Water radical cations,the crucial intermediates in many aqueous reactions and biochemical processes,are difficult to investigate experimentally due to their short lifetime andlowabundance.Herein,ahomemade device based...Water radical cations,the crucial intermediates in many aqueous reactions and biochemical processes,are difficult to investigate experimentally due to their short lifetime andlowabundance.Herein,ahomemade device based on energy-tunable discharge was employed to deposit suitable amounts of energy to atmospheric pressure pure water vapor for abundant production of water radical cations,stabilized as(H_(2)O)n^(+·)(n=2-5)with a maximal abundance of≥8.3×10^(6) cps for(H_(2)O)_(2)^(+·),characterized by mass spectrometry(MS).The abundance of water radical cations was optimized by adjusting the experimental parameters such as the discharge voltage(2.5 kV),temperature of the MS inlet(140℃),carrier gas flow(20mL/min),and the distance between the discharge tip and MS inlet(12 mm).The ambient formation of water radical cationswas further confirmedby thehigh reactivity of as-prepared water radical cations,which reacted with benzene,ethyl acetate,and dimethyl disulfide instantly,showing rich chemistry with ionic and radical characteristics.Moreover,the computations usingCCSD(T)//MP2 method and density functional theory confirmed that the O-O single-electron bound dimer(B),as well as the hydronium hydroxyl radical complex(A),accounted for the unusual chemistry of the water radical cations,providing a facile approach to access the high reactivity ofwater radical cations under the ambient conditions.展开更多
Indole-derived radical cations, open-shell reactive species, display distinctive dual reactivity due to the carbon-centered radical and more electrophilic carbocation, which frequently appear in a variety of single el...Indole-derived radical cations, open-shell reactive species, display distinctive dual reactivity due to the carbon-centered radical and more electrophilic carbocation, which frequently appear in a variety of single electron oxidation reactions for synthesizing structurally diverse functionalized indoles and indolines. Electrocatalysis is considered as a synthetically attractive and environmentally friendly alternative for driving the single electron oxidation of indoles. Remarkable achievements in electrocatalytic indolederived radical cation-mediated indole functionalization have been realized so far. This review comprehensively summarizes the recent progresses in the applications of electrocatalytic indole radical cations,including C(sp~2)–H functionalization, dearomative 2,3-difunctionalization, and ring-opening reaction, emphasizing the vital single electron oxidation steps of indoles, the substrates scope and limitations, and the reaction mechanisms.展开更多
Development of practical and versatile electrophilic difluoromethylating reagent is still a grand challenge so far due to its inherent instability or low reactivity.Herein,we report the design and synthesis of difluor...Development of practical and versatile electrophilic difluoromethylating reagent is still a grand challenge so far due to its inherent instability or low reactivity.Herein,we report the design and synthesis of difluoromethyl phenoxathiinium tetrafluoroborate(PT-CF_(2)H^(+)BF_(4)^(-)) as a novel difluoromethylating reagent,which proves to be a bench-stable,general,powerful and versatile reagent with divergent·CF_(2)H,CF_(2)H^(+),and:CF_(2) reactivities.Making use of this reagent,we demonstrated a vast array of difluoromethyl radical transfer reactions via diverse pathways involving photocatalyst-free visible-light induction,visible-light photoredox catalysis and visible-light mediation single electron transfer of EDA complex.Moreover,the green and highly effective CF_(2)H^(+) and:CF_(2) transfer reactions were also readily accomplished.展开更多
A highly persistent benzoanthracenyl radical(BAR1)protected by five substituents at strategic positions is synthesized.BAR1 exhibited half-life time of 108 h in air-saturated solution,which allowed for detailed charac...A highly persistent benzoanthracenyl radical(BAR1)protected by five substituents at strategic positions is synthesized.BAR1 exhibited half-life time of 108 h in air-saturated solution,which allowed for detailed characterization in the solution.The combined experimental and theoretical study reveals the properties associated with its asymmetric structure and spin distribution.One-electron oxidation of BAR1 afforded stable cationic species BAR1+,whose structure is unambiguously determined by the NMR spectroscopy.展开更多
The reactions between gatifloxacin(GFX) and various one-electron oxidants,such as ˙OH,N3˙,Br2˙ˉ,and SO4˙ˉ,have been studied by pulse radiolysis techniques.The GFX radical anion formed in the reaction of GFX with...The reactions between gatifloxacin(GFX) and various one-electron oxidants,such as ˙OH,N3˙,Br2˙ˉ,and SO4˙ˉ,have been studied by pulse radiolysis techniques.The GFX radical anion formed in the reaction of GFX with eaqˉ could either be protonated or deprotonated,and the absorption of GFX radical anion was located at 390 nm.The transient species produced by the reaction of GFX with ˙OH radical shows a broad band in the 380?600 nm region with a shoulder,while the oxidation by N3˙,SO4˙ˉ,and Br2˙ˉ results in an absorption band with λmax = 370 nm.At neutral condition(pH 7),the rate constants of GFX reacting with ˙OH,N3˙,Br2˙ˉ,SO4˙ˉ and eaqˉ are estimated to be 1.0 × 1010,3.1 × 109,2.8 × 109,3.0 × 109,and 1.8 × 1010 dm3 mol?1 s?1,respectively.From the pH dependence on the formation of electron adducts and on the rate constant of GFX with eaqˉ,the pKa of GFX radical anion is estimated to be 5.5 and 9.3.展开更多
IN the last few years phenothiazine(PTH)and its derivatives have captured much attention inthe fields of medicines,biology,and microelectronic materials due to their ability to ef-ficiently photosensitize acid product...IN the last few years phenothiazine(PTH)and its derivatives have captured much attention inthe fields of medicines,biology,and microelectronic materials due to their ability to ef-ficiently photosensitize acid production in the presence of vicinal dibromides and hence tochange the solubilization of polymer films.The photophysical and photochemical properties re-lated to the processes have been studied.Monica Barra et al.found that the triplet展开更多
The optimized structure of the tetrathiafulvalence radical-cation dimer(TTF·+-TTF·+) with all-real frequencies is obtained at MP2/6-311G level,which exhibits the attraction between two molecular cation TTF&#...The optimized structure of the tetrathiafulvalence radical-cation dimer(TTF·+-TTF·+) with all-real frequencies is obtained at MP2/6-311G level,which exhibits the attraction between two molecular cation TTF·+.The new attraction interaction is a 20-center-2-electron intermolecular covalent π /π bonding with a telescope shape.The covalent π /π bonding has the bonding energy of about -21 kcal·mol-1 and is concealed by the Coulombic repulsion between two TTF·+ cations.This intermolecular covalent attraction also influences the structure of the TTF·+ subunit,i.e.,its molecular plane is bent by an angle θ=5.6°.This work provides new knowledge on intermolecular interaction.展开更多
Introduction Bilirubin (BR) is generally regarded as a toxic compound when accumulated at an abnormally high concentration in biological tissues, and in fact a normal adult man produces about 300 mg of BR a day. Howev...Introduction Bilirubin (BR) is generally regarded as a toxic compound when accumulated at an abnormally high concentration in biological tissues, and in fact a normal adult man produces about 300 mg of BR a day. However, it was proposed that the bile pigments BR and biliverdin(BV), which is the precursor of BR, may protect vitamin A and linoleie acid from oxidative destruction in the intestinal tract Further stud展开更多
Electron transfer reaction between vitamin A (1) and tris(p-bromophenyl)aminium hexachloroautimonate (2) in dichloromethane (DCM) has been investigated by means of UV-VIS absorption and ESR spectroscopy. The title ra... Electron transfer reaction between vitamin A (1) and tris(p-bromophenyl)aminium hexachloroautimonate (2) in dichloromethane (DCM) has been investigated by means of UV-VIS absorption and ESR spectroscopy. The title radical cation formed in the reaction was characterized by a new absorption band around 600 nm and a singlet unresolved ESR spectrum with g factor of 2.0038-2.0039 and line width of 20 G. Further studies indicated that ESR pattern and parameters of the radical cation generated by 7-irradiation of 1 in CFCl3 matrix at 77 K are consistent with that resulted in the chemical oxidation in DCM at ambient temperature.展开更多
Studies on the mechanism of the reactions involving coenzyme NAD(P)H and its model compounds are of considerable significance for understanding the role and the mechanism of this coenzyme in living cells. Although the...Studies on the mechanism of the reactions involving coenzyme NAD(P)H and its model compounds are of considerable significance for understanding the role and the mechanism of this coenzyme in living cells. Although there have been extensive studies on the mechanism of hydride transfer for NADH and its models, a展开更多
基金supported by a grant from the National Natural Science Foundation of China(grant no.215201-02007)the US National Science Foundation(grant no.1905087).
文摘Water radical cations,the crucial intermediates in many aqueous reactions and biochemical processes,are difficult to investigate experimentally due to their short lifetime andlowabundance.Herein,ahomemade device based on energy-tunable discharge was employed to deposit suitable amounts of energy to atmospheric pressure pure water vapor for abundant production of water radical cations,stabilized as(H_(2)O)n^(+·)(n=2-5)with a maximal abundance of≥8.3×10^(6) cps for(H_(2)O)_(2)^(+·),characterized by mass spectrometry(MS).The abundance of water radical cations was optimized by adjusting the experimental parameters such as the discharge voltage(2.5 kV),temperature of the MS inlet(140℃),carrier gas flow(20mL/min),and the distance between the discharge tip and MS inlet(12 mm).The ambient formation of water radical cationswas further confirmedby thehigh reactivity of as-prepared water radical cations,which reacted with benzene,ethyl acetate,and dimethyl disulfide instantly,showing rich chemistry with ionic and radical characteristics.Moreover,the computations usingCCSD(T)//MP2 method and density functional theory confirmed that the O-O single-electron bound dimer(B),as well as the hydronium hydroxyl radical complex(A),accounted for the unusual chemistry of the water radical cations,providing a facile approach to access the high reactivity ofwater radical cations under the ambient conditions.
基金the National Natural Science Foundation of China (No.22261019)the Jiangxi Provincial Natural Science Foundation (No.20224BAB213004)+1 种基金the Education Department of Jiangxi Province(Nos.GJJ211134 and GJJ211137)the PhD start-up fund of Jiangxi Science&Technology Normal University (No.2021BSQD32) for financial support。
文摘Indole-derived radical cations, open-shell reactive species, display distinctive dual reactivity due to the carbon-centered radical and more electrophilic carbocation, which frequently appear in a variety of single electron oxidation reactions for synthesizing structurally diverse functionalized indoles and indolines. Electrocatalysis is considered as a synthetically attractive and environmentally friendly alternative for driving the single electron oxidation of indoles. Remarkable achievements in electrocatalytic indolederived radical cation-mediated indole functionalization have been realized so far. This review comprehensively summarizes the recent progresses in the applications of electrocatalytic indole radical cations,including C(sp~2)–H functionalization, dearomative 2,3-difunctionalization, and ring-opening reaction, emphasizing the vital single electron oxidation steps of indoles, the substrates scope and limitations, and the reaction mechanisms.
基金supported by the National Natural Science Foundation of China(92056201)Guangdong Basic and Applied Basic Research Foundation(2023A1515011008)Shenzhen Science and Technology Program(the Stable Support Plan Program 20220808130958001)。
文摘Development of practical and versatile electrophilic difluoromethylating reagent is still a grand challenge so far due to its inherent instability or low reactivity.Herein,we report the design and synthesis of difluoromethyl phenoxathiinium tetrafluoroborate(PT-CF_(2)H^(+)BF_(4)^(-)) as a novel difluoromethylating reagent,which proves to be a bench-stable,general,powerful and versatile reagent with divergent·CF_(2)H,CF_(2)H^(+),and:CF_(2) reactivities.Making use of this reagent,we demonstrated a vast array of difluoromethyl radical transfer reactions via diverse pathways involving photocatalyst-free visible-light induction,visible-light photoredox catalysis and visible-light mediation single electron transfer of EDA complex.Moreover,the green and highly effective CF_(2)H^(+) and:CF_(2) transfer reactions were also readily accomplished.
基金National Natural Science Foundation of China(No.21971187)Natural Science Foundation of Tianjin,China(No.19JCJQJC62700)Haihe Laboratory of Sustainable Chemical Transformations and Training Plan for Young Core Teachers of Colleges and Universities in Henan Province,China(No.2019GGJS093).
文摘A highly persistent benzoanthracenyl radical(BAR1)protected by five substituents at strategic positions is synthesized.BAR1 exhibited half-life time of 108 h in air-saturated solution,which allowed for detailed characterization in the solution.The combined experimental and theoretical study reveals the properties associated with its asymmetric structure and spin distribution.One-electron oxidation of BAR1 afforded stable cationic species BAR1+,whose structure is unambiguously determined by the NMR spectroscopy.
基金supported by the National Natural Science Foundation of China (21173252)
文摘The reactions between gatifloxacin(GFX) and various one-electron oxidants,such as ˙OH,N3˙,Br2˙ˉ,and SO4˙ˉ,have been studied by pulse radiolysis techniques.The GFX radical anion formed in the reaction of GFX with eaqˉ could either be protonated or deprotonated,and the absorption of GFX radical anion was located at 390 nm.The transient species produced by the reaction of GFX with ˙OH radical shows a broad band in the 380?600 nm region with a shoulder,while the oxidation by N3˙,SO4˙ˉ,and Br2˙ˉ results in an absorption band with λmax = 370 nm.At neutral condition(pH 7),the rate constants of GFX reacting with ˙OH,N3˙,Br2˙ˉ,SO4˙ˉ and eaqˉ are estimated to be 1.0 × 1010,3.1 × 109,2.8 × 109,3.0 × 109,and 1.8 × 1010 dm3 mol?1 s?1,respectively.From the pH dependence on the formation of electron adducts and on the rate constant of GFX with eaqˉ,the pKa of GFX radical anion is estimated to be 5.5 and 9.3.
文摘IN the last few years phenothiazine(PTH)and its derivatives have captured much attention inthe fields of medicines,biology,and microelectronic materials due to their ability to ef-ficiently photosensitize acid production in the presence of vicinal dibromides and hence tochange the solubilization of polymer films.The photophysical and photochemical properties re-lated to the processes have been studied.Monica Barra et al.found that the triplet
基金Supported by the National Natural Science Foundation of China (Grant No. 20773046)
文摘The optimized structure of the tetrathiafulvalence radical-cation dimer(TTF·+-TTF·+) with all-real frequencies is obtained at MP2/6-311G level,which exhibits the attraction between two molecular cation TTF·+.The new attraction interaction is a 20-center-2-electron intermolecular covalent π /π bonding with a telescope shape.The covalent π /π bonding has the bonding energy of about -21 kcal·mol-1 and is concealed by the Coulombic repulsion between two TTF·+ cations.This intermolecular covalent attraction also influences the structure of the TTF·+ subunit,i.e.,its molecular plane is bent by an angle θ=5.6°.This work provides new knowledge on intermolecular interaction.
基金Supported by the National Natural Science Foundation the State Education Commission of China
文摘Introduction Bilirubin (BR) is generally regarded as a toxic compound when accumulated at an abnormally high concentration in biological tissues, and in fact a normal adult man produces about 300 mg of BR a day. However, it was proposed that the bile pigments BR and biliverdin(BV), which is the precursor of BR, may protect vitamin A and linoleie acid from oxidative destruction in the intestinal tract Further stud
基金Project supported by the National Natural Science Foundation and the State Education Commission of China.
文摘 Electron transfer reaction between vitamin A (1) and tris(p-bromophenyl)aminium hexachloroautimonate (2) in dichloromethane (DCM) has been investigated by means of UV-VIS absorption and ESR spectroscopy. The title radical cation formed in the reaction was characterized by a new absorption band around 600 nm and a singlet unresolved ESR spectrum with g factor of 2.0038-2.0039 and line width of 20 G. Further studies indicated that ESR pattern and parameters of the radical cation generated by 7-irradiation of 1 in CFCl3 matrix at 77 K are consistent with that resulted in the chemical oxidation in DCM at ambient temperature.
文摘Studies on the mechanism of the reactions involving coenzyme NAD(P)H and its model compounds are of considerable significance for understanding the role and the mechanism of this coenzyme in living cells. Although there have been extensive studies on the mechanism of hydride transfer for NADH and its models, a
