以TiO_2/Ti为阳极,活性炭纤维(ACF)为阴极,建立新型光电-Fenton体系。采用Box-Behnken Design(BBD)响应曲面法设计实验,考察初始pH、反应时间、电流密度和曝气量4个因素及其交互作用对光电-Fenton体系中·OH生成量的影响,建立·...以TiO_2/Ti为阳极,活性炭纤维(ACF)为阴极,建立新型光电-Fenton体系。采用Box-Behnken Design(BBD)响应曲面法设计实验,考察初始pH、反应时间、电流密度和曝气量4个因素及其交互作用对光电-Fenton体系中·OH生成量的影响,建立·OH生成量与影响因素间的数学模型,并进行参数优化,探索光电-Fenton运行的最优参数值。研究表明,4因素对·OH生成量的影响强弱顺序为:pH>反应时间>电流密度>曝气量,且4因素两两之间均存在一定的交互作用,其中反应时间与pH和曝气量之间的交互效应尤为显著。在pH 4.49、反应时间130.49 min、电流密度6.99 m A·cm-2、曝气量1 474.90 m L·min^(-1)条件下,·OH的生成量最大。经实验验证,实际值与模型预测值拟合性良好,偏差仅为2.35%。展开更多
A new binuclear Cu（Ⅱ） complex with nitronyl nitroxide radicals [Cu（NIT3Py）2Cl2]2（NIT3Py = 2-（3＇-pyridinyl）-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide） has been synthesized and structurally characterized b...A new binuclear Cu（Ⅱ） complex with nitronyl nitroxide radicals [Cu（NIT3Py）2Cl2]2（NIT3Py = 2-（3＇-pyridinyl）-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide） has been synthesized and structurally characterized by X-ray diffraction analysis.It crystallizes in monoclinic,space group C2/c with a = 38.483（4）,b = 7.2450（8）,c = 27.559（3） ,β = 134.0180（10）°,V = 5525.6（10） 3,C48H64Cl4Cu2N12O8,Mr = 1206.00,Z = 4,Dc = 1.450 g/cm3,μ（MoKα） = 1.025 mm-1,F（000） = 2504,S = 1.066,the final R = 0.0471 and wR = 0.1121 for 3286 observed reflections（I 2σ（I））.The title complex consists of centrosymmetric dinuclear units [Cu（NIT3Py）2Cl2]2,in which the copper ions are square-pyramidally coordinated by two pyridyl nitrogen atoms of two radical ligands and three chlorine anions,two of which bridge the copper ions.The magnetic measurements show ferromagnetic interactions between the copper ions and the radical ligands.展开更多
Knowledge about electronic structures is important to gain an understanding of the unique functional properties of diradicaloids.In this study,we synthesized and characterized a diradicaloid in which two phenalenyl ra...Knowledge about electronic structures is important to gain an understanding of the unique functional properties of diradicaloids.In this study,we synthesized and characterized a diradicaloid in which two phenalenyl radical sites are coupled antiferromagnetically via a through-space interaction.The results of quantum chemical,physicochemical(^(1)H NMR,electronic absorption,cyclic voltammetry,SQUID,ESR),and chemical reactivity studies show that this diradicaloid has singlet diradical character.An assessment of the nature of the bonding interaction between two radical sites in this species using DFT calculations demonstrates that a small spatial overlap between the two SOMOs in this diradicaloid provides an efficient electron exchange path for the singlet state to be substantially lower in energy than the triplet state.展开更多
In this paper, the reaction mechanism of HOCO with its radical has been investigated deeply by density functional theory（DFT）, while the geometries and harmonic vibration frequencies of the reactants, intermediates,...In this paper, the reaction mechanism of HOCO with its radical has been investigated deeply by density functional theory（DFT）, while the geometries and harmonic vibration frequencies of the reactants, intermediates, transition states and products have been calculated at the B3LYP/6-311＋＋G＊＊ level. The CCSD（T）/cc-p VQZ method was used to further calculate the single-point energy of each stationary point along the reaction channel. The result shows that channels（b） and（d） via carbon-carbon intermediates are competing with the ones（e）,（f）,（i） and（l） through carbon-oxygen intermediates, and the six channels are dominant for the title reaction to produce HCOOH and CO2. The result also indicates that the hydrogen abstraction from the HOCO radical can be performed quickly by the self-interaction of HOCO in the absence of other radicals or atoms, which indirectly proves for the first time that the ground-state cis-HOCO radical is not decomposed by the tunneling effect. In addition, the charges of natural population analysis（NPA） and the variation of chemical bonds have been analyzed by the Natural Bond Orbital（NBO） method along with the important reaction path.展开更多
Rare-earth metal boroxides are not only rare and of great synthetic challenge but also important theoretically due to their unrevealed bonding characteristics.In this paper,we report the synthesis,characterization,and...Rare-earth metal boroxides are not only rare and of great synthetic challenge but also important theoretically due to their unrevealed bonding characteristics.In this paper,we report the synthesis,characterization,and bonding characteristics of the 4f-block metal boroxide complexes ^(Mes)DAD_(2)LuOB(C_(6)F_(5))X(4-Lu,X=C_(6)F_(5);5-Lu,X=NC_(13)H_(10))with two chelating radical-anionic 1,4-diazabutadiene(DAD)ligands.The synthesis of 4-Lu or 5-Lu involved three steps,during which the radical-anionic DAD ligands could be kept stable:(1)the reaction of LuCl_(3),^(Mes)DAD,and potassium graphite(KC8)afforded the diradical rare-earth metal chloride ^(Mes)DAD_(2)LuCl·tetrahydrofuran(THF)(1-Lu);(2)the salt metathesis of 1-Lu with two alkali metal amides gave lutetium bis(diazabutadiene)amides 2-Lu or 3-Lu,respectively;and(3)2-Lu or 3-Lu reacted with B(C_(6)F_(5))_(3)·H_(2)O,resulting in the formation of rare-earth metal boroxides 4-Lu or 5-Lu.The radical-anionic nature of DAD ligands in these complexes were proven by their bond lengths and coordination modes in single-crystal structures.DFT calculations clearly show the bonding of 4-Lu can be divided into three major types of Lu-O orbital interactions,which can be categorized asσ-donation,π-donation,and d-π-conjugation.The triple Lu-O orbital interactions cooperatively make a Lu-O single bond and contribute to the linear Lu-O-B structure.展开更多
Introduction of substituents to organic radical is important to increase the stability and realize its applications as multifunctional materials.In this work,pentafluorophenyl group was introduced to 6-position of oly...Introduction of substituents to organic radical is important to increase the stability and realize its applications as multifunctional materials.In this work,pentafluorophenyl group was introduced to 6-position of olympicenyl radical(OR)via a newly designed synthetic strategy to afford the fourth OR derivative,OR4.Due to the combined electro-withdrawing effect and steric hindrance of pentafluorophenyl,OR4 was stable and isolable in crystalline state.展开更多
Quantum calculations(mainly DFT)and molecular dynamics are increasingly effective tools to evaluate the physical chemical properties of natural and bio-inspired compounds.Free Radical Scavenging Capacity.Thermodynamic...Quantum calculations(mainly DFT)and molecular dynamics are increasingly effective tools to evaluate the physical chemical properties of natural and bio-inspired compounds.Free Radical Scavenging Capacity.Thermodynamic parameters(mainly bond dissociation enthalpies(BDE)of the O-H phenolic bond)allowed an accurate prediction of the antioxidant capacities of展开更多
文摘以TiO_2/Ti为阳极,活性炭纤维(ACF)为阴极,建立新型光电-Fenton体系。采用Box-Behnken Design(BBD)响应曲面法设计实验,考察初始pH、反应时间、电流密度和曝气量4个因素及其交互作用对光电-Fenton体系中·OH生成量的影响,建立·OH生成量与影响因素间的数学模型,并进行参数优化,探索光电-Fenton运行的最优参数值。研究表明,4因素对·OH生成量的影响强弱顺序为:pH>反应时间>电流密度>曝气量,且4因素两两之间均存在一定的交互作用,其中反应时间与pH和曝气量之间的交互效应尤为显著。在pH 4.49、反应时间130.49 min、电流密度6.99 m A·cm-2、曝气量1 474.90 m L·min^(-1)条件下,·OH的生成量最大。经实验验证,实际值与模型预测值拟合性良好,偏差仅为2.35%。
基金supported by the National Natural Science Foundation of China (No. 20901059)the Technological Development Foundation Project of Tianjin Educational Committee (No. 20080503)
文摘A new binuclear Cu（Ⅱ） complex with nitronyl nitroxide radicals [Cu（NIT3Py）2Cl2]2（NIT3Py = 2-（3＇-pyridinyl）-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide） has been synthesized and structurally characterized by X-ray diffraction analysis.It crystallizes in monoclinic,space group C2/c with a = 38.483（4）,b = 7.2450（8）,c = 27.559（3） ,β = 134.0180（10）°,V = 5525.6（10） 3,C48H64Cl4Cu2N12O8,Mr = 1206.00,Z = 4,Dc = 1.450 g/cm3,μ（MoKα） = 1.025 mm-1,F（000） = 2504,S = 1.066,the final R = 0.0471 and wR = 0.1121 for 3286 observed reflections（I 2σ（I））.The title complex consists of centrosymmetric dinuclear units [Cu（NIT3Py）2Cl2]2,in which the copper ions are square-pyramidally coordinated by two pyridyl nitrogen atoms of two radical ligands and three chlorine anions,two of which bridge the copper ions.The magnetic measurements show ferromagnetic interactions between the copper ions and the radical ligands.
基金the JSPS for KAKENHI funding(Grant No.JP21H01918 and JP20K21194)a Grant-in-Aid for Transformative Research Areas(A)“Condensed Conjugation”(JSPS for KAKENHI funding Grant No.JP20H05865)from MEXT,Japan.
文摘Knowledge about electronic structures is important to gain an understanding of the unique functional properties of diradicaloids.In this study,we synthesized and characterized a diradicaloid in which two phenalenyl radical sites are coupled antiferromagnetically via a through-space interaction.The results of quantum chemical,physicochemical(^(1)H NMR,electronic absorption,cyclic voltammetry,SQUID,ESR),and chemical reactivity studies show that this diradicaloid has singlet diradical character.An assessment of the nature of the bonding interaction between two radical sites in this species using DFT calculations demonstrates that a small spatial overlap between the two SOMOs in this diradicaloid provides an efficient electron exchange path for the singlet state to be substantially lower in energy than the triplet state.
基金supported by the National Natural Science Foundation of China(50673085,20677053)the Basic Research Programs of Qingdao Science and Technology Plan(No.13-1-4-233-jch)
文摘In this paper, the reaction mechanism of HOCO with its radical has been investigated deeply by density functional theory（DFT）, while the geometries and harmonic vibration frequencies of the reactants, intermediates, transition states and products have been calculated at the B3LYP/6-311＋＋G＊＊ level. The CCSD（T）/cc-p VQZ method was used to further calculate the single-point energy of each stationary point along the reaction channel. The result shows that channels（b） and（d） via carbon-carbon intermediates are competing with the ones（e）,（f）,（i） and（l） through carbon-oxygen intermediates, and the six channels are dominant for the title reaction to produce HCOOH and CO2. The result also indicates that the hydrogen abstraction from the HOCO radical can be performed quickly by the self-interaction of HOCO in the absence of other radicals or atoms, which indirectly proves for the first time that the ground-state cis-HOCO radical is not decomposed by the tunneling effect. In addition, the charges of natural population analysis（NPA） and the variation of chemical bonds have been analyzed by the Natural Bond Orbital（NBO） method along with the important reaction path.
基金supported by the Natural Science Foundation of China(nos.21725201 and 21890721).
文摘Rare-earth metal boroxides are not only rare and of great synthetic challenge but also important theoretically due to their unrevealed bonding characteristics.In this paper,we report the synthesis,characterization,and bonding characteristics of the 4f-block metal boroxide complexes ^(Mes)DAD_(2)LuOB(C_(6)F_(5))X(4-Lu,X=C_(6)F_(5);5-Lu,X=NC_(13)H_(10))with two chelating radical-anionic 1,4-diazabutadiene(DAD)ligands.The synthesis of 4-Lu or 5-Lu involved three steps,during which the radical-anionic DAD ligands could be kept stable:(1)the reaction of LuCl_(3),^(Mes)DAD,and potassium graphite(KC8)afforded the diradical rare-earth metal chloride ^(Mes)DAD_(2)LuCl·tetrahydrofuran(THF)(1-Lu);(2)the salt metathesis of 1-Lu with two alkali metal amides gave lutetium bis(diazabutadiene)amides 2-Lu or 3-Lu,respectively;and(3)2-Lu or 3-Lu reacted with B(C_(6)F_(5))_(3)·H_(2)O,resulting in the formation of rare-earth metal boroxides 4-Lu or 5-Lu.The radical-anionic nature of DAD ligands in these complexes were proven by their bond lengths and coordination modes in single-crystal structures.DFT calculations clearly show the bonding of 4-Lu can be divided into three major types of Lu-O orbital interactions,which can be categorized asσ-donation,π-donation,and d-π-conjugation.The triple Lu-O orbital interactions cooperatively make a Lu-O single bond and contribute to the linear Lu-O-B structure.
基金support from the National Natural Science Foundation of China(Grant Nos.22201206,22222110,21971187)the National Science Foundation Of Tianjin(19JCJQJC62700)+1 种基金the China Postdoctoral Science Foundation(2022M722358)the Haihe Laboratory of Sustainable Chemical Transformations.
文摘Introduction of substituents to organic radical is important to increase the stability and realize its applications as multifunctional materials.In this work,pentafluorophenyl group was introduced to 6-position of olympicenyl radical(OR)via a newly designed synthetic strategy to afford the fourth OR derivative,OR4.Due to the combined electro-withdrawing effect and steric hindrance of pentafluorophenyl,OR4 was stable and isolable in crystalline state.
文摘Quantum calculations(mainly DFT)and molecular dynamics are increasingly effective tools to evaluate the physical chemical properties of natural and bio-inspired compounds.Free Radical Scavenging Capacity.Thermodynamic parameters(mainly bond dissociation enthalpies(BDE)of the O-H phenolic bond)allowed an accurate prediction of the antioxidant capacities of
