Additives are frequently utilized to tackle dendrite and corrosion problems haunting zinc anode,thanks to their abundant functional groups.However,the relationship between functional groups geometric structures of add...Additives are frequently utilized to tackle dendrite and corrosion problems haunting zinc anode,thanks to their abundant functional groups.However,the relationship between functional groups geometric structures of additives and their working mechanisms stays rarely focused.Herein,in this work,through comparatively study cucurbit[6]uril (CB[6]) and cucurbit[8]uril (CB[8]) as additive,we reveal the critical role of functional groups structures in achieving solvation and interface chemistry regulations for advanced aqueous zinc-metal batteries(AZMBs).Bestowed with abundant carbonyl groups and characteristic cavity structure,both CB molecules enhance the electrolyte stability via reshaping hydrogen bond network.Besides,they both preferentially adsorb on Zn anode to induce a N-containing functional solid electrolyte interphase (SEI) to suppress corrosions.Still,among the two,CB[6] demonstrates more effective in solvation regulations.With its optimized cavity size and carbonyl oxygen spacing,higher nucleophilicity is obtained and bidentate coordination is achieved with enhanced control over Zn^(2+)deposition guidance,contributing to a dendritefree Zn anode.As a result,CB[6] delivers exceptional performance,achieving a cycle life exceeding 5000 h and maintaining high capacity retention over 1000 cycles in PANI//Zn full cells.This work highlights the critical role of functional group geometric structures in additive design,providing a theoretical basis for the development of advanced multifunctional additives for AZMBs.展开更多
The bidentate phosphine oxide ligand 1,8-bis(diphenylphosphino) naphthalene oxide (NAPO) and its EuⅢ complex 1 Eu(TTA)3(NAPO) (TTA=2-thenoyltrifluoroacetonate) were chosen to study the effect of bidentate phosphine o...The bidentate phosphine oxide ligand 1,8-bis(diphenylphosphino) naphthalene oxide (NAPO) and its EuⅢ complex 1 Eu(TTA)3(NAPO) (TTA=2-thenoyltrifluoroacetonate) were chosen to study the effect of bidentate phosphine oxide ligand on the photophysical properties of the corresponding complex. The intramolecular energy transfer processes of 1 were studied. The investigation showed that with bidentate structure NAPO could suppress solvent-induced quenching by enforcing the ligand-ligand interaction and the rigidi...展开更多
Copolymer of 2-vinylpyridine and vinylacetate coordinated with dicarbonylrhodium used as a catalyst for carbonylation of methanol to acetic acid and anhydride has been studied. The structural characteristics of the co...Copolymer of 2-vinylpyridine and vinylacetate coordinated with dicarbonylrhodium used as a catalyst for carbonylation of methanol to acetic acid and anhydride has been studied. The structural characteristics of the copolymer ligand and complex, and the influences of the reaction conditions on the carbonylation catalyzed by this polymer complex have been investigated. In comparison with small molecule catalyst of Rh complex, the bidentate copolymer coordinated complex has better thermal stability. The reaction mechanism of the carbonylation reaction is also illustrated.展开更多
The catalytic property of propylene dimerization by several nickel (Ⅱ), cobalt (Ⅱ) complexes containing N-P bidentate ligands was studied in combination with organoaluminum co-catalysts. The effects of the type of a...The catalytic property of propylene dimerization by several nickel (Ⅱ), cobalt (Ⅱ) complexes containing N-P bidentate ligands was studied in combination with organoaluminum co-catalysts. The effects of the type of aluminum co-catalysts and its relative amount, the nature of precursors in terms of ligand backbone and metal center were investigated. The results indicated that precursor I (N,N-dimethyl-2-(diphenylphosphino)aniline nickel (Ⅱ) dichloride) exhibited high activity in propylene dimerization in the presence of the strong Lewis acid Et3Al2Cl3, whereas low productivity by its cobalt analogues was observed under identical reaction conditions.展开更多
The title complex N,O-bis{[2-[（2,4-dimethylphenyl）imino]-5-methoxyl]-phenol}-palladium（Ⅱ）（CC_（32）H_（32）N_2O_4Pd） has been synthesized by the reaction of 2-[（2,4-dimethylphenyl）imino]-5-methoxyl-phenol wit...The title complex N,O-bis{[2-[（2,4-dimethylphenyl）imino]-5-methoxyl]-phenol}-palladium（Ⅱ）（CC_（32）H_（32）N_2O_4Pd） has been synthesized by the reaction of 2-[（2,4-dimethylphenyl）imino]-5-methoxyl-phenol with Pd（CH_3COO）_2,and characterized by elemental analysis,IR spectrum and single-crystal X-ray diffraction analysis.The crystal belongs to the monoclinic system,space group P2_1/c with a = 12.058（2）,b = 8.3624（17）,c = 14.735（3） ？,β = 107.66（3）°,V = 1415.7（5）？~3,C_（32）H_（32）N_2O_4Pd,Mr = 615,Z = 2,D_c = 1.443 Mg/m^3,μ = 0.695 mm^（-1）,F（000） = 632,T = 293（2） K,the final R = 0.0514 and w R = 0.1356（I 〉 2s（I））.Under the co-catalysis of methylaluminoxane（MAO）,the palladium compound exhibited favorable catalytic activity for the polymerization of norbornene（NB）.展开更多
In this study,we investigated improving the performance of a layered double hydroxide(LDH)for the adsorption of As(III)and As(V)by controlling the morphology of LDH crystals.The LDH was synthesized via a simple coprec...In this study,we investigated improving the performance of a layered double hydroxide(LDH)for the adsorption of As(III)and As(V)by controlling the morphology of LDH crystals.The LDH was synthesized via a simple coprecipitation method using barely soluble MgO as a precursor and succinic acid(SA)as a morphological control agent.Doping the LDH crystals with carboxylate ions(RCOO−)derived from SA caused the crystals to develop in a radial direction.This changed the pore characteristics and increased the density of active surface sites.Subsequently,SA/MgFe-LDH showed excellent affinity for As(III)and As(V)with maximum sorption densities of 2.42 and 1.60 mmol/g,respectively.By comparison,the pristine MgFe-LDH had sorption capacities of 1.56 and 1.31 mmol/g for As(III)and As(V),respectively.The LDH was effective over a wide pH range for As(III)adsorption(pH 3-8.5)and As(V)adsorption(pH 3-6.5).Using a combination of spectroscopy and sorption modeling calculations,the main sorption mechanism of As(III)and As(V)on SA/MgFe-LDH was identified as inner-sphere complexation via ligand exchangewith hydroxyl group(-OH)and RCOO−.Specifically,bidentate As-Fe complexeswere proposed for both As(III)and As(V)uptake,with the magnitude of formation varying with the initial As concentration.Importantly,the As-laden adsorbent had satisfactory stability in simulated real landfill leachate.These findings demonstrate that SA/MgFe-LDH exhibits considerable potential for remediation of As-contaminated water.展开更多
Main observation and conclusion A set of Pd-catalyzed ortho-directed C-H glycosylation reactions with glycosyl chloride donors using various N-linked bidentate auxil-iaries has been developed for synthesis of C-arygly...Main observation and conclusion A set of Pd-catalyzed ortho-directed C-H glycosylation reactions with glycosyl chloride donors using various N-linked bidentate auxil-iaries has been developed for synthesis of C-aryglycosides.A broad range of pyranose and furanose moieties can be installed on the ortho position of arylamine,carbazole,indole and benzylamine type substrates in high yield and with high regio-and diastereoselec-tivity.These auxiliaries can be readily installed and removed under relatively mild conditions.展开更多
A new complex formed from strontium nitrate and 1,8-naphthyridine-N-oxide with a 1:2 stoichiometry has been synthesized and characterized by elemental analyses, infrared spectra, Raman spectra, fluorescence spectra, D...A new complex formed from strontium nitrate and 1,8-naphthyridine-N-oxide with a 1:2 stoichiometry has been synthesized and characterized by elemental analyses, infrared spectra, Raman spectra, fluorescence spectra, DTA-TG, solubility and molar conductance measurements. A single crystal X-ray structural analysis indicates that a kind of double bidentate and bridging nitrate group which has never been reported in literature is present in the new complex. The coordination number of the strontium ion is 10.展开更多
The reactions of 1,3-dinitro-2-chloro-5-trifluorotoluene(DNCTT)(1)and its bridged com- pounds with bidentate nucleophiles have been investigated.Primary or secondary diamines and diethylene glycol react with 1 and its...The reactions of 1,3-dinitro-2-chloro-5-trifluorotoluene(DNCTT)(1)and its bridged com- pounds with bidentate nucleophiles have been investigated.Primary or secondary diamines and diethylene glycol react with 1 and its bridged derivatives by replacing the substituent grouppara to CF_3, whereas ethanedithiol reacts either by replacing the substituent group para to CF_3 or by displacing both groups and a nitro group.The results have been rationalized in terms of electronic effects and nucleophilicity of the nucleophiles.展开更多
By allowing H_(2)SeO_(4),Cy_(2)NH,CyNH_(2) or Bz2NH to react respectively with SnPh_(3)Cl(in methanol),SnPh_(2)Cl_(2)(in water+methanol)and MgCl_(2)·6H_(2)O(in methanol)in specific ratios,the studied complexes ar...By allowing H_(2)SeO_(4),Cy_(2)NH,CyNH_(2) or Bz2NH to react respectively with SnPh_(3)Cl(in methanol),SnPh_(2)Cl_(2)(in water+methanol)and MgCl_(2)·6H_(2)O(in methanol)in specific ratios,the studied complexes are obtained.The suggested structures are discrete and polymer,the environment of the tin center being trans trigonal bipyramidal(compound 1),tetrahedral(compound 2)and octahedral(compound 3),the anions behaving as a bidentate selenate.展开更多
The mechanism of dimethyl carbonate（DMC） formation from CO2 and methanol is investigated using three well-shaped CeO2 catalysts, nanorod, nanocube and octahedron, which are packed with different crystal planes. In s...The mechanism of dimethyl carbonate（DMC） formation from CO2 and methanol is investigated using three well-shaped CeO2 catalysts, nanorod, nanocube and octahedron, which are packed with different crystal planes. In situ Fourier Transform Infrared Spectroscopy（FTIR） is employed to probe each reaction step in the DMC synthesis. The number of –OH groups and the species of CO2 adsorptions on ceria surface have significant influence on the activity of ceria with different morphologies. Rod-ceria has favorable catalytic activity because of the large amount of –OH groups and the formation of bidentate carbonate species.展开更多
A series of MnMgA10 samples with different amounts of Ce doping were facilely prepared using coprecipitation method and their catalytic soot combustion activity was evaluated by temperature programmed oxidation reacti...A series of MnMgA10 samples with different amounts of Ce doping were facilely prepared using coprecipitation method and their catalytic soot combustion activity was evaluated by temperature programmed oxidation reaction （TPO）. The methods of X-ray diffraction （XRD）, Brumauer-Emmett-Teller （BET）, H2-TPR, NO-TPO and in situ 1R were used to characterize the physio- chemical properties of these samples. Dopant Ce improved the soot combustion performance of MnMgA10 catalyst due to the en- hanced redox ability. Introduction of NOx led to the further increase of catalytic soot oxidation activity on these samples. Over Ce-containing samples, the catalytic activity was slightly decreased as the amount of dopant Ce increased in 02. Diftbrently, in NO＋O2, a certain amount of dopant Ce was much more favorable and excess amount of Ce resulted in a sharp drop of the catalytic soot combustion activity. Both NO： and nitrates were found to have great contributions to the effects of NOx on the soot combustion activity of Ce-doped catalysts. More NO2 was generated as dopant Ce increased. When appropriate amount of Ce was introduced, the as-formed NO2 was stored as bridging bidentate nitrate on Mn-Ce site, which was confirmed to have higher reactivity with soot than nitrite or monodentate nitrate on Mn and/or Ce sites. Overall, Mno.sMg2.sCeo.lAlo.90 was considered as the most potential catalyst for soot combustion.展开更多
It has recently been proposed that recalcitrant dissolved organic carbon(DOC) in groundwater plays a potent etiological role in the peculiar distribution of chronic kidney disease of unknown etiology(CKDu).This study ...It has recently been proposed that recalcitrant dissolved organic carbon(DOC) in groundwater plays a potent etiological role in the peculiar distribution of chronic kidney disease of unknown etiology(CKDu).This study aims to elucidate the interactions of Ca^2+and SO4^2-with a model organic fraction of humic acid(SHA) to determine the possible relationship of CKDu incidence with the DOC in drinking water.XPS and FT-IR methods respectively determined the surface functional groups and chemical composition of protonated dissolved organic carbon(HDOC) in a CKDu high-risk zone(HR) of Sri Lanka and in SHA.Higher surface C composition(87.9%) and lower O(11.4%) were observed for HDOC from the HR region than for SHA(C: 73.8%, O: 24.7%).Aromatic C with less Ocontaining functional groups was observed in HDOC.The IR band at 1170 cm^-1 confirms the formation of organic sulfonate(C–SO3^-) on SHA.A band at 1213 cm^-1 due to organic sulfonate in HDOC from the CKDu HR region was also identified.The IR band at 866 cm^-1 evidenced the formation of CaCO3 on SHA above pH 7.4.XPS data confirmed the presence of sulfur oxidation states corresponding to SO3^2-and SO4^2-at 168.9 eV and 170.1 eV binding energies,respectively.The binding energies at 347 eV and 351 eV for Ca 2p3/2 and Ca 2p1/2 eV,respectively, confirmed the bidentate complexation of Ca^2+with COO-and sulfonate groups on SHA.The organic sulfonate formed is postulated as a uremic toxicant.展开更多
The catalytic properties of a series of (dppe) MCl2 [M = Fe(II), Co(II), Ni(II)] in combination with EAO (ethylaluminoxane) for ethylene oligomerization have been investigated. Treatment of the bidentate phosphine met...The catalytic properties of a series of (dppe) MCl2 [M = Fe(II), Co(II), Ni(II)] in combination with EAO (ethylaluminoxane) for ethylene oligomerization have been investigated. Treatment of the bidentate phosphine metal complexes with EAO in toluene generated in situ active catalysts which catalyze oligomerizaton of ethylene to low-carbon olefins. The effects of reaction temperature, ratios of n(Al) : n(M) and reaction periods on catalytic activity and product distribution have been studied. The activity of cobalt complex with EAO at 200C was 4021 g/g(Co)h, and the selectivity of C4-10 olefins is 95.5%.展开更多
Coordination polymer {[Cu（NPPCA）3（NO3）（H20）]-NOyH20}n 1 （ NPPCA = N-（4＇- nitrophenyl）-4-pyridinecarboxamide） has been synthesized by the reaction of NPPCA with copper（H） nitrate in ethanol-water solution ...Coordination polymer {[Cu（NPPCA）3（NO3）（H20）]-NOyH20}n 1 （ NPPCA = N-（4＇- nitrophenyl）-4-pyridinecarboxamide） has been synthesized by the reaction of NPPCA with copper（H） nitrate in ethanol-water solution and characterized by X-ray diffraction. 1 crystallizes in the monoclinic space, group P21/n, a = 17.341（6）A, b = 6.744（2）A, c = 34.555（12）A, β = 100.493（6）°, V = 3974（2） A^3, Z = 4. Each copper（H） ion has a distorted octahedral coordination geometry. Nitrate anion adopts the unusual coordination mode linking two adjacent copper（H） ions to form a one-dimensional coordination polymer and these chains are further linked by noncovalent interactions.展开更多
Coordination behavior of bidentate ligand ethylenediamine with a new chiral zine bisporphyrin O.O-C,-AA-C,-(TPP),Zn, was investigated by Uv-Vis titration and 'H-NMRspectroscopy. which further evidenced that ac-c,-...Coordination behavior of bidentate ligand ethylenediamine with a new chiral zine bisporphyrin O.O-C,-AA-C,-(TPP),Zn, was investigated by Uv-Vis titration and 'H-NMRspectroscopy. which further evidenced that ac-c,-AA-c,-(TPP)Zn, tends to form linear assemblywith ethylenediamine in chloroform.展开更多
Design and synthesis of organic chelating agents containing nitrogen and sulfur as donor atoms and their metal complexes is an interesting field of research for their different types of activities. The bi-dentate N,N ...Design and synthesis of organic chelating agents containing nitrogen and sulfur as donor atoms and their metal complexes is an interesting field of research for their different types of activities. The bi-dentate N,N chelating agent such as 2,2-Bipyridal has been playing a vital role in synthetic and medicinal chemistry. 2,2-Bipyridal has been used to prepare many mixed-ligand complexes. Different ligand complexes prepared from 2,2-Bipyridyl are used in different areas such as molecular catalysis, solar energy conversion, calorimetric analysis, herbicides, molecular recognition, self-assembly, antineoplastic agents, and nucleic acid probes. Another important property of these types of compounds is the triplet state photosensitizing character of bipyridyl nucleus, which is shown in metal complexes. It is also found that compounds containing O,S,N atoms have received considerable attention because of their pharmacological studies like anticancer, antibacterial, and antitumour activities. Therefore, it has been decided to synthesize Schiff bases derived from 2,2’- bipyridyl-5,5’-dicarbaldehyde compounds with O,S,N and F-containing amines and study their antibacterial properties. Several new Schiff bases have been synthesized and fully characterized by spectral data. This paper presents the synthesis and characterization of newly designed Schiff bases.展开更多
成语a tooth for a tooth经常跟在an eye for an eye后面连用,汉语成语“以眼还眼,以牙还牙”就是从英语翻译过来的译借词语。表示“牙齿”的tooth是单数名词,它的复数形式是teeth;这种不规则的名词变化形式在英语中还有单数的foot(脚)...成语a tooth for a tooth经常跟在an eye for an eye后面连用,汉语成语“以眼还眼,以牙还牙”就是从英语翻译过来的译借词语。表示“牙齿”的tooth是单数名词,它的复数形式是teeth;这种不规则的名词变化形式在英语中还有单数的foot(脚)和复数的feet。至于单数名词food(食物)的一个对立形式feed就是个动词了,表示“喂食”的意思。由tooth构成的复合词很多,例如:toothache(牙痛),tooth-brush(牙刷),toothcomb(细齿梳),toothglass(漱口杯),展开更多
基金financially supported by the National Natural Science Foundation of China(Nos.52403048 and 52402267)Natural Science Foundation of Jiangsu Province(No.BK20241497)+2 种基金Research Start-up fund of Xihua university(Z221035)Xihua University Science and Technology Innovation Competition Project for Postgraduate Students(Nos.YK20240028,YK20240045,and YK20240075)the Opening Project of State Key Laboratory of Polymer Materials Engineering(Sichuan University)(No.sklpme2023-3-9)
文摘Additives are frequently utilized to tackle dendrite and corrosion problems haunting zinc anode,thanks to their abundant functional groups.However,the relationship between functional groups geometric structures of additives and their working mechanisms stays rarely focused.Herein,in this work,through comparatively study cucurbit[6]uril (CB[6]) and cucurbit[8]uril (CB[8]) as additive,we reveal the critical role of functional groups structures in achieving solvation and interface chemistry regulations for advanced aqueous zinc-metal batteries(AZMBs).Bestowed with abundant carbonyl groups and characteristic cavity structure,both CB molecules enhance the electrolyte stability via reshaping hydrogen bond network.Besides,they both preferentially adsorb on Zn anode to induce a N-containing functional solid electrolyte interphase (SEI) to suppress corrosions.Still,among the two,CB[6] demonstrates more effective in solvation regulations.With its optimized cavity size and carbonyl oxygen spacing,higher nucleophilicity is obtained and bidentate coordination is achieved with enhanced control over Zn^(2+)deposition guidance,contributing to a dendritefree Zn anode.As a result,CB[6] delivers exceptional performance,achieving a cycle life exceeding 5000 h and maintaining high capacity retention over 1000 cycles in PANI//Zn full cells.This work highlights the critical role of functional group geometric structures in additive design,providing a theoretical basis for the development of advanced multifunctional additives for AZMBs.
基金Project supported by the National Natural Science Foundation of China (90406021, 50903028)Science and Technology Bureau of Heilongjiang Province (QC08C10)
文摘The bidentate phosphine oxide ligand 1,8-bis(diphenylphosphino) naphthalene oxide (NAPO) and its EuⅢ complex 1 Eu(TTA)3(NAPO) (TTA=2-thenoyltrifluoroacetonate) were chosen to study the effect of bidentate phosphine oxide ligand on the photophysical properties of the corresponding complex. The intramolecular energy transfer processes of 1 were studied. The investigation showed that with bidentate structure NAPO could suppress solvent-induced quenching by enforcing the ligand-ligand interaction and the rigidi...
文摘Copolymer of 2-vinylpyridine and vinylacetate coordinated with dicarbonylrhodium used as a catalyst for carbonylation of methanol to acetic acid and anhydride has been studied. The structural characteristics of the copolymer ligand and complex, and the influences of the reaction conditions on the carbonylation catalyzed by this polymer complex have been investigated. In comparison with small molecule catalyst of Rh complex, the bidentate copolymer coordinated complex has better thermal stability. The reaction mechanism of the carbonylation reaction is also illustrated.
文摘The catalytic property of propylene dimerization by several nickel (Ⅱ), cobalt (Ⅱ) complexes containing N-P bidentate ligands was studied in combination with organoaluminum co-catalysts. The effects of the type of aluminum co-catalysts and its relative amount, the nature of precursors in terms of ligand backbone and metal center were investigated. The results indicated that precursor I (N,N-dimethyl-2-(diphenylphosphino)aniline nickel (Ⅱ) dichloride) exhibited high activity in propylene dimerization in the presence of the strong Lewis acid Et3Al2Cl3, whereas low productivity by its cobalt analogues was observed under identical reaction conditions.
基金Supported by the Natural Science Foundation of Fujian Province(2010J01026)the Ministry of Education of China(No.208066)+1 种基金the Education Department of Fujian Province(JA07029)the State Key Laboratory of Structural Chemistry(No.20130013)
文摘The title complex N,O-bis{[2-[（2,4-dimethylphenyl）imino]-5-methoxyl]-phenol}-palladium（Ⅱ）（CC_（32）H_（32）N_2O_4Pd） has been synthesized by the reaction of 2-[（2,4-dimethylphenyl）imino]-5-methoxyl-phenol with Pd（CH_3COO）_2,and characterized by elemental analysis,IR spectrum and single-crystal X-ray diffraction analysis.The crystal belongs to the monoclinic system,space group P2_1/c with a = 12.058（2）,b = 8.3624（17）,c = 14.735（3） ？,β = 107.66（3）°,V = 1415.7（5）？~3,C_（32）H_（32）N_2O_4Pd,Mr = 615,Z = 2,D_c = 1.443 Mg/m^3,μ = 0.695 mm^（-1）,F（000） = 632,T = 293（2） K,the final R = 0.0514 and w R = 0.1356（I 〉 2s（I））.Under the co-catalysis of methylaluminoxane（MAO）,the palladium compound exhibited favorable catalytic activity for the polymerization of norbornene（NB）.
文摘In this study,we investigated improving the performance of a layered double hydroxide(LDH)for the adsorption of As(III)and As(V)by controlling the morphology of LDH crystals.The LDH was synthesized via a simple coprecipitation method using barely soluble MgO as a precursor and succinic acid(SA)as a morphological control agent.Doping the LDH crystals with carboxylate ions(RCOO−)derived from SA caused the crystals to develop in a radial direction.This changed the pore characteristics and increased the density of active surface sites.Subsequently,SA/MgFe-LDH showed excellent affinity for As(III)and As(V)with maximum sorption densities of 2.42 and 1.60 mmol/g,respectively.By comparison,the pristine MgFe-LDH had sorption capacities of 1.56 and 1.31 mmol/g for As(III)and As(V),respectively.The LDH was effective over a wide pH range for As(III)adsorption(pH 3-8.5)and As(V)adsorption(pH 3-6.5).Using a combination of spectroscopy and sorption modeling calculations,the main sorption mechanism of As(III)and As(V)on SA/MgFe-LDH was identified as inner-sphere complexation via ligand exchangewith hydroxyl group(-OH)and RCOO−.Specifically,bidentate As-Fe complexeswere proposed for both As(III)and As(V)uptake,with the magnitude of formation varying with the initial As concentration.Importantly,the As-laden adsorbent had satisfactory stability in simulated real landfill leachate.These findings demonstrate that SA/MgFe-LDH exhibits considerable potential for remediation of As-contaminated water.
基金G.C.thanks NSFC-91753124,NSFC-21672105,NSFC-21421062,and NSFC-21725204 for financial support of this work.
文摘Main observation and conclusion A set of Pd-catalyzed ortho-directed C-H glycosylation reactions with glycosyl chloride donors using various N-linked bidentate auxil-iaries has been developed for synthesis of C-aryglycosides.A broad range of pyranose and furanose moieties can be installed on the ortho position of arylamine,carbazole,indole and benzylamine type substrates in high yield and with high regio-and diastereoselec-tivity.These auxiliaries can be readily installed and removed under relatively mild conditions.
文摘A new complex formed from strontium nitrate and 1,8-naphthyridine-N-oxide with a 1:2 stoichiometry has been synthesized and characterized by elemental analyses, infrared spectra, Raman spectra, fluorescence spectra, DTA-TG, solubility and molar conductance measurements. A single crystal X-ray structural analysis indicates that a kind of double bidentate and bridging nitrate group which has never been reported in literature is present in the new complex. The coordination number of the strontium ion is 10.
文摘The reactions of 1,3-dinitro-2-chloro-5-trifluorotoluene(DNCTT)(1)and its bridged com- pounds with bidentate nucleophiles have been investigated.Primary or secondary diamines and diethylene glycol react with 1 and its bridged derivatives by replacing the substituent grouppara to CF_3, whereas ethanedithiol reacts either by replacing the substituent group para to CF_3 or by displacing both groups and a nitro group.The results have been rationalized in terms of electronic effects and nucleophilicity of the nucleophiles.
文摘By allowing H_(2)SeO_(4),Cy_(2)NH,CyNH_(2) or Bz2NH to react respectively with SnPh_(3)Cl(in methanol),SnPh_(2)Cl_(2)(in water+methanol)and MgCl_(2)·6H_(2)O(in methanol)in specific ratios,the studied complexes are obtained.The suggested structures are discrete and polymer,the environment of the tin center being trans trigonal bipyramidal(compound 1),tetrahedral(compound 2)and octahedral(compound 3),the anions behaving as a bidentate selenate.
基金Financial support by Natural Science Foundation of China (NSFC) (Nos. 21325626, 21176179, U1510203)the Program for New Century Excellent Talents in University (No. NCET-13-0411)the Program of Introducing Talents of Discipline to Universities (No. B06006)
文摘The mechanism of dimethyl carbonate（DMC） formation from CO2 and methanol is investigated using three well-shaped CeO2 catalysts, nanorod, nanocube and octahedron, which are packed with different crystal planes. In situ Fourier Transform Infrared Spectroscopy（FTIR） is employed to probe each reaction step in the DMC synthesis. The number of –OH groups and the species of CO2 adsorptions on ceria surface have significant influence on the activity of ceria with different morphologies. Rod-ceria has favorable catalytic activity because of the large amount of –OH groups and the formation of bidentate carbonate species.
基金supported by National Natural Science Foundation of China(21107030,21277060,21077043)the Foundation for Outstanding Young Scientist in Shandong Province(BS2011HZ002)
文摘A series of MnMgA10 samples with different amounts of Ce doping were facilely prepared using coprecipitation method and their catalytic soot combustion activity was evaluated by temperature programmed oxidation reaction （TPO）. The methods of X-ray diffraction （XRD）, Brumauer-Emmett-Teller （BET）, H2-TPR, NO-TPO and in situ 1R were used to characterize the physio- chemical properties of these samples. Dopant Ce improved the soot combustion performance of MnMgA10 catalyst due to the en- hanced redox ability. Introduction of NOx led to the further increase of catalytic soot oxidation activity on these samples. Over Ce-containing samples, the catalytic activity was slightly decreased as the amount of dopant Ce increased in 02. Diftbrently, in NO＋O2, a certain amount of dopant Ce was much more favorable and excess amount of Ce resulted in a sharp drop of the catalytic soot combustion activity. Both NO： and nitrates were found to have great contributions to the effects of NOx on the soot combustion activity of Ce-doped catalysts. More NO2 was generated as dopant Ce increased. When appropriate amount of Ce was introduced, the as-formed NO2 was stored as bridging bidentate nitrate on Mn-Ce site, which was confirmed to have higher reactivity with soot than nitrite or monodentate nitrate on Mn and/or Ce sites. Overall, Mno.sMg2.sCeo.lAlo.90 was considered as the most potential catalyst for soot combustion.
基金supported by the Joint Research Program of National Natural Science Foundation, ChinaNational Science Foundation, Sri Lanka (NSFC-NSF SL) (No.21861142020)+1 种基金the Program of China–Sri Lanka Joint Research and Demonstration Center for Water Technology and China– Sri Lanka Joint Center for Education and Research by Chinese Academy of Sciences, Chinathe Chinese Academy of Sciences–The World Academy of Sciences (CAS–TWAS) President’s Fellowship Program for International Ph.D.students.
文摘It has recently been proposed that recalcitrant dissolved organic carbon(DOC) in groundwater plays a potent etiological role in the peculiar distribution of chronic kidney disease of unknown etiology(CKDu).This study aims to elucidate the interactions of Ca^2+and SO4^2-with a model organic fraction of humic acid(SHA) to determine the possible relationship of CKDu incidence with the DOC in drinking water.XPS and FT-IR methods respectively determined the surface functional groups and chemical composition of protonated dissolved organic carbon(HDOC) in a CKDu high-risk zone(HR) of Sri Lanka and in SHA.Higher surface C composition(87.9%) and lower O(11.4%) were observed for HDOC from the HR region than for SHA(C: 73.8%, O: 24.7%).Aromatic C with less Ocontaining functional groups was observed in HDOC.The IR band at 1170 cm^-1 confirms the formation of organic sulfonate(C–SO3^-) on SHA.A band at 1213 cm^-1 due to organic sulfonate in HDOC from the CKDu HR region was also identified.The IR band at 866 cm^-1 evidenced the formation of CaCO3 on SHA above pH 7.4.XPS data confirmed the presence of sulfur oxidation states corresponding to SO3^2-and SO4^2-at 168.9 eV and 170.1 eV binding energies,respectively.The binding energies at 347 eV and 351 eV for Ca 2p3/2 and Ca 2p1/2 eV,respectively, confirmed the bidentate complexation of Ca^2+with COO-and sulfonate groups on SHA.The organic sulfonate formed is postulated as a uremic toxicant.
文摘The catalytic properties of a series of (dppe) MCl2 [M = Fe(II), Co(II), Ni(II)] in combination with EAO (ethylaluminoxane) for ethylene oligomerization have been investigated. Treatment of the bidentate phosphine metal complexes with EAO in toluene generated in situ active catalysts which catalyze oligomerizaton of ethylene to low-carbon olefins. The effects of reaction temperature, ratios of n(Al) : n(M) and reaction periods on catalytic activity and product distribution have been studied. The activity of cobalt complex with EAO at 200C was 4021 g/g(Co)h, and the selectivity of C4-10 olefins is 95.5%.
基金This project is supported by the Natural Science Foundation of Education Bureau of Liaoning Province,China.
文摘Coordination polymer {[Cu（NPPCA）3（NO3）（H20）]-NOyH20}n 1 （ NPPCA = N-（4＇- nitrophenyl）-4-pyridinecarboxamide） has been synthesized by the reaction of NPPCA with copper（H） nitrate in ethanol-water solution and characterized by X-ray diffraction. 1 crystallizes in the monoclinic space, group P21/n, a = 17.341（6）A, b = 6.744（2）A, c = 34.555（12）A, β = 100.493（6）°, V = 3974（2） A^3, Z = 4. Each copper（H） ion has a distorted octahedral coordination geometry. Nitrate anion adopts the unusual coordination mode linking two adjacent copper（H） ions to form a one-dimensional coordination polymer and these chains are further linked by noncovalent interactions.
文摘Coordination behavior of bidentate ligand ethylenediamine with a new chiral zine bisporphyrin O.O-C,-AA-C,-(TPP),Zn, was investigated by Uv-Vis titration and 'H-NMRspectroscopy. which further evidenced that ac-c,-AA-c,-(TPP)Zn, tends to form linear assemblywith ethylenediamine in chloroform.
文摘Design and synthesis of organic chelating agents containing nitrogen and sulfur as donor atoms and their metal complexes is an interesting field of research for their different types of activities. The bi-dentate N,N chelating agent such as 2,2-Bipyridal has been playing a vital role in synthetic and medicinal chemistry. 2,2-Bipyridal has been used to prepare many mixed-ligand complexes. Different ligand complexes prepared from 2,2-Bipyridyl are used in different areas such as molecular catalysis, solar energy conversion, calorimetric analysis, herbicides, molecular recognition, self-assembly, antineoplastic agents, and nucleic acid probes. Another important property of these types of compounds is the triplet state photosensitizing character of bipyridyl nucleus, which is shown in metal complexes. It is also found that compounds containing O,S,N atoms have received considerable attention because of their pharmacological studies like anticancer, antibacterial, and antitumour activities. Therefore, it has been decided to synthesize Schiff bases derived from 2,2’- bipyridyl-5,5’-dicarbaldehyde compounds with O,S,N and F-containing amines and study their antibacterial properties. Several new Schiff bases have been synthesized and fully characterized by spectral data. This paper presents the synthesis and characterization of newly designed Schiff bases.
文摘成语a tooth for a tooth经常跟在an eye for an eye后面连用,汉语成语“以眼还眼,以牙还牙”就是从英语翻译过来的译借词语。表示“牙齿”的tooth是单数名词,它的复数形式是teeth;这种不规则的名词变化形式在英语中还有单数的foot(脚)和复数的feet。至于单数名词food(食物)的一个对立形式feed就是个动词了,表示“喂食”的意思。由tooth构成的复合词很多,例如:toothache(牙痛),tooth-brush(牙刷),toothcomb(细齿梳),toothglass(漱口杯),
