Aqueous zinc-ion batteries(AZIBs)have developed rapidly in recent years but still face several challenges,including zinc dendrites growth,hydrogen evolution reaction,passivation and corrosion.The pH of the electrolyte...Aqueous zinc-ion batteries(AZIBs)have developed rapidly in recent years but still face several challenges,including zinc dendrites growth,hydrogen evolution reaction,passivation and corrosion.The pH of the electrolyte plays a crucial role in these processes,significantly impacting the stability and reversibility of Zn^(2+)deposition.Therefore,pH-buffer tris(hydroxymethyl)amino methane(tris)is chosen as a versatile electrolyte additive to address these issues.Tris can buffer electrolyte pH at Zn/electrolyte interface by protonated/deprotonated nature of amino group,optimize the coordination environment of zinc solvate ions by its strong interaction with zinc ions,and simultaneously create an in-situ stable solid electrolyte interface membrane on the zinc anode surface.These synergistic effects effectively restrain dendrite formation and side reactions,resulting in a highly stable and reversible Zn anode,thereby enhancing the electrochemical performance of AZIBs.The Zn||Zn battery with 0.15 wt%tris additives maintains stable cycling for 1500 h at 4 mA·cm^(−2) and 1120 h at 10 mA·cm^(−2).Furthermore,the Coulombic efficiency reaches~99.2%at 4 mA·cm^(−2)@1 mAh·cm^(−2).The Zn||NVO full batteries also demonstrated a stable specific capacity and exceptional capacity retention.展开更多
Photoinduced molecular oxygen activation is crucial for artificial photosynthesis.However,metal-free semiconductor photocatalysts with high activation efficiency are still lacking up to now.Herein,two isomorphic tris(...Photoinduced molecular oxygen activation is crucial for artificial photosynthesis.However,metal-free semiconductor photocatalysts with high activation efficiency are still lacking up to now.Herein,two isomorphic tris(triazolo)triazine-based covalent organic frameworks were successfully constructed under solvothermal conditions.And they possess high crystallinity,inherent porosity with large surface area and good stability.Strong electron donor-acceptor skeletons expand the visible light harvesting,also facilitate the charge separation and thus lead to their superior activity of photoinduced molecular oxygen activation including photosynthesis of tetrahydroquinolines and hydrogen peroxide.This work provides a way to improve the efficiency of molecular oxygen activation through the rational design of COFs,and also opens new avenues for the construction of highly active and metal-free photocatalysts toward sustainable solar-to-chemical energy conversion.展开更多
In situ thickness dependent photoluminescence （PL） measurements of tris（8-hydroxyquinoline） aluminum（Alq3） film were performed. At the beginning of Alq3 deposition on the glass substrate, the Alq3 emission showe...In situ thickness dependent photoluminescence （PL） measurements of tris（8-hydroxyquinoline） aluminum（Alq3） film were performed. At the beginning of Alq3 deposition on the glass substrate, the Alq3 emission showed a sharp red-shift. Further deposition of Alq3 resulted slight red-shift, and finally tended to saturated value. The total red-shift of about 12 nm was observed for the Alq3 film thickness range from 2 to 500 nm.This red-shift was attributed to the change from the 2D to 3D exciton state with increasing Alq3 film thickness. Meanwhile, the PL intensity of Alq3 emission increased continuously, and showed a rate change at the initial deposition of Alq3 due to non-rediative decay of excitons arised from the interaction between excitons and the substrate, and finally tended to saturation with the Alq3 thickness.展开更多
Tris缓冲体系下,通过在NiTi表面包裹聚多巴胺薄膜来提高其耐腐蚀性能。研究分别在10mMTris pH=8.5和50mMTris p H=8.5条件下,改变多巴胺的初始浓度,考察了成膜后的NiTi耐蚀性能。结果表明,10mM的Tris体系下,聚多巴胺修饰NiTi的耐蚀性能...Tris缓冲体系下,通过在NiTi表面包裹聚多巴胺薄膜来提高其耐腐蚀性能。研究分别在10mMTris pH=8.5和50mMTris p H=8.5条件下,改变多巴胺的初始浓度,考察了成膜后的NiTi耐蚀性能。结果表明,10mM的Tris体系下,聚多巴胺修饰NiTi的耐蚀性能并不是随着多巴胺的浓度增加而增强;相比之下,50mM的Tris体系下,聚多巴胺修饰NiTi的耐腐蚀性能随着多巴胺浓度的增加而增强。展开更多
In vitro degradation is an important approach to screening appropriate biomedical magnesium（Mg） alloys at low cost. However, corrosion products deposited on Mg alloys exert a critical impact on corrosion resistance....In vitro degradation is an important approach to screening appropriate biomedical magnesium（Mg） alloys at low cost. However, corrosion products deposited on Mg alloys exert a critical impact on corrosion resistance. There are no acceptable criteria on the evaluation on degradation rate of Mg alloys. Understanding the degradation behavior of Mg alloys in presence of Tris buffer is necessary. An investigation was made to compare the influence of Tris-HCl and Tris on the corrosion behavior of Mg alloy AZ31 in the presence of various anions of simulated body fluids via hydrogen evolution, p H value and electrochemical tests.The results demonstrated that the Tris-HCl buffer resulted in general corrosion due to the inhibition of the formation of corrosion products and thus increased the corrosion rate of the AZ31 alloy. Whereas Tris gave rise to pitting corrosion or general corrosion due to the fact that the hydrolysis of the amino-group of Tris led to an increase in solution p H value, and promoted the formation of corrosion products and thus a significant reduction in corrosion rate. In addition, the corrosion mechanisms in the presence of Tris-HCl and Tris were proposed. Tris-HCl as a buffer prevented the formation of precipitates of HCO;, SO;,HPO;and H;PO;ions during the corrosion of the AZ31 alloy due to its lower buffering p H value（x.x）.Thus, both the hydrogen evolution rate and corrosion current density of the alloy were approximately one order of magnitude higher in presence of Tris-HCl than Tris and Tris-free saline solutions.展开更多
Tris(trimethylsilyl)borate(TMSB) has been intensively studied to improve the performances of lithiumion batteries. However, it is still an interesting issue needed to be resolved for the research on the Li^(+) solvati...Tris(trimethylsilyl)borate(TMSB) has been intensively studied to improve the performances of lithiumion batteries. However, it is still an interesting issue needed to be resolved for the research on the Li^(+) solvation structure affected by TMSB additive. Herein, the electrochemical tests, quantum chemistry calculations, potential-resolved in-situ electrochemical impedance spectroscopy measurements and surface analyses were used to explore the effects of Li^(+) solvation structure with TMSB additive on the formation of the cathode electrolyte interface(CEI) film in LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)/Li half cells. The results reveal that the TMSB additive is easy to complex with Li^(+) ion, thus weaken the intermolecular force between Li^(+) ions and ethylene carbonate solvent, which is benefit for the cycle performance. Besides, the changed Li^(+) solvation structure results in a thin and dense CEI film containing compounds with Si–O and B–O bonds which is favorable to the transfer of Li^(+) ions. As a result, the performances of the LNCM811/Li half cells are effectively improved. This research provides a new idea to construct a high-performance CEI film by adjusting the Li^(+) solvation structures.展开更多
The ring-opening polymerization of e-caprolactone (CL) initiated by novel single lanthanide tris(4-tert-butylphenolate)s [Ln(OTBP)3] is reported. Single-component La(OTBP)3 can effectively prepare polycaprolactone (PC...The ring-opening polymerization of e-caprolactone (CL) initiated by novel single lanthanide tris(4-tert-butylphenolate)s [Ln(OTBP)3] is reported. Single-component La(OTBP)3 can effectively prepare polycaprolactone (PCL) with over 90% yield and viscosity average molecular weight about 60 x 10 under quite mild conditions: molar ratio of CL to initiator is 1000, 60 C, 2 h in toluene. Mechanism study indicates that the monomer inserts into the growing chain via the break of acyl-oxygen bond of CL.展开更多
Three-dimensional(3D)graphene oxide-tris(4-aminophenyl)amine(GO-TAPAx:y)composites with different GO-to-TAPA mass ratios(x:y)were prepared by a facile one-step ultrasonic treatment.GOTAPAx:y composites were characteri...Three-dimensional(3D)graphene oxide-tris(4-aminophenyl)amine(GO-TAPAx:y)composites with different GO-to-TAPA mass ratios(x:y)were prepared by a facile one-step ultrasonic treatment.GOTAPAx:y composites were characterized by scanning electron microscopy(SEM),nitrogen(N2)adsorption-desorption isotherms,Fourier transform infrared spectroscopy(FTIR),X-ray photoelectron spectroscopy(XPS)and thermogravimetric analysis(TGA).Behavior and mechanism of GO-TAPAx:yco mposites for the adsorption of rare earth elements(REEs)were investigated.The adso rption capacities of GO-TAPA1;2 composite for Yb^3+,Er^3+,Nd^3+,La^3+and Y^3+are 30.88,26.52,20.60,11.24 and 10.52 mg/g,respectively.Effects of some important parameters including GO-to-TAPA mass ratios,contact time,reaction temperature and initial Yb^3+concentration on the adsorption were evaluated in detail.FTIR spectral and XPS analyses show that the metal complexations and ion exchanges between nitrogen/oxygen-containing species of the adsorbents and REEs are involved in the adsorption procedure besides the conventional adsorption based on specific surface area,indicating the introduction of specific molecules onto GO is beneficial to its adsorption ability.The convenient reusability and applicability of GO-TAPAx:y composites toward real samples also demonstrate their feasibility in the enrichment of REE ions.展开更多
Antimony mercaplde heat stabilizer for polyvinyl chlorideis synthesized from antimony trioxide and mercaptocarboxylic acid esters, HS(CH2).COoi-C8H17 (n=1～2) at 100～115 C In the presence of 0. 5%～1 % an organic aci...Antimony mercaplde heat stabilizer for polyvinyl chlorideis synthesized from antimony trioxide and mercaptocarboxylic acid esters, HS(CH2).COoi-C8H17 (n=1～2) at 100～115 C In the presence of 0. 5%～1 % an organic acid catalyst. Some physicochemicalconstants of the compounds, such as density and refractive index, aredetermined. The complexes are hydrolabll in aqueous solutions andthe bond of Sb-S is weaker than that of Sb-o. The forming bondproperty of antimony tris (mercaptoacid ester ) has been elucidatedby measurement of infrared spectra in comparison with mercaptocarboxylic acid esters. The polyvinyl chloride resins containing antimony mercaptide heat stabilizers, do not darken at elevated temperatures and exhibit a high degree of stability. It is proposed that mercaptocarboxylic acid ester freeradicals can esterify PVC microradicals at carbon atoms with upaired electrons.展开更多
α, α＇-Benzylidene bis（4-hydroxycoumarin） derivatives were readily prepared in a few minutes with good yields through the reaction of an aromatic aldehyde and 4-hydroxycoumarin in aqueous media in the presence of ...α, α＇-Benzylidene bis（4-hydroxycoumarin） derivatives were readily prepared in a few minutes with good yields through the reaction of an aromatic aldehyde and 4-hydroxycoumarin in aqueous media in the presence of catalytic tris（hydrogensulfato） boron [B（HSO_4）_3].展开更多
The polymerization of n-hexyl isocyanate(HNCO) was carried out in the presence of a novel single initiator, rare earth tris(2,6-di-tert-butyl-4-methylphenolate)[Ln(OAr)_3]. The influences of reaction conditions such a...The polymerization of n-hexyl isocyanate(HNCO) was carried out in the presence of a novel single initiator, rare earth tris(2,6-di-tert-butyl-4-methylphenolate)[Ln(OAr)_3]. The influences of reaction conditions such as the monomer concentration, the polymerization temperature and time, and the types of solvents on the polymerization of HNCO were studied. Polymerizations of phenyl, i-propyl, p-tolyl, n-butyl and n-octyl isocyanates with La(OAr)_3 were also examined.展开更多
Tris(2-chloroethyl) phosphate(TCEP) is a typical phosphate flame retardant. Its potential adverse health effects have recently aroused concern. We investigated the seasonal variations of TCEP concentrations in the raw...Tris(2-chloroethyl) phosphate(TCEP) is a typical phosphate flame retardant. Its potential adverse health effects have recently aroused concern. We investigated the seasonal variations of TCEP concentrations in the raw, finished and tap water samples from two drinking water treatment plants(DWTPs) in China, and evaluated the cytotoxicity and apoptosis/necrosis of organic extracts(OEs) in water samples. We enriched TCEP and OEs in water samples by solid-phase extraction method. The TCEP concentrations in water samples were determined by gas chromatography–mass spectrometry. Normal human liver cell line L02 was treated with OEs in the water samples, and then the cytotoxicity and apoptosis/necrosis were measured by 3-(4, 5-dimethyithiazol-2-yl)-2,5-diphenyl-tetrazolium bromide assay and flow cytometry, respectively. The results showed that cytotoxicities of OEs in raw water samples from both DWTPs in summer and winter were stronger than those in spring and autumn, cytotoxicity of OEs in finished and tap water samples from both DWTPs in summer and autumn were stronger than those in spring and winter. In all seasons, the maximal concentrations(100 mL water/mL cell culture) of OEs in the raw water samples from both DWTPs induced late apoptosis/necrosis. The reasons for seasonal variations of TCEP in water samples and potential toxic effects of other pollutants in the water samples need to be further investigated.展开更多
The extraction of Eu（Ⅲ） with β-diketone, HA, and monodentate or bidentate Lewis bases, B, into chloroform and the luminescence properties of the extracted species were studied. Pivaloyltrifluoroacetone, Hpta, and ...The extraction of Eu（Ⅲ） with β-diketone, HA, and monodentate or bidentate Lewis bases, B, into chloroform and the luminescence properties of the extracted species were studied. Pivaloyltrifluoroacetone, Hpta, and 2-thenoyltfifluoroacetone, Htta, were used as the β-diketones. The Lewis bases, B, were tetraethyl methylene diphosphonate, POPO, which was bidentate, and diethyl benzylphosphonate, PhPO which was monodentate. Based on the extraction data, the stability constants, log β, of the first complexes between tfis（β-diketonato）Eu（Ⅲ） and the phosphonate, EuA3B, were determined to be 6.0 for the POPO complex and 3.40 for the PhPO complex. The Eu（Ⅲ） luminescence intensity in the EuA3POPO was larger than EuA3 where A was either pta or tta at similar concentrations of Eu（Ⅲ）, while that in Eu（pta）3PhPO was stronger than EuA3; however, in Eu（tta）3PhPO, it was weaker than Eu（tta）3. The POPO functions as a sensitizer, and the PhPO functions as a quencher for the tta chelate and as a sensitizer for the pta chelate. From the lifetime and quantum yield, φ, of the Eu（Ⅲ） luminescence in the complexes as well as the observation of the extractability of Eu（Ⅲ） with the Hpta and the phosphonates and of the luminescence spectra of the complexes, it was confirmed that the extraction of Eu（Ⅲ） was remarkably enhanced with a β-diketonate and a strong Lewis base, and also the ternary complex that was formed as the extracted species, showed luminescence enhancement. This phenomenon may be due the formation of a strong bond between the Eu（Ⅲ） and the strong Lewis base leading to more hydrophobicity in the extracted species and also to more effective energy transfer from the Lewis base to the Eu（Ⅲ）. It was not significant whether the donor atoms were N or O.展开更多
基金supported by the Fund of Xuzhou Science and Technology Key R&D Program(Social Development)Project(No.KC22289)the Postgraduate Research&Practice Innovation Program of Jiangsu Province(No.KYCX22_2783).
文摘Aqueous zinc-ion batteries(AZIBs)have developed rapidly in recent years but still face several challenges,including zinc dendrites growth,hydrogen evolution reaction,passivation and corrosion.The pH of the electrolyte plays a crucial role in these processes,significantly impacting the stability and reversibility of Zn^(2+)deposition.Therefore,pH-buffer tris(hydroxymethyl)amino methane(tris)is chosen as a versatile electrolyte additive to address these issues.Tris can buffer electrolyte pH at Zn/electrolyte interface by protonated/deprotonated nature of amino group,optimize the coordination environment of zinc solvate ions by its strong interaction with zinc ions,and simultaneously create an in-situ stable solid electrolyte interface membrane on the zinc anode surface.These synergistic effects effectively restrain dendrite formation and side reactions,resulting in a highly stable and reversible Zn anode,thereby enhancing the electrochemical performance of AZIBs.The Zn||Zn battery with 0.15 wt%tris additives maintains stable cycling for 1500 h at 4 mA·cm^(−2) and 1120 h at 10 mA·cm^(−2).Furthermore,the Coulombic efficiency reaches~99.2%at 4 mA·cm^(−2)@1 mAh·cm^(−2).The Zn||NVO full batteries also demonstrated a stable specific capacity and exceptional capacity retention.
文摘Photoinduced molecular oxygen activation is crucial for artificial photosynthesis.However,metal-free semiconductor photocatalysts with high activation efficiency are still lacking up to now.Herein,two isomorphic tris(triazolo)triazine-based covalent organic frameworks were successfully constructed under solvothermal conditions.And they possess high crystallinity,inherent porosity with large surface area and good stability.Strong electron donor-acceptor skeletons expand the visible light harvesting,also facilitate the charge separation and thus lead to their superior activity of photoinduced molecular oxygen activation including photosynthesis of tetrahydroquinolines and hydrogen peroxide.This work provides a way to improve the efficiency of molecular oxygen activation through the rational design of COFs,and also opens new avenues for the construction of highly active and metal-free photocatalysts toward sustainable solar-to-chemical energy conversion.
基金This work is supported by the National Natural Science Foundation of China （No. 10274072, 20240430654）the Specialized Research Fund for the Doctoral Program of Higher Education of China （No. 20030335017）.
文摘In situ thickness dependent photoluminescence （PL） measurements of tris（8-hydroxyquinoline） aluminum（Alq3） film were performed. At the beginning of Alq3 deposition on the glass substrate, the Alq3 emission showed a sharp red-shift. Further deposition of Alq3 resulted slight red-shift, and finally tended to saturated value. The total red-shift of about 12 nm was observed for the Alq3 film thickness range from 2 to 500 nm.This red-shift was attributed to the change from the 2D to 3D exciton state with increasing Alq3 film thickness. Meanwhile, the PL intensity of Alq3 emission increased continuously, and showed a rate change at the initial deposition of Alq3 due to non-rediative decay of excitons arised from the interaction between excitons and the substrate, and finally tended to saturation with the Alq3 thickness.
文摘Tris缓冲体系下,通过在NiTi表面包裹聚多巴胺薄膜来提高其耐腐蚀性能。研究分别在10mMTris pH=8.5和50mMTris p H=8.5条件下,改变多巴胺的初始浓度,考察了成膜后的NiTi耐蚀性能。结果表明,10mM的Tris体系下,聚多巴胺修饰NiTi的耐蚀性能并不是随着多巴胺的浓度增加而增强;相比之下,50mM的Tris体系下,聚多巴胺修饰NiTi的耐腐蚀性能随着多巴胺浓度的增加而增强。
基金supported by the National Natural Science Foundation of China (Grant Nos. 51241001 and 51571134)SDUST Research Fund (No. 2014TDJH104)
文摘In vitro degradation is an important approach to screening appropriate biomedical magnesium（Mg） alloys at low cost. However, corrosion products deposited on Mg alloys exert a critical impact on corrosion resistance. There are no acceptable criteria on the evaluation on degradation rate of Mg alloys. Understanding the degradation behavior of Mg alloys in presence of Tris buffer is necessary. An investigation was made to compare the influence of Tris-HCl and Tris on the corrosion behavior of Mg alloy AZ31 in the presence of various anions of simulated body fluids via hydrogen evolution, p H value and electrochemical tests.The results demonstrated that the Tris-HCl buffer resulted in general corrosion due to the inhibition of the formation of corrosion products and thus increased the corrosion rate of the AZ31 alloy. Whereas Tris gave rise to pitting corrosion or general corrosion due to the fact that the hydrolysis of the amino-group of Tris led to an increase in solution p H value, and promoted the formation of corrosion products and thus a significant reduction in corrosion rate. In addition, the corrosion mechanisms in the presence of Tris-HCl and Tris were proposed. Tris-HCl as a buffer prevented the formation of precipitates of HCO;, SO;,HPO;and H;PO;ions during the corrosion of the AZ31 alloy due to its lower buffering p H value（x.x）.Thus, both the hydrogen evolution rate and corrosion current density of the alloy were approximately one order of magnitude higher in presence of Tris-HCl than Tris and Tris-free saline solutions.
基金supported by the National Natural Science Foundation of China(51962019)the Natural Science Foundation of Gansu Province(20JR5RA469)+1 种基金the Education Department of Gansu Province:"Star of Innovation"Project for Outstanding Graduate Students(2021CXZX-455)the Lanzhou University of Technology Hongliu First-class Discipline Construction Program。
文摘Tris(trimethylsilyl)borate(TMSB) has been intensively studied to improve the performances of lithiumion batteries. However, it is still an interesting issue needed to be resolved for the research on the Li^(+) solvation structure affected by TMSB additive. Herein, the electrochemical tests, quantum chemistry calculations, potential-resolved in-situ electrochemical impedance spectroscopy measurements and surface analyses were used to explore the effects of Li^(+) solvation structure with TMSB additive on the formation of the cathode electrolyte interface(CEI) film in LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)/Li half cells. The results reveal that the TMSB additive is easy to complex with Li^(+) ion, thus weaken the intermolecular force between Li^(+) ions and ethylene carbonate solvent, which is benefit for the cycle performance. Besides, the changed Li^(+) solvation structure results in a thin and dense CEI film containing compounds with Si–O and B–O bonds which is favorable to the transfer of Li^(+) ions. As a result, the performances of the LNCM811/Li half cells are effectively improved. This research provides a new idea to construct a high-performance CEI film by adjusting the Li^(+) solvation structures.
基金supported by the National Natural Science Foundation of China.(Grant No.20174033 and 20254001)the Special Found for Major State Basic Research Project(Grant No.G1999064801)the Committee of Science and Technology of Zhejiang Province.
文摘The ring-opening polymerization of e-caprolactone (CL) initiated by novel single lanthanide tris(4-tert-butylphenolate)s [Ln(OTBP)3] is reported. Single-component La(OTBP)3 can effectively prepare polycaprolactone (PCL) with over 90% yield and viscosity average molecular weight about 60 x 10 under quite mild conditions: molar ratio of CL to initiator is 1000, 60 C, 2 h in toluene. Mechanism study indicates that the monomer inserts into the growing chain via the break of acyl-oxygen bond of CL.
基金Project supported by National Natural Science Foundation of China(51674292)Fundamental Research Funds for the Central Universities of Central South University(2019zzts434)。
文摘Three-dimensional(3D)graphene oxide-tris(4-aminophenyl)amine(GO-TAPAx:y)composites with different GO-to-TAPA mass ratios(x:y)were prepared by a facile one-step ultrasonic treatment.GOTAPAx:y composites were characterized by scanning electron microscopy(SEM),nitrogen(N2)adsorption-desorption isotherms,Fourier transform infrared spectroscopy(FTIR),X-ray photoelectron spectroscopy(XPS)and thermogravimetric analysis(TGA).Behavior and mechanism of GO-TAPAx:yco mposites for the adsorption of rare earth elements(REEs)were investigated.The adso rption capacities of GO-TAPA1;2 composite for Yb^3+,Er^3+,Nd^3+,La^3+and Y^3+are 30.88,26.52,20.60,11.24 and 10.52 mg/g,respectively.Effects of some important parameters including GO-to-TAPA mass ratios,contact time,reaction temperature and initial Yb^3+concentration on the adsorption were evaluated in detail.FTIR spectral and XPS analyses show that the metal complexations and ion exchanges between nitrogen/oxygen-containing species of the adsorbents and REEs are involved in the adsorption procedure besides the conventional adsorption based on specific surface area,indicating the introduction of specific molecules onto GO is beneficial to its adsorption ability.The convenient reusability and applicability of GO-TAPAx:y composites toward real samples also demonstrate their feasibility in the enrichment of REE ions.
文摘Antimony mercaplde heat stabilizer for polyvinyl chlorideis synthesized from antimony trioxide and mercaptocarboxylic acid esters, HS(CH2).COoi-C8H17 (n=1～2) at 100～115 C In the presence of 0. 5%～1 % an organic acid catalyst. Some physicochemicalconstants of the compounds, such as density and refractive index, aredetermined. The complexes are hydrolabll in aqueous solutions andthe bond of Sb-S is weaker than that of Sb-o. The forming bondproperty of antimony tris (mercaptoacid ester ) has been elucidatedby measurement of infrared spectra in comparison with mercaptocarboxylic acid esters. The polyvinyl chloride resins containing antimony mercaptide heat stabilizers, do not darken at elevated temperatures and exhibit a high degree of stability. It is proposed that mercaptocarboxylic acid ester freeradicals can esterify PVC microradicals at carbon atoms with upaired electrons.
文摘α, α＇-Benzylidene bis（4-hydroxycoumarin） derivatives were readily prepared in a few minutes with good yields through the reaction of an aromatic aldehyde and 4-hydroxycoumarin in aqueous media in the presence of catalytic tris（hydrogensulfato） boron [B（HSO_4）_3].
文摘The polymerization of n-hexyl isocyanate(HNCO) was carried out in the presence of a novel single initiator, rare earth tris(2,6-di-tert-butyl-4-methylphenolate)[Ln(OAr)_3]. The influences of reaction conditions such as the monomer concentration, the polymerization temperature and time, and the types of solvents on the polymerization of HNCO were studied. Polymerizations of phenyl, i-propyl, p-tolyl, n-butyl and n-octyl isocyanates with La(OAr)_3 were also examined.
基金supported by the National Natural Science Foundations of China (Nos.81273023 and 81472947)
文摘Tris(2-chloroethyl) phosphate(TCEP) is a typical phosphate flame retardant. Its potential adverse health effects have recently aroused concern. We investigated the seasonal variations of TCEP concentrations in the raw, finished and tap water samples from two drinking water treatment plants(DWTPs) in China, and evaluated the cytotoxicity and apoptosis/necrosis of organic extracts(OEs) in water samples. We enriched TCEP and OEs in water samples by solid-phase extraction method. The TCEP concentrations in water samples were determined by gas chromatography–mass spectrometry. Normal human liver cell line L02 was treated with OEs in the water samples, and then the cytotoxicity and apoptosis/necrosis were measured by 3-(4, 5-dimethyithiazol-2-yl)-2,5-diphenyl-tetrazolium bromide assay and flow cytometry, respectively. The results showed that cytotoxicities of OEs in raw water samples from both DWTPs in summer and winter were stronger than those in spring and autumn, cytotoxicity of OEs in finished and tap water samples from both DWTPs in summer and autumn were stronger than those in spring and winter. In all seasons, the maximal concentrations(100 mL water/mL cell culture) of OEs in the raw water samples from both DWTPs induced late apoptosis/necrosis. The reasons for seasonal variations of TCEP in water samples and potential toxic effects of other pollutants in the water samples need to be further investigated.
基金a Grant-in-Aid for Scientific Research(C), (No19550096) from the Ministry of Education, Science, Sports, and Culture, Japan
文摘The extraction of Eu（Ⅲ） with β-diketone, HA, and monodentate or bidentate Lewis bases, B, into chloroform and the luminescence properties of the extracted species were studied. Pivaloyltrifluoroacetone, Hpta, and 2-thenoyltfifluoroacetone, Htta, were used as the β-diketones. The Lewis bases, B, were tetraethyl methylene diphosphonate, POPO, which was bidentate, and diethyl benzylphosphonate, PhPO which was monodentate. Based on the extraction data, the stability constants, log β, of the first complexes between tfis（β-diketonato）Eu（Ⅲ） and the phosphonate, EuA3B, were determined to be 6.0 for the POPO complex and 3.40 for the PhPO complex. The Eu（Ⅲ） luminescence intensity in the EuA3POPO was larger than EuA3 where A was either pta or tta at similar concentrations of Eu（Ⅲ）, while that in Eu（pta）3PhPO was stronger than EuA3; however, in Eu（tta）3PhPO, it was weaker than Eu（tta）3. The POPO functions as a sensitizer, and the PhPO functions as a quencher for the tta chelate and as a sensitizer for the pta chelate. From the lifetime and quantum yield, φ, of the Eu（Ⅲ） luminescence in the complexes as well as the observation of the extractability of Eu（Ⅲ） with the Hpta and the phosphonates and of the luminescence spectra of the complexes, it was confirmed that the extraction of Eu（Ⅲ） was remarkably enhanced with a β-diketonate and a strong Lewis base, and also the ternary complex that was formed as the extracted species, showed luminescence enhancement. This phenomenon may be due the formation of a strong bond between the Eu（Ⅲ） and the strong Lewis base leading to more hydrophobicity in the extracted species and also to more effective energy transfer from the Lewis base to the Eu（Ⅲ）. It was not significant whether the donor atoms were N or O.
