Syngas to aromatics(STA)over bifunctional catalysts has attracted much attention in recent years,but the mechanism underlying the formation of aromatics remains controversial.The critical reaction intermediates,carbox...Syngas to aromatics(STA)over bifunctional catalysts has attracted much attention in recent years,but the mechanism underlying the formation of aromatics remains controversial.The critical reaction intermediates,carboxylates,were first identified and then confirmed to essentially promote aromatization in the syngas conversion over a ZnCrAlO_(x)&H-ZSM-5 composite catalyst.This study provides evidence that the carboxylates can be formed during the reactions of formate species and olefins.In addition,it is shown that the carboxylates favor the formation of aromatics over H-ZSM-5 even in the presence of H2.A novel mechanism for the formation of aromatics via the generation and transformation of carboxylate intermediates is proposed,and the transformation of carboxylates to aromatics via methyl-2-cyclopenten-1-one(MCPO)intermediates is indeed likely.A better understanding of the formation mechanism of aromatics would help optimize the composite catalyst.展开更多
Nano-sized caiboxylales Na2C7H3NO4 and Na2C6H2N2O4 were prepared and investigated as anode materials for lithium-ion batteries.Both carboxylates exhibit high reversible capacities around 190 mAh/g above a cut-off volt...Nano-sized caiboxylales Na2C7H3NO4 and Na2C6H2N2O4 were prepared and investigated as anode materials for lithium-ion batteries.Both carboxylates exhibit high reversible capacities around 190 mAh/g above a cut-off voltage of 0.8 V vs.Li＋/Li.potentially improving the safety of the batteries.In addition,good rate performance and long cycle life of these carboxylates make them promising candidates as anode materials for lithium-ion batteries.展开更多
Vitamin B12 was applied as catalyst for the one-pot three-component synthesis of 3,4,5-trisubstituted furan-2（5H）-ones from the condensation between aldehydes, amines and dialkylacetylendicarboxylates at ambient tem...Vitamin B12 was applied as catalyst for the one-pot three-component synthesis of 3,4,5-trisubstituted furan-2（5H）-ones from the condensation between aldehydes, amines and dialkylacetylendicarboxylates at ambient temperature in Et OH. In addition, N-aryl-3-aminodihydropyrrol-2-one-4-carboxylates were synthesised using mentioned catalyst at ambient temperature in Et OH from condensation between formaldehyde, amines, and dialkylacetylenedicarboxylates. This methodology has number of advantages such as： use of green and nonhazardous catalyst, clean work up, short reaction times,high yields and no need to column chromatography.展开更多
Eight tri(2-methyl-2-phznylpropyl) germylpropionates have been synthesized. and their structures were characterized by elemental analysis, IR, multinuclear NMR(H-1,C-13.Sn-119) and MS. The spectroscopic studies reveal...Eight tri(2-methyl-2-phznylpropyl) germylpropionates have been synthesized. and their structures were characterized by elemental analysis, IR, multinuclear NMR(H-1,C-13.Sn-119) and MS. The spectroscopic studies revealed that compounds of this type possess a tetrahedral geometry, which have been expected to have good biological activity.展开更多
Three unique metal-organic framework coordination polymers, [Eu_2(bptc)(bdc)_2(H_2O)]_n(1), [Gd_2(bptc)(bdc)_2(H_2O)_4]_n(2) and [Dy_2(bptc)(bdc)_2(H_2O)_4]n(3)(1,2-H_2 BDC = 1,2-benzenedicarboylic acid, H_2 bptc = 4,...Three unique metal-organic framework coordination polymers, [Eu_2(bptc)(bdc)_2(H_2O)]_n(1), [Gd_2(bptc)(bdc)_2(H_2O)_4]_n(2) and [Dy_2(bptc)(bdc)_2(H_2O)_4]n(3)(1,2-H_2 BDC = 1,2-benzenedicarboylic acid, H_2 bptc = 4,4?-biphenyldicarboxylic acid) were synthesized by mixing two different multi-carboxylic acids with Ln2 O3(Ln = Eu, Gd and Dy) in hydrothermal condition. The three compounds are all three-dimensional and compounds 2 and 3 contain 4.289 × 6.507 ?~2 rectangularshaped one-dimensional open channels along the a direction. Additionally, the magnetic, luminescent and thermogravimetric properties were studied in detail.展开更多
A novel and general carbon-nitrogen and carbon-carbon cross-coupling reaction between 3,4-dihydropyrimidine-2-thiones and copper（Ⅰ） carboxylates were performed in the presence of palladium acetate.The copper（Ⅰ） ...A novel and general carbon-nitrogen and carbon-carbon cross-coupling reaction between 3,4-dihydropyrimidine-2-thiones and copper（Ⅰ） carboxylates were performed in the presence of palladium acetate.The copper（Ⅰ） carboxylates act not only as desulfurative reagents but also as sources of carbon nudeophiles.A wide array of highly substituted and functionalized pyrimidines scaffolds were synthesized in good yields.展开更多
Five novel europium(Ⅲ)complexes with 2-[4-(dibutylamino)-2-hydroxybenzoyl]benzoic acid(DAHB)as primary ligand and bathophenanthroline(batho),2,2’-bipyridyl(bipy),5,6-dimethyl-1,10-phenanthroline(dmph),1,10-phenanthr...Five novel europium(Ⅲ)complexes with 2-[4-(dibutylamino)-2-hydroxybenzoyl]benzoic acid(DAHB)as primary ligand and bathophenanthroline(batho),2,2’-bipyridyl(bipy),5,6-dimethyl-1,10-phenanthroline(dmph),1,10-phenanthroline(phen)as ancillary ligands were syn-thesized via solution precipitation method.The structural formulae of synthesized complexes were speculated to be Eu(DABH)_(3)·2H_(2)O(C1),Eu(DABH)_(3)·batho(C2),Eu(DABH)_(3)·bipy(C3),Eu(DABH)_(3)·dmph(C4)and Eu(DABH)_(3)·phen(C5)by elemental analysis,infrared spectroscopy and proton nuclear magnetic resonance spec-troscopy(^(1)H-NMR).The photoluminescent properties and thermal stability of the complexes were investigated by photoluminescent spectroscopy and thermogravimetric analysis(TG-DTG),respectively.The Commission Inter-nationale de I’Eclairage(CIE)color coordinates,Judd–Ofelt intensity parameter(Ω_(2)),total quantum yield,intrinsic quantum efficiency and energy transfer dynamics of com-plexes were also explored.The excitation spectra of com-plexes are extended up to visible region.These complexes exhibit characteristic photoemission of Eu^(3+)metal ion with high color purity in red region attributed to efficient energy transfer from ligand to metal ion.The replacement of water molecules from coordination sphere of europium ion by ancillary ligands results in enhancement of luminescent properties of the C2–C5 complexes,indicating that ancillary ligands act as additional light harvesting centers in sensiti-zation phenomenon.The thermal studies show that these complexes are suitable for meeting the requirement of temperature for fabrication of OLEDs devices.展开更多
In the present study, new series of pyridinium carboxylate protic ionic liquids(PILs) were synthesized by pairing pyridinium cation with carboxylate anion from C_1–C_3 forming pyridinium formate([C_5H_6N^+][HCOO^-]),...In the present study, new series of pyridinium carboxylate protic ionic liquids(PILs) were synthesized by pairing pyridinium cation with carboxylate anion from C_1–C_3 forming pyridinium formate([C_5H_6N^+][HCOO^-]),pyridinium acetate([C_5H_6N^+][CH_3COO^-]) and pyridinium propionate([C_5H_6N^+][CH_3CH_2COO^-]) respectively.The physical properties namely, density, viscosity, surface tension(298.15–343.15) K, and refractive index(293.15–323.15) K were measured. Thermal properties namely, glass transition temperature, molar heat capacity, and thermal decomposition temperatures were also determined. The thermal expansivity was calculated using the experimental density data. The effect of increasing the alkyl chain length on the thermophysical properties of the pyridinium carboxylate PILs has been evaluated. As expected the physical properties i.e. density,viscosity, surface tension and refractive index of the investigated pyridinium carboxylates decreased with increasing temperature. In general pyridinium carboxylate PILs possessed low viscosity, high thermal stability and excellent hydrogen bonding capability, and these properties lead them to outperform conventional solvents employed for lignin dissolution.展开更多
Methods of optical spectroscopy and X-ray crystallography data were used to examine the effect of architecture of carboxylate anions on structure of the Eu3＋ coordination centre in europium earboxylates with 1,10-phe...Methods of optical spectroscopy and X-ray crystallography data were used to examine the effect of architecture of carboxylate anions on structure of the Eu3＋ coordination centre in europium earboxylates with 1,10-phenanthroline Eu（RCOO）3·Phen. Luminescence spectra of europium acetate, nitropropionate, benzoate, naphthylcarboxylates, phenylacetates, phenoxyacetate, triphenylpropionate were investigated. A few of europium carboxylates with 2,2＇-bipyridine Eu（RCOO）3·Bpy and europium salts Eu（RCOO）3·nH2O were also studied. Vibrational IR and Raman spectra of phenylacetate family were analyzed. The crystal structure of nitropropionate Eu（NO2C2H4COO）3·Phen was solved by X-my diffraction method. The predominant influence of steric hindrances on Eu^3＋ coordination centre was observed at increase of the size of aromatic flagment of carboxylate anions. It was demonstrated, that introduction of the methylene bridges between the carboxylic group and aromatic rings of ligand weakens the effect of steric factor.展开更多
Seventeen derivatives of mixed trialkyltin carboxylates with the formula (PhMe2SiCH2)Cy2SnO2CR have been synthesised.The results of IR NMR(1H,13C,119Sn) and MS showed that this kind of compounds is four-coordinated an...Seventeen derivatives of mixed trialkyltin carboxylates with the formula (PhMe2SiCH2)Cy2SnO2CR have been synthesised.The results of IR NMR(1H,13C,119Sn) and MS showed that this kind of compounds is four-coordinated and that there are two good linear relationships between the δ 119Sn and Hammett constants of para-substitutent of the corresponding aryloxy-acetates and arylcarboxylates.These compounds have a good acaricidal activity in the preliminary bioassay tests.展开更多
A series of novel triphenylphosphine stabilized silver carboxylates, potential precursors for CVD growth of ultrafast interconnection link in microelectronic devices, have been prepared and characterized.
While the versatile composition of layered double hydroxides(LDHs)allows the introduction of almost any polyvalent cation in their structure,the exchangeable negatively charged ions intercalated between the plates inc...While the versatile composition of layered double hydroxides(LDHs)allows the introduction of almost any polyvalent cation in their structure,the exchangeable negatively charged ions intercalated between the plates increase their vast range of functionalities.Here we report on the preparation and optical properties of pillared Eu^(3+)-substituted ZnAl LDHs intercalated by aliphatic dicarboxylates:-OOC-(CH_(2))_(n-2)-COO-.The basal distance in these materials is dependent on the size and packing of the intercalated anions.By varying the number(n)of carbon atoms in the aliphatic chain from 2 to 12,the interlayer gallery of these ZnAlEu LDHs is considerably expanded from 0.9 to 2.1 nm.In the interlayer gallery,the aliphatic dicarboxylates form a monolayer,with the aliphatic chain inclined by an angleα≈63°with the hydroxide layers.The carbon atom in the COO-group is 0.43 nm far from the metal plane,showing that these carboxylates are not grafted in the brucite-like layers.These LDHs are thermally stable up to around 150℃,after which dehydroxylation of the hydroxide layers is observed.The Judd-Ofelt intensity parameters were obtained and compared to the Eu^(3+)-containing complexes with the same ligand series indicating a more symmetrical and less polarizable chemical environment around the rare earth ion.展开更多
A new series of metal complex carboxylates（MCC）made of [Co（en）3]3＋（MC）and either 2,6-naphthalenedicarboxylic（NDC）or 4,4-biphenyldicarboxylic（BPDC）were synthesized and structurally characterized.The four new...A new series of metal complex carboxylates（MCC）made of [Co（en）3]3＋（MC）and either 2,6-naphthalenedicarboxylic（NDC）or 4,4-biphenyldicarboxylic（BPDC）were synthesized and structurally characterized.The four new compounds have a general formula（MC）2（C）3·n（vip）with the vips of dimethylformamide（DMF）and dimethyl sulfoxide（DMSO）and water.All the structures represent a pillared-layer type,where the layer consists of MC cations,carboxylate anions or water molecules via a large number of hydrogen bonds.The layers are pillared by the organic residues of NDC or BPDC,resulting in the inclusion cavities where the vip molecules reside.Although their topological structures are similar,they crystallize in different crystal structures due to the rearrangement of pillars and hydrogen-bonded layers.展开更多
A one-pot transformation of aliphatic and aromatic tertiary amines to novel fluorinated enaminones has been developed,utilizing perfluoroalkyl ether carboxylates(PFECA salts)featuring“-CF_(2)O-”units as the fluorine...A one-pot transformation of aliphatic and aromatic tertiary amines to novel fluorinated enaminones has been developed,utilizing perfluoroalkyl ether carboxylates(PFECA salts)featuring“-CF_(2)O-”units as the fluorine-containing reagents.Carbonyl fluoride,acyl fluorides and anhydrides by thermal decomposition of these PFECA salts were proposed to act as key active species that trigger the tandem oxidation-acylation process of tertiary amines,through enamine intermediates.展开更多
Under hydrothermal and solvothermal conditions,two novel cobalt-based complexes,{[Co_(2)(CIA)(OH)(1,4-dtb)]·3.2H_(2)O}n(HU23)and{[Co_(2)(CIA)(OH)(1,4-dib)]·3.5H2O·DMF}n(HU24),were successfully construct...Under hydrothermal and solvothermal conditions,two novel cobalt-based complexes,{[Co_(2)(CIA)(OH)(1,4-dtb)]·3.2H_(2)O}n(HU23)and{[Co_(2)(CIA)(OH)(1,4-dib)]·3.5H2O·DMF}n(HU24),were successfully constructed by coordinatively assembling the semi-rigid multidentate ligand 5-(1-carboxyethoxy)isophthalic acid(H₃CIA)with the Nheterocyclic ligands 1,4-di(4H-1,2,4-triazol-4-yl)benzene(1,4-dtb)and 1,4-di(1H-imidazol-1-yl)benzene(1,4-dib),respectively,around Co^(2+)ions.Single-crystal X-ray diffraction analysis revealed that in both complexes HU23 and HU24,the CIA^(3-)anions adopt aκ^(7)-coordination mode,bridging six Co^(2+)ions via their five carboxylate oxygen atoms and one ether oxygen atom.This linkage forms tetranuclear[Co4(μ3-OH)2]^(6+)units.These Co-oxo cluster units were interconnected by CIA^(3-)anions to assemble into 2D kgd-type structures featuring a 3,6-connected topology.The 2D layers were further connected by 1,4-dtb and 1,4-dib,resulting in 3D pillar-layered frameworks for HU23 and HU24.Notably,despite the similar configurations of 1,4-dtb and 1,4-dib,differences in their coordination spatial orientations lead to topological divergence in the 3D frameworks of HU23 and HU24.Topological analysis indicates that the frameworks of HU23 and HU24 can be simplified into a 3,10-connected net(point symbol:(4^(10).6^(3).8^(2))(4^(3))_(2))and a 3,8-connected tfz-d net(point symbol:(4^(3))_(2)((4^(6).6^(18).8^(4)))),respectively.This structural differentiation confirms the precise regulatory role of ligands on the topology of metal-organic frameworks.Moreover,the ultraviolet-visible absorption spectra confirmed that HU23 and HU24 have strong absorption capabilities for ultraviolet and visible light.According to the Kubelka-Munk method,their bandwidths were 2.15 and 2.08 eV,respectively,which are consistent with those of typical semiconductor materials.Variable-temperature magnetic susceptibility measurements(2-300 K)revealed significant antiferromagnetic coupling in both complexes,with their effective magnetic moments decreasing markedly as the temperature lowered.CCDC:2457554,HU23;2457553,HU24.展开更多
In this study,polyacrylic acid(PAA)films were employed as a model system,and a series of PAA films with tunable water wettability was systematically prepared by varying molecular weight and curing temperature.Using at...In this study,polyacrylic acid(PAA)films were employed as a model system,and a series of PAA films with tunable water wettability was systematically prepared by varying molecular weight and curing temperature.Using attenuated total reflectance Fourier-transform infrared spectroscopy(ATR-FTIR),the molecular configurations of surface carboxyl groups(COOH),free carboxyl(COOH_(f))and hydrogen-bonded carboxyl(COOH_(HB),were directly correlated with the polar component of surface energy(γ^(s,p)).By decomposing theγ^(s,p)values of the PAA thin films as a sum of the contributions of COOH_(f)and COOH_(H B),the intrinsic polar component of surface energy of COOH_(H B)(γ_(H B)^(s,p*))was quantified for the first time as 8.34 mN/m,significantly lower than that of COOH_(f)(γ_(f)^(s,p*)=34 mN/m).This result highlights that hydrogen bonding markedly reduces theγ^(s,p),providing a rational explanation for the relatively large water contact angle observed on PAA thin films.Furthermore,it establishes a thermodynamic basis for estimating the fraction of surface COOH_(H B)groups(f H B)from wettability measurements.Further extension of the model to carboxyl-terminated self-assembled monolayers(COOH-SAMs)revealed that surface COOH density(ΣCOOH)critically regulates wetting behavior:whenΣCOOH ranges from 4.30 to 5.25 nm^(-2),COOH groups predominantly exist in a free state and facilitate effective hydration layers,thereby promoting superhydrophilicity.Overall,this study not only establishes a unified thermodynamic framework linking surface COOH configurations to macroscopic wettability,but also validates its universality by extending it to COOH-SAMs systems,thereby providing a unified theoretical framework for the controllable design of hydrophilicity in various COOH-functionalized surfaces.展开更多
Summary of main observation and conclusion An efficient Pd-catalyzed three-component coupling reaction of allyl carboxylates, norbornenes and diboronates is described, which allows efficient assembly of C(sp3)-C(sp3) ...Summary of main observation and conclusion An efficient Pd-catalyzed three-component coupling reaction of allyl carboxylates, norbornenes and diboronates is described, which allows efficient assembly of C(sp3)-C(sp3) and C(sp3)-B bonds in a single process. Moreover, this approach shows advantages of good chemo- and regioselectivity, as well as good substrates suitability.展开更多
The impact of alkali metal carboxylates on the synthesis of colloidal quantum dots(CQDs)was investigated.Through a ligand removal experiment,we demonstrated that due to its high hydrophilic nature,sodium oleate disper...The impact of alkali metal carboxylates on the synthesis of colloidal quantum dots(CQDs)was investigated.Through a ligand removal experiment,we demonstrated that due to its high hydrophilic nature,sodium oleate dispersed in n-octadecene(ODE)with the formation of micelles with the help of other polar molecules,which resulted in reduced concentration of oleic acid and cadmium oleate both in the solution and on the surface of CQDs.These effects allow for control the size of CdSe CQDs in a wide range when synthesizing them by solely changing the amount of sodium oleate,under either cation-rich or anion-rich conditions.Additionally,enhanced ligand dynamics promote morphology transformation and suppress size deviation caused by different morphologies'existence in CQDs synthesis.Alkali metal oleate not only stabilized anion-rich CdSe CQDs but also results in highly crystallized wurtzite structure of CdSe CQDs when synthesizing them with excess anions.Furthermore,under anion-rich synthetic condition,anisotropic growth can be realized,leading to nanorods and nanoplatelets based on the alkali metal ions used.Given their outstanding effects and widely applicable synthetic conditions,alkali metal carboxylates offer new possibilities for designing efficient methods for synthesizing CQDs.展开更多
In this paper, a new type of anionic surfactant containing four carboxylates was synthesized by a four-step synthetic reaction including bromination reaction and primary amide protective reaction. Intermediates and fi...In this paper, a new type of anionic surfactant containing four carboxylates was synthesized by a four-step synthetic reaction including bromination reaction and primary amide protective reaction. Intermediates and final products of each step in the whole synthetic process were characterized by IH NMR and MS. Purification of the anionic surfactant was accomplished through combination of recrystallization and silica gel column chromatography. The structure and the critical micelle concentration （CMC） of this surfactant at different temperatures were also investigated. Unlike traditional mono- carboxylate surfactant easy to form lamellar mesostructure, this surfactant has the hexagonal mesophase structure and comparatively low CMC, hopefu.lly to be applied in the preparation of mesoporous metal oxides.展开更多
文摘Syngas to aromatics(STA)over bifunctional catalysts has attracted much attention in recent years,but the mechanism underlying the formation of aromatics remains controversial.The critical reaction intermediates,carboxylates,were first identified and then confirmed to essentially promote aromatization in the syngas conversion over a ZnCrAlO_(x)&H-ZSM-5 composite catalyst.This study provides evidence that the carboxylates can be formed during the reactions of formate species and olefins.In addition,it is shown that the carboxylates favor the formation of aromatics over H-ZSM-5 even in the presence of H2.A novel mechanism for the formation of aromatics via the generation and transformation of carboxylate intermediates is proposed,and the transformation of carboxylates to aromatics via methyl-2-cyclopenten-1-one(MCPO)intermediates is indeed likely.A better understanding of the formation mechanism of aromatics would help optimize the composite catalyst.
基金supported by the funding from"863"Project(2011AA11A235)"973"Projects(2010CB833102 and 2012CB932900)+1 种基金NSFC(No.51222210 and 11234013)the 100 Talent Project of the Chinese Academy of Sciences
文摘Nano-sized caiboxylales Na2C7H3NO4 and Na2C6H2N2O4 were prepared and investigated as anode materials for lithium-ion batteries.Both carboxylates exhibit high reversible capacities around 190 mAh/g above a cut-off voltage of 0.8 V vs.Li＋/Li.potentially improving the safety of the batteries.In addition,good rate performance and long cycle life of these carboxylates make them promising candidates as anode materials for lithium-ion batteries.
基金financial support from the Research Council of the University of Sistan and Baluchestan,Zahedan, Iran
文摘Vitamin B12 was applied as catalyst for the one-pot three-component synthesis of 3,4,5-trisubstituted furan-2（5H）-ones from the condensation between aldehydes, amines and dialkylacetylendicarboxylates at ambient temperature in Et OH. In addition, N-aryl-3-aminodihydropyrrol-2-one-4-carboxylates were synthesised using mentioned catalyst at ambient temperature in Et OH from condensation between formaldehyde, amines, and dialkylacetylenedicarboxylates. This methodology has number of advantages such as： use of green and nonhazardous catalyst, clean work up, short reaction times,high yields and no need to column chromatography.
文摘Eight tri(2-methyl-2-phznylpropyl) germylpropionates have been synthesized. and their structures were characterized by elemental analysis, IR, multinuclear NMR(H-1,C-13.Sn-119) and MS. The spectroscopic studies revealed that compounds of this type possess a tetrahedral geometry, which have been expected to have good biological activity.
基金supported by the National Natural Science Foundation of China(21571072)the Science and Technology Research Project of Hubei Provincial Department of Education(No.B2018198)
文摘Three unique metal-organic framework coordination polymers, [Eu_2(bptc)(bdc)_2(H_2O)]_n(1), [Gd_2(bptc)(bdc)_2(H_2O)_4]_n(2) and [Dy_2(bptc)(bdc)_2(H_2O)_4]n(3)(1,2-H_2 BDC = 1,2-benzenedicarboylic acid, H_2 bptc = 4,4?-biphenyldicarboxylic acid) were synthesized by mixing two different multi-carboxylic acids with Ln2 O3(Ln = Eu, Gd and Dy) in hydrothermal condition. The three compounds are all three-dimensional and compounds 2 and 3 contain 4.289 × 6.507 ?~2 rectangularshaped one-dimensional open channels along the a direction. Additionally, the magnetic, luminescent and thermogravimetric properties were studied in detail.
基金Financial support from the National Natural Science Foundation of China(Nos.21362032 and 21362031)the NSF of Gansu Province(No.1208RJYA083)
文摘A novel and general carbon-nitrogen and carbon-carbon cross-coupling reaction between 3,4-dihydropyrimidine-2-thiones and copper（Ⅰ） carboxylates were performed in the presence of palladium acetate.The copper（Ⅰ） carboxylates act not only as desulfurative reagents but also as sources of carbon nudeophiles.A wide array of highly substituted and functionalized pyrimidines scaffolds were synthesized in good yields.
基金the Junior Research Fellowship(JRF)from University Grants Commission,New Delhi,India(No.2061410096)。
文摘Five novel europium(Ⅲ)complexes with 2-[4-(dibutylamino)-2-hydroxybenzoyl]benzoic acid(DAHB)as primary ligand and bathophenanthroline(batho),2,2’-bipyridyl(bipy),5,6-dimethyl-1,10-phenanthroline(dmph),1,10-phenanthroline(phen)as ancillary ligands were syn-thesized via solution precipitation method.The structural formulae of synthesized complexes were speculated to be Eu(DABH)_(3)·2H_(2)O(C1),Eu(DABH)_(3)·batho(C2),Eu(DABH)_(3)·bipy(C3),Eu(DABH)_(3)·dmph(C4)and Eu(DABH)_(3)·phen(C5)by elemental analysis,infrared spectroscopy and proton nuclear magnetic resonance spec-troscopy(^(1)H-NMR).The photoluminescent properties and thermal stability of the complexes were investigated by photoluminescent spectroscopy and thermogravimetric analysis(TG-DTG),respectively.The Commission Inter-nationale de I’Eclairage(CIE)color coordinates,Judd–Ofelt intensity parameter(Ω_(2)),total quantum yield,intrinsic quantum efficiency and energy transfer dynamics of com-plexes were also explored.The excitation spectra of com-plexes are extended up to visible region.These complexes exhibit characteristic photoemission of Eu^(3+)metal ion with high color purity in red region attributed to efficient energy transfer from ligand to metal ion.The replacement of water molecules from coordination sphere of europium ion by ancillary ligands results in enhancement of luminescent properties of the C2–C5 complexes,indicating that ancillary ligands act as additional light harvesting centers in sensiti-zation phenomenon.The thermal studies show that these complexes are suitable for meeting the requirement of temperature for fabrication of OLEDs devices.
文摘In the present study, new series of pyridinium carboxylate protic ionic liquids(PILs) were synthesized by pairing pyridinium cation with carboxylate anion from C_1–C_3 forming pyridinium formate([C_5H_6N^+][HCOO^-]),pyridinium acetate([C_5H_6N^+][CH_3COO^-]) and pyridinium propionate([C_5H_6N^+][CH_3CH_2COO^-]) respectively.The physical properties namely, density, viscosity, surface tension(298.15–343.15) K, and refractive index(293.15–323.15) K were measured. Thermal properties namely, glass transition temperature, molar heat capacity, and thermal decomposition temperatures were also determined. The thermal expansivity was calculated using the experimental density data. The effect of increasing the alkyl chain length on the thermophysical properties of the pyridinium carboxylate PILs has been evaluated. As expected the physical properties i.e. density,viscosity, surface tension and refractive index of the investigated pyridinium carboxylates decreased with increasing temperature. In general pyridinium carboxylate PILs possessed low viscosity, high thermal stability and excellent hydrogen bonding capability, and these properties lead them to outperform conventional solvents employed for lignin dissolution.
基金supported by the Russian Foundation for Basic Research (N 08-02-00424-a, N 06-03-32557-a)
文摘Methods of optical spectroscopy and X-ray crystallography data were used to examine the effect of architecture of carboxylate anions on structure of the Eu3＋ coordination centre in europium earboxylates with 1,10-phenanthroline Eu（RCOO）3·Phen. Luminescence spectra of europium acetate, nitropropionate, benzoate, naphthylcarboxylates, phenylacetates, phenoxyacetate, triphenylpropionate were investigated. A few of europium carboxylates with 2,2＇-bipyridine Eu（RCOO）3·Bpy and europium salts Eu（RCOO）3·nH2O were also studied. Vibrational IR and Raman spectra of phenylacetate family were analyzed. The crystal structure of nitropropionate Eu（NO2C2H4COO）3·Phen was solved by X-my diffraction method. The predominant influence of steric hindrances on Eu^3＋ coordination centre was observed at increase of the size of aromatic flagment of carboxylate anions. It was demonstrated, that introduction of the methylene bridges between the carboxylic group and aromatic rings of ligand weakens the effect of steric factor.
基金Supported by the National Natural Science Foundation of China
文摘Seventeen derivatives of mixed trialkyltin carboxylates with the formula (PhMe2SiCH2)Cy2SnO2CR have been synthesised.The results of IR NMR(1H,13C,119Sn) and MS showed that this kind of compounds is four-coordinated and that there are two good linear relationships between the δ 119Sn and Hammett constants of para-substitutent of the corresponding aryloxy-acetates and arylcarboxylates.These compounds have a good acaricidal activity in the preliminary bioassay tests.
基金funds for Y.Pan from Qin-Lan Program of Jiangsu Province,Kua-Shi-Ji Program of Education Ministry,the Key Lab of Fine PetroChemical Technology of Jiangsu Provincethe National 863 High Technology Program are acknowledged.
文摘A series of novel triphenylphosphine stabilized silver carboxylates, potential precursors for CVD growth of ultrafast interconnection link in microelectronic devices, have been prepared and characterized.
基金Project supported by Fundacao de AmparoàPesquisa do Estado de Sao Paulo(FAPESP,2015/19210-0 and 2018/13837-0)Coordenacao de Aperfei?oamento de Pessoal de Nivel Superior(CAPES,1723707,Finance Code 001)Conselho Nacional de Desenvolvimento Cientifico e Tecnológico(CNPq,403055/2016-4)。
文摘While the versatile composition of layered double hydroxides(LDHs)allows the introduction of almost any polyvalent cation in their structure,the exchangeable negatively charged ions intercalated between the plates increase their vast range of functionalities.Here we report on the preparation and optical properties of pillared Eu^(3+)-substituted ZnAl LDHs intercalated by aliphatic dicarboxylates:-OOC-(CH_(2))_(n-2)-COO-.The basal distance in these materials is dependent on the size and packing of the intercalated anions.By varying the number(n)of carbon atoms in the aliphatic chain from 2 to 12,the interlayer gallery of these ZnAlEu LDHs is considerably expanded from 0.9 to 2.1 nm.In the interlayer gallery,the aliphatic dicarboxylates form a monolayer,with the aliphatic chain inclined by an angleα≈63°with the hydroxide layers.The carbon atom in the COO-group is 0.43 nm far from the metal plane,showing that these carboxylates are not grafted in the brucite-like layers.These LDHs are thermally stable up to around 150℃,after which dehydroxylation of the hydroxide layers is observed.The Judd-Ofelt intensity parameters were obtained and compared to the Eu^(3+)-containing complexes with the same ligand series indicating a more symmetrical and less polarizable chemical environment around the rare earth ion.
基金Supported by the National Science Foundation (DMR-0600320)
文摘A new series of metal complex carboxylates（MCC）made of [Co（en）3]3＋（MC）and either 2,6-naphthalenedicarboxylic（NDC）or 4,4-biphenyldicarboxylic（BPDC）were synthesized and structurally characterized.The four new compounds have a general formula（MC）2（C）3·n（vip）with the vips of dimethylformamide（DMF）and dimethyl sulfoxide（DMSO）and water.All the structures represent a pillared-layer type,where the layer consists of MC cations,carboxylate anions or water molecules via a large number of hydrogen bonds.The layers are pillared by the organic residues of NDC or BPDC,resulting in the inclusion cavities where the vip molecules reside.Although their topological structures are similar,they crystallize in different crystal structures due to the rearrangement of pillars and hydrogen-bonded layers.
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB0590000)the National Natural Science Foundation of China(21991122)the National Key Research and Development Program of China(2021YFF0701700).
文摘A one-pot transformation of aliphatic and aromatic tertiary amines to novel fluorinated enaminones has been developed,utilizing perfluoroalkyl ether carboxylates(PFECA salts)featuring“-CF_(2)O-”units as the fluorine-containing reagents.Carbonyl fluoride,acyl fluorides and anhydrides by thermal decomposition of these PFECA salts were proposed to act as key active species that trigger the tandem oxidation-acylation process of tertiary amines,through enamine intermediates.
文摘Under hydrothermal and solvothermal conditions,two novel cobalt-based complexes,{[Co_(2)(CIA)(OH)(1,4-dtb)]·3.2H_(2)O}n(HU23)and{[Co_(2)(CIA)(OH)(1,4-dib)]·3.5H2O·DMF}n(HU24),were successfully constructed by coordinatively assembling the semi-rigid multidentate ligand 5-(1-carboxyethoxy)isophthalic acid(H₃CIA)with the Nheterocyclic ligands 1,4-di(4H-1,2,4-triazol-4-yl)benzene(1,4-dtb)and 1,4-di(1H-imidazol-1-yl)benzene(1,4-dib),respectively,around Co^(2+)ions.Single-crystal X-ray diffraction analysis revealed that in both complexes HU23 and HU24,the CIA^(3-)anions adopt aκ^(7)-coordination mode,bridging six Co^(2+)ions via their five carboxylate oxygen atoms and one ether oxygen atom.This linkage forms tetranuclear[Co4(μ3-OH)2]^(6+)units.These Co-oxo cluster units were interconnected by CIA^(3-)anions to assemble into 2D kgd-type structures featuring a 3,6-connected topology.The 2D layers were further connected by 1,4-dtb and 1,4-dib,resulting in 3D pillar-layered frameworks for HU23 and HU24.Notably,despite the similar configurations of 1,4-dtb and 1,4-dib,differences in their coordination spatial orientations lead to topological divergence in the 3D frameworks of HU23 and HU24.Topological analysis indicates that the frameworks of HU23 and HU24 can be simplified into a 3,10-connected net(point symbol:(4^(10).6^(3).8^(2))(4^(3))_(2))and a 3,8-connected tfz-d net(point symbol:(4^(3))_(2)((4^(6).6^(18).8^(4)))),respectively.This structural differentiation confirms the precise regulatory role of ligands on the topology of metal-organic frameworks.Moreover,the ultraviolet-visible absorption spectra confirmed that HU23 and HU24 have strong absorption capabilities for ultraviolet and visible light.According to the Kubelka-Munk method,their bandwidths were 2.15 and 2.08 eV,respectively,which are consistent with those of typical semiconductor materials.Variable-temperature magnetic susceptibility measurements(2-300 K)revealed significant antiferromagnetic coupling in both complexes,with their effective magnetic moments decreasing markedly as the temperature lowered.CCDC:2457554,HU23;2457553,HU24.
文摘In this study,polyacrylic acid(PAA)films were employed as a model system,and a series of PAA films with tunable water wettability was systematically prepared by varying molecular weight and curing temperature.Using attenuated total reflectance Fourier-transform infrared spectroscopy(ATR-FTIR),the molecular configurations of surface carboxyl groups(COOH),free carboxyl(COOH_(f))and hydrogen-bonded carboxyl(COOH_(HB),were directly correlated with the polar component of surface energy(γ^(s,p)).By decomposing theγ^(s,p)values of the PAA thin films as a sum of the contributions of COOH_(f)and COOH_(H B),the intrinsic polar component of surface energy of COOH_(H B)(γ_(H B)^(s,p*))was quantified for the first time as 8.34 mN/m,significantly lower than that of COOH_(f)(γ_(f)^(s,p*)=34 mN/m).This result highlights that hydrogen bonding markedly reduces theγ^(s,p),providing a rational explanation for the relatively large water contact angle observed on PAA thin films.Furthermore,it establishes a thermodynamic basis for estimating the fraction of surface COOH_(H B)groups(f H B)from wettability measurements.Further extension of the model to carboxyl-terminated self-assembled monolayers(COOH-SAMs)revealed that surface COOH density(ΣCOOH)critically regulates wetting behavior:whenΣCOOH ranges from 4.30 to 5.25 nm^(-2),COOH groups predominantly exist in a free state and facilitate effective hydration layers,thereby promoting superhydrophilicity.Overall,this study not only establishes a unified thermodynamic framework linking surface COOH configurations to macroscopic wettability,but also validates its universality by extending it to COOH-SAMs systems,thereby providing a unified theoretical framework for the controllable design of hydrophilicity in various COOH-functionalized surfaces.
基金the National Program on Key Research Project (No. 2016YFA0602900)the National Natural Science Foundation of China (No. 21420102003)the Guangdong Province Science Foundation (No. 2017B090903003) for financial support.
文摘Summary of main observation and conclusion An efficient Pd-catalyzed three-component coupling reaction of allyl carboxylates, norbornenes and diboronates is described, which allows efficient assembly of C(sp3)-C(sp3) and C(sp3)-B bonds in a single process. Moreover, this approach shows advantages of good chemo- and regioselectivity, as well as good substrates suitability.
基金supported by the Shanghai Rising-Star Program(No.22QA1406300)the National Natural Science Foundation of China(No.U22A2072)the Start-up Funding of ShanghaiTech University.
文摘The impact of alkali metal carboxylates on the synthesis of colloidal quantum dots(CQDs)was investigated.Through a ligand removal experiment,we demonstrated that due to its high hydrophilic nature,sodium oleate dispersed in n-octadecene(ODE)with the formation of micelles with the help of other polar molecules,which resulted in reduced concentration of oleic acid and cadmium oleate both in the solution and on the surface of CQDs.These effects allow for control the size of CdSe CQDs in a wide range when synthesizing them by solely changing the amount of sodium oleate,under either cation-rich or anion-rich conditions.Additionally,enhanced ligand dynamics promote morphology transformation and suppress size deviation caused by different morphologies'existence in CQDs synthesis.Alkali metal oleate not only stabilized anion-rich CdSe CQDs but also results in highly crystallized wurtzite structure of CdSe CQDs when synthesizing them with excess anions.Furthermore,under anion-rich synthetic condition,anisotropic growth can be realized,leading to nanorods and nanoplatelets based on the alkali metal ions used.Given their outstanding effects and widely applicable synthetic conditions,alkali metal carboxylates offer new possibilities for designing efficient methods for synthesizing CQDs.
文摘In this paper, a new type of anionic surfactant containing four carboxylates was synthesized by a four-step synthetic reaction including bromination reaction and primary amide protective reaction. Intermediates and final products of each step in the whole synthetic process were characterized by IH NMR and MS. Purification of the anionic surfactant was accomplished through combination of recrystallization and silica gel column chromatography. The structure and the critical micelle concentration （CMC） of this surfactant at different temperatures were also investigated. Unlike traditional mono- carboxylate surfactant easy to form lamellar mesostructure, this surfactant has the hexagonal mesophase structure and comparatively low CMC, hopefu.lly to be applied in the preparation of mesoporous metal oxides.
