Several new chiral organogallium and indium complexes with chiral Salen (1 and 2) as anxciliary ligands have been synthesized and characterized by elemental analysis, IR, 1H NMR and Mass spectroscopy. For the gallium...Several new chiral organogallium and indium complexes with chiral Salen (1 and 2) as anxciliary ligands have been synthesized and characterized by elemental analysis, IR, 1H NMR and Mass spectroscopy. For the gallium, mono and bimetallic complexes were obtained, whereas ring closure complexes of indium were obtained.展开更多
Three kinds of bimetallic Schiff base titanium complexes with different substituent moieties on organic ligands were synthesized.Ring-opening polymerizations （ROP） of lactides were carried out by using these titaniu...Three kinds of bimetallic Schiff base titanium complexes with different substituent moieties on organic ligands were synthesized.Ring-opening polymerizations （ROP） of lactides were carried out by using these titanium complexes as catalysts.The polymerization data and kinetic studies showed that complex 1a had the highest activity and complex 2a had the lowest activity for ROP of lactides.Moreover,all these three newly synthesized bimetallic titanium complexes showed higher polymerization activity and better molecular weight control than their monometallic counterparts reported in our previous work.展开更多
A number of salen-metal complexes were prepared and their enantioselective catalytic properties toward the asymmetric iodolactonization of （E）- and （Z）-5-substituted-4-pentenoic acid derivatives were investigated....A number of salen-metal complexes were prepared and their enantioselective catalytic properties toward the asymmetric iodolactonization of （E）- and （Z）-5-substituted-4-pentenoic acid derivatives were investigated. The catalyst system based on salen-Co（II） complex exhibited moderate to good enantioselectivity with the e.e. value ranging from 53% to 74%, as well as high regioselectivity of δ- vs. γ-iodolactones. The salen-Co（II） complex showed the highest enantioselectivity on the asymmetric iodolactonizations of （Z）-5-substituted-4-pentenoic acid derivatives among these reagent-controlled iodolactonization protocols known so far.展开更多
A nickel salen complex was encapsulated in the supercages of nanozeolite NaA,LTA(linde type A)structure,using the flexible ligand method.The electrochemical behavior and electrocatalytic activity of a carbon paste ele...A nickel salen complex was encapsulated in the supercages of nanozeolite NaA,LTA(linde type A)structure,using the flexible ligand method.The electrochemical behavior and electrocatalytic activity of a carbon paste electrode(CPE)modified with Ni(II)‐Salen‐A(Ni(II)‐SalenA/CPE)for hydrazine oxidation in0.1mol/L NaOH solution were investigated by cyclic voltammetry,chronoamperometry,and chronocoulometry.First,organic‐template‐free synthesis of nanozeolite LTA was performed and the obtained material was characterized by various techniques.The average particle size of the LTA crystals was estimated to be56.1and72nm by X‐ray diffraction and particle size analysis,respectively.The electron transfer coefficient was found to be0.64and the catalytic rate constant for oxidation of hydrazine at the redox sites of Ni(II)‐SalenA/CPE was found to be1.03×105cm3/(mol·s).Investigation of the electrocatalytic mechanism suggested that oxidation of hydrazine occurred through reaction with Ni3+(Salen)O(OH)and also direct electrooxidation.The anodic peak currents revealed a linear dependence on the square root of the scan rate,indicating a diffusion‐controlled process,and the diffusion coefficient of hydrazine was found to be1.18×10?7cm2/s.The results indicated that Ni(II)‐SalenA/CPE displays good electrocatalytic activity toward hydrazine oxidation owing to the porous structure of nanozeolite LTA and the Ni(II)‐Salen complex.Finally,the general reaction mechanism for the electrooxidation of hydrazine on Ni(II)‐SalenA/CPE in alkaline solution involves the transfer of four electrons,in which the first electron transfer reaction acts as the rate‐limiting step followed by a three‐electron process to generate environmentally friendly nitrogen and water as final products.展开更多
The synthesis and characterization of N,N＇-bis（salicylidene） ethylenediamine, Salen said that were carried out. The behavior of this ligand has been studied in solution in solvent homogeneous and heterogeneous syst...The synthesis and characterization of N,N＇-bis（salicylidene） ethylenediamine, Salen said that were carried out. The behavior of this ligand has been studied in solution in solvent homogeneous and heterogeneous systems in sulphate medium. The use of pH-metric titration, GRAN and JOB＇s methods have permitted the determination of different parameters governing the behavior of Salen in solution such as the acidity constant, the stability constant, the nature of the interaction solvent-solute, the solvation number, the stoichiometry of extracted complex etc.. Then the extraction of the Salen was finally undertaken to words the copper （II） sulfate medium. The pH of complexation, extraction time, the number of protons exchanged and the number of ligands have been finally determined.展开更多
Spin-crossover(SCO)metal complexes are expected to be widely used in data storage materials,display devices and sensors.Although a lot of spin-crossover photoswitches have been developed,the reversible photomodulation...Spin-crossover(SCO)metal complexes are expected to be widely used in data storage materials,display devices and sensors.Although a lot of spin-crossover photoswitches have been developed,the reversible photomodulation cases that work at room temperature are limited.Herein,a novel cobalt complex o-1-Co(II)wherein the salen unit bridges with bis-diarylethene has been designed as switch to construct"off-on"logic operation at room temperature.The complex o-1-Co(II)displays an abrupt,reversible and hysteretic spin crossover(T1/2↓=166 K,T1/2↑=177 K,andΔT1/2=11 K)between the high-spin(HS)and low-spin(LS)states.Meanwhile,photocyclization of o-1-Co(II)with UV light produces a photoresponsive closed form c-1-Co(II),which always stays at low-spin without SCO at all.Moreover,the magnetic switching of the complex can also be achieved with redox reactions between Co(II)and Co(III).展开更多
Six novel chiral dinuclear Salen complexes[Cu 2 L 1 ·H 2 O(3a),Cu 2 L 2 (3b),Ni 2 L 1 ·2H 2 O(4a),Ni 2 L 2 (4b),Mn 2 Cl 2 L 1 ·H 2 O(5a),Mn 2 Cl 2 L 2 (5b)]have been synthesized(L 1 and L 2 are chiral d...Six novel chiral dinuclear Salen complexes[Cu 2 L 1 ·H 2 O(3a),Cu 2 L 2 (3b),Ni 2 L 1 ·2H 2 O(4a),Ni 2 L 2 (4b),Mn 2 Cl 2 L 1 ·H 2 O(5a),Mn 2 Cl 2 L 2 (5b)]have been synthesized(L 1 and L 2 are chiral dimeric Salen ligands with different chain length which were synthesized from(R,R) - diaminocyclohexane,salicylaldehyde,4,4 ’- (1,10 - decaneoxy)sali - cylaldehyde,4,4 ’- (1,6 - hexyloxy)salicylaldehyde).These compounds were charactered by elemental analysis,1 H NMR,FT - IR,UV - Vis and CD spectra.The FT - IR,UV - Vis and CD spectra were discussed and compared with those of monomeric ligand and complex in detail.It was found that the spectra properties of compounds of differ - ent chain length were almost alike,and the properties of dimeric and monomeric compound were similar too.Furthermore Cotton effect and Cotton split of CD spectra of these chiral compounds were explained by the exciton interaction theory.It seemed that the direction of Cotton split depend on the configuration of diaminohexane.(R,R) - diaminohexane determine the chirality of Salen compounds as negative,and the positive and negative compo - nent of Cotton split lie at higher and lower energy respectively.展开更多
基金the National Natural Science Foundation of China (20102002) Science Foundation of Jiangsu Province (BK2001030) and the 863 High Technology Program for their financial support. The research funds for Y. Pan from Qin-Lan Program of Jiangsu Province and
文摘Several new chiral organogallium and indium complexes with chiral Salen (1 and 2) as anxciliary ligands have been synthesized and characterized by elemental analysis, IR, 1H NMR and Mass spectroscopy. For the gallium, mono and bimetallic complexes were obtained, whereas ring closure complexes of indium were obtained.
文摘Three kinds of bimetallic Schiff base titanium complexes with different substituent moieties on organic ligands were synthesized.Ring-opening polymerizations （ROP） of lactides were carried out by using these titanium complexes as catalysts.The polymerization data and kinetic studies showed that complex 1a had the highest activity and complex 2a had the lowest activity for ROP of lactides.Moreover,all these three newly synthesized bimetallic titanium complexes showed higher polymerization activity and better molecular weight control than their monometallic counterparts reported in our previous work.
文摘A number of salen-metal complexes were prepared and their enantioselective catalytic properties toward the asymmetric iodolactonization of （E）- and （Z）-5-substituted-4-pentenoic acid derivatives were investigated. The catalyst system based on salen-Co（II） complex exhibited moderate to good enantioselectivity with the e.e. value ranging from 53% to 74%, as well as high regioselectivity of δ- vs. γ-iodolactones. The salen-Co（II） complex showed the highest enantioselectivity on the asymmetric iodolactonizations of （Z）-5-substituted-4-pentenoic acid derivatives among these reagent-controlled iodolactonization protocols known so far.
文摘A nickel salen complex was encapsulated in the supercages of nanozeolite NaA,LTA(linde type A)structure,using the flexible ligand method.The electrochemical behavior and electrocatalytic activity of a carbon paste electrode(CPE)modified with Ni(II)‐Salen‐A(Ni(II)‐SalenA/CPE)for hydrazine oxidation in0.1mol/L NaOH solution were investigated by cyclic voltammetry,chronoamperometry,and chronocoulometry.First,organic‐template‐free synthesis of nanozeolite LTA was performed and the obtained material was characterized by various techniques.The average particle size of the LTA crystals was estimated to be56.1and72nm by X‐ray diffraction and particle size analysis,respectively.The electron transfer coefficient was found to be0.64and the catalytic rate constant for oxidation of hydrazine at the redox sites of Ni(II)‐SalenA/CPE was found to be1.03×105cm3/(mol·s).Investigation of the electrocatalytic mechanism suggested that oxidation of hydrazine occurred through reaction with Ni3+(Salen)O(OH)and also direct electrooxidation.The anodic peak currents revealed a linear dependence on the square root of the scan rate,indicating a diffusion‐controlled process,and the diffusion coefficient of hydrazine was found to be1.18×10?7cm2/s.The results indicated that Ni(II)‐SalenA/CPE displays good electrocatalytic activity toward hydrazine oxidation owing to the porous structure of nanozeolite LTA and the Ni(II)‐Salen complex.Finally,the general reaction mechanism for the electrooxidation of hydrazine on Ni(II)‐SalenA/CPE in alkaline solution involves the transfer of four electrons,in which the first electron transfer reaction acts as the rate‐limiting step followed by a three‐electron process to generate environmentally friendly nitrogen and water as final products.
文摘The synthesis and characterization of N,N＇-bis（salicylidene） ethylenediamine, Salen said that were carried out. The behavior of this ligand has been studied in solution in solvent homogeneous and heterogeneous systems in sulphate medium. The use of pH-metric titration, GRAN and JOB＇s methods have permitted the determination of different parameters governing the behavior of Salen in solution such as the acidity constant, the stability constant, the nature of the interaction solvent-solute, the solvation number, the stoichiometry of extracted complex etc.. Then the extraction of the Salen was finally undertaken to words the copper （II） sulfate medium. The pH of complexation, extraction time, the number of protons exchanged and the number of ligands have been finally determined.
基金the National Natural Science Foundation of China for the Science Center Program(21788102)the Creative Research Groups(21421004)and Key Project(21636002)+6 种基金the National Natural Science Foundation of China(21905091)the Shanghai Municipal Science and Technology Major Project(Grant 2018SHZDZX03)the Innovation Program of Shanghai Municipal Education CommissionScientific Committee of Shanghai(15XD1501400)the Program of Introducing Talents of Discipline to Universities(B16017)the Shanghai Pujiang Program(18PJ1402200)China Postdoctoral Science Foundation(2019M651418)。
文摘Spin-crossover(SCO)metal complexes are expected to be widely used in data storage materials,display devices and sensors.Although a lot of spin-crossover photoswitches have been developed,the reversible photomodulation cases that work at room temperature are limited.Herein,a novel cobalt complex o-1-Co(II)wherein the salen unit bridges with bis-diarylethene has been designed as switch to construct"off-on"logic operation at room temperature.The complex o-1-Co(II)displays an abrupt,reversible and hysteretic spin crossover(T1/2↓=166 K,T1/2↑=177 K,andΔT1/2=11 K)between the high-spin(HS)and low-spin(LS)states.Meanwhile,photocyclization of o-1-Co(II)with UV light produces a photoresponsive closed form c-1-Co(II),which always stays at low-spin without SCO at all.Moreover,the magnetic switching of the complex can also be achieved with redox reactions between Co(II)and Co(III).
文摘Six novel chiral dinuclear Salen complexes[Cu 2 L 1 ·H 2 O(3a),Cu 2 L 2 (3b),Ni 2 L 1 ·2H 2 O(4a),Ni 2 L 2 (4b),Mn 2 Cl 2 L 1 ·H 2 O(5a),Mn 2 Cl 2 L 2 (5b)]have been synthesized(L 1 and L 2 are chiral dimeric Salen ligands with different chain length which were synthesized from(R,R) - diaminocyclohexane,salicylaldehyde,4,4 ’- (1,10 - decaneoxy)sali - cylaldehyde,4,4 ’- (1,6 - hexyloxy)salicylaldehyde).These compounds were charactered by elemental analysis,1 H NMR,FT - IR,UV - Vis and CD spectra.The FT - IR,UV - Vis and CD spectra were discussed and compared with those of monomeric ligand and complex in detail.It was found that the spectra properties of compounds of differ - ent chain length were almost alike,and the properties of dimeric and monomeric compound were similar too.Furthermore Cotton effect and Cotton split of CD spectra of these chiral compounds were explained by the exciton interaction theory.It seemed that the direction of Cotton split depend on the configuration of diaminohexane.(R,R) - diaminohexane determine the chirality of Salen compounds as negative,and the positive and negative compo - nent of Cotton split lie at higher and lower energy respectively.
