Analysis on the space group distribution in 78 substituted phenols re-vealed its unusual high frequencies in groups with non-centrosymmetry or polar axis orhigher symmetry or Z' > 1. Based on the characteristic...Analysis on the space group distribution in 78 substituted phenols re-vealed its unusual high frequencies in groups with non-centrosymmetry or polar axis orhigher symmetry or Z' > 1. Based on the characteristics of intermolecular H-bondsformed by two OH groups,the space group distribution could be rationalized well.展开更多
An unusual substitution reaction of an aromatic sulfonic group based on 3-carbonyl-4-phenolsulfonic acid was discovered in a diazo-coupling process. The reaction occurred under mild reaction conditions （pH 8.0-9.0, 0...An unusual substitution reaction of an aromatic sulfonic group based on 3-carbonyl-4-phenolsulfonic acid was discovered in a diazo-coupling process. The reaction occurred under mild reaction conditions （pH 8.0-9.0, 0-5 ℃, solvent： water） within a short reaction time （1 h）. A plausible substitution reaction mechanism by phenol-ketone resonance was proposed.展开更多
New calix[4]arene derivatives containing nitro,amino and benzoyl in the upper and lower rims of molecule were successfully synthesized.Their effectiveness towards K+ and Hg2+ across bubbling liquid membrane(BLM) was e...New calix[4]arene derivatives containing nitro,amino and benzoyl in the upper and lower rims of molecule were successfully synthesized.Their effectiveness towards K+ and Hg2+ across bubbling liquid membrane(BLM) was examined.For K+ ion transfer,preserving phenolic hydroxyl in the lower rim of calix[4]arene could enhance its transport ability.When benzoyl replaced phenolic hydroxyl,the transport would fall off,because benzoyl caused steric hindrance on the K+ transfer.The study also revealed that the group having the electron-withdrawing conjugative effect on phenolic hydroxyl,-NO2 in the upper rim of calix[4]arene,made transport ability of calix[4]arene fall off.On the contrary,-NH2 that had electron-repulsive conjugative effect enhanced the transport ability of the compound.For Hg2+ ion,only -NH2 in the upper rim of calix[4]arenes had high affinity for it and contributed to Hg2+ transfer.Transport amount of Hg2+ ion increased with increasing calix[4]arene5 concentration and ΔpH in BLM.展开更多
Mn^(4+)non-equivalent doped fluorides with long-wavelength and narrow-spectrum emission enable ultrawide-gamut display applications.However,existing synthesis schemes result in non-equivalent doped materials with subo...Mn^(4+)non-equivalent doped fluorides with long-wavelength and narrow-spectrum emission enable ultrawide-gamut display applications.However,existing synthesis schemes result in non-equivalent doped materials with suboptimal quantum efficiency.This study develops a group-substituted single-crystal(GSC)method assisted by a pre-nucleation strategy to achieve the growth of high-quality K_(2)LiGaF_(6):Mn^(4+)single crystals with optimal photoluminescence performance and chemical stability.To avoid the adverse effects caused by the long reaction time of Mn^(4+),the GSC method achieves rapid preparation of K_(2)LiGaF_(6):Mn^(4+)single crystals within 12 hours,which is 90%quicker than typical methods and beneficial in preventing the degradation of Mn^(4+).As a result,K_(2)LiGaF_(6):Mn^(4+)not only achieves a high external quantum efficiency of 57.15%but also exhibits excellent stability.A white light-emitting diode(LED)prepared using a blue light chip,commercial green phosphor(β-Sialon:Eu^(2+))and the optimized KLGFM-GSC can achieve an ultrawide color gamut display of 109.3%National Television Standards Committee(NTSC)or 80.7%Recommendation BT.2020(Rec.2020).In summary,synthesizing single crystals with the GSC method has good universality,opening up new ways for the preparation of high-quality Mn^(4+)non-equivalent doped fluoride single crystals and promoting the development of ultrawide color gamut display applications.展开更多
Three substituted α,β,β-trifluorostyrenes(TFS's),i.e.,p-thiomethyltrifluorostyrene(4), p-cyclopropyltrifluorostyrene(5)and p-t-butyltrifluorostyrene(6),have been synthesized.The rate constants(k_2)of the therma...Three substituted α,β,β-trifluorostyrenes(TFS's),i.e.,p-thiomethyltrifluorostyrene(4), p-cyclopropyltrifluorostyrene(5)and p-t-butyltrifluorostyrene(6),have been synthesized.The rate constants(k_2)of the thermal cyclodimerization of these compounds have been measured in the tem- perature range 120—160℃.The polar parameters σ_(mb) of these TFS's calculated from ^(19)F NMR chemi- cal shifts are:for p-thiomethyl,-0.18;p-cyclopropyl,-0.31 and p-t-butyl,-0.22.The spin delo- calization substituent parameters σ'_T(140°)of p-thiomethyl,cyclopropyl and t-butyl groups are 0.59, 0.27 and 0.30 respectively.Thus all of these groups act as electron-donating groups which can also effectively stabilize a spin.展开更多
Ozonation has been proved to be a promising approach for eliminating emerging pollutants in wastewater.In previous studies,emerging pollutants including diverse pharmaceuticals were found to exhibit significantly diff...Ozonation has been proved to be a promising approach for eliminating emerging pollutants in wastewater.In previous studies,emerging pollutants including diverse pharmaceuticals were found to exhibit significantly different ozonation reactivity.However,how the structural differences of emerging pollutants determine ozonation reactivity and mechanisms are still ambiguous.In this work,ozonation of dimethylaminophenazone(DMP)and acetylaminophenazone(AAA)with the same parent structure of phenazone but different substitution groups was investigated,in order to probe influencing mechanisms of structural differences on ozonation reactivity.Results show that DMP reacts with ozone and HOalmost 2 and 1 order of magnitude faster than AAA,respectively.At pH 8,HO· accelerates ozonation of DMP,but decreases ozonation of AAA.Competition simultaneously decreases degradation rate of the two phenazones,but effects on AAA are more significant than that on DMP.According to theoretical calculation results,differences in ozonation reactivity and mechanisms of the two phenazones can be mainly attributed to different substitution groups.The dimethylamino group in the structure of DMP increases the ozonation reactivity of phenazone by increasing reaction orbital energies and altering reaction sites,while the acetylamino group in the structure of AAA decreases the reaction orbital energy and therefore lowers the reactivity.展开更多
文摘Analysis on the space group distribution in 78 substituted phenols re-vealed its unusual high frequencies in groups with non-centrosymmetry or polar axis orhigher symmetry or Z' > 1. Based on the characteristics of intermolecular H-bondsformed by two OH groups,the space group distribution could be rationalized well.
基金supported by the National Natural Science Foundation for Young Scholar of China(No.21276042)the National Science and Technology Pillar Program(No. 2013BAF08B06)Jiaogai Foundation of DUT(No.JGXM201224)
文摘An unusual substitution reaction of an aromatic sulfonic group based on 3-carbonyl-4-phenolsulfonic acid was discovered in a diazo-coupling process. The reaction occurred under mild reaction conditions （pH 8.0-9.0, 0-5 ℃, solvent： water） within a short reaction time （1 h）. A plausible substitution reaction mechanism by phenol-ketone resonance was proposed.
基金Natural Science Foundation of Education Department of Anhui Province,China(No. KJ2011B021)
文摘New calix[4]arene derivatives containing nitro,amino and benzoyl in the upper and lower rims of molecule were successfully synthesized.Their effectiveness towards K+ and Hg2+ across bubbling liquid membrane(BLM) was examined.For K+ ion transfer,preserving phenolic hydroxyl in the lower rim of calix[4]arene could enhance its transport ability.When benzoyl replaced phenolic hydroxyl,the transport would fall off,because benzoyl caused steric hindrance on the K+ transfer.The study also revealed that the group having the electron-withdrawing conjugative effect on phenolic hydroxyl,-NO2 in the upper rim of calix[4]arene,made transport ability of calix[4]arene fall off.On the contrary,-NH2 that had electron-repulsive conjugative effect enhanced the transport ability of the compound.For Hg2+ ion,only -NH2 in the upper rim of calix[4]arenes had high affinity for it and contributed to Hg2+ transfer.Transport amount of Hg2+ ion increased with increasing calix[4]arene5 concentration and ΔpH in BLM.
基金financially supported by the National Key Research and Development Program of China(2022YFB3503800 and 2022YFB3503802)National Natural Science Foundation of China(Grant No.52502172).
文摘Mn^(4+)non-equivalent doped fluorides with long-wavelength and narrow-spectrum emission enable ultrawide-gamut display applications.However,existing synthesis schemes result in non-equivalent doped materials with suboptimal quantum efficiency.This study develops a group-substituted single-crystal(GSC)method assisted by a pre-nucleation strategy to achieve the growth of high-quality K_(2)LiGaF_(6):Mn^(4+)single crystals with optimal photoluminescence performance and chemical stability.To avoid the adverse effects caused by the long reaction time of Mn^(4+),the GSC method achieves rapid preparation of K_(2)LiGaF_(6):Mn^(4+)single crystals within 12 hours,which is 90%quicker than typical methods and beneficial in preventing the degradation of Mn^(4+).As a result,K_(2)LiGaF_(6):Mn^(4+)not only achieves a high external quantum efficiency of 57.15%but also exhibits excellent stability.A white light-emitting diode(LED)prepared using a blue light chip,commercial green phosphor(β-Sialon:Eu^(2+))and the optimized KLGFM-GSC can achieve an ultrawide color gamut display of 109.3%National Television Standards Committee(NTSC)or 80.7%Recommendation BT.2020(Rec.2020).In summary,synthesizing single crystals with the GSC method has good universality,opening up new ways for the preparation of high-quality Mn^(4+)non-equivalent doped fluoride single crystals and promoting the development of ultrawide color gamut display applications.
基金This work was financially supported by the National Natural Science Foundation of China.
文摘Three substituted α,β,β-trifluorostyrenes(TFS's),i.e.,p-thiomethyltrifluorostyrene(4), p-cyclopropyltrifluorostyrene(5)and p-t-butyltrifluorostyrene(6),have been synthesized.The rate constants(k_2)of the thermal cyclodimerization of these compounds have been measured in the tem- perature range 120—160℃.The polar parameters σ_(mb) of these TFS's calculated from ^(19)F NMR chemi- cal shifts are:for p-thiomethyl,-0.18;p-cyclopropyl,-0.31 and p-t-butyl,-0.22.The spin delo- calization substituent parameters σ'_T(140°)of p-thiomethyl,cyclopropyl and t-butyl groups are 0.59, 0.27 and 0.30 respectively.Thus all of these groups act as electron-donating groups which can also effectively stabilize a spin.
基金supported by the National High Technology Research and Development of China(No.2013AA06A305)Program for Changjiang Scholars and Innovative Research Team in University,China Postdoctoral Science Foundation(2013T60128)Hundreds Talents Program of Chinese Academy of Sciences.
文摘Ozonation has been proved to be a promising approach for eliminating emerging pollutants in wastewater.In previous studies,emerging pollutants including diverse pharmaceuticals were found to exhibit significantly different ozonation reactivity.However,how the structural differences of emerging pollutants determine ozonation reactivity and mechanisms are still ambiguous.In this work,ozonation of dimethylaminophenazone(DMP)and acetylaminophenazone(AAA)with the same parent structure of phenazone but different substitution groups was investigated,in order to probe influencing mechanisms of structural differences on ozonation reactivity.Results show that DMP reacts with ozone and HOalmost 2 and 1 order of magnitude faster than AAA,respectively.At pH 8,HO· accelerates ozonation of DMP,but decreases ozonation of AAA.Competition simultaneously decreases degradation rate of the two phenazones,but effects on AAA are more significant than that on DMP.According to theoretical calculation results,differences in ozonation reactivity and mechanisms of the two phenazones can be mainly attributed to different substitution groups.The dimethylamino group in the structure of DMP increases the ozonation reactivity of phenazone by increasing reaction orbital energies and altering reaction sites,while the acetylamino group in the structure of AAA decreases the reaction orbital energy and therefore lowers the reactivity.
