The protonation process of two DTPA bis(amide) derivatives, DTPA-BDMA and DTPA-BDEA, was studied by using 1H NMR titration and MOPAC calculation. Their protonation process was proposed in the order of the central amin...The protonation process of two DTPA bis(amide) derivatives, DTPA-BDMA and DTPA-BDEA, was studied by using 1H NMR titration and MOPAC calculation. Their protonation process was proposed in the order of the central amine, the terminal amines, the central carboxyl, the terminal carboxyl, the other terminal carboxyl and central amine. During the protonation of the terminal amine, them existed a large fraction of proton transfer from the central amine to the other terminal amine.展开更多
以纳米TiO2(P25)粉末作为催化剂光降解茜素黄R.GC-MS和LC-MS检测结果表明,有3种可能的降解途径:①茜素黄R(C13H8N3O5Na)水解生成的C13H8N3O5-(H)与光催化产生的.OH自由基发生取代反应生成C13H8N3O6-(I)和C13H8N3O7-(J),进一步脱羧分别生...以纳米TiO2(P25)粉末作为催化剂光降解茜素黄R.GC-MS和LC-MS检测结果表明,有3种可能的降解途径:①茜素黄R(C13H8N3O5Na)水解生成的C13H8N3O5-(H)与光催化产生的.OH自由基发生取代反应生成C13H8N3O6-(I)和C13H8N3O7-(J),进一步脱羧分别生成C12H9N3O4(L)和C12H9N3O5(M);②H分子发生脱羧反应生成C12H9N3O3(K),进一步反应生成C12H11N3(C)和C12H12N2(D);③H分子中氮氮键发生断裂而生成C6H6N2O2(A)、C6H4N2O4(B)、C6H8N2(E)、C6H6O(F)和C7H7NO3(G).所有生成的中间产物被继续降解,最终矿化为CO2和H2O等无机小分子物质.利用Molecular Orbital PACkage中的PM3半经验方法对茜素黄R分子构型优化计算,结果表明,茜素黄R的羧基净电荷密度为-0.680,在实验条件下(pH为2.86)羧基易吸附在TiO2表面,而成为.OH进攻的最有利位置,实验检测到羟基化的产物(J和I).茜素黄R的羧基和苯环相连的C—C键长最长,反应过程中易发生脱羧反应,实验检测到脱羧后的产物(K);—N N—键长较长,易断裂生成芳胺类化合物(A,E,G等).茜素黄R带羧基和羟基的苯环电荷密度为-0.160,带硝基苯环电荷为-0.165,易吸附在催化剂表面而被自由基进攻,生成羟基化产物.计算结果和实验检测结果一致.动力学研究表明,茜素黄R光催化降解的动力学符合Langmuir-Hinshelwood模型计算的结果.展开更多
Theoretical investigation on the structures of the octacoordinated [Nd(CO3)4]5-and the nonacoordinated [Nd(CO3)4.OH2]5-complexes, using the SPARKLE parameters of the lanthanides within MOPAC, revealed that they posses...Theoretical investigation on the structures of the octacoordinated [Nd(CO3)4]5-and the nonacoordinated [Nd(CO3)4.OH2]5-complexes, using the SPARKLE parameters of the lanthanides within MOPAC, revealed that they possessed dodecahedral and square antiprismatic structures respectively with an average Nd-O distance of 0.249 nm. These structures and the Nd-O distances agreed well with those experimentally found in the crystal structures. Replacing the water molecule with a fluoride ion or a mondentatecarbonato ligand resulted in a nonacoordinated distorted square antiprismatic structures where the trans-carbonato groups were twisted. The corresponding decacoordinated structures with two fluoride ions or a bidentatecarbonato group, [Nd(CO3)4·F2]7-and [Nd(CO3)5]7-, were also investigated. In both cases considerable twisting of the transcarbonato groups was observed.展开更多
The title complexes were modeled using the semiempirical MOPAC and the newly developed SPARKLE paramerters of the lanthanides. The calculated bond dis tances and angles agreed well with those found from crystal struct...The title complexes were modeled using the semiempirical MOPAC and the newly developed SPARKLE paramerters of the lanthanides. The calculated bond dis tances and angles agreed well with those found from crystal structure measuremen ts. This technique allows us to screen a large number of molecules and get struc tural information within a very short time.展开更多
1 Results We have recently reported the successful use of some new ionophores in construction of PVC-based membrane selective sensors for Fe3+,Ni2+,Co2+,Hg2+ and Cd2+ ions by some Schiff base ligands. Schiff bases are...1 Results We have recently reported the successful use of some new ionophores in construction of PVC-based membrane selective sensors for Fe3+,Ni2+,Co2+,Hg2+ and Cd2+ ions by some Schiff base ligands. Schiff bases are one of the most important classes of ligand in coordination chemistry. In this work we reported the optimized structures of four tetra dentate mono azo Schiff base compounds.Using AM1,PM3 and MNDO semi-empirical methods for the optimization of the compounds,then we compared all of theoreti...展开更多
基金Project supported by the Scientific Foundation of Chinese Academy of Sciences
文摘The protonation process of two DTPA bis(amide) derivatives, DTPA-BDMA and DTPA-BDEA, was studied by using 1H NMR titration and MOPAC calculation. Their protonation process was proposed in the order of the central amine, the terminal amines, the central carboxyl, the terminal carboxyl, the other terminal carboxyl and central amine. During the protonation of the terminal amine, them existed a large fraction of proton transfer from the central amine to the other terminal amine.
文摘以纳米TiO2(P25)粉末作为催化剂光降解茜素黄R.GC-MS和LC-MS检测结果表明,有3种可能的降解途径:①茜素黄R(C13H8N3O5Na)水解生成的C13H8N3O5-(H)与光催化产生的.OH自由基发生取代反应生成C13H8N3O6-(I)和C13H8N3O7-(J),进一步脱羧分别生成C12H9N3O4(L)和C12H9N3O5(M);②H分子发生脱羧反应生成C12H9N3O3(K),进一步反应生成C12H11N3(C)和C12H12N2(D);③H分子中氮氮键发生断裂而生成C6H6N2O2(A)、C6H4N2O4(B)、C6H8N2(E)、C6H6O(F)和C7H7NO3(G).所有生成的中间产物被继续降解,最终矿化为CO2和H2O等无机小分子物质.利用Molecular Orbital PACkage中的PM3半经验方法对茜素黄R分子构型优化计算,结果表明,茜素黄R的羧基净电荷密度为-0.680,在实验条件下(pH为2.86)羧基易吸附在TiO2表面,而成为.OH进攻的最有利位置,实验检测到羟基化的产物(J和I).茜素黄R的羧基和苯环相连的C—C键长最长,反应过程中易发生脱羧反应,实验检测到脱羧后的产物(K);—N N—键长较长,易断裂生成芳胺类化合物(A,E,G等).茜素黄R带羧基和羟基的苯环电荷密度为-0.160,带硝基苯环电荷为-0.165,易吸附在催化剂表面而被自由基进攻,生成羟基化产物.计算结果和实验检测结果一致.动力学研究表明,茜素黄R光催化降解的动力学符合Langmuir-Hinshelwood模型计算的结果.
文摘Theoretical investigation on the structures of the octacoordinated [Nd(CO3)4]5-and the nonacoordinated [Nd(CO3)4.OH2]5-complexes, using the SPARKLE parameters of the lanthanides within MOPAC, revealed that they possessed dodecahedral and square antiprismatic structures respectively with an average Nd-O distance of 0.249 nm. These structures and the Nd-O distances agreed well with those experimentally found in the crystal structures. Replacing the water molecule with a fluoride ion or a mondentatecarbonato ligand resulted in a nonacoordinated distorted square antiprismatic structures where the trans-carbonato groups were twisted. The corresponding decacoordinated structures with two fluoride ions or a bidentatecarbonato group, [Nd(CO3)4·F2]7-and [Nd(CO3)5]7-, were also investigated. In both cases considerable twisting of the transcarbonato groups was observed.
文摘The title complexes were modeled using the semiempirical MOPAC and the newly developed SPARKLE paramerters of the lanthanides. The calculated bond dis tances and angles agreed well with those found from crystal structure measuremen ts. This technique allows us to screen a large number of molecules and get struc tural information within a very short time.
文摘1 Results We have recently reported the successful use of some new ionophores in construction of PVC-based membrane selective sensors for Fe3+,Ni2+,Co2+,Hg2+ and Cd2+ ions by some Schiff base ligands. Schiff bases are one of the most important classes of ligand in coordination chemistry. In this work we reported the optimized structures of four tetra dentate mono azo Schiff base compounds.Using AM1,PM3 and MNDO semi-empirical methods for the optimization of the compounds,then we compared all of theoreti...
