Disulfides have been synthesized by oxidation of thiols using air as oxidant catalyzed by Co-Salophen with high yields,mild and neutral conditions,and easy procedures of the catalyst.The products were confirmed by ~1H...Disulfides have been synthesized by oxidation of thiols using air as oxidant catalyzed by Co-Salophen with high yields,mild and neutral conditions,and easy procedures of the catalyst.The products were confirmed by ~1H NMR and IR.展开更多
The laminated transition metal disulfides(TMDs),which are well known as typical two-dimensional(2D)semiconductive materials,possess a unique layered structure,leading to their wide-spread applications in various field...The laminated transition metal disulfides(TMDs),which are well known as typical two-dimensional(2D)semiconductive materials,possess a unique layered structure,leading to their wide-spread applications in various fields,such as catalysis,energy storage,sensing,etc.In recent years,a lot of research work on TMDs based functional materials in the fields of electromagnetic wave absorption(EMA)has been carried out.Therefore,it is of great significance to elaborate the influence of TMDs on EMA in time to speed up the application.In this review,recent advances in the development of electromagnetic wave(EMW)absorbers based on TMDs,ranging from the VIB group to the VB group are summarized.Their compositions,microstructures,electronic properties,and synthesis methods are presented in detail.Particularly,the modulation of structure engineering from the aspects of heterostructures,defects,morphologies and phases are systematically summarized,focusing on optimizing impedance matching and increasing dielectric and magnetic losses in the EMA materials with tunable EMW absorption performance.Milestones as well as the challenges are also identified to guide the design of new TMDs based dielectric EMA materials with high performance.展开更多
An efficient and convenient tert-butyl nitrite-catalyzed selective aerobic oxidation of thiols has been developed. Under the optimal reaction conditions, a number of thiol derivatives including aromatic thiols, hetero...An efficient and convenient tert-butyl nitrite-catalyzed selective aerobic oxidation of thiols has been developed. Under the optimal reaction conditions, a number of thiol derivatives including aromatic thiols, heteroaromatic thiols and aliphatic thiols can be converted into their corresponding disulfides in good to excellent yields.展开更多
Sodium alkyl thiosulfates(Bunte salts) can be readily reduced to the corresponding disulfides with TiCl4/Sm system in good to excellent yields under mild conditions
TEMPO(2,2,6,6-tetramethylpipe ridine-1-oxyl)is well-established in orangocatalysis that usually work in synergy with transition-metal catalysis or semiconductor photocatalysis.Here,TEMPO was turned into a visible ligh...TEMPO(2,2,6,6-tetramethylpipe ridine-1-oxyl)is well-established in orangocatalysis that usually work in synergy with transition-metal catalysis or semiconductor photocatalysis.Here,TEMPO was turned into a visible light photocatalyst to conduct the selective aerobic oxidation of thiols into disulfides.With O2 as an oxidant,a mild and efficient protocol for the selective oxidation of thiols into disulfides including symmetrical and unsymmetrical ones with 5 mol%of TEPMO as a photocatalyst was developed at room temperature under the irradiation of 460 nm blue LEDs.It was found that a complex formed between TEMPO and thiols underpinned the visible light activity and disulfides were obtained in very high isolated yields.This work suggests that TEMPO takes diverse roles in for photocatalytic selective oxidative transformations with O2 as the oxidant.展开更多
The metal-free S–S bond exchange reaction of symmetrical disulfides catalyzed by NFSI is described. This novel protocol provides a facile and efficient approach to accessing important unsymmetrical disulfides.Further...The metal-free S–S bond exchange reaction of symmetrical disulfides catalyzed by NFSI is described. This novel protocol provides a facile and efficient approach to accessing important unsymmetrical disulfides.Furthermore, this strategy could also be utilized in the late-stage functionalization of amino acids, drugs,and natural products. The broad substrate scope, good functional group tolerance and easy accessibility of catalyst indicate that this strategy affords a green and practical complementary method to various unsymmetrical disulfides.展开更多
The disulfides reacted with zinc in DMF, followed by alkyl halides, giving unsymmetrical thioether in excellent yields. This reaction takes place under mild and neutral conditions.
A simple and general method for the synthesis of bi(acyl)disulfides is reported.Sulfur is allowed to react with sodium hydroxide to give sodium disulfide at 65℃ under PTC,which can react with acyl halides to afford b...A simple and general method for the synthesis of bi(acyl)disulfides is reported.Sulfur is allowed to react with sodium hydroxide to give sodium disulfide at 65℃ under PTC,which can react with acyl halides to afford bi(acyl)disulfides in good to excellent isolated yields.The effects of solvents and phase transfer catalysts are discussed.展开更多
The redox state of cellular thiols is widely studied because it was recently linked to many different diseases and pathologies. In this work we quantified the concentrations of protein disulfides (PSSP) and thiol-prot...The redox state of cellular thiols is widely studied because it was recently linked to many different diseases and pathologies. In this work we quantified the concentrations of protein disulfides (PSSP) and thiol-protein mixed disulfides (XSSP) in rat tissues (liver, kidney and heart) and cells (Raw 264.7) by an improved method of XSSP and PSSP determination after oxidative stress induced by diamide. Under native and denaturing conditions, a thiol block by N-ethymaleimide was introduced to avoid thiol exchange reaction activations by protein SH groups (PSH) (PSH + XSSP ←→ PSSP + XSH) and alterations of original XSSP/PSSP levels. Low molecular weight thiols (XSH) and PSH were respectively measured by HPLC on supernatants and on corresponding pellets by DTNB (Ellman’s reagent) after dithiothreitol reduction. PSSP concentrations of liver, heart and kidney were respectively 0.304, 0.605 and 0.785 μmoles/g and after diamide exposure they were significantly augmented of about 65%-70% in liver and heart, but not in the kidney. Normal XSSP, that were -20 times lower than normal PSSP were induced by diamide in liver and heart of about 40 times, but not in kidney. Thermodynamic criteria regarding the pKa values of thiols engaged as PSSP and GSSP were used to interpret dethiolation mechanisms via thiol exchange reactions.展开更多
This work presents the visible-light photocatalytic selective oxidation of thiols to disulfides with molecular oxygen(O2) on anatase TiO2. The high specific surface area of anatase TiO2 proved to be especially critica...This work presents the visible-light photocatalytic selective oxidation of thiols to disulfides with molecular oxygen(O2) on anatase TiO2. The high specific surface area of anatase TiO2 proved to be especially critical in conferring high photocatalytic activity. Herein, surface complexation between thiol and TiO2 gives rise to photocatalytic activity under irradiation with 520 nm green light-emitting diodes(LEDs), resulting in excellent reaction activity, substrate scope, and functional group tolerance. The transformation was extremely efficient for the selective oxidation of various thiols, particularly with substrates bearing electron-withdrawing groups(reaction times of less than 10 min). To date, the longest wavelength of visible light that this system can utilize is 520 nm by the surface complex of substrate-TiO2. Importantly, O2 was found to act as the electron and proton acceptor, rather than to incorporate into the substrates. Our findings regarding this surface complex-based photocatalytic system can allow one to understand the interaction between the conduction band electrons and O2.展开更多
The simultaneous utilization of photogenerated electrons and holes in one cooperative photoredox system for the dehydrocoupling of thiols into value-added disulfides and clean hydrogen(H_(2))fuel meets the development...The simultaneous utilization of photogenerated electrons and holes in one cooperative photoredox system for the dehydrocoupling of thiols into value-added disulfides and clean hydrogen(H_(2))fuel meets the development criteria of green chemistry.Herein,we report the synthesis and application of cocatalyst PdS decorated ZnIn_(2)S_(4)(PdS-ZIS)composites for photocatalytic coupling of thiols into disulfides and H2 evolution under visible light irradiation.The superior photocatalytic performance over PdS-ZIS composites compared with blank ZIS is attributed to the function of PdS as oxidation cocatalyst,which dramatically promotes the separation and transfer of photogenerated charge carriers due to its excellent hole trapping ability.In-situ Fourier transform infrared spectra reveal the dynamic variation of reactants on the catalyst surface.Electron paramagnetic resonance technology confirms that sulfur-centered radicals are the key reaction intermediates in this coupling process.Moreover,the application of PdS-ZIS composites to the dehydrocoupling of various thiols with different substituent groups into the corresponding S-S coupling products has been demonstrated to be practicable.This work is expected to offer insights into the rational design of cocatalyst-decorated semiconductor photocatalysts with efficient utilization of photogenerated electrons and holes for the co-production of high-value chemicals and clean H2 energy in a cooperative photoredox catalysis process.展开更多
Nitrodisulfides were reduced by SmI2/HMPA in anhydrous THF at room temperature to produce active intermediates (samarium thiolates and amides), which were 'living' double-anions and reacted smoothly with aldeh...Nitrodisulfides were reduced by SmI2/HMPA in anhydrous THF at room temperature to produce active intermediates (samarium thiolates and amides), which were 'living' double-anions and reacted smoothly with aldehydes or ketones to afford benzothiazolines in good yields under mild and neutral conditions.展开更多
An efficient synthesis of α-thioenamine compounds via a K_(2)S_(2)O_(8)-promoted cross-dehydrogenative coupling reaction between heterocyclic thiols and enamine esters in an aqueous medium has been developed.The reac...An efficient synthesis of α-thioenamine compounds via a K_(2)S_(2)O_(8)-promoted cross-dehydrogenative coupling reaction between heterocyclic thiols and enamine esters in an aqueous medium has been developed.The reaction showed good tolerance for enamine esters and heterocyclic thiols with various functional groups,producingα-thioenamine derivatives in moderate to high yields.Mechanistic studies revealed that heterocyclic thiols react with K_(2)S_(2)O_(8) in water to form reactive disulfides in situ,which then react with enamine esters to generate a series ofα-thioenamines.Building on the proposed mechanism,we developed a sulfenylation reaction of enamine esters with disulfides without the need for an oxidant.This oxidant-free approach has been successfully employed to synthesize DNA-taggedα-thioenamine,demonstrating its considerable potential for various synthetic applications.展开更多
Potassium-ion batteries(PIBs)are highly attractive and are promising energy storage technology because of their cost-effectiveness,superior safety,environmental friendliness,as well as high standard K/K^(+)redox poten...Potassium-ion batteries(PIBs)are highly attractive and are promising energy storage technology because of their cost-effectiveness,superior safety,environmental friendliness,as well as high standard K/K^(+)redox potential,and abundance and low cost of potassium.Transition metal disulfides(TMDs)have a wide interlayer spacing that is attractive as a K^(+)storage site in PIBs.Moreover,TMDs have high reversible capacity and are low cost.Nevertheless,they have not been extensively studied.The practical application of TMDs is impeded by their fast capacity fading and poor rate performance.More well-focused research should aim for the commercialization of TMDs in PIBs.This paper reviews(a)the main strategies to enhance the application of TMDs in PIBs;(b)the recent development of using TMDs such as MoS_(2),WS_(2),and SnS_(2) as electrode materials for PIBs,including their structure,performance,and defects,as well as the methods to alleviate their defects;(c)the associated electrochemical processes;and(d)the critical issues,challenges,and prospects.展开更多
Lamellar compounds such as the disulfides of molybdenum and tungsten are widely used as additives in lubricant oils or as solid lubricants in aerospace industries.The dioxides of these two transition metals have ident...Lamellar compounds such as the disulfides of molybdenum and tungsten are widely used as additives in lubricant oils or as solid lubricants in aerospace industries.The dioxides of these two transition metals have identical microstructures with those of the disulfides.The differences in the lubrication behaviors of disulfide and dioxides were investigated theoretically.Tungsten dioxide and molybdenum dioxide exhibit higher bond strengths at the interface and lower interlayer interactions than those of the disulfides which indicates their superlubricity.Furthermore,the topography of the electron density of the single layer nanostructure determined their sliding potential barrier;the dioxides showed a weaker electronic cloud distribution between the two neighboring oxygen atoms,which facilitated the oxygen atoms of the counterpart to go through.For commensurate friction,the dioxides exhibited nearly the same value of friction work,and same was the case for the disulfides.The lower positive value of friction work for the dioxides confirmed their improved lubricity than the disulfides and the higher mechanical strength of the bulk dioxides demonstrated that they are excellent solid lubricants in vacuum.展开更多
The photocatalytic oxidative coupling of thiols is one of the most popular methods to synthesize the disulfides.Triphenylamine and its derivatives(TPAs)are promising for the above reaction,but suffer from the easy pol...The photocatalytic oxidative coupling of thiols is one of the most popular methods to synthesize the disulfides.Triphenylamine and its derivatives(TPAs)are promising for the above reaction,but suffer from the easy polymerization and difficult separation.To overcome these obstacles while controlling the photogenerated electrons transfer directly to target substrates,herein,we constructed one TPA-based metal-organic framework(MOF),(Me_(2)NH_(2))[Sr(TCBPA)]·DMA·3H_(2)O(1),by direct self-assembly of tris(4′-carboxybiphenyl)amine(H_(3)TCBPA)and photoredox inert strontium ion(Sr^(2+)).DFT calculations revealed that the valence band maximum(VBM)and the conduction band minimum(CBM)are mainly located on TCBPA^(3-),successfully inhibiting the undesirable electron migration to metal nodes.Experimental results indicated that 1 displays superior performance than homogeneous H_(3)TCBPA,which may result from the abundant π…π and C—H…π interactions between the well-arranged TCBPA^(3-)and the build-in electric field between the anionic framework and the Me_(2)NH^(2+).This work highlights that immobilizing TPAs into MOFs is one promising approach to designing heterogeneous photocatalysts for the synthesis of disulfides by oxidative coupling of thiols.展开更多
Using visible light as energy to form free radicals has important synthetic value.A novel and efficient visible-lightmediated strategy has been developed for the generation of thiobenzene radicals through cerium-catal...Using visible light as energy to form free radicals has important synthetic value.A novel and efficient visible-lightmediated strategy has been developed for the generation of thiobenzene radicals through cerium-catalyzed activation of the disulfides.Through this photochemical reaction,various 3-sulfenylated quinoxalin-2(1H)-ones can be conveniently obtained in good yields with good functional group tolerance.Our transformation provides an alternative that allows rapid access to various C3 sulfenylated quinoxalin-2(1H)-ones in a sustainable and practical manner.展开更多
Fundamental understandings on the dynamics of charge carriers and excitonic quasiparticles in semiconductors are of central importance for both many-body physics and promising optoelectronic and photonic applications....Fundamental understandings on the dynamics of charge carriers and excitonic quasiparticles in semiconductors are of central importance for both many-body physics and promising optoelectronic and photonic applications.Here,we investigated the carrier dynamics and many-body interactions in two-dimensional(2D)transition metal dichalcogenides(TMDs),using monolayer WS2 as an example,by employing femtosecond broadband pump-probe spectroscopy.Three time regimes for the exciton energy renormalization are unambiguously revealed with a distinct red-blue-red shift upon above-bandgap optical excitations.We attribute the dominant physical process in the three typical regimes to free carrier screening effect,Coulombic exciton-exciton interactions and Auger photocarrier generation,respectively,which show distinct dependence on the optical excitation wavelength,pump fluences and/or lattice temperature.An intrinsic exciton radiative lifetime of about 1.2 picoseconds(ps)in monolayer WS2 is unraveled at low temperature,and surprisingly the efficient Auger nonradiative decay of both bright and dark excitons puts the system in a nonequilibrium state at the nanosecond timescale.In addition,the dynamics of trions at low temperature is observed to be significantly different from that of excitons,e.g.,a long radiative lifetime of^108.7 ps at low excitation densities and the evolution of trion energy as a function of delay times.Our findings elucidate the dynamics of excitonic quasiparticles and the intricate many-body physics in 2D semiconductors,underpinning the future development of photonics,valleytronics and optoelectronics based on 2D semiconductors.展开更多
A highly practical method to access unsymmetrical and symmetrical thiosulfonates in moderate to excellent yields has been developed through NBS-promoted sulfenylation of sulfinates with disulfides. The present process...A highly practical method to access unsymmetrical and symmetrical thiosulfonates in moderate to excellent yields has been developed through NBS-promoted sulfenylation of sulfinates with disulfides. The present process enables the use of two RS in RSSR and shows broad functional group tolerance, which represents an atom-economical and practical procedure for the synthesis of thiosulfonates. A plausible mechanism for the role of NBS as a promoter for the cleavage of disulfides generating N-（organothio）succinimide that then undergos facile sulenylation with sulfinates is proposed.展开更多
文摘Disulfides have been synthesized by oxidation of thiols using air as oxidant catalyzed by Co-Salophen with high yields,mild and neutral conditions,and easy procedures of the catalyst.The products were confirmed by ~1H NMR and IR.
基金This work was supported by the National Natural Science Foundation of China(52372289,52102368,52072192 and 51977009)Regional Joint Fund for Basic Research and Applied Basic Research of Guangdong Province(No.2020SA001515110905).
文摘The laminated transition metal disulfides(TMDs),which are well known as typical two-dimensional(2D)semiconductive materials,possess a unique layered structure,leading to their wide-spread applications in various fields,such as catalysis,energy storage,sensing,etc.In recent years,a lot of research work on TMDs based functional materials in the fields of electromagnetic wave absorption(EMA)has been carried out.Therefore,it is of great significance to elaborate the influence of TMDs on EMA in time to speed up the application.In this review,recent advances in the development of electromagnetic wave(EMW)absorbers based on TMDs,ranging from the VIB group to the VB group are summarized.Their compositions,microstructures,electronic properties,and synthesis methods are presented in detail.Particularly,the modulation of structure engineering from the aspects of heterostructures,defects,morphologies and phases are systematically summarized,focusing on optimizing impedance matching and increasing dielectric and magnetic losses in the EMA materials with tunable EMW absorption performance.Milestones as well as the challenges are also identified to guide the design of new TMDs based dielectric EMA materials with high performance.
基金financially supported by the National Natural Science Foundation of China (Nos. 21376224, 21206147)
文摘An efficient and convenient tert-butyl nitrite-catalyzed selective aerobic oxidation of thiols has been developed. Under the optimal reaction conditions, a number of thiol derivatives including aromatic thiols, heteroaromatic thiols and aliphatic thiols can be converted into their corresponding disulfides in good to excellent yields.
文摘Sodium alkyl thiosulfates(Bunte salts) can be readily reduced to the corresponding disulfides with TiCl4/Sm system in good to excellent yields under mild conditions
基金supported by the National Natural Science Foundation of China(Nos.21773173,21503086)the Fundamental Research Funds for the Central Universities(No.2042018kf0212)the start-up fund of Wuhan University。
文摘TEMPO(2,2,6,6-tetramethylpipe ridine-1-oxyl)is well-established in orangocatalysis that usually work in synergy with transition-metal catalysis or semiconductor photocatalysis.Here,TEMPO was turned into a visible light photocatalyst to conduct the selective aerobic oxidation of thiols into disulfides.With O2 as an oxidant,a mild and efficient protocol for the selective oxidation of thiols into disulfides including symmetrical and unsymmetrical ones with 5 mol%of TEPMO as a photocatalyst was developed at room temperature under the irradiation of 460 nm blue LEDs.It was found that a complex formed between TEMPO and thiols underpinned the visible light activity and disulfides were obtained in very high isolated yields.This work suggests that TEMPO takes diverse roles in for photocatalytic selective oxidative transformations with O2 as the oxidant.
基金the financial support from the National Natural Science Foundation of China (Nos. 21572026, 21702019)Postgraduate Research & Practice Innovation Program of Jiangsu Province (No. SJCX20_0952)Advanced Catalysis and Green Manufacturing Collaborative Innovation Center, Changzhou University
文摘The metal-free S–S bond exchange reaction of symmetrical disulfides catalyzed by NFSI is described. This novel protocol provides a facile and efficient approach to accessing important unsymmetrical disulfides.Furthermore, this strategy could also be utilized in the late-stage functionalization of amino acids, drugs,and natural products. The broad substrate scope, good functional group tolerance and easy accessibility of catalyst indicate that this strategy affords a green and practical complementary method to various unsymmetrical disulfides.
文摘The disulfides reacted with zinc in DMF, followed by alkyl halides, giving unsymmetrical thioether in excellent yields. This reaction takes place under mild and neutral conditions.
文摘A simple and general method for the synthesis of bi(acyl)disulfides is reported.Sulfur is allowed to react with sodium hydroxide to give sodium disulfide at 65℃ under PTC,which can react with acyl halides to afford bi(acyl)disulfides in good to excellent isolated yields.The effects of solvents and phase transfer catalysts are discussed.
文摘The redox state of cellular thiols is widely studied because it was recently linked to many different diseases and pathologies. In this work we quantified the concentrations of protein disulfides (PSSP) and thiol-protein mixed disulfides (XSSP) in rat tissues (liver, kidney and heart) and cells (Raw 264.7) by an improved method of XSSP and PSSP determination after oxidative stress induced by diamide. Under native and denaturing conditions, a thiol block by N-ethymaleimide was introduced to avoid thiol exchange reaction activations by protein SH groups (PSH) (PSH + XSSP ←→ PSSP + XSH) and alterations of original XSSP/PSSP levels. Low molecular weight thiols (XSH) and PSH were respectively measured by HPLC on supernatants and on corresponding pellets by DTNB (Ellman’s reagent) after dithiothreitol reduction. PSSP concentrations of liver, heart and kidney were respectively 0.304, 0.605 and 0.785 μmoles/g and after diamide exposure they were significantly augmented of about 65%-70% in liver and heart, but not in the kidney. Normal XSSP, that were -20 times lower than normal PSSP were induced by diamide in liver and heart of about 40 times, but not in kidney. Thermodynamic criteria regarding the pKa values of thiols engaged as PSSP and GSSP were used to interpret dethiolation mechanisms via thiol exchange reactions.
文摘This work presents the visible-light photocatalytic selective oxidation of thiols to disulfides with molecular oxygen(O2) on anatase TiO2. The high specific surface area of anatase TiO2 proved to be especially critical in conferring high photocatalytic activity. Herein, surface complexation between thiol and TiO2 gives rise to photocatalytic activity under irradiation with 520 nm green light-emitting diodes(LEDs), resulting in excellent reaction activity, substrate scope, and functional group tolerance. The transformation was extremely efficient for the selective oxidation of various thiols, particularly with substrates bearing electron-withdrawing groups(reaction times of less than 10 min). To date, the longest wavelength of visible light that this system can utilize is 520 nm by the surface complex of substrate-TiO2. Importantly, O2 was found to act as the electron and proton acceptor, rather than to incorporate into the substrates. Our findings regarding this surface complex-based photocatalytic system can allow one to understand the interaction between the conduction band electrons and O2.
文摘The simultaneous utilization of photogenerated electrons and holes in one cooperative photoredox system for the dehydrocoupling of thiols into value-added disulfides and clean hydrogen(H_(2))fuel meets the development criteria of green chemistry.Herein,we report the synthesis and application of cocatalyst PdS decorated ZnIn_(2)S_(4)(PdS-ZIS)composites for photocatalytic coupling of thiols into disulfides and H2 evolution under visible light irradiation.The superior photocatalytic performance over PdS-ZIS composites compared with blank ZIS is attributed to the function of PdS as oxidation cocatalyst,which dramatically promotes the separation and transfer of photogenerated charge carriers due to its excellent hole trapping ability.In-situ Fourier transform infrared spectra reveal the dynamic variation of reactants on the catalyst surface.Electron paramagnetic resonance technology confirms that sulfur-centered radicals are the key reaction intermediates in this coupling process.Moreover,the application of PdS-ZIS composites to the dehydrocoupling of various thiols with different substituent groups into the corresponding S-S coupling products has been demonstrated to be practicable.This work is expected to offer insights into the rational design of cocatalyst-decorated semiconductor photocatalysts with efficient utilization of photogenerated electrons and holes for the co-production of high-value chemicals and clean H2 energy in a cooperative photoredox catalysis process.
基金We thank the National Natural Science Foundation of China (Project! No.29872010)the Laboratory of Organometallic Chemistry,
文摘Nitrodisulfides were reduced by SmI2/HMPA in anhydrous THF at room temperature to produce active intermediates (samarium thiolates and amides), which were 'living' double-anions and reacted smoothly with aldehydes or ketones to afford benzothiazolines in good yields under mild and neutral conditions.
基金the financial support from the Key R&D Projects of Hainan Province(No.ZDYF2024SHFZ065)the Cultivation Research Foundation of Hainan Medical University(No.RZ2300002021 to Dulin Kong,No.RZ2400001591 to Guangkuan Zhao)the Postgraduate Innovation Project of Hainan Medical University(No.HYYB2023A07 to Wenyan Wei)。
文摘An efficient synthesis of α-thioenamine compounds via a K_(2)S_(2)O_(8)-promoted cross-dehydrogenative coupling reaction between heterocyclic thiols and enamine esters in an aqueous medium has been developed.The reaction showed good tolerance for enamine esters and heterocyclic thiols with various functional groups,producingα-thioenamine derivatives in moderate to high yields.Mechanistic studies revealed that heterocyclic thiols react with K_(2)S_(2)O_(8) in water to form reactive disulfides in situ,which then react with enamine esters to generate a series ofα-thioenamines.Building on the proposed mechanism,we developed a sulfenylation reaction of enamine esters with disulfides without the need for an oxidant.This oxidant-free approach has been successfully employed to synthesize DNA-taggedα-thioenamine,demonstrating its considerable potential for various synthetic applications.
基金supported by the Shandong Province Natural Science Foundation(no.ZR2023ME181)the National Natural Science Foundation of China(no.52305313)the Natural Science Foundation of Hunan Province(nos.2023JJ40553 and 2023JJ60433).
文摘Potassium-ion batteries(PIBs)are highly attractive and are promising energy storage technology because of their cost-effectiveness,superior safety,environmental friendliness,as well as high standard K/K^(+)redox potential,and abundance and low cost of potassium.Transition metal disulfides(TMDs)have a wide interlayer spacing that is attractive as a K^(+)storage site in PIBs.Moreover,TMDs have high reversible capacity and are low cost.Nevertheless,they have not been extensively studied.The practical application of TMDs is impeded by their fast capacity fading and poor rate performance.More well-focused research should aim for the commercialization of TMDs in PIBs.This paper reviews(a)the main strategies to enhance the application of TMDs in PIBs;(b)the recent development of using TMDs such as MoS_(2),WS_(2),and SnS_(2) as electrode materials for PIBs,including their structure,performance,and defects,as well as the methods to alleviate their defects;(c)the associated electrochemical processes;and(d)the critical issues,challenges,and prospects.
基金the National Nature Science Foundation of China，the 'Top Hundred Talents' Program of Chinese Academy of Sciences and the National Key Basic Research and Development (973) Program of China (2013CB632300) for financial support
文摘Lamellar compounds such as the disulfides of molybdenum and tungsten are widely used as additives in lubricant oils or as solid lubricants in aerospace industries.The dioxides of these two transition metals have identical microstructures with those of the disulfides.The differences in the lubrication behaviors of disulfide and dioxides were investigated theoretically.Tungsten dioxide and molybdenum dioxide exhibit higher bond strengths at the interface and lower interlayer interactions than those of the disulfides which indicates their superlubricity.Furthermore,the topography of the electron density of the single layer nanostructure determined their sliding potential barrier;the dioxides showed a weaker electronic cloud distribution between the two neighboring oxygen atoms,which facilitated the oxygen atoms of the counterpart to go through.For commensurate friction,the dioxides exhibited nearly the same value of friction work,and same was the case for the disulfides.The lower positive value of friction work for the dioxides confirmed their improved lubricity than the disulfides and the higher mechanical strength of the bulk dioxides demonstrated that they are excellent solid lubricants in vacuum.
基金supported by NSFC(22101160)the"1331"Project of Shanxi ProvinceResearch Project Supported by Shanxi Scholarship Council of China(2020-088).
文摘The photocatalytic oxidative coupling of thiols is one of the most popular methods to synthesize the disulfides.Triphenylamine and its derivatives(TPAs)are promising for the above reaction,but suffer from the easy polymerization and difficult separation.To overcome these obstacles while controlling the photogenerated electrons transfer directly to target substrates,herein,we constructed one TPA-based metal-organic framework(MOF),(Me_(2)NH_(2))[Sr(TCBPA)]·DMA·3H_(2)O(1),by direct self-assembly of tris(4′-carboxybiphenyl)amine(H_(3)TCBPA)and photoredox inert strontium ion(Sr^(2+)).DFT calculations revealed that the valence band maximum(VBM)and the conduction band minimum(CBM)are mainly located on TCBPA^(3-),successfully inhibiting the undesirable electron migration to metal nodes.Experimental results indicated that 1 displays superior performance than homogeneous H_(3)TCBPA,which may result from the abundant π…π and C—H…π interactions between the well-arranged TCBPA^(3-)and the build-in electric field between the anionic framework and the Me_(2)NH^(2+).This work highlights that immobilizing TPAs into MOFs is one promising approach to designing heterogeneous photocatalysts for the synthesis of disulfides by oxidative coupling of thiols.
基金supported by the National Natural Science Foundation of China(No.21302171)the Zhejiang Shuren University Basic Scientific Research Special Funds,the“Ten-thousand Talents Plan”of Zhejiang Province(No.2019R51012).
文摘Using visible light as energy to form free radicals has important synthetic value.A novel and efficient visible-lightmediated strategy has been developed for the generation of thiobenzene radicals through cerium-catalyzed activation of the disulfides.Through this photochemical reaction,various 3-sulfenylated quinoxalin-2(1H)-ones can be conveniently obtained in good yields with good functional group tolerance.Our transformation provides an alternative that allows rapid access to various C3 sulfenylated quinoxalin-2(1H)-ones in a sustainable and practical manner.
基金Q.H.X.gratefully acknowledges the support from Singapore Ministry of Education via AcRF Tier 3 Programme(No.MOE2018-T3-1-002)Tier 2 project(No.MOE2017-T2-1-040)Singapore National Research Foundation via NRF-ANR project(No.NRF2017-NRF-ANR0052D-Chiral).
文摘Fundamental understandings on the dynamics of charge carriers and excitonic quasiparticles in semiconductors are of central importance for both many-body physics and promising optoelectronic and photonic applications.Here,we investigated the carrier dynamics and many-body interactions in two-dimensional(2D)transition metal dichalcogenides(TMDs),using monolayer WS2 as an example,by employing femtosecond broadband pump-probe spectroscopy.Three time regimes for the exciton energy renormalization are unambiguously revealed with a distinct red-blue-red shift upon above-bandgap optical excitations.We attribute the dominant physical process in the three typical regimes to free carrier screening effect,Coulombic exciton-exciton interactions and Auger photocarrier generation,respectively,which show distinct dependence on the optical excitation wavelength,pump fluences and/or lattice temperature.An intrinsic exciton radiative lifetime of about 1.2 picoseconds(ps)in monolayer WS2 is unraveled at low temperature,and surprisingly the efficient Auger nonradiative decay of both bright and dark excitons puts the system in a nonequilibrium state at the nanosecond timescale.In addition,the dynamics of trions at low temperature is observed to be significantly different from that of excitons,e.g.,a long radiative lifetime of^108.7 ps at low excitation densities and the evolution of trion energy as a function of delay times.Our findings elucidate the dynamics of excitonic quasiparticles and the intricate many-body physics in 2D semiconductors,underpinning the future development of photonics,valleytronics and optoelectronics based on 2D semiconductors.
基金Supporting intbrmation tbr this article is available on the WWW under http：//dx.doi.org/10.1002/cjoc.201200028 or from the author.Acknowledgement This work was supported by the National Natural Science Foundation of China （Nos. 21102105 and 21072153）.
文摘A highly practical method to access unsymmetrical and symmetrical thiosulfonates in moderate to excellent yields has been developed through NBS-promoted sulfenylation of sulfinates with disulfides. The present process enables the use of two RS in RSSR and shows broad functional group tolerance, which represents an atom-economical and practical procedure for the synthesis of thiosulfonates. A plausible mechanism for the role of NBS as a promoter for the cleavage of disulfides generating N-（organothio）succinimide that then undergos facile sulenylation with sulfinates is proposed.
