Fused polycyclic N-heterocycles are very important scaffolds in biomedicinal chemistry and materials science.Intramolecular alkyne hydroamination is a powerful method for the construction of N-heterocycles.In the last...Fused polycyclic N-heterocycles are very important scaffolds in biomedicinal chemistry and materials science.Intramolecular alkyne hydroamination is a powerful method for the construction of N-heterocycles.In the last two decades,copper-catalyzed domino reactions based on intramolecular alkyne hydroamination has emerged as a robust strategy for assembling various fused polycyclic N-heterocycles.Great progress has been achieved in this area.This short review covers the advances made in copper-catalyzed domino synthesis of fused polycyclic N-heterocycles based on the strategy from 2008 to 2023,and will hopefully serve as an inspiration towards the exploration of new copper-catalyzed versions of the transformation.The domino transformations are introduced and discussed from five aspects according to the different key processes involved in these reactions.展开更多
The production of high-valued organonitrogen chemicals,especially N-heterocycles,requires artificial N_(2)fixation accompanied by the consumption of fossil resources.To avoid the use of these energy-and resource-inten...The production of high-valued organonitrogen chemicals,especially N-heterocycles,requires artificial N_(2)fixation accompanied by the consumption of fossil resources.To avoid the use of these energy-and resource-intensive processes,we develop a sustainable strategy to convert nitrogen-rich animal biomass into N-heterocycles through a thermochemical conversion process(TCP)under atmospheric pressure.A high percentage of N-heterocycles(87.51%)were obtained after the TCP of bovine skin due to the abundance of nitrogen-containing amino acids(e.g.,glycine,proline,and L-hydroxyproline).Animal biomass with more diverse amino acid composition(e.g.,muscles)yielded higher concentrations of amines/amides and nitriles after TCP.In addition,by introducing catalysts(KOH for pyrrole and Al_(2)O_(3)for cyclo-Gly-Pro)to TCP,the production quantities of pyrrole and cyclo-Gly-Pro increased to 30.79 mg g^(-1)and 38.88 mg g^(-1),respectively.This approach can be used to convert the significant animal biomass waste generated annually from animal culls into valued organonitrogen chemicals while circumventing NH3-dependent and petro-chemical-dependent synthesis routes.展开更多
Synthetic N-heterocyclic compounds,such as quinoxalines,have shown a crucial role in pharmaceutical as well as food and dye industries.However,the traditional synthesis toward N-heterocycles relies on multistep energy...Synthetic N-heterocyclic compounds,such as quinoxalines,have shown a crucial role in pharmaceutical as well as food and dye industries.However,the traditional synthesis toward N-heterocycles relies on multistep energy and costintensive non-sustainable processes.Here,we report a facile approach that allows one-step conversion of biomass-derived carbohydrates to valuable quinoxalines in the presence of aryl-1,2-diamines in water without any harmful metal catalysts/organic solvents via spontaneously engineering involved cascade reactions under hydrothermal conditions.Aryl-1,2-diamines are revealed as the key to propel this transformation through boosting carbohydrate fragmentation into small 1,2-dicarbonyl intermediates and subsequently trapping them for constituting stable quinoxaline scaffolds therefore avoiding a myriad of undesired side reactions.The tunability of product selectivity can be also achievable by adjusting the basicity of the reaction environment.Both batch and continuous-flow integrated processes were verified for production of quinoxalines in an exceptionally eco-benign manner(E-factor<1),showing superior sustainability and economic viability.展开更多
The aqueous zinc-organic battery is a promising candidate for large-scale energy storage.However,the rational design of advanced organic cathodes with high capacity,long lifespan,and high rate capability remains a big...The aqueous zinc-organic battery is a promising candidate for large-scale energy storage.However,the rational design of advanced organic cathodes with high capacity,long lifespan,and high rate capability remains a big challenge.Herein,we propose that extending theπ-conjugation by N-heterocycles can provide more active sites,lead to insolubility,and facilitate charge transfer,thus boosting the overall electrochemical performance of organic electrodes.Based on this concept,a novel organic compound,dipyrido[3ʹ,2ʹ:5,6;2″,3″:7,8]quinoxalino[2,3-i]dipyrido[3,2-a:2ʹ,3ʹ-c]phenazine-10,21-dione(DQDPD),has been rationally designed and evaluated as the cathode for aqueous zinc batteries.Excitingly,DQDPD shows a record high capacity(509 mAh g^(−1) at 0.1 A g^(−1),corresponding to a record-breaking energy density of 348 Wh kg^(−1)),excellent cycling stability(92%capacity retention after 7500 cycles at 10 A g^(−1)),and fast-charging capability(161 mAh g^(−1) at 20 A g^(−1)).Our work offers new ideas in the molecular engineering of organic electrodes for high-performance rechargeable batteries.展开更多
The development of an efficient and sustainable synthetic route for formaldehyde production from renewable feedstock,especially in combination with a subsequent transformation to straightforwardly construct valuable c...The development of an efficient and sustainable synthetic route for formaldehyde production from renewable feedstock,especially in combination with a subsequent transformation to straightforwardly construct valuable chemicals,is highly desirable.Herein,we report a novel manganese-catalyzed dehydrogenative cyclization of methanol as a formaldehyde surrogate with a variety of dinucleophiles for facile synthesis of N-heterocycles.The in situ generated formaldehyde via catalytic methanol dehydrogenation can be selectively trapped by diverse dinucleophiles to avoid several possible side reactions.The utilty of this transformation is further highlighted by its successful appliation to the synthesis of 13C-labeled N-heterocycles using 13CH_(3)OH as a readily accessible 13C-isotope reagent.展开更多
Catalytic amination of alkenes is one of the most attractive reactions for the construction of complex heterocycles with nitrogen centers. Herein, we present that synergistic photoredox and cobaloxime catalysis allows...Catalytic amination of alkenes is one of the most attractive reactions for the construction of complex heterocycles with nitrogen centers. Herein, we present that synergistic photoredox and cobaloxime catalysis allows for highly efficient and mild dehydrogenative reactions between various NH nucleophiles and di-, tri-, and tetrasubstituted alkenes in the absence of external oxidants, thus enabling access to an array of N-heterocycles. Notably, both Z-and E-alkene-containing N-heterocycles are accessible. Mechanistic studies indicated that the Z-cinnamyl derivatives could be generated by photocatalytic E to Z alkene isomerization through an energy transfer process. Moreover, we find that sluggish energy transfer could inhibit the E to Z alkene isomerization process, thus offering the cinnamyl derivatives with E-selectivity. Our results highlight the benefits of the reactions using dual photoredox and cobaloxime catalysis to lead to diverse N-heterocycles.展开更多
Chiral benzo-fused N-heterocycles are frequently found in natural and synthetic products.However,their synthesis usually suffers from different limitations such as difficulty in accessing appropriate starting material...Chiral benzo-fused N-heterocycles are frequently found in natural and synthetic products.However,their synthesis usually suffers from different limitations such as difficulty in accessing appropriate starting materials and unsatisfactory stereoselectivities.In this work,an unprecedented chiral sulfide-catalyzed enantioselective Friedel-Crafts-type electrophilic chlorination is shown to construct various 3,4-functionalized tetrahydroquinolines with excellent enantio-and diastereoselectivities from readily available aniline derivatives.Interestingly,employing N-allyl 1-naphthanilides as substrates,divergent reactions via chlorocarbocyclization and dearomatization occurred to afford two chiral polycyclic benzo-fused N-heterocycles.The system that we developed extends the scope of asymmetric chlorination to general substrateswithout the need of a N-H group,and significantly promotes the synthesis of enantioenriched benzo-fused N-heterocycles.展开更多
An operationally simple protocol was designed for the enantioselective silane reduction (ESR) of ketones using air- and moisture-stable [Ir(OMe)(cod)]<sub>2</sub> (cod = 1,5-cyclooctadiene) (3) as a metal ...An operationally simple protocol was designed for the enantioselective silane reduction (ESR) of ketones using air- and moisture-stable [Ir(OMe)(cod)]<sub>2</sub> (cod = 1,5-cyclooctadiene) (3) as a metal catalyst precursor. This reaction was driven by chiral hydroxyamide-functionalized azolium salt 2. The catalytic ESR reaction could be performed under benchtop conditions at room temperature. Treatment of 2 with 3 in THF yielded the monodentate IrCl(NHC)(cod) (NHC = N-heterocyclic carbene) complex 4 in 93% yield, herein the anionic methoxy ligand of 3 serves as an internal base that deprotonates the azolium ring of 2. The well-defined Ir complex 4 catalyzed the ESR reaction of propiophenone (6) with (EtO)<sub>2</sub>MeSiH using the pre-mixing reaction procedure. Based on this success, the catalytic ESR reaction was designed and implemented using an in situ-generated NHC/Ir catalyst derived from 2 and 3. Thus, a wide variety of aryl ketones could be reduced to the corresponding optically active alcohols in moderate to excellent stereoselectivities at room temperature without temperature control. Since the high catalytic activity of 3 was observed, we next evaluated several other transition metal catalyst precursors for the catalytic ESR reaction under the influence of 2. This evaluation revealed that Ir(acac)(cod) (acac = acetylacetonate) (28) and [IrCl(cod)]<sub>2</sub> (5) can be successfully used as metal catalyst precursors in the ESR reaction.展开更多
Electrocatalytic nitrogen reduction reaction(NRR)at ambient conditions holds great promise for sustainably synthesizing ammonia(NH3),while developing highly-efficient,long-term stable,and inexpensive catalysts to acti...Electrocatalytic nitrogen reduction reaction(NRR)at ambient conditions holds great promise for sustainably synthesizing ammonia(NH3),while developing highly-efficient,long-term stable,and inexpensive catalysts to activate the inert N≡N bond is a key scientific issue.In this work,on the basis of the concept"N-heterocyclic carbenes(NHCs)",we propose a carbon decorated graphitic-carbon nitride(C/g-C3N4)as novel metal-free NRR electrocatalyst by means of density functional theory(DFT)computations.Our results reveal that the introduced C atom in g-C3N4 surface can be regarded as NHCs and catalytic sites for activating N≡N bond,and are stabilized by the g-C3N4 substrate due to sterically disfavored dimerization.Especially,this NHCs-based heterogeneous catalysis can efficiently reduce the activated N2 molecule to NH3 with a low overpotential of 0.05 V via an enzymatic mechanism.Our work is the first report of NHCs-based electrocatalyst for N2 fixation,thus opening an alternative avenue for advancing sustainable NH3 production.展开更多
N-Heterocyclic carbene(NHC)-based cages have emerged as a prominent and dynamic research area within the research field of chemistry. Leveraging the distinctive electronic and steric properties of NHC ligands, the des...N-Heterocyclic carbene(NHC)-based cages have emerged as a prominent and dynamic research area within the research field of chemistry. Leveraging the distinctive electronic and steric properties of NHC ligands, the design, synthesis, and application of these corresponding cages have garnered substantial scholarly interest. In recent years, we have witnessed the successful fabrication of diverse NHC-based cages through a range of synthetic methodologies, which hold significant potential for applications in molecular recognition and catalysis. In this review, we delve into the foundational synthetic strategies that underlie the creation of NHC-based cages, employing approaches encompassing metal–NHC chelation, coordination assembly,and covalent bonding. Additionally, we compile the diverse applications of these cages within catalytic processes and molecular recognition. Lastly, we shed light on the current limitations of synthesis and outline future trends in the development of NHCbased cages.展开更多
N-heterocyclic carbene-catalyzed enantioselective kinetic resolutions,dynamic kinetic resolutions,and desymmetrization reactions are systematically reviewed.The content is organized according to the activation modes i...N-heterocyclic carbene-catalyzed enantioselective kinetic resolutions,dynamic kinetic resolutions,and desymmetrization reactions are systematically reviewed.The content is organized according to the activation modes involved in these transformations.Future advances within this highly active research field are discussed from our perspectives on the topic.展开更多
The highly efficient method has been developed for the synthesis of NHC·VOCl_(3) containing symmetrical or unsymmetrical Nheterocyclic carbene(NHC) ligands by the transmetallation reaction of NHC·AgCl with V...The highly efficient method has been developed for the synthesis of NHC·VOCl_(3) containing symmetrical or unsymmetrical Nheterocyclic carbene(NHC) ligands by the transmetallation reaction of NHC·AgCl with VOCl_(3).The total isolated yield of VOCl_(3)[1,3-(2,4,6-Me_(3)C_(6)H_(2))_(2)(NCH=)_(2)C:](V4') reached 86% by transmetallation reaction,which is much higher than that(48%) by direct coordination method.This methodology has also been used to synthesize the novel vanadium complexes containing unsymmetrical NHC ligands of VOCl_(3)[PhCH_(2)NCH=CHNR)C:](V5',R=2,4,6-Me_(3)C_(6)H_(2);V6',R=2,4-Me_(2)-6-Ph-C_(6)H_(2);V7',R=2,6-^(i)Pr_(2)-C_(6)H_(3)) with high yield,which could not be obtained by direct coordination method.The catalytic activity and copolymerization ability would be improved by introducing unsymmetrical NHC ligands due to their less steric bulky effect.The vanadium complex V5' containing unsymmetrical NHC ligand exhibits higher catalytic activity(3.7×10^(5)g_(copolymer)·mol^(-1) of V·h^(-1)) than that of V4' containing symmetrical NHC ligand.Moreover,the higher propylene incorporation ratio(45.6 mol%) in the copolymers of ethylene with propylene could be obtained by using V5' than that(39.9%) by using V4'.The results would provide a highly efficient strategy for the synthesis of early transition metal complexes containing versitile NHC ligands,affording the catalyst with both high catalytic activity and copolymerization ability for the synthesis of high performance polyolefin elastomers.展开更多
Reactions of the 6-hydroxy-thiopyrano[3,4-c]pyridine-5-carbonitrile derivative 1 withα-halo-carbonyl compounds gave the ortho-substituted intermediates 2a-c which were converted into furo[2,3-b]thiopyrano[4,3-d]pyrid...Reactions of the 6-hydroxy-thiopyrano[3,4-c]pyridine-5-carbonitrile derivative 1 withα-halo-carbonyl compounds gave the ortho-substituted intermediates 2a-c which were converted into furo[2,3-b]thiopyrano[4,3-d]pyridines 3a-c by fusion of a furan moiety under basic conditions.Further cyclization of 3a-c led to a fusion of a pyrimidine ring,yielding the tetracyclic products 6,7 and 8.In addition,condensation of 6 with various aromatic aldehydes afforded the corresponding imines 9a,b.Mannich reaction of 7 gave products 10a,b.展开更多
The ubiquity of N-heterocycles in marketed drugs makes the development of metal-free methodologies for constructing C–N bonds of considerable importance.As an environmentally friendly method,electro-oxidative intramo...The ubiquity of N-heterocycles in marketed drugs makes the development of metal-free methodologies for constructing C–N bonds of considerable importance.As an environmentally friendly method,electro-oxidative intramolecular C–H amination has emerged as a powerful platform for synthesizing nitrogen-containing heterocycles under metal-and external oxidant-free conditions.In this minireview,the main achievements in this direction since 2020 are summarized,with an emphasis on the substrate scope and mechanistic aspects.The reactions are classifi ed into two categories:direct and indirect electro-oxidative intramolecular C–H aminations.展开更多
Nickel(II) complexes Ni(L1)2 (1) and Ni(L2)2·CH3CN·H2O (2) (L1Cl = 2-(3-benzyl- 2,3-dihydroimidazlo-1-yl)-N-(pyridin-2-yl)acetamide, chloride salt, L2Cl = 2-(3-naphthalene-2- ylmethyl)-2,3-d...Nickel(II) complexes Ni(L1)2 (1) and Ni(L2)2·CH3CN·H2O (2) (L1Cl = 2-(3-benzyl- 2,3-dihydroimidazlo-1-yl)-N-(pyridin-2-yl)acetamide, chloride salt, L2Cl = 2-(3-naphthalene-2- ylmethyl)-2,3-dihydro-imidazlo-1-yl)-N-phenylacetamide, chloride salt) with amide-functionalized imidazolium NHC ligand were synthesized and determined by single-crystal X-ray diffraction. Complex 1 crystallizes in the monoclinic system, space group P21/cwith a = 9.2561(19), b = 15.138(3), c = 20.750(4) A, β = 90.216(3)°, V = 2907.3(10) A^3 and Z = 4. Complex 2 crystallizes in the orthorhombic system, space group Pbca with a = 15.5469(16), b = 15.3521(15), c = 31.177(3) A, V = 7441.2(13) ?3 and Z = 8. They are stable in the air and formed via intermolecular weak interactions, including C-H···π contacts and C–H···O hydrogen bonds. Complex 1 was applied in Suzuki coupling reaction through the investigation of reaction conditions under the optimal choice conditions: 80 ℃, K3PO4, 3% mol catalysts, 6% mol PPh3 and toluene as solvent system could afford 96% yield in 5 h.展开更多
We report new heterogeneous organocatalyst based on silica hybrid supported N-heterocyclic carbene(NHC-)species.The organocatalyst is formed from an imidazolium iodide based ionosilica material,followed by iodide/acet...We report new heterogeneous organocatalyst based on silica hybrid supported N-heterocyclic carbene(NHC-)species.The organocatalyst is formed from an imidazolium iodide based ionosilica material,followed by iodide/acetate anion exchange.The imidazolium acetate generates the organocatalytic carbene via partial deprotonation of the imidazolium ring in situ.As monitored via EDX,solid state NMR and ion chromatography measurements,the iodide/acetate exchange involving the imidazolium ionosilica material took place only in small extent.Despite the fact that the exchanged material contains only a very small amount of acetate,we observed good catalytic activity and recyclability in cyanosilylation reactions of ketones with trimethylsilyl cyanide.The versatility of the catalyst was highlighted via reaction with several substrates,yielding the corresponding cyanohydrins in good yields.In recycling experiments,the material showed decreasing catalytic activity starting from the third reaction cycle,but high catalytic activity can be regenerated via another acetate treatment.Our work is important as it highlights the possibility to combine carbene chemistry and silica,which are antagonistic at a first glance.We show that imidazolium acetate based ionosilicas are therefore heterogeneous'proto-carbenes',and that there is no need to form strongly basic silica supported NHCs to obtain heterogeneous NHC-organocatalysts.This work therefore opens the route towards heterogeneous and re-usable NHC-organocatalysts from supported ionic liquid imidazolium acetates.展开更多
In this paper,a new Pd-based complex that contains A^-heterocyclic carbene(NHC)and triphenylphosphine(PPh?)ligands was synthesized.The c/5-(NHC)PdBr2(PPh3)complex has been prepared by the substitution of 3?chloropyrid...In this paper,a new Pd-based complex that contains A^-heterocyclic carbene(NHC)and triphenylphosphine(PPh?)ligands was synthesized.The c/5-(NHC)PdBr2(PPh3)complex has been prepared by the substitution of 3?chloropyridine ligand in(NHC)PdBr2(3-chloropyridine)complex with triphenylphosphine.This complex has been characterized by using 1^H NMR,^31P{^1H}NMR,^13C{^1H}NMR,FTIR,UV-Vis spectroscopy and elemental analysis techniques.The molecular and crystal structures of the cz5-(NHC)PdBr2(PPh3)complex were determined by singlecrystal X-ray diffraction method.展开更多
<span style="font-family:Verdana;">To synthesize, characterize and evaluate the antitumor potential derived from ruthenium compounds was generated in this study, from the precursor K[RuCl</span>&...<span style="font-family:Verdana;">To synthesize, characterize and evaluate the antitumor potential derived from ruthenium compounds was generated in this study, from the precursor K[RuCl</span><sub><span style="font-family:Verdana;">4</span></sub><span style="font-family:Verdana;">(bipy)] a route in a simple and reproducible synthesis for a novel compound of coordinating Ru</span><sup><span style="font-family:Verdana;">+3</span></sup><span style="font-family:Verdana;"> with bipy and L-trip. The spectroscopic characterization in the mi</span><span style="font-family:Verdana;">ddle infrared region (FTIR) shows the interactions between Ru-(L-trip), evidenced by the displacement of the carboxylate ion band for</span><span><span style="font-family:Verdana;"> higher energies, and also by the displacements of aliphatic amine bands, suggesting that bidentate coordination of the L-trip ligand occurred. Analysis of the results obtained with thermoanalytical techniques showed that the minimum formula of the compound, [RuCl</span><sub><span style="font-family:Verdana;">2</span></sub><span style="font-family:Verdana;">(bipy)(L-trip)]1/2H</span><sub><span style="font-family:Verdana;">2</span></sub><span style="font-family:Verdana;">O. Evaluation of the</span></span><span><span style="font-family:Verdana;"> antitumor potential of precursor K[RuCl</span><sub><span style="font-family:Verdana;">4</span></sub><span style="font-family:Verdana;">(bipy)] showed the toxic effects on MCF-7 cell line, but </span></span><span style="font-family:Verdana;">did not show selectivity and not reached PBMC cells to the same extent. The evaluation of the antitumor potential of the newly synthesized compound, [RuCl</span><sub><span style="font-family:Verdana;">2</span></sub><span style="font-family:Verdana;">(bipy)(L-trip)], demonstrated that the insertion of an L-tryptophan molecule into the precursor coordination sphere made it selective when compared to PBMC cells, for MCF-7 type tumor cells.</span>展开更多
A pentagonal-prismatic cylinder[Ag5(L)2](PF6)5 obtained from the pentaphenylpyrrole-bridged pentaimidazolium salt H5-L(PF6)5 and AgI ions was determined by X-ray diffraction analyses.The target organometallic cylinder...A pentagonal-prismatic cylinder[Ag5(L)2](PF6)5 obtained from the pentaphenylpyrrole-bridged pentaimidazolium salt H5-L(PF6)5 and AgI ions was determined by X-ray diffraction analyses.The target organometallic cylinder not only exhibited enhanced fluorescence emission in dilute solution at room temperature but also showed an improved phosphorescence ratio compared with the free precursor and maintained a long lifetime(1.39 s)in the solid state at 77 K.Furthermore,the experimental results and DFT calculations confirmed that the formation of the organometallic cylinder promoted intersystem crossing.Meanwhile,the frontier orbitals of[Ag5(L)2](PF6)5 showed the main contribution of building block PPP as the luminescence source of[Ag5(L)2](PF6)5 by a modest heavy-atom effect.These results provide a strategy for constructing enhanced phosphorescent emission and long lifetime organometallic supramolecular phosphorescent materials.展开更多
The complex (Ind)NiBr(1,3-bisbenzylimidazol-2-ylidene) (Ind = indenyl) 1 has been prepared in ca. 65% yield via the reaction of (Ind)2Ni with an equivalent of 1,3-bis-benzylimidazolium bromide in THF/CH2Cl2 at...The complex (Ind)NiBr(1,3-bisbenzylimidazol-2-ylidene) (Ind = indenyl) 1 has been prepared in ca. 65% yield via the reaction of (Ind)2Ni with an equivalent of 1,3-bis-benzylimidazolium bromide in THF/CH2Cl2 at 45℃, supported by elemental analysis, NMR spectroscopy and X-ray crystal determination. The crystal belongs to the triclinic system, space group Pi with a = 7.072(1), b = 11.264(2), c = 14.541(3)°A, α = 102.21(3),β = 93.44(3),γ = 90.81(3)°, V = 1129.7(4)°A^3, Z = 2, Mr = 502.08, Dc = 1.476 g/cm^3, F(000) = 512, μ= 2.642 mm^-1, R = 0.0490 and wR = 0.1137 for 3913 observed reflections (I〉 2σ(I)). The center nickel atom is coordinated by a bromide ligand, a carbene carbon and three carbon atoms of the five-membered indenyl group to form either a highly distorted square pyramid or a highly distorted square plane.展开更多
基金financial supports from the Natural Science Foundation of Zhejiang Province(LY21B020005)the National Natural Science Foundation of China(21202152).
文摘Fused polycyclic N-heterocycles are very important scaffolds in biomedicinal chemistry and materials science.Intramolecular alkyne hydroamination is a powerful method for the construction of N-heterocycles.In the last two decades,copper-catalyzed domino reactions based on intramolecular alkyne hydroamination has emerged as a robust strategy for assembling various fused polycyclic N-heterocycles.Great progress has been achieved in this area.This short review covers the advances made in copper-catalyzed domino synthesis of fused polycyclic N-heterocycles based on the strategy from 2008 to 2023,and will hopefully serve as an inspiration towards the exploration of new copper-catalyzed versions of the transformation.The domino transformations are introduced and discussed from five aspects according to the different key processes involved in these reactions.
基金supported by the National Talents ProgramNational Natural Science Foundation of China(22178233,22108181)+3 种基金Talents Program of Sichuan ProvinceDouble First-Class University Plan of Sichuan UniversityState Key Laboratory of Polymer Materials Engineering(sklpme 2020-03-01)The Sichuan Province Postdoctoral Special Funding.
文摘The production of high-valued organonitrogen chemicals,especially N-heterocycles,requires artificial N_(2)fixation accompanied by the consumption of fossil resources.To avoid the use of these energy-and resource-intensive processes,we develop a sustainable strategy to convert nitrogen-rich animal biomass into N-heterocycles through a thermochemical conversion process(TCP)under atmospheric pressure.A high percentage of N-heterocycles(87.51%)were obtained after the TCP of bovine skin due to the abundance of nitrogen-containing amino acids(e.g.,glycine,proline,and L-hydroxyproline).Animal biomass with more diverse amino acid composition(e.g.,muscles)yielded higher concentrations of amines/amides and nitriles after TCP.In addition,by introducing catalysts(KOH for pyrrole and Al_(2)O_(3)for cyclo-Gly-Pro)to TCP,the production quantities of pyrrole and cyclo-Gly-Pro increased to 30.79 mg g^(-1)and 38.88 mg g^(-1),respectively.This approach can be used to convert the significant animal biomass waste generated annually from animal culls into valued organonitrogen chemicals while circumventing NH3-dependent and petro-chemical-dependent synthesis routes.
基金supported by the National Natural Science Foundation of China(21932006)the China Postdoctoral Science Foundation(2019M652058)
文摘Synthetic N-heterocyclic compounds,such as quinoxalines,have shown a crucial role in pharmaceutical as well as food and dye industries.However,the traditional synthesis toward N-heterocycles relies on multistep energy and costintensive non-sustainable processes.Here,we report a facile approach that allows one-step conversion of biomass-derived carbohydrates to valuable quinoxalines in the presence of aryl-1,2-diamines in water without any harmful metal catalysts/organic solvents via spontaneously engineering involved cascade reactions under hydrothermal conditions.Aryl-1,2-diamines are revealed as the key to propel this transformation through boosting carbohydrate fragmentation into small 1,2-dicarbonyl intermediates and subsequently trapping them for constituting stable quinoxaline scaffolds therefore avoiding a myriad of undesired side reactions.The tunability of product selectivity can be also achievable by adjusting the basicity of the reaction environment.Both batch and continuous-flow integrated processes were verified for production of quinoxalines in an exceptionally eco-benign manner(E-factor<1),showing superior sustainability and economic viability.
基金supported by the National Natural Science Foundation of China(grant no.52103313)the Fundamental Research Funds for the Central Universities(grant no.531118010111)the Natural Science Foundation of Hunan Province(grant no.2021JJ30094).
文摘The aqueous zinc-organic battery is a promising candidate for large-scale energy storage.However,the rational design of advanced organic cathodes with high capacity,long lifespan,and high rate capability remains a big challenge.Herein,we propose that extending theπ-conjugation by N-heterocycles can provide more active sites,lead to insolubility,and facilitate charge transfer,thus boosting the overall electrochemical performance of organic electrodes.Based on this concept,a novel organic compound,dipyrido[3ʹ,2ʹ:5,6;2″,3″:7,8]quinoxalino[2,3-i]dipyrido[3,2-a:2ʹ,3ʹ-c]phenazine-10,21-dione(DQDPD),has been rationally designed and evaluated as the cathode for aqueous zinc batteries.Excitingly,DQDPD shows a record high capacity(509 mAh g^(−1) at 0.1 A g^(−1),corresponding to a record-breaking energy density of 348 Wh kg^(−1)),excellent cycling stability(92%capacity retention after 7500 cycles at 10 A g^(−1)),and fast-charging capability(161 mAh g^(−1) at 20 A g^(−1)).Our work offers new ideas in the molecular engineering of organic electrodes for high-performance rechargeable batteries.
基金This project was supported by the National Natural Science Foundation of China(Nos.91845107 and 21822106)the Foundation of the Department of Education of Guangdong Province(2018KZDXM070 and 2021KTSCX140)。
文摘The development of an efficient and sustainable synthetic route for formaldehyde production from renewable feedstock,especially in combination with a subsequent transformation to straightforwardly construct valuable chemicals,is highly desirable.Herein,we report a novel manganese-catalyzed dehydrogenative cyclization of methanol as a formaldehyde surrogate with a variety of dinucleophiles for facile synthesis of N-heterocycles.The in situ generated formaldehyde via catalytic methanol dehydrogenation can be selectively trapped by diverse dinucleophiles to avoid several possible side reactions.The utilty of this transformation is further highlighted by its successful appliation to the synthesis of 13C-labeled N-heterocycles using 13CH_(3)OH as a readily accessible 13C-isotope reagent.
基金supported by the Natural Science Foundation of the Jiangsu Higher Education Institutions of China (18KJA350001)the Priority Academic Program Development of the Jiangsu Higher Education Institutes (PAPD)。
文摘Catalytic amination of alkenes is one of the most attractive reactions for the construction of complex heterocycles with nitrogen centers. Herein, we present that synergistic photoredox and cobaloxime catalysis allows for highly efficient and mild dehydrogenative reactions between various NH nucleophiles and di-, tri-, and tetrasubstituted alkenes in the absence of external oxidants, thus enabling access to an array of N-heterocycles. Notably, both Z-and E-alkene-containing N-heterocycles are accessible. Mechanistic studies indicated that the Z-cinnamyl derivatives could be generated by photocatalytic E to Z alkene isomerization through an energy transfer process. Moreover, we find that sluggish energy transfer could inhibit the E to Z alkene isomerization process, thus offering the cinnamyl derivatives with E-selectivity. Our results highlight the benefits of the reactions using dual photoredox and cobaloxime catalysis to lead to diverse N-heterocycles.
基金the National Natural Science Foundation of China(grant nos.91856109 and 21772239)the Fundamental Research Funds for the Central Universities(grant no.20lgzd21)the Leading Scientific,Technical and Innovation Talents of Guangdong Special Support Program(grant no.2019TX05Y638)for financial support.
文摘Chiral benzo-fused N-heterocycles are frequently found in natural and synthetic products.However,their synthesis usually suffers from different limitations such as difficulty in accessing appropriate starting materials and unsatisfactory stereoselectivities.In this work,an unprecedented chiral sulfide-catalyzed enantioselective Friedel-Crafts-type electrophilic chlorination is shown to construct various 3,4-functionalized tetrahydroquinolines with excellent enantio-and diastereoselectivities from readily available aniline derivatives.Interestingly,employing N-allyl 1-naphthanilides as substrates,divergent reactions via chlorocarbocyclization and dearomatization occurred to afford two chiral polycyclic benzo-fused N-heterocycles.The system that we developed extends the scope of asymmetric chlorination to general substrateswithout the need of a N-H group,and significantly promotes the synthesis of enantioenriched benzo-fused N-heterocycles.
文摘An operationally simple protocol was designed for the enantioselective silane reduction (ESR) of ketones using air- and moisture-stable [Ir(OMe)(cod)]<sub>2</sub> (cod = 1,5-cyclooctadiene) (3) as a metal catalyst precursor. This reaction was driven by chiral hydroxyamide-functionalized azolium salt 2. The catalytic ESR reaction could be performed under benchtop conditions at room temperature. Treatment of 2 with 3 in THF yielded the monodentate IrCl(NHC)(cod) (NHC = N-heterocyclic carbene) complex 4 in 93% yield, herein the anionic methoxy ligand of 3 serves as an internal base that deprotonates the azolium ring of 2. The well-defined Ir complex 4 catalyzed the ESR reaction of propiophenone (6) with (EtO)<sub>2</sub>MeSiH using the pre-mixing reaction procedure. Based on this success, the catalytic ESR reaction was designed and implemented using an in situ-generated NHC/Ir catalyst derived from 2 and 3. Thus, a wide variety of aryl ketones could be reduced to the corresponding optically active alcohols in moderate to excellent stereoselectivities at room temperature without temperature control. Since the high catalytic activity of 3 was observed, we next evaluated several other transition metal catalyst precursors for the catalytic ESR reaction under the influence of 2. This evaluation revealed that Ir(acac)(cod) (acac = acetylacetonate) (28) and [IrCl(cod)]<sub>2</sub> (5) can be successfully used as metal catalyst precursors in the ESR reaction.
基金financially supported in China by the National Natural Science Foundation of China(21103224 and 21878227)Natural Science Funds for Distinguished Young Scholar of Heilongjiang Province(No.JC2018004)+2 种基金Natural Science Foundation of Hebei Province of China(B2019202210)in USA by NSF-CREST Center for Innovation,Research and Education in Environmental Nanotechnology(CIRE2N)(Grant Number HRD-1736093)supported by the Supercomputing Center in Harbin Normal University and Lvliang。
文摘Electrocatalytic nitrogen reduction reaction(NRR)at ambient conditions holds great promise for sustainably synthesizing ammonia(NH3),while developing highly-efficient,long-term stable,and inexpensive catalysts to activate the inert N≡N bond is a key scientific issue.In this work,on the basis of the concept"N-heterocyclic carbenes(NHCs)",we propose a carbon decorated graphitic-carbon nitride(C/g-C3N4)as novel metal-free NRR electrocatalyst by means of density functional theory(DFT)computations.Our results reveal that the introduced C atom in g-C3N4 surface can be regarded as NHCs and catalytic sites for activating N≡N bond,and are stabilized by the g-C3N4 substrate due to sterically disfavored dimerization.Especially,this NHCs-based heterogeneous catalysis can efficiently reduce the activated N2 molecule to NH3 with a low overpotential of 0.05 V via an enzymatic mechanism.Our work is the first report of NHCs-based electrocatalyst for N2 fixation,thus opening an alternative avenue for advancing sustainable NH3 production.
基金supported by the National Natural Science Foundation of China (22271060)the Department of Chemistry at Fudan University。
文摘N-Heterocyclic carbene(NHC)-based cages have emerged as a prominent and dynamic research area within the research field of chemistry. Leveraging the distinctive electronic and steric properties of NHC ligands, the design, synthesis, and application of these corresponding cages have garnered substantial scholarly interest. In recent years, we have witnessed the successful fabrication of diverse NHC-based cages through a range of synthetic methodologies, which hold significant potential for applications in molecular recognition and catalysis. In this review, we delve into the foundational synthetic strategies that underlie the creation of NHC-based cages, employing approaches encompassing metal–NHC chelation, coordination assembly,and covalent bonding. Additionally, we compile the diverse applications of these cages within catalytic processes and molecular recognition. Lastly, we shed light on the current limitations of synthesis and outline future trends in the development of NHCbased cages.
基金supported by the National Natural Science Foundation of China (21961006,32172459,22371057)Science and Technology Department of Guizhou Province (Qiankehejichu-ZK[2021]Key033)+1 种基金Program of Introducing Talents of Discipline to Universities of China (111 Program,D20023) at Guizhou UniversityFrontiers Science Center for Asymmetric Synthesis and Medicinal Molecules,Department of Education,Guizhou Province (Qianjiaohe KY (2020)004),Guizhou University (China)。
文摘N-heterocyclic carbene-catalyzed enantioselective kinetic resolutions,dynamic kinetic resolutions,and desymmetrization reactions are systematically reviewed.The content is organized according to the activation modes involved in these transformations.Future advances within this highly active research field are discussed from our perspectives on the topic.
基金financially supported by the National Natural Science Foundation of China (Nos.21774006 and 21634002)。
文摘The highly efficient method has been developed for the synthesis of NHC·VOCl_(3) containing symmetrical or unsymmetrical Nheterocyclic carbene(NHC) ligands by the transmetallation reaction of NHC·AgCl with VOCl_(3).The total isolated yield of VOCl_(3)[1,3-(2,4,6-Me_(3)C_(6)H_(2))_(2)(NCH=)_(2)C:](V4') reached 86% by transmetallation reaction,which is much higher than that(48%) by direct coordination method.This methodology has also been used to synthesize the novel vanadium complexes containing unsymmetrical NHC ligands of VOCl_(3)[PhCH_(2)NCH=CHNR)C:](V5',R=2,4,6-Me_(3)C_(6)H_(2);V6',R=2,4-Me_(2)-6-Ph-C_(6)H_(2);V7',R=2,6-^(i)Pr_(2)-C_(6)H_(3)) with high yield,which could not be obtained by direct coordination method.The catalytic activity and copolymerization ability would be improved by introducing unsymmetrical NHC ligands due to their less steric bulky effect.The vanadium complex V5' containing unsymmetrical NHC ligand exhibits higher catalytic activity(3.7×10^(5)g_(copolymer)·mol^(-1) of V·h^(-1)) than that of V4' containing symmetrical NHC ligand.Moreover,the higher propylene incorporation ratio(45.6 mol%) in the copolymers of ethylene with propylene could be obtained by using V5' than that(39.9%) by using V4'.The results would provide a highly efficient strategy for the synthesis of early transition metal complexes containing versitile NHC ligands,affording the catalyst with both high catalytic activity and copolymerization ability for the synthesis of high performance polyolefin elastomers.
文摘Reactions of the 6-hydroxy-thiopyrano[3,4-c]pyridine-5-carbonitrile derivative 1 withα-halo-carbonyl compounds gave the ortho-substituted intermediates 2a-c which were converted into furo[2,3-b]thiopyrano[4,3-d]pyridines 3a-c by fusion of a furan moiety under basic conditions.Further cyclization of 3a-c led to a fusion of a pyrimidine ring,yielding the tetracyclic products 6,7 and 8.In addition,condensation of 6 with various aromatic aldehydes afforded the corresponding imines 9a,b.Mannich reaction of 7 gave products 10a,b.
基金the funding from the Natural Science Foundation of Henan Province(No.222300420102)the start-up funding from Anyang Institute of Technology(No.BSJ2021049)Postdoctoral Innovation Practice Base in Anyang Institute of Technology(No.BHJ2021009).
文摘The ubiquity of N-heterocycles in marketed drugs makes the development of metal-free methodologies for constructing C–N bonds of considerable importance.As an environmentally friendly method,electro-oxidative intramolecular C–H amination has emerged as a powerful platform for synthesizing nitrogen-containing heterocycles under metal-and external oxidant-free conditions.In this minireview,the main achievements in this direction since 2020 are summarized,with an emphasis on the substrate scope and mechanistic aspects.The reactions are classifi ed into two categories:direct and indirect electro-oxidative intramolecular C–H aminations.
基金supported by the National Natural Science Foundation of China(21102117)the Education Department of Sichuan Province(09ZX010)the College Student Science and Technology Innovation Key Foundation of China West Normal University
文摘Nickel(II) complexes Ni(L1)2 (1) and Ni(L2)2·CH3CN·H2O (2) (L1Cl = 2-(3-benzyl- 2,3-dihydroimidazlo-1-yl)-N-(pyridin-2-yl)acetamide, chloride salt, L2Cl = 2-(3-naphthalene-2- ylmethyl)-2,3-dihydro-imidazlo-1-yl)-N-phenylacetamide, chloride salt) with amide-functionalized imidazolium NHC ligand were synthesized and determined by single-crystal X-ray diffraction. Complex 1 crystallizes in the monoclinic system, space group P21/cwith a = 9.2561(19), b = 15.138(3), c = 20.750(4) A, β = 90.216(3)°, V = 2907.3(10) A^3 and Z = 4. Complex 2 crystallizes in the orthorhombic system, space group Pbca with a = 15.5469(16), b = 15.3521(15), c = 31.177(3) A, V = 7441.2(13) ?3 and Z = 8. They are stable in the air and formed via intermolecular weak interactions, including C-H···π contacts and C–H···O hydrogen bonds. Complex 1 was applied in Suzuki coupling reaction through the investigation of reaction conditions under the optimal choice conditions: 80 ℃, K3PO4, 3% mol catalysts, 6% mol PPh3 and toluene as solvent system could afford 96% yield in 5 h.
基金The authors thank the GDR LIPS#3585 for financial support.
文摘We report new heterogeneous organocatalyst based on silica hybrid supported N-heterocyclic carbene(NHC-)species.The organocatalyst is formed from an imidazolium iodide based ionosilica material,followed by iodide/acetate anion exchange.The imidazolium acetate generates the organocatalytic carbene via partial deprotonation of the imidazolium ring in situ.As monitored via EDX,solid state NMR and ion chromatography measurements,the iodide/acetate exchange involving the imidazolium ionosilica material took place only in small extent.Despite the fact that the exchanged material contains only a very small amount of acetate,we observed good catalytic activity and recyclability in cyanosilylation reactions of ketones with trimethylsilyl cyanide.The versatility of the catalyst was highlighted via reaction with several substrates,yielding the corresponding cyanohydrins in good yields.In recycling experiments,the material showed decreasing catalytic activity starting from the third reaction cycle,but high catalytic activity can be regenerated via another acetate treatment.Our work is important as it highlights the possibility to combine carbene chemistry and silica,which are antagonistic at a first glance.We show that imidazolium acetate based ionosilicas are therefore heterogeneous'proto-carbenes',and that there is no need to form strongly basic silica supported NHCs to obtain heterogeneous NHC-organocatalysts.This work therefore opens the route towards heterogeneous and re-usable NHC-organocatalysts from supported ionic liquid imidazolium acetates.
基金the Inonu University Scientific and Technology Center for the FT-IR,1H NMR,31P NMR,13C NMR,elemental analysis and UV-Vis spectroscopy of the complex,and the Dokuz Eylul University for the use of Oxford Rigaku Xcalibur Eos Diffractometer(purchased under University Research Grant No:2010.KB.FEN.13)
文摘In this paper,a new Pd-based complex that contains A^-heterocyclic carbene(NHC)and triphenylphosphine(PPh?)ligands was synthesized.The c/5-(NHC)PdBr2(PPh3)complex has been prepared by the substitution of 3?chloropyridine ligand in(NHC)PdBr2(3-chloropyridine)complex with triphenylphosphine.This complex has been characterized by using 1^H NMR,^31P{^1H}NMR,^13C{^1H}NMR,FTIR,UV-Vis spectroscopy and elemental analysis techniques.The molecular and crystal structures of the cz5-(NHC)PdBr2(PPh3)complex were determined by singlecrystal X-ray diffraction method.
文摘<span style="font-family:Verdana;">To synthesize, characterize and evaluate the antitumor potential derived from ruthenium compounds was generated in this study, from the precursor K[RuCl</span><sub><span style="font-family:Verdana;">4</span></sub><span style="font-family:Verdana;">(bipy)] a route in a simple and reproducible synthesis for a novel compound of coordinating Ru</span><sup><span style="font-family:Verdana;">+3</span></sup><span style="font-family:Verdana;"> with bipy and L-trip. The spectroscopic characterization in the mi</span><span style="font-family:Verdana;">ddle infrared region (FTIR) shows the interactions between Ru-(L-trip), evidenced by the displacement of the carboxylate ion band for</span><span><span style="font-family:Verdana;"> higher energies, and also by the displacements of aliphatic amine bands, suggesting that bidentate coordination of the L-trip ligand occurred. Analysis of the results obtained with thermoanalytical techniques showed that the minimum formula of the compound, [RuCl</span><sub><span style="font-family:Verdana;">2</span></sub><span style="font-family:Verdana;">(bipy)(L-trip)]1/2H</span><sub><span style="font-family:Verdana;">2</span></sub><span style="font-family:Verdana;">O. Evaluation of the</span></span><span><span style="font-family:Verdana;"> antitumor potential of precursor K[RuCl</span><sub><span style="font-family:Verdana;">4</span></sub><span style="font-family:Verdana;">(bipy)] showed the toxic effects on MCF-7 cell line, but </span></span><span style="font-family:Verdana;">did not show selectivity and not reached PBMC cells to the same extent. The evaluation of the antitumor potential of the newly synthesized compound, [RuCl</span><sub><span style="font-family:Verdana;">2</span></sub><span style="font-family:Verdana;">(bipy)(L-trip)], demonstrated that the insertion of an L-tryptophan molecule into the precursor coordination sphere made it selective when compared to PBMC cells, for MCF-7 type tumor cells.</span>
基金supported by the National Natural Science Foundation of China(22025107)the National Youth Top-notch Talent Support Program of China,Xi'an Key Laboratory of Functional Supramolecular Structure and Materialsthe FM&EM International Joint Laboratory of Northwest University.
文摘A pentagonal-prismatic cylinder[Ag5(L)2](PF6)5 obtained from the pentaphenylpyrrole-bridged pentaimidazolium salt H5-L(PF6)5 and AgI ions was determined by X-ray diffraction analyses.The target organometallic cylinder not only exhibited enhanced fluorescence emission in dilute solution at room temperature but also showed an improved phosphorescence ratio compared with the free precursor and maintained a long lifetime(1.39 s)in the solid state at 77 K.Furthermore,the experimental results and DFT calculations confirmed that the formation of the organometallic cylinder promoted intersystem crossing.Meanwhile,the frontier orbitals of[Ag5(L)2](PF6)5 showed the main contribution of building block PPP as the luminescence source of[Ag5(L)2](PF6)5 by a modest heavy-atom effect.These results provide a strategy for constructing enhanced phosphorescent emission and long lifetime organometallic supramolecular phosphorescent materials.
基金This work was supported by the National Natural Science Foundation of China (No. 20272040) and the Key Lab. of Organic Synthesis of Jiangsu Province
文摘The complex (Ind)NiBr(1,3-bisbenzylimidazol-2-ylidene) (Ind = indenyl) 1 has been prepared in ca. 65% yield via the reaction of (Ind)2Ni with an equivalent of 1,3-bis-benzylimidazolium bromide in THF/CH2Cl2 at 45℃, supported by elemental analysis, NMR spectroscopy and X-ray crystal determination. The crystal belongs to the triclinic system, space group Pi with a = 7.072(1), b = 11.264(2), c = 14.541(3)°A, α = 102.21(3),β = 93.44(3),γ = 90.81(3)°, V = 1129.7(4)°A^3, Z = 2, Mr = 502.08, Dc = 1.476 g/cm^3, F(000) = 512, μ= 2.642 mm^-1, R = 0.0490 and wR = 0.1137 for 3913 observed reflections (I〉 2σ(I)). The center nickel atom is coordinated by a bromide ligand, a carbene carbon and three carbon atoms of the five-membered indenyl group to form either a highly distorted square pyramid or a highly distorted square plane.