Direct conversion of methane into C1 oxygenates under mild condition with high selectivity is a desired goal in the field of energy and chemistry.But it still remains a great challenge due to the intrinsic inertness o...Direct conversion of methane into C1 oxygenates under mild condition with high selectivity is a desired goal in the field of energy and chemistry.But it still remains a great challenge due to the intrinsic inertness of methane originating from strong C-H bonds(104 kcal/mol),low solubility in the solvent,and poor selectivity.Herein,we present a direct single-step conversion of methane to formic acid(HCOOH)using molecular oxygen(O_(2)) as the oxidant under gentle conditions on a decatungstate-doped porous cerium metal-organic framework(Ce-MOF),W_(10)@Ce-bpdc.The HCOOH yield of W_(10)@Ce-bpdc-2 was 155μmol/gcatat room temperature in 12 h.The process and mechanism of conversion of methane to HCOOH was revealed by spectroscopic characteristics and controlled experiments.In the presence of light,O_(2)was converted to H_(2)O_(2)by catalyst and then to·OH radicals in solution,which interact with methane and undergo intermediates to produce HCOOH.Our experiment provides a new way to catalyze methane in combination with MOF and polyoxometalates(POMs).展开更多
Furfuryl ethyl ether(FEE)is considered as one of the most important candidates for biofuels due to its high-octane number.However,it is still challenging to produce FEE via the biomass-based route under mild condition...Furfuryl ethyl ether(FEE)is considered as one of the most important candidates for biofuels due to its high-octane number.However,it is still challenging to produce FEE via the biomass-based route under mild conditions.Here,we developed a photoinduced catalytic transfer hydrogenation(CTH)process for the efficient production of FEE through the reduction etherification of furfural(FF)using Na_(4)W_(10)O_(32)(NaDT),Pd/C,and ethanol as the hydrogen atom transfer(HAT)catalyst,hydrogenation catalyst,and the H donor,respectively.Notably,the introduction of brominated benzene(PhBr)as an additive significantly promoted the yield of FEE to 92.7%.A series of experiments and characterization results indicated that the attachment and detachment of Br atoms on Pd/C catalyst surface effectively regulate the balance between H^(+)sites and Pd sites in the NaDT+Pd/C catalytic system.The balance facilitates the preferential acetalization of FF catalyzed by H^(+)sites,followed by hydrogenation to efficiently produce FEE catalyzed by Pd sites.This photoinduced CTH process exhibits good stability and recyclability as well as universality for the transformation of various organic substrates under mild conditions.展开更多
The selective oxidation of para-xylene(PX)to terephthalic acid(TPA)has received increasing attention due to the industrial applications of TPA.However,the oxidation of the C(sp^(3))‒H bond of PX is still a main challe...The selective oxidation of para-xylene(PX)to terephthalic acid(TPA)has received increasing attention due to the industrial applications of TPA.However,the oxidation of the C(sp^(3))‒H bond of PX is still a main challenge because of the higher bond dissociation energy.Herein,an efficient photocatalytic system for the oxidation of PX to TPA was developed by using tetrabutylammonium decatungstate(TBADT)photocatalyst using atmospheric oxygen as oxidant and 365 nm LED light irradiation.The resulting TPA product was easily separated from the post-reaction solution through simple filtration treatment with a 93.4%yield in CH3CN(37.5%1 mol L^(‒1) HCl)solvent after 19-h photocatalysis.Given the easy separation of TPA and the excellent recycling stability of TBADT,a continuous-flow photoreactor was successfully designed with promising prospect for potential industrial application.Mechanistic studies elucidated that the presence of HCl additive benefits the structural integrity of[W10O32]4−anions and the transition from excited states[W_(10)O_(32)]^(4‒*)to wO active species,leading to enhanced photooxidation performance.展开更多
We have developed a versatile,mild protocol for trifluoromethylthiolation reactions of aldehydes with catalysis by a decatungstate hydrogen atom transfer photocatalyst under redox-neutral conditions.The protocol is hi...We have developed a versatile,mild protocol for trifluoromethylthiolation reactions of aldehydes with catalysis by a decatungstate hydrogen atom transfer photocatalyst under redox-neutral conditions.The protocol is highly selective,operationally simple,and compatible with a wide array of sensitive functional groups.It can be used for late-stage functionalization of bioactive molecules,which makes it convenient for drug discovery.展开更多
A new decatungstate incorporated metal-organic framework {[Co2（bpdo）5（H2O）n- W10O32]}n·nbpdo·2nH2O（1, bpdo = 4,4＇-bis（pyridine-N-oxide） has been synthesized through a one-step hydrothermal reaction a...A new decatungstate incorporated metal-organic framework {[Co2（bpdo）5（H2O）n- W10O32]}n·nbpdo·2nH2O（1, bpdo = 4,4＇-bis（pyridine-N-oxide） has been synthesized through a one-step hydrothermal reaction and characterized by elemental analyses, IR, solid UV-vis absorption spectra, and single-crystal X-ray diffraction. The structural analysis indicates that 1 displays a one-dimensional ladder structure with [W10O32]4- as vip incorporated by electrostatic interaction. The photocatalytic property of the framework toward a rhodamine B （RhB） solution was also investigated. The results indicated that compound 1 possesses high photocatalytic activity in heterogeneous system under sunlight irradiated.展开更多
A novel Cu（II）-2,2＇-bipy-supported （bipy = bipyridine） mixed valence decatungstate, [Cu（2,2＇-bipy）2]2Na2W6^VW4^VIO30·2H2O 1, has been synthesized and structurally characterized by X-ray analysis. The crys...A novel Cu（II）-2,2＇-bipy-supported （bipy = bipyridine） mixed valence decatungstate, [Cu（2,2＇-bipy）2]2Na2W6^VW4^VIO30·2H2O 1, has been synthesized and structurally characterized by X-ray analysis. The crystal of 1 is of triclinic, space group P1^- with a= 10.9393（10）, b = 12.0492（2）, c = 12.3783（2）A, a = 80.631（10）, β= 70.226（10）, γ= 72.329（9）^o, V = 1459.64（4）A^3, Z = 1, Dc = 3.582 g/cm^3, F（000） = 1404, R = 0.0553 and wR = 0.1242 for 4607 observed reflections （I 〉 2σ（I））. The EPR spectrum of 1 indicates that its unpaired electrons are placed in the dx2-y2 orbital of the ground state of Cun. Furthermore, compound 1 shows an antiferromagnetic interaction.展开更多
The photochemical behavior of polyoxometalates（POMs）have been studied extensivelyIn homogeneous solutions［1-3]．However，the major drawback to the practical applications ofthe homogeneous systems is the high ...The photochemical behavior of polyoxometalates（POMs）have been studied extensivelyIn homogeneous solutions［1-3]．However，the major drawback to the practical applications ofthe homogeneous systems is the high water solubility of POMs，which impedes the readyrecovery and the reuse of the photocatalysts．Therefore，the preparation of insoluble POMs Isconsidered．More recently，we haveprepared insoluble POMs，i．e，Keggin－type microporousPOMs，H3PW12O40／SiO2 or H4SiW12O40／SiO2，and paratungstate A－containing pillaredcompound，Mg12Al6（OH）36（W7O24）·4H2O，for the purpose of photo－oxidation of aqueous展开更多
We first describe a photoinduced decatungstate-catalyzed direct coupling of cycloalkanes and cyclic aldimines.The desired products were generated in moderate to good yields with wide substrate scope under mild reactio...We first describe a photoinduced decatungstate-catalyzed direct coupling of cycloalkanes and cyclic aldimines.The desired products were generated in moderate to good yields with wide substrate scope under mild reaction conditions.The mechanistic study revealed a radical process.In addition,the usefulness of the reaction in organic synthesis was proved by the scale-up synthesis as well as the late-stage modification of drug-like molecules.展开更多
In this work the heterogenization in polymeric membranes of decatungstate,a photocatalyst for oxidation reactions,was reported.Solid state characterization techniques confirmed that the catalyst structure was preserve...In this work the heterogenization in polymeric membranes of decatungstate,a photocatalyst for oxidation reactions,was reported.Solid state characterization techniques confirmed that the catalyst structure was preserved within the polymeric membranes.The catalytic membranes were successfully applied in the aerobic photo-oxidation of phenol,one of the main organic pollutants in wastewater,providing stable and recyclable photocatalytic systems.The dependence of the phenol degradation rate by the catalyst loading and transmembrane pressure was shown.By comparison with homogeneous reaction,the catalyst heterogenized in membrane appears to be more efficient concerning the rate of phenol photodegradation and mineralization.展开更多
基金supported by the National Natural Science Foundation of China (Nos. 92261118, 92161103, 22071180)。
文摘Direct conversion of methane into C1 oxygenates under mild condition with high selectivity is a desired goal in the field of energy and chemistry.But it still remains a great challenge due to the intrinsic inertness of methane originating from strong C-H bonds(104 kcal/mol),low solubility in the solvent,and poor selectivity.Herein,we present a direct single-step conversion of methane to formic acid(HCOOH)using molecular oxygen(O_(2)) as the oxidant under gentle conditions on a decatungstate-doped porous cerium metal-organic framework(Ce-MOF),W_(10)@Ce-bpdc.The HCOOH yield of W_(10)@Ce-bpdc-2 was 155μmol/gcatat room temperature in 12 h.The process and mechanism of conversion of methane to HCOOH was revealed by spectroscopic characteristics and controlled experiments.In the presence of light,O_(2)was converted to H_(2)O_(2)by catalyst and then to·OH radicals in solution,which interact with methane and undergo intermediates to produce HCOOH.Our experiment provides a new way to catalyze methane in combination with MOF and polyoxometalates(POMs).
文摘Furfuryl ethyl ether(FEE)is considered as one of the most important candidates for biofuels due to its high-octane number.However,it is still challenging to produce FEE via the biomass-based route under mild conditions.Here,we developed a photoinduced catalytic transfer hydrogenation(CTH)process for the efficient production of FEE through the reduction etherification of furfural(FF)using Na_(4)W_(10)O_(32)(NaDT),Pd/C,and ethanol as the hydrogen atom transfer(HAT)catalyst,hydrogenation catalyst,and the H donor,respectively.Notably,the introduction of brominated benzene(PhBr)as an additive significantly promoted the yield of FEE to 92.7%.A series of experiments and characterization results indicated that the attachment and detachment of Br atoms on Pd/C catalyst surface effectively regulate the balance between H^(+)sites and Pd sites in the NaDT+Pd/C catalytic system.The balance facilitates the preferential acetalization of FF catalyzed by H^(+)sites,followed by hydrogenation to efficiently produce FEE catalyzed by Pd sites.This photoinduced CTH process exhibits good stability and recyclability as well as universality for the transformation of various organic substrates under mild conditions.
文摘The selective oxidation of para-xylene(PX)to terephthalic acid(TPA)has received increasing attention due to the industrial applications of TPA.However,the oxidation of the C(sp^(3))‒H bond of PX is still a main challenge because of the higher bond dissociation energy.Herein,an efficient photocatalytic system for the oxidation of PX to TPA was developed by using tetrabutylammonium decatungstate(TBADT)photocatalyst using atmospheric oxygen as oxidant and 365 nm LED light irradiation.The resulting TPA product was easily separated from the post-reaction solution through simple filtration treatment with a 93.4%yield in CH3CN(37.5%1 mol L^(‒1) HCl)solvent after 19-h photocatalysis.Given the easy separation of TPA and the excellent recycling stability of TBADT,a continuous-flow photoreactor was successfully designed with promising prospect for potential industrial application.Mechanistic studies elucidated that the presence of HCl additive benefits the structural integrity of[W10O32]4−anions and the transition from excited states[W_(10)O_(32)]^(4‒*)to wO active species,leading to enhanced photooxidation performance.
基金the National Natural Science Foundation of China (Nos.21732002, 22077071) for generous financial support for our programs。
文摘We have developed a versatile,mild protocol for trifluoromethylthiolation reactions of aldehydes with catalysis by a decatungstate hydrogen atom transfer photocatalyst under redox-neutral conditions.The protocol is highly selective,operationally simple,and compatible with a wide array of sensitive functional groups.It can be used for late-stage functionalization of bioactive molecules,which makes it convenient for drug discovery.
基金Supported by the Foundation of Education Department of Henan Province(No.2009A150003)
文摘A new decatungstate incorporated metal-organic framework {[Co2（bpdo）5（H2O）n- W10O32]}n·nbpdo·2nH2O（1, bpdo = 4,4＇-bis（pyridine-N-oxide） has been synthesized through a one-step hydrothermal reaction and characterized by elemental analyses, IR, solid UV-vis absorption spectra, and single-crystal X-ray diffraction. The structural analysis indicates that 1 displays a one-dimensional ladder structure with [W10O32]4- as vip incorporated by electrostatic interaction. The photocatalytic property of the framework toward a rhodamine B （RhB） solution was also investigated. The results indicated that compound 1 possesses high photocatalytic activity in heterogeneous system under sunlight irradiated.
基金Supported by the NNSFC (90206040)NSF of Fujian Province (2006F3134, 2005J058)
文摘A novel Cu（II）-2,2＇-bipy-supported （bipy = bipyridine） mixed valence decatungstate, [Cu（2,2＇-bipy）2]2Na2W6^VW4^VIO30·2H2O 1, has been synthesized and structurally characterized by X-ray analysis. The crystal of 1 is of triclinic, space group P1^- with a= 10.9393（10）, b = 12.0492（2）, c = 12.3783（2）A, a = 80.631（10）, β= 70.226（10）, γ= 72.329（9）^o, V = 1459.64（4）A^3, Z = 1, Dc = 3.582 g/cm^3, F（000） = 1404, R = 0.0553 and wR = 0.1242 for 4607 observed reflections （I 〉 2σ（I））. The EPR spectrum of 1 indicates that its unpaired electrons are placed in the dx2-y2 orbital of the ground state of Cun. Furthermore, compound 1 shows an antiferromagnetic interaction.
基金National Natural Science Foundation of China(No.20071007)and the Foundation for University KeyTeacher by the Ministry of Education of China.
文摘The photochemical behavior of polyoxometalates（POMs）have been studied extensivelyIn homogeneous solutions［1-3]．However，the major drawback to the practical applications ofthe homogeneous systems is the high water solubility of POMs，which impedes the readyrecovery and the reuse of the photocatalysts．Therefore，the preparation of insoluble POMs Isconsidered．More recently，we haveprepared insoluble POMs，i．e，Keggin－type microporousPOMs，H3PW12O40／SiO2 or H4SiW12O40／SiO2，and paratungstate A－containing pillaredcompound，Mg12Al6（OH）36（W7O24）·4H2O，for the purpose of photo－oxidation of aqueous
基金supported by the National Natural Science Foundation of China(Nos.21402116 and 21502111)the Key Scientific and Technological Project of Henan Province(No.222102310607)+2 种基金the Key Science Research of Education Committee in Henan Province(Nos.21A150044 and 22A150051)the Shandong Provincial Natural Science Foundation(Nos.ZR2023QH502 and ZR2023QB172)the Doctoral Research Foundation of Zaozhuang University.
文摘We first describe a photoinduced decatungstate-catalyzed direct coupling of cycloalkanes and cyclic aldimines.The desired products were generated in moderate to good yields with wide substrate scope under mild reaction conditions.The mechanistic study revealed a radical process.In addition,the usefulness of the reaction in organic synthesis was proved by the scale-up synthesis as well as the late-stage modification of drug-like molecules.
基金Financial support from the"Ministero dell’Istruzione dell’Università e della Ricerca"(MIUR)(CEMIF.CAL-CLAB01TYEF and CAMERE-RBNE03JCR5)is gratefully acknowledged.
文摘In this work the heterogenization in polymeric membranes of decatungstate,a photocatalyst for oxidation reactions,was reported.Solid state characterization techniques confirmed that the catalyst structure was preserved within the polymeric membranes.The catalytic membranes were successfully applied in the aerobic photo-oxidation of phenol,one of the main organic pollutants in wastewater,providing stable and recyclable photocatalytic systems.The dependence of the phenol degradation rate by the catalyst loading and transmembrane pressure was shown.By comparison with homogeneous reaction,the catalyst heterogenized in membrane appears to be more efficient concerning the rate of phenol photodegradation and mineralization.
