Developing BiVO_(4)photoanode with efficient carrier transfer and fast water oxidation kinetics is the permanent pursuit to achieve the state-of-art solar-driven photoelectrochemical(PEC)water splitting.The capacity t...Developing BiVO_(4)photoanode with efficient carrier transfer and fast water oxidation kinetics is the permanent pursuit to achieve the state-of-art solar-driven photoelectrochemical(PEC)water splitting.The capacity to increase the PEC activity of BiVO_(4)by loading oxygen evolution co-catalysts(OECs)has been proven,however it suffers from sluggish charge carriers dynamics brought on by the complicated interface between BiVO_(4)and OECs as well as poor long-term durability.Herein,we connected OECs(NiFeOx)and photoanode with a Al-O bridge for bettering the PEC performance of BiVO_(4).The Al-O bridge served as a channel to extract hole from BiVO_(4)to Ni Fe Ox,thus boosting charge carriers separation and preventing BiVO_(4) from photo-corrosion.The Al-O bridging photoanode(NiFeO_(x)/Al_(2)O_(3)/BiVO_(4))demonstrated a high photocurrent density of 5.87 m A/cm^(2)at 1.23 V vs.RHE and long-term photostability in comparison to Ni Fe Ox/BiVO_(4)photoanode.This study proposes a unique technique to boost charge carriers separation between BiVO_(4) and OECs for high-efficiency solar-driven PEC water splitting.展开更多
The monoaminotrinitro iron phthalocyanine(FeMATNPc)is used to connect with isonicotinic acid(INA)for amide bonding and axial coordination to synthetic a unique catalyst FeMATNPc-INA,which is loaded in polyacrylonitril...The monoaminotrinitro iron phthalocyanine(FeMATNPc)is used to connect with isonicotinic acid(INA)for amide bonding and axial coordination to synthetic a unique catalyst FeMATNPc-INA,which is loaded in polyacrylonitrile(PAN)nanofibers by electrospinning.The introduction of INA destroys theπ-πconjugated stack structure in phthalocyanine molecules and exposes more active sites.The FeMATNPc-INA structure is characterized by X-ray photoelectron spectroscopy and UV-visible absorption spectrum,and the FeMATNPcINA/PAN structure is characterized by Fourier transform infrared spectroscopy and X-ray diffraction.The FeMATNPc-INA/PAN can effectively activate peroxymonosulfate(PMS)to eliminate carbamazepine(CBZ)within 40 minutes(PMS 1.5 mmol/L)in the dark.The effects of catalyst dosage,PMS concentration,pH and inorganic anion on the degradation of CBZ are investigated.It has been confirmed by electron paramagnetic resonance,gas chromatography–mass spectroscopy and free radical capture experiments that the catalytic system is degraded by·OH,SO4^(·-)and Fe(IV)=O are the major active species,the singlet oxygen(^(1)O_(2))is the secondary active species.The degradation process of CBZ is analyzed by ultra-high performance liquid chromatography-mass spectrometry and the aromatic compounds have been degraded to small molecular acids.展开更多
Bridged polycyclic lactams are important structural units in organic functional materials,natural products,and pharmaceuticals.A flexible and efficient anion cascade reaction was developed for the preparation of bridg...Bridged polycyclic lactams are important structural units in organic functional materials,natural products,and pharmaceuticals.A flexible and efficient anion cascade reaction was developed for the preparation of bridged polycyclic lactams from readily available malonamides and 1,4‑dien-3-ones.Various highly substituted bridged polycyclic lactams were synthesized in good to excellent yields by tandem nucleophilic sequences in the presence of t BuOK in commercially available EtOH solvent at 60℃.Notably,the simple reactions can be run on a gram scale.Mechanistically,bis-Michael addition reaction and hemiaminalization reactions are involved in the tandem transformation.展开更多
Conjugated homopolymers based on six-member rings,e.g.,polyfluorene,always exhibit blue emission and conjugated homopolymers based on five-member rings,e.g.,polythiophene,can give red emission with low efficiency.In t...Conjugated homopolymers based on six-member rings,e.g.,polyfluorene,always exhibit blue emission and conjugated homopolymers based on five-member rings,e.g.,polythiophene,can give red emission with low efficiency.In this work,we report a series of new conjugated homopolymers based on six-member rings with high-efficiency deep-red emission.The repeating units of the red light emitting homopolymers are double B←N bridged bipyridine(BNBP)with the boron atoms functionalized with diphenyl,borafluorene,and 2,7-di-tert-butyl-borafluorene groups,respectively.The relationship between the chemical structures and the opto-electronic properties of the monomers and the homopolymers has been systematically studied.The three polymers emit pure red light(λ_(max)=656 nm)or deep red light(λ_(max)=693 nm)with fluorescence quantum efficiency in solution higher than 60%.The polymers can be used as the emitters in solution-processed organic light-emitting diodes with red emission and decent device performance.This work indicates a new strategy to design highly efficient light emitting conjugated polymers.展开更多
From the standpoint of chemical structures,the organic backbones of energetic materials can be classified into aromatic rings,nonaromatic rings,and open chains.Although the category of aromatic energetic compounds exh...From the standpoint of chemical structures,the organic backbones of energetic materials can be classified into aromatic rings,nonaromatic rings,and open chains.Although the category of aromatic energetic compounds exhibits several advantages in the regulation of energetic properties,the nonaromatic heterocycles,assembling nitramino explosophores with simple alkyl bridges,still have prevailed in benchmark materials.The methylene bridge plays a pivotal role in the constructions of the classic nonaromatic heterocycle-based energetic compounds,e.g.,hexahydro-1,3,5-trinitro-1,3,5-triazine(RDX)and octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine(HMX),whereas ethylene bridge is the core moiety of state-of-the-art explosive 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane(CL-20).In this context,it is of great interest to employ simple and practical bridges to assemble aromatic and nonaromatic nitrogen-rich heterocycles,thereby expanding the structural diversity of energetic materials,e.g.,bridged and fused nitrogen-rich poly-heterocycles.Furthermore,alkyl-bridged poly-heterocycles highlight the potential for the open chain type of energetic materials.In this review,the development of alkyl bridges in linking nitrogen-rich heterocycles is presented,and the perspective of the newly constructed energetic backbones is summarized for the future design of advanced energetic materials.展开更多
A novel organotin complex of μ-pentaoxygen bridged penta（bis-benzyltin） bissalicylate has been synthesized by the reaction of bis-benzyltin oxide and salicylic acid and its structure has been determined by X-ray di...A novel organotin complex of μ-pentaoxygen bridged penta（bis-benzyltin） bissalicylate has been synthesized by the reaction of bis-benzyltin oxide and salicylic acid and its structure has been determined by X-ray diffraction. The crystal belongs to monoclinic, space group P21/n with a = 1.7206（5）, b = 2.1401（6）, c = 2.1488（6）nm, β= 93.325（5）°, V = 7.899（4） nm^3, Z = 4, Dc = 1.564 g/cm^3,μ（MoKα） = 16.17cm^-1, Mr = 1859.94, F（000） = 3692, R1= 0.0755 and wR2= 0.1557. According to structural analysis, the coordination geometry of tin is a distorted trigonal bipyramid, and the ladder-like structure is shaped by four Sn2O2 planar four-membered rings.展开更多
A facile and effective method to synthesize TS‐1zeolite aggregates has been presented.The crystallization of silanized seeds and nanocrystallites led to large and irregular TS‐1zeolite aggregates ranging from5to40μ...A facile and effective method to synthesize TS‐1zeolite aggregates has been presented.The crystallization of silanized seeds and nanocrystallites led to large and irregular TS‐1zeolite aggregates ranging from5to40μm in size,based on the special sol‐gel chemistry of bridged organosilane.Epoxidation of1‐hexene and cyclohexene was used as a probe reaction to investigate the catalytic performance of the resulting materials.These TS‐1zeolite aggregates possessed both the conventional nanoparticle properties of TS‐1zeolites and variable surface hydrophilic/hydrophobic features,which enhanced the catalytic properties of hydroperoxides for alkene epoxidation.Moreover,the large aggregates effectively simplified the separation procedure during preparation and catalytic reactions.展开更多
A glutathione peroxidase（GPX） mimic, 2-selenium bridged β-cyclodextrin（2-SeCD）, was synthesized. In order to examine its role and mechanism in treating stroke we chose stroke-prone spontaneously hypertensive rats...A glutathione peroxidase（GPX） mimic, 2-selenium bridged β-cyclodextrin（2-SeCD）, was synthesized. In order to examine its role and mechanism in treating stroke we chose stroke-prone spontaneously hypertensive rats（SHRsp） as animal model. 56 SHRsps of 8-week olds were randomly divided into several groups： test groups （low, moderate, high dose of 2-SeCD） and control groups（positive and negative）. After onset of the stroke, the rats in test groups were orally administrated with different amounts of 2-SeCD, the positive control group with ebselen, and the negative control group with drinking water. The treatment lasted two weeks, followed by observation of the rats for 10 days, meanwhile blood pressure, biochemical parameters of plasma, and the contents of nitric oxide（NO） and malondialdehyde（MDA） in plasma and brain were determined. The results show that there were significant differences in contents of NO and MDA in plasma and brain between the test groups（high, moderate dose of 2-SeCD） and negative control group. The NO contents of the test groups were obviously higher than that of the negative control group （P〈0.01）. The MDA contents of the test groups（high, moderate dose of 2-SeCD） were obviously lower than that of the negative control group（P〈0.01）. The mechanism of 2-SeCD in treating stroke was discussed, which maybe related to the increase of NO and the decrease of MDA in plasma and brain tissue, but the exact mechanism should be further studied. Moreover, the tendencies of changes in systolic blood pressure, contents of NO and MDA, and other physiological parameters for the test groups were shown to be much better than the corresponding parameters for the positive group（the group with ebselen）（P〈0.05）, indicating that the treatment effect of 2-SeCD is better than that of ebselen.展开更多
To investigate the treatment effect of 2-selenium bridged β -cyclodextrin(2-SeCD),a GPX mimic,on the stroke of stroke-prone spontaneously hypertensive rats(SHRSP),fifty-two SHRSP of 8-week old were randomly divided i...To investigate the treatment effect of 2-selenium bridged β -cyclodextrin(2-SeCD),a GPX mimic,on the stroke of stroke-prone spontaneously hypertensive rats(SHRSP),fifty-two SHRSP of 8-week old were randomly divided into four groups A,B,C and control group D. The rats of groups A,B,C and D were given 1.0%-1.5% NaCl mass fraction as drinking fluid. After onset of stroke,groups A,B and C were given \{orally\} 16.05,160.5 and 1605 mg·kg -1 ·day -1 of 2-SeCD,respectively,and group D was given water for \{2 weeks.\} The clinical score of stroke,systolic blood pressure(SBP),survival time of rats were recorded and the histopathologic examinations of their brain and carotid artery were made after decapitation. The clinical scores of stroke after treatment with 160.5 mg·kg -1 ·day -1 (Group B) and 1605 mg·kg -1 ·day -1 (Group C) of 2-SeCD are 2.55±0.98 and 1.98±0.79,respectively,those are obviously lower than that of group D(3.41±0.83,p<0.01). The survival days in group B(10.0±8.6) and group C(14.4±7.9) are longer than that for group D(4.7±2.9,p<0.01). The electron microscope study showed that the endothelium of carotid artery was near to normal in group B and group C,while it was seriously injured in control group D and mildly injured in group A. 2-SeCD may effectively be used to treat the stroke for SHRSP.展开更多
A novel brideed bis（β-cvclodextrin）, 4, 4＇-diaminodiphenyl ether-bfiged-bis （6-aimino-6-deoxv-β-cyclodextrin） 3, has been synthesized and its inclusion complexation behavior with three linear＇vip dyes （AR, ...A novel brideed bis（β-cvclodextrin）, 4, 4＇-diaminodiphenyl ether-bfiged-bis （6-aimino-6-deoxv-β-cyclodextrin） 3, has been synthesized and its inclusion complexation behavior with three linear＇vip dyes （AR, NR and MB ） has been investigated by. means of fluorescence spectrometry. The-result obtained demonstrated that the novel bridged bis（β-cyclodextnn） showed much higher affinities towards vip dyes than native β-cyclodextrin.展开更多
Two novel and well-defined polyhedral oligomeric silsesquioxanes（POSS） with two same Si_8O_（12） cores and a reactive NH group, namely bridged-POSS（2a and 2b）,have been prepared by the traditional ＇corner-cappin...Two novel and well-defined polyhedral oligomeric silsesquioxanes（POSS） with two same Si_8O_（12） cores and a reactive NH group, namely bridged-POSS（2a and 2b）,have been prepared by the traditional ＇corner-capping＇ reaction.X-ray diffraction demonstrates that those two POSS have the similar T_8 structure.From the thermo-gravimetric analysis,bridged-POSS shows the belter thermal degradation stability than the contrastive POSS.展开更多
A new carbon bridged cyclopentadienyl chromium complex of the type [（C5H4）C（CH3）2 CH2（C5H4N）]CrCl2 was prepared by treatment of CrCl3·（THF）3 in THF solution with the lithium salt of ligand containing cycl...A new carbon bridged cyclopentadienyl chromium complex of the type [（C5H4）C（CH3）2 CH2（C5H4N）]CrCl2 was prepared by treatment of CrCl3·（THF）3 in THF solution with the lithium salt of ligand containing cyclopentadienyl and pyridyl groups. The chromium complex was characterized by 1H NMR and elemental analysis（EA）, and the crystal structure was determined by X-ray diffraction analysis. Activated by Al（i-Bu）3, the chromium complex displayed a very high activity for methyl methacrylate（MMA） polymerization. After 24 hours,more than 95.5% MMA was converted to polymethyl methacrylate（PMMA） with a viscosity average molecular weight（Wη） of 416000 g·mol-1 at 60 ℃ for MMA/ Al（i-Bu）3 /chromium catalyst molar ratio of up to 2000：20：1. Effects of temperature, molar ratios of MMA/catalyst and catalyst/cocatalyst on the polymerization have been studied. The high conversion of MMA and high molecular weight of PMMA with narrow molecular weight distribution is caused by the unique stable active site formed by the new chromium complex and aluminum cocatalyst.展开更多
To the Editor:Biliary drainage is most frequently performed among endoscopic procedures using pancreatobiliary endoscopy.A large-diameter metallic stent can significantly extend the patency period rather than a plasti...To the Editor:Biliary drainage is most frequently performed among endoscopic procedures using pancreatobiliary endoscopy.A large-diameter metallic stent can significantly extend the patency period rather than a plastic stent for extrahepatic biliary stricture.;However,the optimal drainage for the hilar biliary obstruction is still controversial.展开更多
Dicyanide building block cis-Fe（phen）2（CN）2 and [MnⅢ（salen）]（ClO4） have been used to design and synthesize a cyanide-bridged complex, resulting in a heterobimetallic one-dimensional（1D） zigzag chain complex...Dicyanide building block cis-Fe（phen）2（CN）2 and [MnⅢ（salen）]（ClO4） have been used to design and synthesize a cyanide-bridged complex, resulting in a heterobimetallic one-dimensional（1D） zigzag chain complex 1, [cis-Fe（phen）2（CN）2Mn（salen）]（PF6）（phen =1,10-phenanthroline, salen=N,N-ethylenebis-（salicylideneaminato） dianion）. Single-crystal X-ray diffraction analysis shows complex 1 crystallizes in the monoclinic P2（1/c） space group and the asymmetric unit contains one [-NC-Fe（phen）2（μ-CN）-MnⅢ-（salen）-]＋ cation and one PF6- anion. In the cationic structure of 1, each FeⅡ（phen）2（CN）2 connects two [MnⅢ（salen）]＋ with two cyanide groups in a cis-conformation, and in turn each [MnⅢ（salen）]＋ unit links two FeⅡ（phen）2（CN）2 building blocks in a trans-conformation, resulting in a 1D [-NC-FeⅡ-CN-MnⅢ-]n chain. Furthermore, the electronic absorption spectra and electrochemical and magnetic properties of complex 1 have also been studied.展开更多
A new organocatalytic double annulation cascade involving scission/recombination of N-O bonds of nitrones is reported for the first time, and used to produce a range of hitherto unprecedented tricyclic bridged-fused b...A new organocatalytic double annulation cascade involving scission/recombination of N-O bonds of nitrones is reported for the first time, and used to produce a range of hitherto unprecedented tricyclic bridged-fused benzo[d]azepines bearing three stereogenic centers with moderate to good yields and complete diastereoselectivity. A quinine-catalyzed reaction of yne–allenone esters with nitrones worked well and provided a convergent and regioselective pathway to access these three-dimensional scaffolds from the planar conjugated system. Density functional theory(DFT) calculations have been applied to understand the key process for forming diradical intermediates.展开更多
The synthesis is and crystal structure are reported for the sheet-like compourd [CU2(oxpn)Fe(CN )5(NO)]. there oxpn is the dianion of M, M'-bis(3-aminopropyl)oxamide. This compound crustallizes in the orthogonal s...The synthesis is and crystal structure are reported for the sheet-like compourd [CU2(oxpn)Fe(CN )5(NO)]. there oxpn is the dianion of M, M'-bis(3-aminopropyl)oxamide. This compound crustallizes in the orthogonal space group Puma. with a=11 .413(4), b=22.242(5), c=7.736(2) A, and Z=4.The structure was refined to conventionat discrepancy factors R=0.047 and Pw=0.054. The Cu(II ) and Fe(III)centers are bridged by oxpn and cyanide, the formal behaves as a his-terdentate tigand bound to cooper(II)ion to form (II) dimers. whereas the latter bridges Cu(II) and Fe(III) centers in both symmetric and asymetric end- to-end bis-monodentate fashions, spreading out along be plane to form a 20 network. The Structure is made up of CuFe unit with Cu(II) and Fe(III) ions locating in a distorted square-based pyramid and a compressed octahedron, respectively.展开更多
The crystal structure of the ternary complex [Cu (L)(2, 2'-bipy)H2 O]·2H2O(L=phenylmalonate) has been determined by X-ray diffraction methods. The copperf(II) centerin five-coordinate Square-pyramidal structu...The crystal structure of the ternary complex [Cu (L)(2, 2'-bipy)H2 O]·2H2O(L=phenylmalonate) has been determined by X-ray diffraction methods. The copperf(II) centerin five-coordinate Square-pyramidal structure.It is of interest in this structure that the complexinvolves a metal ion bridge ligand-ligand aromatic ring stacking interaction展开更多
The low-cost CuBr-promoted domino Biginelli reaction among readily available ketones,salicylaldehyde derivatives and 3-amino-1,2,4-triazole was studied under solvothermal conditions,giving the novel bridged polyhetero...The low-cost CuBr-promoted domino Biginelli reaction among readily available ketones,salicylaldehyde derivatives and 3-amino-1,2,4-triazole was studied under solvothermal conditions,giving the novel bridged polyheterocycles bearing two or three stereocenters depending on the starting ketones.This multicomponent reaction proceeded with high diastereoselectivity(dr>20:1)based on a combined~1 H NMR,crystallographic and supercritical fluid chromatographic(SFC)analysis of the product.Time-dependent high-resolution mass spectrometry(HRMS)was performed to track the reaction process,and several key intermediates were identified,leading to the drawing of a plausible reaction mechanism.Density functional theory(DFT)calculation was supplemented,and two reaction pathways were differentiated.Moreover,in vitro antitumor activity was evaluated using HeLa and HepG2 cell lines,and two of these polyheterocycles demonstrated promising activities against HepG2 cells with EC50 down to 10μmol/L.Additionally,ESI-MS/MS studies on all the polyheterocycles suggest a common fragmentation pathway(loss of one molecule of amino-triazole)they shared,providing the first-hand fragmentation rules for future rapid structural identification of them.The multicomponent domino reaction presented here may offer prospects for future design of more efficient strategies to access medicinally important bridged polyheterocycles.展开更多
Two bridged purine dinucleosides, bis(2-N-acetyl-6-N-alkylylene-2,6-diaminopurine-2',3',5'-triacetyl-beta-D-ribofuranoside), were synthesized fi om the reaction of the key medium 3, 2-acetylamino-6-[1-(1,2...Two bridged purine dinucleosides, bis(2-N-acetyl-6-N-alkylylene-2,6-diaminopurine-2',3',5'-triacetyl-beta-D-ribofuranoside), were synthesized fi om the reaction of the key medium 3, 2-acetylamino-6-[1-(1,2,4-triazolyl)]-purine-2',3',5'-triacetyl-beta-D-ribofuranoside with dialkylamine.展开更多
The heterobinuclear complex of formula Cu (oxap )Gd(phen)2 (CIO4 )3 has been synthesized, where oxap denotes the N, N'-bis (2-aminopropyl )oxamido dianion and phen represents 1,10-phenanthroline. The complex was c...The heterobinuclear complex of formula Cu (oxap )Gd(phen)2 (CIO4 )3 has been synthesized, where oxap denotes the N, N'-bis (2-aminopropyl )oxamido dianion and phen represents 1,10-phenanthroline. The complex was characterized with ESR and variable temperature magnetic susceptibility (4- 300K). The least-squares fit of the experimental sosceptibilities yielded J=2. 25cm-1. The observed Gd (Ⅲ)-Cu (Ⅱ) coupling is ferromagnetic.One Plausible mechanism that can cause a ferromagnetic coupling between Gd(Ⅱ) and Cu (Ⅱ) is discussed in terms of spin-polarization.展开更多
基金financially supported by the National Natural Science Foundation of China(No.52173277)the Fundamental Research Funds for the Central Universities of Chang’an University(No.300102299304)+1 种基金the Innovative Research Team for Science and Technology of Shaanxi Province(No.2022TD-04)the open program of Key Laboratories of Fine Chemicals and Surfactants in Sichuan Provincial Universities(No.2023JXZ03)。
文摘Developing BiVO_(4)photoanode with efficient carrier transfer and fast water oxidation kinetics is the permanent pursuit to achieve the state-of-art solar-driven photoelectrochemical(PEC)water splitting.The capacity to increase the PEC activity of BiVO_(4)by loading oxygen evolution co-catalysts(OECs)has been proven,however it suffers from sluggish charge carriers dynamics brought on by the complicated interface between BiVO_(4)and OECs as well as poor long-term durability.Herein,we connected OECs(NiFeOx)and photoanode with a Al-O bridge for bettering the PEC performance of BiVO_(4).The Al-O bridge served as a channel to extract hole from BiVO_(4)to Ni Fe Ox,thus boosting charge carriers separation and preventing BiVO_(4) from photo-corrosion.The Al-O bridging photoanode(NiFeO_(x)/Al_(2)O_(3)/BiVO_(4))demonstrated a high photocurrent density of 5.87 m A/cm^(2)at 1.23 V vs.RHE and long-term photostability in comparison to Ni Fe Ox/BiVO_(4)photoanode.This study proposes a unique technique to boost charge carriers separation between BiVO_(4) and OECs for high-efficiency solar-driven PEC water splitting.
基金supported by National Natural Science Foundation of China (No.22006136)。
文摘The monoaminotrinitro iron phthalocyanine(FeMATNPc)is used to connect with isonicotinic acid(INA)for amide bonding and axial coordination to synthetic a unique catalyst FeMATNPc-INA,which is loaded in polyacrylonitrile(PAN)nanofibers by electrospinning.The introduction of INA destroys theπ-πconjugated stack structure in phthalocyanine molecules and exposes more active sites.The FeMATNPc-INA structure is characterized by X-ray photoelectron spectroscopy and UV-visible absorption spectrum,and the FeMATNPcINA/PAN structure is characterized by Fourier transform infrared spectroscopy and X-ray diffraction.The FeMATNPc-INA/PAN can effectively activate peroxymonosulfate(PMS)to eliminate carbamazepine(CBZ)within 40 minutes(PMS 1.5 mmol/L)in the dark.The effects of catalyst dosage,PMS concentration,pH and inorganic anion on the degradation of CBZ are investigated.It has been confirmed by electron paramagnetic resonance,gas chromatography–mass spectroscopy and free radical capture experiments that the catalytic system is degraded by·OH,SO4^(·-)and Fe(IV)=O are the major active species,the singlet oxygen(^(1)O_(2))is the secondary active species.The degradation process of CBZ is analyzed by ultra-high performance liquid chromatography-mass spectrometry and the aromatic compounds have been degraded to small molecular acids.
基金National Natural Science Foundation of China(NSFC,Nos.21772032,21877206,and 22101074)the 111 Project(No.D17007)+3 种基金Excellent Youth Foundation of Henan Scientific Committee(No.222300420012)China Postdoctoral Science Foundation(No.2019M660173)the Natural Science Foundation of Henan Province(No.202300410233)Henan Key Laboratory of Organic Functional Molecules and Drug Innovation for financial support。
文摘Bridged polycyclic lactams are important structural units in organic functional materials,natural products,and pharmaceuticals.A flexible and efficient anion cascade reaction was developed for the preparation of bridged polycyclic lactams from readily available malonamides and 1,4‑dien-3-ones.Various highly substituted bridged polycyclic lactams were synthesized in good to excellent yields by tandem nucleophilic sequences in the presence of t BuOK in commercially available EtOH solvent at 60℃.Notably,the simple reactions can be run on a gram scale.Mechanistically,bis-Michael addition reaction and hemiaminalization reactions are involved in the tandem transformation.
基金financially supported by the National Natural Science Foundation of China(Nos.22135007 and 52073281)。
文摘Conjugated homopolymers based on six-member rings,e.g.,polyfluorene,always exhibit blue emission and conjugated homopolymers based on five-member rings,e.g.,polythiophene,can give red emission with low efficiency.In this work,we report a series of new conjugated homopolymers based on six-member rings with high-efficiency deep-red emission.The repeating units of the red light emitting homopolymers are double B←N bridged bipyridine(BNBP)with the boron atoms functionalized with diphenyl,borafluorene,and 2,7-di-tert-butyl-borafluorene groups,respectively.The relationship between the chemical structures and the opto-electronic properties of the monomers and the homopolymers has been systematically studied.The three polymers emit pure red light(λ_(max)=656 nm)or deep red light(λ_(max)=693 nm)with fluorescence quantum efficiency in solution higher than 60%.The polymers can be used as the emitters in solution-processed organic light-emitting diodes with red emission and decent device performance.This work indicates a new strategy to design highly efficient light emitting conjugated polymers.
基金National Natural Science Foundation of China(Grant Nos.22075023,22205022,and 22235003)to provide fund for conducting experiments。
文摘From the standpoint of chemical structures,the organic backbones of energetic materials can be classified into aromatic rings,nonaromatic rings,and open chains.Although the category of aromatic energetic compounds exhibits several advantages in the regulation of energetic properties,the nonaromatic heterocycles,assembling nitramino explosophores with simple alkyl bridges,still have prevailed in benchmark materials.The methylene bridge plays a pivotal role in the constructions of the classic nonaromatic heterocycle-based energetic compounds,e.g.,hexahydro-1,3,5-trinitro-1,3,5-triazine(RDX)and octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine(HMX),whereas ethylene bridge is the core moiety of state-of-the-art explosive 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane(CL-20).In this context,it is of great interest to employ simple and practical bridges to assemble aromatic and nonaromatic nitrogen-rich heterocycles,thereby expanding the structural diversity of energetic materials,e.g.,bridged and fused nitrogen-rich poly-heterocycles.Furthermore,alkyl-bridged poly-heterocycles highlight the potential for the open chain type of energetic materials.In this review,the development of alkyl bridges in linking nitrogen-rich heterocycles is presented,and the perspective of the newly constructed energetic backbones is summarized for the future design of advanced energetic materials.
基金This work was supported by the Natural Science Foundation (05JJ40015) and Basic Research(03JZY3036) of the Hunan Province ,Key Foundation of Education Committee of HuNan Province(03A009) and Sustentation Fund of HenYang Science& Technology bureau (2004-25, 2005KG01-09)
文摘A novel organotin complex of μ-pentaoxygen bridged penta（bis-benzyltin） bissalicylate has been synthesized by the reaction of bis-benzyltin oxide and salicylic acid and its structure has been determined by X-ray diffraction. The crystal belongs to monoclinic, space group P21/n with a = 1.7206（5）, b = 2.1401（6）, c = 2.1488（6）nm, β= 93.325（5）°, V = 7.899（4） nm^3, Z = 4, Dc = 1.564 g/cm^3,μ（MoKα） = 16.17cm^-1, Mr = 1859.94, F（000） = 3692, R1= 0.0755 and wR2= 0.1557. According to structural analysis, the coordination geometry of tin is a distorted trigonal bipyramid, and the ladder-like structure is shaped by four Sn2O2 planar four-membered rings.
基金supported by the National Natural Science Foundation of China (21503081,21503073,21403070,21707093)the National Key Research and Development Program of China (2017YFA0403102)~~
文摘A facile and effective method to synthesize TS‐1zeolite aggregates has been presented.The crystallization of silanized seeds and nanocrystallites led to large and irregular TS‐1zeolite aggregates ranging from5to40μm in size,based on the special sol‐gel chemistry of bridged organosilane.Epoxidation of1‐hexene and cyclohexene was used as a probe reaction to investigate the catalytic performance of the resulting materials.These TS‐1zeolite aggregates possessed both the conventional nanoparticle properties of TS‐1zeolites and variable surface hydrophilic/hydrophobic features,which enhanced the catalytic properties of hydroperoxides for alkene epoxidation.Moreover,the large aggregates effectively simplified the separation procedure during preparation and catalytic reactions.
基金the National Natural Science Foundation of China(No.20572035)Jilin University(No.419070100087).
文摘A glutathione peroxidase（GPX） mimic, 2-selenium bridged β-cyclodextrin（2-SeCD）, was synthesized. In order to examine its role and mechanism in treating stroke we chose stroke-prone spontaneously hypertensive rats（SHRsp） as animal model. 56 SHRsps of 8-week olds were randomly divided into several groups： test groups （low, moderate, high dose of 2-SeCD） and control groups（positive and negative）. After onset of the stroke, the rats in test groups were orally administrated with different amounts of 2-SeCD, the positive control group with ebselen, and the negative control group with drinking water. The treatment lasted two weeks, followed by observation of the rats for 10 days, meanwhile blood pressure, biochemical parameters of plasma, and the contents of nitric oxide（NO） and malondialdehyde（MDA） in plasma and brain were determined. The results show that there were significant differences in contents of NO and MDA in plasma and brain between the test groups（high, moderate dose of 2-SeCD） and negative control group. The NO contents of the test groups were obviously higher than that of the negative control group （P〈0.01）. The MDA contents of the test groups（high, moderate dose of 2-SeCD） were obviously lower than that of the negative control group（P〈0.01）. The mechanism of 2-SeCD in treating stroke was discussed, which maybe related to the increase of NO and the decrease of MDA in plasma and brain tissue, but the exact mechanism should be further studied. Moreover, the tendencies of changes in systolic blood pressure, contents of NO and MDA, and other physiological parameters for the test groups were shown to be much better than the corresponding parameters for the positive group（the group with ebselen）（P〈0.05）, indicating that the treatment effect of 2-SeCD is better than that of ebselen.
文摘To investigate the treatment effect of 2-selenium bridged β -cyclodextrin(2-SeCD),a GPX mimic,on the stroke of stroke-prone spontaneously hypertensive rats(SHRSP),fifty-two SHRSP of 8-week old were randomly divided into four groups A,B,C and control group D. The rats of groups A,B,C and D were given 1.0%-1.5% NaCl mass fraction as drinking fluid. After onset of stroke,groups A,B and C were given \{orally\} 16.05,160.5 and 1605 mg·kg -1 ·day -1 of 2-SeCD,respectively,and group D was given water for \{2 weeks.\} The clinical score of stroke,systolic blood pressure(SBP),survival time of rats were recorded and the histopathologic examinations of their brain and carotid artery were made after decapitation. The clinical scores of stroke after treatment with 160.5 mg·kg -1 ·day -1 (Group B) and 1605 mg·kg -1 ·day -1 (Group C) of 2-SeCD are 2.55±0.98 and 1.98±0.79,respectively,those are obviously lower than that of group D(3.41±0.83,p<0.01). The survival days in group B(10.0±8.6) and group C(14.4±7.9) are longer than that for group D(4.7±2.9,p<0.01). The electron microscope study showed that the endothelium of carotid artery was near to normal in group B and group C,while it was seriously injured in control group D and mildly injured in group A. 2-SeCD may effectively be used to treat the stroke for SHRSP.
基金supported by the Yunnan Province Natural Science Foundation （Nos. 2003C009M and 2003B0014Q）
文摘A novel brideed bis（β-cvclodextrin）, 4, 4＇-diaminodiphenyl ether-bfiged-bis （6-aimino-6-deoxv-β-cyclodextrin） 3, has been synthesized and its inclusion complexation behavior with three linear＇vip dyes （AR, NR and MB ） has been investigated by. means of fluorescence spectrometry. The-result obtained demonstrated that the novel bridged bis（β-cyclodextnn） showed much higher affinities towards vip dyes than native β-cyclodextrin.
基金the National Natural Science Foundation of China(No20772092)the Hubei Province Natural Science Fund for Distinguished Young Scholars(No2007ABB021) for financial support
文摘Two novel and well-defined polyhedral oligomeric silsesquioxanes（POSS） with two same Si_8O_（12） cores and a reactive NH group, namely bridged-POSS（2a and 2b）,have been prepared by the traditional ＇corner-capping＇ reaction.X-ray diffraction demonstrates that those two POSS have the similar T_8 structure.From the thermo-gravimetric analysis,bridged-POSS shows the belter thermal degradation stability than the contrastive POSS.
基金Funded by the National Natural Science Foundation of China(No.51204125)the Natural Science Foundation of Hubei Province(Nos.2014CFB812 and 2014CFB810)the Open Fund Project Funded by the Key Laboratory of Coal Conversion and New Carbon Materials of Hubei Province in China(No.WKDM201302)
文摘A new carbon bridged cyclopentadienyl chromium complex of the type [（C5H4）C（CH3）2 CH2（C5H4N）]CrCl2 was prepared by treatment of CrCl3·（THF）3 in THF solution with the lithium salt of ligand containing cyclopentadienyl and pyridyl groups. The chromium complex was characterized by 1H NMR and elemental analysis（EA）, and the crystal structure was determined by X-ray diffraction analysis. Activated by Al（i-Bu）3, the chromium complex displayed a very high activity for methyl methacrylate（MMA） polymerization. After 24 hours,more than 95.5% MMA was converted to polymethyl methacrylate（PMMA） with a viscosity average molecular weight（Wη） of 416000 g·mol-1 at 60 ℃ for MMA/ Al（i-Bu）3 /chromium catalyst molar ratio of up to 2000：20：1. Effects of temperature, molar ratios of MMA/catalyst and catalyst/cocatalyst on the polymerization have been studied. The high conversion of MMA and high molecular weight of PMMA with narrow molecular weight distribution is caused by the unique stable active site formed by the new chromium complex and aluminum cocatalyst.
文摘To the Editor:Biliary drainage is most frequently performed among endoscopic procedures using pancreatobiliary endoscopy.A large-diameter metallic stent can significantly extend the patency period rather than a plastic stent for extrahepatic biliary stricture.;However,the optimal drainage for the hilar biliary obstruction is still controversial.
基金Supported by the Project of Hubei Provincial Department of Education(No.Q20144302 and Q20164302)the Natural Science Foundation of Hubei Province(No.2013CFA015)+1 种基金the Doctoral Scientific Research Foundation of Jingchu University of Technology(No.QDB201603)the Open Project Program of Hubei Key Laboratory of Drug Synthesis and Optimization,Jingchu University of Technology(No.OPP2016ZD02)
文摘Dicyanide building block cis-Fe（phen）2（CN）2 and [MnⅢ（salen）]（ClO4） have been used to design and synthesize a cyanide-bridged complex, resulting in a heterobimetallic one-dimensional（1D） zigzag chain complex 1, [cis-Fe（phen）2（CN）2Mn（salen）]（PF6）（phen =1,10-phenanthroline, salen=N,N-ethylenebis-（salicylideneaminato） dianion）. Single-crystal X-ray diffraction analysis shows complex 1 crystallizes in the monoclinic P2（1/c） space group and the asymmetric unit contains one [-NC-Fe（phen）2（μ-CN）-MnⅢ-（salen）-]＋ cation and one PF6- anion. In the cationic structure of 1, each FeⅡ（phen）2（CN）2 connects two [MnⅢ（salen）]＋ with two cyanide groups in a cis-conformation, and in turn each [MnⅢ（salen）]＋ unit links two FeⅡ（phen）2（CN）2 building blocks in a trans-conformation, resulting in a 1D [-NC-FeⅡ-CN-MnⅢ-]n chain. Furthermore, the electronic absorption spectra and electrochemical and magnetic properties of complex 1 have also been studied.
基金financial support from the National Natural Science Foundation of China (Nos. 21871112 and 21971090)。
文摘A new organocatalytic double annulation cascade involving scission/recombination of N-O bonds of nitrones is reported for the first time, and used to produce a range of hitherto unprecedented tricyclic bridged-fused benzo[d]azepines bearing three stereogenic centers with moderate to good yields and complete diastereoselectivity. A quinine-catalyzed reaction of yne–allenone esters with nitrones worked well and provided a convergent and regioselective pathway to access these three-dimensional scaffolds from the planar conjugated system. Density functional theory(DFT) calculations have been applied to understand the key process for forming diradical intermediates.
文摘The synthesis is and crystal structure are reported for the sheet-like compourd [CU2(oxpn)Fe(CN )5(NO)]. there oxpn is the dianion of M, M'-bis(3-aminopropyl)oxamide. This compound crustallizes in the orthogonal space group Puma. with a=11 .413(4), b=22.242(5), c=7.736(2) A, and Z=4.The structure was refined to conventionat discrepancy factors R=0.047 and Pw=0.054. The Cu(II ) and Fe(III)centers are bridged by oxpn and cyanide, the formal behaves as a his-terdentate tigand bound to cooper(II)ion to form (II) dimers. whereas the latter bridges Cu(II) and Fe(III) centers in both symmetric and asymetric end- to-end bis-monodentate fashions, spreading out along be plane to form a 20 network. The Structure is made up of CuFe unit with Cu(II) and Fe(III) ions locating in a distorted square-based pyramid and a compressed octahedron, respectively.
文摘The crystal structure of the ternary complex [Cu (L)(2, 2'-bipy)H2 O]·2H2O(L=phenylmalonate) has been determined by X-ray diffraction methods. The copperf(II) centerin five-coordinate Square-pyramidal structure.It is of interest in this structure that the complexinvolves a metal ion bridge ligand-ligand aromatic ring stacking interaction
基金supported by the National Natural Science Foundation of China(Nos.21901067,22171075)Starting Grant from the Ministry of Human Resource and Social Security of China(Q.L.)+1 种基金the NSFC of Guangxi Province(Nos.91122032,2017GXNSFDA198040)the BAGUI talent program(No.2019AC26001)。
文摘The low-cost CuBr-promoted domino Biginelli reaction among readily available ketones,salicylaldehyde derivatives and 3-amino-1,2,4-triazole was studied under solvothermal conditions,giving the novel bridged polyheterocycles bearing two or three stereocenters depending on the starting ketones.This multicomponent reaction proceeded with high diastereoselectivity(dr>20:1)based on a combined~1 H NMR,crystallographic and supercritical fluid chromatographic(SFC)analysis of the product.Time-dependent high-resolution mass spectrometry(HRMS)was performed to track the reaction process,and several key intermediates were identified,leading to the drawing of a plausible reaction mechanism.Density functional theory(DFT)calculation was supplemented,and two reaction pathways were differentiated.Moreover,in vitro antitumor activity was evaluated using HeLa and HepG2 cell lines,and two of these polyheterocycles demonstrated promising activities against HepG2 cells with EC50 down to 10μmol/L.Additionally,ESI-MS/MS studies on all the polyheterocycles suggest a common fragmentation pathway(loss of one molecule of amino-triazole)they shared,providing the first-hand fragmentation rules for future rapid structural identification of them.The multicomponent domino reaction presented here may offer prospects for future design of more efficient strategies to access medicinally important bridged polyheterocycles.
文摘Two bridged purine dinucleosides, bis(2-N-acetyl-6-N-alkylylene-2,6-diaminopurine-2',3',5'-triacetyl-beta-D-ribofuranoside), were synthesized fi om the reaction of the key medium 3, 2-acetylamino-6-[1-(1,2,4-triazolyl)]-purine-2',3',5'-triacetyl-beta-D-ribofuranoside with dialkylamine.
文摘The heterobinuclear complex of formula Cu (oxap )Gd(phen)2 (CIO4 )3 has been synthesized, where oxap denotes the N, N'-bis (2-aminopropyl )oxamido dianion and phen represents 1,10-phenanthroline. The complex was characterized with ESR and variable temperature magnetic susceptibility (4- 300K). The least-squares fit of the experimental sosceptibilities yielded J=2. 25cm-1. The observed Gd (Ⅲ)-Cu (Ⅱ) coupling is ferromagnetic.One Plausible mechanism that can cause a ferromagnetic coupling between Gd(Ⅱ) and Cu (Ⅱ) is discussed in terms of spin-polarization.
