The stability constants of the binary complexes of Mn2+ with nicotinamide (NA) were determined from potentiometric pH titrations data at 15.0 , 25.0 and 35.0oC and I = 0.1,0.2,0.4 mol L-1 (NaClO4). The formation of bi...The stability constants of the binary complexes of Mn2+ with nicotinamide (NA) were determined from potentiometric pH titrations data at 15.0 , 25.0 and 35.0oC and I = 0.1,0.2,0.4 mol L-1 (NaClO4). The formation of binary 1:1 , 1:2 NA-Mn complexes at three different temperatures and the influence of three different ionic strength on their stability were reported. The thermodynamic parameters (DGof, DSof, DHof) for the complex formation reaction were estimated from stability constant at different temperatures.展开更多
A new ligand, N,N-BIS (6-metyl-2-pyridinecarboxylamide-N-oxide)-1,2-ethane (L) and six lanthanide(Ⅲ) complexes (RE=La, Sm, Eu, Tb, Gd, Yb) were synthesized and characterized in detail. The results indicated that the ...A new ligand, N,N-BIS (6-metyl-2-pyridinecarboxylamide-N-oxide)-1,2-ethane (L) and six lanthanide(Ⅲ) complexes (RE=La, Sm, Eu, Tb, Gd, Yb) were synthesized and characterized in detail. The results indicated that the composition of the binary complexes was determined as [REL(H2O)(NO3)2]NO3·nH2O (n=0-2), and the Eu3+ complex had bright red fluorescence in solid state. Three complexes of Eu3+, Tb3+, and Gd3+ with 6-methylpicolinic acid N-oxide (L’) were also synthesized. The relative intensity of sensitized luminescence for Eu3+ increased in the following order: L>L’. The phosphorescence spectra of the Gd3+ complexes at 77 K were measured. The energies of excited triplet state for the ligands were 20704 cm-1 (L) and 20408 cm-1 (L’). The facts that the ligands sensitized Eu3+ strongly and the order of the emission intensity for Eu3+ complexes were explained by ΔE(T-5D). This meant that the triplet energy level of the ligand was the main factor to influence RE3+ luminescence.展开更多
A new ligand, N,N′-Bis(6-methyl-2-pyridine-N-oxide)-1,3-propane (L), and some binary lanthanide complexes (Ln=Eu^(3+), Tb^(3+)) were synthesized and characterized in detail. The composition of the binary complexes wa...A new ligand, N,N′-Bis(6-methyl-2-pyridine-N-oxide)-1,3-propane (L), and some binary lanthanide complexes (Ln=Eu^(3+), Tb^(3+)) were synthesized and characterized in detail. The composition of the binary complexes was determined as LnL(NO_3)_3. They are 1∶1 electrolytes in DMF. The complexes have strong characteristic line fluorescence emission spectra, and it is also found that TbL(NO_3)_3 complex has stronger luminescence intensity than EuL(NO_3)_3 in solid state and in methanol.展开更多
The reactions of imidazoquinoxaline and 1,3,5-H3 btc acid under different condition have been investigated. The different degree of hydrolysis reaction leads to two different adducts being produced, namely, [（Hdiam Q...The reactions of imidazoquinoxaline and 1,3,5-H3 btc acid under different condition have been investigated. The different degree of hydrolysis reaction leads to two different adducts being produced, namely, [（Hdiam Quin）＋（H2btc）-]（1）, and [（diam Quin）4（Imi Quin）·4H2O]（2）. Both compounds were characterized by X-ray crystallography. Crystal data for 1： monoclinic, space group Pn with a = 9.868（2）, b = 5.3172（11）, c = 15.387（3）A, β = 91.10（3）°, C17H14N4O6, Mr = 370.32, V = 807.2（3）A3, Z = 2, Dc = 1.524 g/cm3, μ（Mo Kα） = 0.118 mm-1, F（000） = 384, the final R = 0.0385 and w R = 0.0869 for 2294 observed reflections（I 〉 2σ（I））. Crystal data for 2： triclinic, space group P1 with a = 9.825（2）, b = 14.144（3）, c = 16.054（3） A, α = 101.06（3）, β = 102.55（3）, γ = 92.46（3）°, C（44）H40N（20）O4, Mr = 912.96, V = 2128.8（7） A3, Z = 2, Dc = 1.424 g/cm3, μ（Mo Kα） = 0.099 mm-1, F（000） = 952, the final R = 0.0554 and w R = 0.1662 for 6563 observed reflections（I 〉 2σ（I））. X-ray diffraction analysis reveals that compound 1 is a salt. Imidazoquinoxaline was wholly hydrolyzed into 2,3-diaminoquinoxaline and protonated as a cation with H2btc-acting as an anion. However, in compound 2, the imidazoquinoxaline is only partly hydrolyzed, and the resulting 2,3-diaminoquinoxaline forms adduct with the intacted imidazoquinoxaline. Both are further aggregated into 3D frameworks by strong hydrogen bonding even π-π interactions.展开更多
文摘The stability constants of the binary complexes of Mn2+ with nicotinamide (NA) were determined from potentiometric pH titrations data at 15.0 , 25.0 and 35.0oC and I = 0.1,0.2,0.4 mol L-1 (NaClO4). The formation of binary 1:1 , 1:2 NA-Mn complexes at three different temperatures and the influence of three different ionic strength on their stability were reported. The thermodynamic parameters (DGof, DSof, DHof) for the complex formation reaction were estimated from stability constant at different temperatures.
基金Project supported by the National Natural Science Foundation of China (29571013)
文摘A new ligand, N,N-BIS (6-metyl-2-pyridinecarboxylamide-N-oxide)-1,2-ethane (L) and six lanthanide(Ⅲ) complexes (RE=La, Sm, Eu, Tb, Gd, Yb) were synthesized and characterized in detail. The results indicated that the composition of the binary complexes was determined as [REL(H2O)(NO3)2]NO3·nH2O (n=0-2), and the Eu3+ complex had bright red fluorescence in solid state. Three complexes of Eu3+, Tb3+, and Gd3+ with 6-methylpicolinic acid N-oxide (L’) were also synthesized. The relative intensity of sensitized luminescence for Eu3+ increased in the following order: L>L’. The phosphorescence spectra of the Gd3+ complexes at 77 K were measured. The energies of excited triplet state for the ligands were 20704 cm-1 (L) and 20408 cm-1 (L’). The facts that the ligands sensitized Eu3+ strongly and the order of the emission intensity for Eu3+ complexes were explained by ΔE(T-5D). This meant that the triplet energy level of the ligand was the main factor to influence RE3+ luminescence.
文摘A new ligand, N,N′-Bis(6-methyl-2-pyridine-N-oxide)-1,3-propane (L), and some binary lanthanide complexes (Ln=Eu^(3+), Tb^(3+)) were synthesized and characterized in detail. The composition of the binary complexes was determined as LnL(NO_3)_3. They are 1∶1 electrolytes in DMF. The complexes have strong characteristic line fluorescence emission spectra, and it is also found that TbL(NO_3)_3 complex has stronger luminescence intensity than EuL(NO_3)_3 in solid state and in methanol.
基金supported by the National Natural Science Foundation of China(No.21171075)Start-up Fund for Advanced Professional of Jiangsu University(No.08JDG031)
文摘The reactions of imidazoquinoxaline and 1,3,5-H3 btc acid under different condition have been investigated. The different degree of hydrolysis reaction leads to two different adducts being produced, namely, [（Hdiam Quin）＋（H2btc）-]（1）, and [（diam Quin）4（Imi Quin）·4H2O]（2）. Both compounds were characterized by X-ray crystallography. Crystal data for 1： monoclinic, space group Pn with a = 9.868（2）, b = 5.3172（11）, c = 15.387（3）A, β = 91.10（3）°, C17H14N4O6, Mr = 370.32, V = 807.2（3）A3, Z = 2, Dc = 1.524 g/cm3, μ（Mo Kα） = 0.118 mm-1, F（000） = 384, the final R = 0.0385 and w R = 0.0869 for 2294 observed reflections（I 〉 2σ（I））. Crystal data for 2： triclinic, space group P1 with a = 9.825（2）, b = 14.144（3）, c = 16.054（3） A, α = 101.06（3）, β = 102.55（3）, γ = 92.46（3）°, C（44）H40N（20）O4, Mr = 912.96, V = 2128.8（7） A3, Z = 2, Dc = 1.424 g/cm3, μ（Mo Kα） = 0.099 mm-1, F（000） = 952, the final R = 0.0554 and w R = 0.1662 for 6563 observed reflections（I 〉 2σ（I））. X-ray diffraction analysis reveals that compound 1 is a salt. Imidazoquinoxaline was wholly hydrolyzed into 2,3-diaminoquinoxaline and protonated as a cation with H2btc-acting as an anion. However, in compound 2, the imidazoquinoxaline is only partly hydrolyzed, and the resulting 2,3-diaminoquinoxaline forms adduct with the intacted imidazoquinoxaline. Both are further aggregated into 3D frameworks by strong hydrogen bonding even π-π interactions.
