was attained via manipulating intramolecular multiple hydrogen bonding from E/Z configurational isomers.Such structural regulation further enabled photocontrolled kinetics for the formation and exchange reactions of cyclic hemiaminal ethers from secondary amines exhibiting kinetic rate reversal from E/Z isomers.The varied capability of E/Z configurational isomers in engaging in multiple hydrogen bonds of azo attached carboxylate with ammonium salt accounts for the difference.Moreover,the photoswitching performance of azobenzenes in different solutions was readily regulated by dynamic covalent reactions with amines.The dynamic reactivity control with visible light and associated mechanistic foundation add into the collection of photoswitchable dynamic covalent chemistry and would lay the foundation for subsequent biological and material applications.展开更多
A visible-light-enabled,photocatalyst-free hydroacylation reaction of azodicarboxylic acid derivatives was described.This radical conjugate addition(RCA)protocol relied on the dual role of 4-acyl-1,4-dihydropyridine(a...A visible-light-enabled,photocatalyst-free hydroacylation reaction of azodicarboxylic acid derivatives was described.This radical conjugate addition(RCA)protocol relied on the dual role of 4-acyl-1,4-dihydropyridine(acyl-DHP)reagents that besides being as radical reservoirs,they also enabled the conversion of radical adducts to anion intermediates via reduction.Under“catalyst-oxidant-additive free”conditions,a wide range of structurally different acyl hydrazide products were readily obtained in 56%—99%yields.The utility of this transformation was further demonstrated by the scale-up synthesis and downstream derivatization.展开更多
The electrochemical reduction strategy of nitrobenzenes is developed.The chemistry occurs under ambient conditions.The protocol uses inert electrodes and the solvent,DMSO,plays a dual role as a reducing agent.Its synt...The electrochemical reduction strategy of nitrobenzenes is developed.The chemistry occurs under ambient conditions.The protocol uses inert electrodes and the solvent,DMSO,plays a dual role as a reducing agent.Its synthetic value has been demonstrated by the highly efficient synthesis of symmetric,unsymmetric and cyclic azo compounds.展开更多
A method for Cu(Ⅱ)-catalyzed dehydrogenative amidation of azoarene using air as the terminal oxidant was developed. Various amides, such as arylamides, alkylamides, lactams, and imides, are all effective amidation re...A method for Cu(Ⅱ)-catalyzed dehydrogenative amidation of azoarene using air as the terminal oxidant was developed. Various amides, such as arylamides, alkylamides, lactams, and imides, are all effective amidation reagents and provide the desired products in moderate to excellent yields. Notably, good yields can also be obtained on a gram-scale with this amidation reaction.In this protocol of azoarene amidation, the catalyst(Cu(OAc)_2) and oxidant(air) are inexpensive and readily available, and the process is highly efficient and atom economical.展开更多
A new method for the synthesis of azo Schiff an base ligand in which the azo and azomethine groups are coordination sites was developed through a Schiff base precursor. The precursor, N-4-methoxybenzylidene-3-hydroxyp...A new method for the synthesis of azo Schiff an base ligand in which the azo and azomethine groups are coordination sites was developed through a Schiff base precursor. The precursor, N-4-methoxybenzylidene-3-hydroxyphenylamine （SB） derived from 3-aminophenol was regioselectively coupled with a diazonium ion para to the hydroxyl group of the amine component of the Schiff base. The para selectivity was controlled by the directing effect of the hydroxyl group. The ligand and its nickel（Ⅱ） complex were characterized by elemental analyses, IR and UV-Vis spectroscopy. The analytical and spectral data supported the mononuclear formulation of the complex with metal to ligand ratio （M ： L = 1 ： 2） and suggested a square planar geometry for the complex.展开更多
Stimulus-sensitive surfaces with tunable morphologies exhibit a wide range of applications in the fields of surface science and engineering.Herein,a cost-effective yet practical strategy is proposed to fabricate photo...Stimulus-sensitive surfaces with tunable morphologies exhibit a wide range of applications in the fields of surface science and engineering.Herein,a cost-effective yet practical strategy is proposed to fabricate photo-sensitive patterning surface on film/substrate wrinkle system based on an azo-containing polyblend.By manipulating the stress field of the bilayer system globally and/or locally upon the stress relaxation triggered by the reversible cis-trans isomerization of the azobenzene,heating/cooling triggered surface wrinkles on the polyblend films could be tailor-made with visible-light-irradiation.Notably,upon selective photo-irradiation,bespoke surface patterns may be cyclically generated or eliminated,allowing these reconfigurable patterned polyblend surfaces to be used as rewritable information storage media for non-ink printing.The as-prepared photo-printed information patterns with high-resolution are shown to be rewritable for multiple cycles and legible for over 90 d in dark ambient conditions.This study not only provides a versatile strategy for flourishing the stimulus-sensitive systems,but also sheds light on the stress relaxation-triggered morphological evolution of the wrinkling polyblend films.展开更多
Two discotic liquid crystalline(LC)molecules consisting of a bowl-shaped corannulene core and five-fold photoactive azobenzene branches with differe nt pa raff i nk side chai ns were developed.Their self-assembly,phot...Two discotic liquid crystalline(LC)molecules consisting of a bowl-shaped corannulene core and five-fold photoactive azobenzene branches with differe nt pa raff i nk side chai ns were developed.Their self-assembly,photo-resp on sive behavior and charge-carrier tran sport properties were investigated in detail.A wider mesophase temperature range was achieved when utilizi ng Ion ger and furcal flexible side chai n substituti on.2D XRD measureme nts revealed the n-packed cora nnulen e-ce ntered lb(i.e.,with furcal side alkoxy I chains)exhibited helical columnar LC phase.This packing structure also led to a higher hole charge carrier mobility of 7.07 ×1O^(-2) cm^(2)-V^(-1)s^(-1) compared to that of the counterpart la with linear side chain substitutions.展开更多
Water-soluble thermal initiators are important radical sources to be applied in various fields.However,the uncontrolled radical generation from the high sensitivity of initiators may cause disadvantages in the applica...Water-soluble thermal initiators are important radical sources to be applied in various fields.However,the uncontrolled radical generation from the high sensitivity of initiators may cause disadvantages in the applications.Here,we present a series of supramolecular radical switches regulated by the host-vip chemistry between initiators and cucurbit[8]uril(CB[8]).Thermal initiators(VA-044,VA-056,VA-057)can be spontaneously encapsulated into the cavity of CB[8]to“turn off”their radical-generation ability.Their activity will instantaneously“turn on”in the presence of other competitors such as 1-adamantylamine(ADA).Further,we demonstrated the free radical polymerization of N-isopropylacrylamide using initiators,inhibiting its activity by binding with CB[8]and initiating reaction by adding ADA.These novel supramolecular radical switches provide a facile strategy to control the generation of free radicals in a“plug-and-play”manner,which may arouse research interests in polymerization,catalysis,and the biomedical field.展开更多
基金supported by the Natural Science Foundation of Jiangsu Province(BK20221541)National Natural Science Foundation of China(21707052)Jiangsu Agriculture Science and Technology Innovation Fund(CX(20)3108).
文摘Herein,an oxygen-doped porous g-C_(3)N_(4)photocatalyst modified with atomically dispersed Fe(Fe_(1)/OPCN)issuccessfully prepared and exhibits significant superiority in removing refractory sulfonic azo contaminants fromwater via catalyst-contaminant interaction.The elimination performance of Fe_(1)/OPCN towards acid red 9,acidred 13 and amaranth containing similar azonaphthalene structure and increasing sulfonic acid groups increasesgradually.The amaranth degradation rate of Fe_(1)/OPCN is 17.7 and 6.1 times as that of homogeneous Fenton andOPCN,respectively.In addition,Fe_(1)/OPCN also has more outstanding removal activities towards other con-taminantswith sulfonic acid and azo groups alone.The considerable enhancement for removing sulfonic azocontaminants of Fe_(1)/OPCN is mainly ascribed to the following aspects:(1)The modified Fe could enhance theadsorption towards sulfonic azo compounds to accelerate the mass transfer,act as e^(-)acceptor to promoteinterfacial charge separation,and trigger the self-Fenton reaction to convert in-situ generated H_(2)O_(2)into·OH.(2)Fe(Ⅲ)could coordinate with-N=N-to form d-πconjugation,which could attract e^(-)transfer to attack-N=N-bond.Meanwhile,the inhibited charge recombination could release more free h^(þ)to oxidize sulfonicacid groups into SO4^(-)·.(3)Under the cooperation of abundant multiple active species(·O_(2)^(-),h^(þ),e^(-),·OH,SO4^(-)·)formed during the degradation reaction,sulfonic azo compounds could be completely mineralized into harmlesssmall molecules(CO_(2),H_(2)O,etc.)by means of-N=N-cleavage,hydroxyl substitution,and aromatic ringopening.This work offers a novel approach for effectively eliminating refractory sulfonic azo compounds fromwastewater.
文摘Chlorosulfonyl-containing pyrazolone azo compounds (2a, 2b) have been prepared by reaction of the corresponding sodium sulfonate (1a, 1b) with thionyl chloride in the presence of a catalytic quantity of N,Ndimethylformamide in dry benzene. The effects of reaction temperature, time, catalyst and solvent amount on the yield of 2a and 2b were investigated. The results show that chlorination of 1a and 1b under optimal conditions gives 2a and 2b in 95.5% and 99.2% yield respectively. The given method is facile and suitable for large-scale synthesis.
基金Project (No. 20072033) supported by the National Natural ScienceFoundation of China and Specialized Research Fund for the DoctoralProgram of Higher Education of China
文摘Amides can be obtained in good to excellent yield by Sm/TiCl4 mediated reductive cleavage of N=N bond in azo compounds and successive acylation in one pot. It offers an alternative method for the synthesis of amides from very simple starting materials directly.
文摘Eleven new-typed azo compounds were synthesized in good yields by dehydrogenating the corresponding aryl substituted semicarbazides using potassium ferricyanide and sodium hydroxide system under solid-state conditions.
文摘The abnormal metabolic activity of the tumor can increase the oxygen consumption in tumor cells,and the poor blood perfusion often happens in tumor regions as well,which are the main reasons that result in a hypoxic situation in the tumor.A fluorescence probe,AQD,with selective response toward hypoxia was designed for the detection of hypoxic tumor cells,which was obtained by the covalent connection of a large planar conjugated fluorophore with good fluorescence stability and a N,N-dimethylaniline moiety via the azo bond.The introduction of the azo bond in AQD caused significant fluorescence emission quenching,and the probe was reduced under hypoxic conditions to release the fluorophore via breaking the azo bond,resulting in the gradual recovery of fluorescence emission.Probe AQD exhibited a remarkable fluorescence response in hypoxic conditions,high selectivity,and good biocompatibility,which was successfully used for the imaging of hypoxic tumor cells and realized the detection of hypoxic A549 cells.
基金supported by the National Natural Science Foundation of China(21890723,21921002)。
文摘Asymmetric synthesis of enantioenriched azo compounds bearing tetrasubstituted stereocenter was achieved through chiral N,N′-dioxide/metal Lewis acid promoted interrupted Japp-Klingemann reaction of aryldiazonium tetrafluoroborate salts with nucleophiles under mild conditions. This protocol features wide substrate scope and good functional group compatibility.Azaarene-containing chiral azo compounds were stable enough in Japp-Klingemann reaction condition. The key to success of the reaction was the employment of metal salt/N,N′-dioxide ligand and the dual-task roles of the base. Moreover, the X-ray crystal structure of Ni(II)/N,N′-dioxide/substrate complex confirmed that the substrate was activated by bidentate coordination, which shed light on the origin of chiral control of the reaction.
文摘A new series of aromatic azo compounds with one, two, three and five azobenzene units were facilely constructed by dehydrochlorination reaction between p-hydroxyazobenzene, 4,4＇-dihydroxyazobenzene and cyanuric chloride under very mild conditions. Their solubility, crystallinity, thermostability, UV-vis absorption properties and photoisomerization behaviors were carefully examined. When the number of azobenzene unit grew, the solubility of the synthesized compounds basically decreased, the crystallinity of the synthesized compounds firstly rose then dropped, while the thermostability and UV-vis absorption ability of the synthesized compounds greatly im- proved. All the aromatic azo compounds exhibited typical reversible photoisomerization behaviors and were expected to be applied in photosensitive material areas.
基金sponsored by Isfahan University of technology(IUT)
文摘Fully conjugated Schiff base macrocycle has been prepared through a simple and mild condition,a one-pot cyclization procedure of four-component without using a template.The condensation reaction of related bis（hydroxybenzaldehyde） with phenylenediamines to prepare a conjugated[2 ＋ 2]Schiff base macrocycle has been investigated and fluorescent[2 ＋ 2]Schiff base macrocycles with N_2O_2 binding pockets has been prepared and characterized by elemental analysis,^1H NMR,IR,fluorescent,UV-visible and MALDI mass spectroscopies.
基金the National Natural Science Foundation of China (No. 21373157)
文摘Potassium 5,5＇-azobis（1-nitraminotetrazolate）,（K2ABNAT）, a new green primary explosive, was synthesized via a safe and convenient synthetic procedure based on methylcarbazate and cyanogen azide. The compound was characterized by single-crystal X-ray diffraction, IR spectroscopy, Raman spectroscopy, multinuclear NMR spectroscopy, elemental analysis, and differential scanning calorimetry（DSC）. With the calculated（CBS-4M） heat of formation（617.0 kJ/mol） and the room temperature X-ray density（2.11 g/cm^3）, impressive values for the detonation parameters such as detonation velocity（8367 m/s） and pressure（31.5 GPa） were computed using the EXPLO5 program. The superior calculated energetic performance show it could serve as a green replacement for the widely used primary explosive,lead（II） azide, which contains toxic ingredient.
基金This project was supported by the Natural Science Foundation of Henan province, China.
文摘A novel palladium-coordinating Azo-type liquid crystalline polysiloxane （Pd-AZLCP） has been synthesized by chelation reaction of polymeric ligand, Azo-type liquid crystalline polysiloxane（AZLCP）, with palladium dichloride and potassium chloride in the presence of tetrahydrofuran （THF） as reaction medium instead of dioxane/water system, which has been used since Cope first reported the synthesis of palladium-azobenzene in 1965 . The mesogenic behaviors examined by DSC, temperature-variable X-ray diffraction and polarizing microscopy indicate that the incorporation of Pd ions into the liquid crystal polymer can play a positive effect on the mesogenic property of the parent polymeric ligand. It is exhibited that the isotropization temperature T;is increased and the mesophase range ΔT has been widened, too.
基金NSFC(S(92156010,22071247,22471274,and 22401279)the Key Research Program of Frontier Sciences(QYZDB-SSW-SLHO3O)of CAS+1 种基金the Postdoctoral Fellowship Program of China Postdoctoral Science Foundation(GZC20241725)Fujian Science&Technology Innovation Laboratory for Optoelectronic Information of China(2021ZR112)for funding.
文摘The visible light-driven photoswitches are attracting widespread attention,but it is challenging to leverage their phototriggered structural changes to regulate dynamic bonds,assemblies,and materials.Herein,we incorporated reversible covalent sites of aldehyde ring-chain tautomers into all-visible-light azobenzenes toward a versatile platform for light-controlled formation/exchange of dynamic C—N bonds from secondary amines.The movement of ring-chain equilibrium was attained via manipulating intramolecular multiple hydrogen bonding from E/Z configurational isomers.Such structural regulation further enabled photocontrolled kinetics for the formation and exchange reactions of cyclic hemiaminal ethers from secondary amines exhibiting kinetic rate reversal from E/Z isomers.The varied capability of E/Z configurational isomers in engaging in multiple hydrogen bonds of azo attached carboxylate with ammonium salt accounts for the difference.Moreover,the photoswitching performance of azobenzenes in different solutions was readily regulated by dynamic covalent reactions with amines.The dynamic reactivity control with visible light and associated mechanistic foundation add into the collection of photoswitchable dynamic covalent chemistry and would lay the foundation for subsequent biological and material applications.
基金support from the National Natural Science Foundation of China(21702013 and 22271010)the Fundamental Research Funds for the Central Universities(XK1802-6)at the BUCT.
文摘A visible-light-enabled,photocatalyst-free hydroacylation reaction of azodicarboxylic acid derivatives was described.This radical conjugate addition(RCA)protocol relied on the dual role of 4-acyl-1,4-dihydropyridine(acyl-DHP)reagents that besides being as radical reservoirs,they also enabled the conversion of radical adducts to anion intermediates via reduction.Under“catalyst-oxidant-additive free”conditions,a wide range of structurally different acyl hydrazide products were readily obtained in 56%—99%yields.The utility of this transformation was further demonstrated by the scale-up synthesis and downstream derivatization.
基金This work was supported by the National Natural Science Foundation of China(Nos.21871226,21502160,21572194)the Scientific Research Fund of Hunan Provincial Education Department(No.19B564).
文摘The electrochemical reduction strategy of nitrobenzenes is developed.The chemistry occurs under ambient conditions.The protocol uses inert electrodes and the solvent,DMSO,plays a dual role as a reducing agent.Its synthetic value has been demonstrated by the highly efficient synthesis of symmetric,unsymmetric and cyclic azo compounds.
基金supported by the National Natural Science Foundation of China (21102005)Program for Innovative Research Team of Science and Technology in the University of Henan Province (18IRTSTHN004)
文摘A method for Cu(Ⅱ)-catalyzed dehydrogenative amidation of azoarene using air as the terminal oxidant was developed. Various amides, such as arylamides, alkylamides, lactams, and imides, are all effective amidation reagents and provide the desired products in moderate to excellent yields. Notably, good yields can also be obtained on a gram-scale with this amidation reaction.In this protocol of azoarene amidation, the catalyst(Cu(OAc)_2) and oxidant(air) are inexpensive and readily available, and the process is highly efficient and atom economical.
文摘A new method for the synthesis of azo Schiff an base ligand in which the azo and azomethine groups are coordination sites was developed through a Schiff base precursor. The precursor, N-4-methoxybenzylidene-3-hydroxyphenylamine （SB） derived from 3-aminophenol was regioselectively coupled with a diazonium ion para to the hydroxyl group of the amine component of the Schiff base. The para selectivity was controlled by the directing effect of the hydroxyl group. The ligand and its nickel（Ⅱ） complex were characterized by elemental analyses, IR and UV-Vis spectroscopy. The analytical and spectral data supported the mononuclear formulation of the complex with metal to ligand ratio （M ： L = 1 ： 2） and suggested a square planar geometry for the complex.
基金supports from the National Natural Science Foundation of China (Nos.21704033,52173168)the Natural Science Foundation of Shandong Province (Nos.ZR2020LFG009,SZR1946)the China Postdoctoral Science Foundation (No.2019M662441).
文摘Stimulus-sensitive surfaces with tunable morphologies exhibit a wide range of applications in the fields of surface science and engineering.Herein,a cost-effective yet practical strategy is proposed to fabricate photo-sensitive patterning surface on film/substrate wrinkle system based on an azo-containing polyblend.By manipulating the stress field of the bilayer system globally and/or locally upon the stress relaxation triggered by the reversible cis-trans isomerization of the azobenzene,heating/cooling triggered surface wrinkles on the polyblend films could be tailor-made with visible-light-irradiation.Notably,upon selective photo-irradiation,bespoke surface patterns may be cyclically generated or eliminated,allowing these reconfigurable patterned polyblend surfaces to be used as rewritable information storage media for non-ink printing.The as-prepared photo-printed information patterns with high-resolution are shown to be rewritable for multiple cycles and legible for over 90 d in dark ambient conditions.This study not only provides a versatile strategy for flourishing the stimulus-sensitive systems,but also sheds light on the stress relaxation-triggered morphological evolution of the wrinkling polyblend films.
基金supported by the National Natural Science Foundation of China(Nos.51973153,21875157).
文摘Two discotic liquid crystalline(LC)molecules consisting of a bowl-shaped corannulene core and five-fold photoactive azobenzene branches with differe nt pa raff i nk side chai ns were developed.Their self-assembly,photo-resp on sive behavior and charge-carrier tran sport properties were investigated in detail.A wider mesophase temperature range was achieved when utilizi ng Ion ger and furcal flexible side chai n substituti on.2D XRD measureme nts revealed the n-packed cora nnulen e-ce ntered lb(i.e.,with furcal side alkoxy I chains)exhibited helical columnar LC phase.This packing structure also led to a higher hole charge carrier mobility of 7.07 ×1O^(-2) cm^(2)-V^(-1)s^(-1) compared to that of the counterpart la with linear side chain substitutions.
基金supported bythe National Natural Science Foundation of China(No.51903195).
文摘Water-soluble thermal initiators are important radical sources to be applied in various fields.However,the uncontrolled radical generation from the high sensitivity of initiators may cause disadvantages in the applications.Here,we present a series of supramolecular radical switches regulated by the host-vip chemistry between initiators and cucurbit[8]uril(CB[8]).Thermal initiators(VA-044,VA-056,VA-057)can be spontaneously encapsulated into the cavity of CB[8]to“turn off”their radical-generation ability.Their activity will instantaneously“turn on”in the presence of other competitors such as 1-adamantylamine(ADA).Further,we demonstrated the free radical polymerization of N-isopropylacrylamide using initiators,inhibiting its activity by binding with CB[8]and initiating reaction by adding ADA.These novel supramolecular radical switches provide a facile strategy to control the generation of free radicals in a“plug-and-play”manner,which may arouse research interests in polymerization,catalysis,and the biomedical field.
