EPR spectra of four new gadolinium complexes with Schiff bases in polycrystalline powder and those of these complexes in three organic solvents were investigated at different temperatures. It has been observed for the...EPR spectra of four new gadolinium complexes with Schiff bases in polycrystalline powder and those of these complexes in three organic solvents were investigated at different temperatures. It has been observed for the first time that their freezing solution spectra are quite different from each other. In THF one peak was observed only, but there were three peaks and typical "U" spectral features appearing in DMF and DMSO at low temperatures. On the basis of spin Hamiltonian of S = 7/2 system, the correlations between crystal field strength in complexes and local symmetry around Gd3+ ions are discussed.展开更多
A new cucurbit[6]uril bridged binuclear complex {[Gd(H2O)6]2[Q6(H2O)]}Cl6·4H2O, where Q6 represents cucurbit[6]uril, has been synthesized and characterized by X-ray diffraction. The crystal structure shows that t...A new cucurbit[6]uril bridged binuclear complex {[Gd(H2O)6]2[Q6(H2O)]}Cl6·4H2O, where Q6 represents cucurbit[6]uril, has been synthesized and characterized by X-ray diffraction. The crystal structure shows that the complex has an extended cucurbit[6]uril-bridged structure consisting of two gadolinium(III) ions, in which each gadolinium(III) ion is coordinated with two neighboring carbonylic oxygen atoms of Q6 and six oxygen atoms of water molecules that leans toward one side of the portal. One disordered guest water molecule resides in the Q6 molecule cavity and occupies two different positions. Hydrogen bonds assemble the complex to three- dimensional supramolecular structure.展开更多
Five neutral macromolecular polyester gadolinium （Ⅲ） complexes with pendant hydrophobic alkyland aromatic functional groups were prepared. The longitudinal relaxation rates of these complexes weremeasured. One of t...Five neutral macromolecular polyester gadolinium （Ⅲ） complexes with pendant hydrophobic alkyland aromatic functional groups were prepared. The longitudinal relaxation rates of these complexes weremeasured. One of these Gd （Ⅲ） complexes was chosen for the acute toxicity test and T<sub>1</sub>-weighted imagingmeasurement. Preliminary results showed that. compared with Gd-DTPA. the neutral macromoleculargadolinium （Ⅲ） complexes provide higher T<sub>1</sub> relaxivity enhancement and longer function duration.展开更多
Gadolinium diethylenetriamine-pentaacetic bisdopamide (Gd-DTPA-2DA) was synthesized by the incorporation of dopamine to diethylenetriaminepentaacetic acid (DTPA) and further reaction with gadolinium chloride. In vitro...Gadolinium diethylenetriamine-pentaacetic bisdopamide (Gd-DTPA-2DA) was synthesized by the incorporation of dopamine to diethylenetriaminepentaacetic acid (DTPA) and further reaction with gadolinium chloride. In vitro and in vivo properties were also evaluated. Gadolinium complex Gd-DTPA-2DA possessed higher relaxation effectiveness and less cytotoxicity to HeLa cells than that of Gd-DTPA. Moreover, Gd-DTPA-2DA greatly enhanced the contrast of MR images of the brains, provided prolonged intravascular duration, and produced highly contrasted visualization of the brain.展开更多
The EPR spectra of three new gadolinium complexes with noncyclic polyether Schiff bases in powder and those of these complexes in organic solvents were investigated at different temperatures. It was observed that EPR ...The EPR spectra of three new gadolinium complexes with noncyclic polyether Schiff bases in powder and those of these complexes in organic solvents were investigated at different temperatures. It was observed that EPR spectra of nine and four peaks of Gd(Ⅲ) complexes in polycrystalline powder and freezing samples appeared at low temperature respectively for the first time. The interpretations of these results obtained on the basis of spin Hamiltonian of s = 7/2 system are satisfactory. The correlations of EPR feature between crystal-field strength in complexes and local symmetry around Gd3+ ions were revealed. The crystal-field parameters b20 and the asymmetry parameters λ’ of complexes were estimated. A series of interesting regularity and new results were obtained.展开更多
A new quaternary mixed anion complex of gadolinium(Ⅲ), [Gd(CH 3CH 2COO) 2(N O 3)(phen)] 2, was synthesized and structurally characterized. The ESR spectr um of the complex with effective g values of 5.314, 2 473 and ...A new quaternary mixed anion complex of gadolinium(Ⅲ), [Gd(CH 3CH 2COO) 2(N O 3)(phen)] 2, was synthesized and structurally characterized. The ESR spectr um of the complex with effective g values of 5.314, 2 473 and 1.880 in poly crys talline powder at room temperature is quite different from the U spectrum. The c oordination number of Gd 3+ is nine with a monocapped square antiprism geom etry. And the stacking effect was observed in the complex. The crystal of the co mplex belongs to triclinic with space group P 1, a=0.9626(4) n m, b=0.9732(4) nm, c=1.1758(5) nm, α=102.45(1)°, β=108.16(1) °, γ=96.68(2)°, V=1.0018(7) nm3, Z=2, D c=1.80 g·cm -3 , μ(MoKα)=33.63 mm -1, F(000)=530, GOF=1.80, R=0.023 and R w=0.027.展开更多
The title complex crystallizes in the triclinic system, space group P1 with a=16.9568(5), b=18.8631(6), c=24.1640(8), α=100.110(1), β=92\^330(1), γ=113.368(1)°, V=7602.54(4)~3, D_c=3.002 g/cm^3, F(000)=589...The title complex crystallizes in the triclinic system, space group P1 with a=16.9568(5), b=18.8631(6), c=24.1640(8), α=100.110(1), β=92\^330(1), γ=113.368(1)°, V=7602.54(4)~3, D_c=3.002 g/cm^3, F(000)=5893, M_r=6245.25, μ(Mo Kα)=5.010mm^-1, Z=2 and final R=0.0722 and wR=0\^1960 for 16015 observed reflections with I≥2σ(I). The Gd(Ⅲ) ion is coordinated by nine oxygen atoms, forming a distorted mono-capped square antiprism, while the Mo(Ⅵ) ions have their different coordination numbers such as 4,5 and 6 with different configurations such as tetrahedron, square pyramid and octahedron, respectively.展开更多
The formation of colourless gadolinium complexes (x,y,z), between x gadolinium ions, y ligands and z protons, of some organic acids, has been studied in aqueous solution. In this work we present the results of investi...The formation of colourless gadolinium complexes (x,y,z), between x gadolinium ions, y ligands and z protons, of some organic acids, has been studied in aqueous solution. In this work we present the results of investigations on the interaction of the gadolinium ion (Gd3+) with malic acid (C4H6O5, a-hydroxyl dicarboxylic acid), in dilute aqueous solution for pH values between 5.5 and 7.5. Colourless gadolinium complexes of malate ions have no absorption band UV-visible, the indirect photometric detection (IPD) technique was used and studies have identified a major tri-nuclear complex of malate ion (﹣OOC-CH2-CHOH-COO﹣). The formation of this new colourless complex is derived from three Gd(III) ions that react with two malate ions and two hydronium ions (H3O+), giving for this colourless complex, a (3,2,2) composition and apparent stability constant depends on the acidity of the medium, with logK'322 = 18.88 ± 0.05 at pH = 6.30. To complement previous results and to propose a probable structure for this new complex detected in solution, studies of IR spectroscopy have been conducted to identify the chelation sites for both ligands. The results were analysed and show that this organometallic gadolinium complex, contains two different sites, respectively, two lateral tetradentate mono-nuclear sites and a single central bidentate mono-nuclear site. From these results, the reaction of formation, the stability constant and the probable structure of this new colourless organometallic gadolinium complex are proposed.展开更多
A novel heterometallic complex [Na2Cu2Gd2(pdc)4(H2O)14·2H2O] (H3pdc = 1H- pyrazole-3,5-dicarboxylic acid) has been synthesized and characterized by IR spectra, elemental analysis, and single-crystal X-ray analysi...A novel heterometallic complex [Na2Cu2Gd2(pdc)4(H2O)14·2H2O] (H3pdc = 1H- pyrazole-3,5-dicarboxylic acid) has been synthesized and characterized by IR spectra, elemental analysis, and single-crystal X-ray analysis. The crystal belongs to the monoclinic system, space group P21/c with a = 7.9521(18), b = 12.251(3), c = 22.293(5) , β = 110.173(5)o, V = 2038.5(8) 3, Mr = 1388.13, Z = 2, F(000) = 1352, Dc = 2.261 g/cm3, μ = 4.380 mm-1, the final R = 0.0409 and wR = 0.0622 for 2453 observed reflections with I > 2σ(I). The structural analysis shows that the NaI, CuII and GdII ions are linked together by two kinds of bridging ligands (pdc3- and H2O) to form a main moiety [Na2Cu2Gd2(pdc)4(H2O)14], which can be regarded as a centrosymmetric dimmer of [NaCuGd(pdc)2(H2O)7]. Many hydrogen bonds exist in the complex to build a 3D supramolecular framework.展开更多
The heteronuclear gadolinium copper complex was synthesized. Its crystal structure was determined by single crystal diffraction. The crystal crystallizes in triclinic, space group P 1, a=0 8483(1) nm, b =0 9642(2) nm,...The heteronuclear gadolinium copper complex was synthesized. Its crystal structure was determined by single crystal diffraction. The crystal crystallizes in triclinic, space group P 1, a=0 8483(1) nm, b =0 9642(2) nm, c =1 2838(2) nm, α =111 17(1)°, β = 93 52(1)°, γ =100 89(1)°, Z =2, D c=2 335 g·cm -3 . The complex appears as a zigzag 1D chain. Each gadolinium ion is coordinated by three carboxylic oxygen atoms and six oxygen atoms from H 2O. Each copper ion is chelated by NTA with its nitrogen atom and three oxygen atoms of three carboxyl groups, and coordinated by a chlorine ion. The ClO 4 - is located between the chains as a counter ion.展开更多
基金Project supported by the National Natural Science Foundation of China and the Natural Science Foundation of Zhejiang Province.
文摘EPR spectra of four new gadolinium complexes with Schiff bases in polycrystalline powder and those of these complexes in three organic solvents were investigated at different temperatures. It has been observed for the first time that their freezing solution spectra are quite different from each other. In THF one peak was observed only, but there were three peaks and typical "U" spectral features appearing in DMF and DMSO at low temperatures. On the basis of spin Hamiltonian of S = 7/2 system, the correlations between crystal field strength in complexes and local symmetry around Gd3+ ions are discussed.
基金supported by the National Natural Science Foundation of China(No.20471056)
文摘A new cucurbit[6]uril bridged binuclear complex {[Gd(H2O)6]2[Q6(H2O)]}Cl6·4H2O, where Q6 represents cucurbit[6]uril, has been synthesized and characterized by X-ray diffraction. The crystal structure shows that the complex has an extended cucurbit[6]uril-bridged structure consisting of two gadolinium(III) ions, in which each gadolinium(III) ion is coordinated with two neighboring carbonylic oxygen atoms of Q6 and six oxygen atoms of water molecules that leans toward one side of the portal. One disordered guest water molecule resides in the Q6 molecule cavity and occupies two different positions. Hydrogen bonds assemble the complex to three- dimensional supramolecular structure.
基金Project supported by the Chinese Academy of Sciences and the State Sciences and Technology Commission of China.
文摘Five neutral macromolecular polyester gadolinium （Ⅲ） complexes with pendant hydrophobic alkyland aromatic functional groups were prepared. The longitudinal relaxation rates of these complexes weremeasured. One of these Gd （Ⅲ） complexes was chosen for the acute toxicity test and T<sub>1</sub>-weighted imagingmeasurement. Preliminary results showed that. compared with Gd-DTPA. the neutral macromoleculargadolinium （Ⅲ） complexes provide higher T<sub>1</sub> relaxivity enhancement and longer function duration.
基金Project supported by National Natural Science Foundation of China (51173140)Key Natural Science Foundation of Hubei Province (2009CDA052)Wuhan Scientific and Technological Research and Development Program, Hubei Province (201060623274)
文摘Gadolinium diethylenetriamine-pentaacetic bisdopamide (Gd-DTPA-2DA) was synthesized by the incorporation of dopamine to diethylenetriaminepentaacetic acid (DTPA) and further reaction with gadolinium chloride. In vitro and in vivo properties were also evaluated. Gadolinium complex Gd-DTPA-2DA possessed higher relaxation effectiveness and less cytotoxicity to HeLa cells than that of Gd-DTPA. Moreover, Gd-DTPA-2DA greatly enhanced the contrast of MR images of the brains, provided prolonged intravascular duration, and produced highly contrasted visualization of the brain.
文摘The EPR spectra of three new gadolinium complexes with noncyclic polyether Schiff bases in powder and those of these complexes in organic solvents were investigated at different temperatures. It was observed that EPR spectra of nine and four peaks of Gd(Ⅲ) complexes in polycrystalline powder and freezing samples appeared at low temperature respectively for the first time. The interpretations of these results obtained on the basis of spin Hamiltonian of s = 7/2 system are satisfactory. The correlations of EPR feature between crystal-field strength in complexes and local symmetry around Gd3+ ions were revealed. The crystal-field parameters b20 and the asymmetry parameters λ’ of complexes were estimated. A series of interesting regularity and new results were obtained.
文摘A new quaternary mixed anion complex of gadolinium(Ⅲ), [Gd(CH 3CH 2COO) 2(N O 3)(phen)] 2, was synthesized and structurally characterized. The ESR spectr um of the complex with effective g values of 5.314, 2 473 and 1.880 in poly crys talline powder at room temperature is quite different from the U spectrum. The c oordination number of Gd 3+ is nine with a monocapped square antiprism geom etry. And the stacking effect was observed in the complex. The crystal of the co mplex belongs to triclinic with space group P 1, a=0.9626(4) n m, b=0.9732(4) nm, c=1.1758(5) nm, α=102.45(1)°, β=108.16(1) °, γ=96.68(2)°, V=1.0018(7) nm3, Z=2, D c=1.80 g·cm -3 , μ(MoKα)=33.63 mm -1, F(000)=530, GOF=1.80, R=0.023 and R w=0.027.
基金Supported by the Science Foundation of Fujian Science Committee.
文摘The title complex crystallizes in the triclinic system, space group P1 with a=16.9568(5), b=18.8631(6), c=24.1640(8), α=100.110(1), β=92\^330(1), γ=113.368(1)°, V=7602.54(4)~3, D_c=3.002 g/cm^3, F(000)=5893, M_r=6245.25, μ(Mo Kα)=5.010mm^-1, Z=2 and final R=0.0722 and wR=0\^1960 for 16015 observed reflections with I≥2σ(I). The Gd(Ⅲ) ion is coordinated by nine oxygen atoms, forming a distorted mono-capped square antiprism, while the Mo(Ⅵ) ions have their different coordination numbers such as 4,5 and 6 with different configurations such as tetrahedron, square pyramid and octahedron, respectively.
文摘The formation of colourless gadolinium complexes (x,y,z), between x gadolinium ions, y ligands and z protons, of some organic acids, has been studied in aqueous solution. In this work we present the results of investigations on the interaction of the gadolinium ion (Gd3+) with malic acid (C4H6O5, a-hydroxyl dicarboxylic acid), in dilute aqueous solution for pH values between 5.5 and 7.5. Colourless gadolinium complexes of malate ions have no absorption band UV-visible, the indirect photometric detection (IPD) technique was used and studies have identified a major tri-nuclear complex of malate ion (﹣OOC-CH2-CHOH-COO﹣). The formation of this new colourless complex is derived from three Gd(III) ions that react with two malate ions and two hydronium ions (H3O+), giving for this colourless complex, a (3,2,2) composition and apparent stability constant depends on the acidity of the medium, with logK'322 = 18.88 ± 0.05 at pH = 6.30. To complement previous results and to propose a probable structure for this new complex detected in solution, studies of IR spectroscopy have been conducted to identify the chelation sites for both ligands. The results were analysed and show that this organometallic gadolinium complex, contains two different sites, respectively, two lateral tetradentate mono-nuclear sites and a single central bidentate mono-nuclear site. From these results, the reaction of formation, the stability constant and the probable structure of this new colourless organometallic gadolinium complex are proposed.
基金supported by the National Natural Science Foundation of China (No 20571039)National Basic Research Program of China (2007CB925103)+3 种基金National 863 Research Project (2006 A03Z219)Natural Science Foundation of Jiangsu Province (BK2007199)the State Postdoctoral Foundation of China (No 2006040932)the Postdoctoral Foundation of Jiangsu Province (No 0602008B)
文摘A novel heterometallic complex [Na2Cu2Gd2(pdc)4(H2O)14·2H2O] (H3pdc = 1H- pyrazole-3,5-dicarboxylic acid) has been synthesized and characterized by IR spectra, elemental analysis, and single-crystal X-ray analysis. The crystal belongs to the monoclinic system, space group P21/c with a = 7.9521(18), b = 12.251(3), c = 22.293(5) , β = 110.173(5)o, V = 2038.5(8) 3, Mr = 1388.13, Z = 2, F(000) = 1352, Dc = 2.261 g/cm3, μ = 4.380 mm-1, the final R = 0.0409 and wR = 0.0622 for 2453 observed reflections with I > 2σ(I). The structural analysis shows that the NaI, CuII and GdII ions are linked together by two kinds of bridging ligands (pdc3- and H2O) to form a main moiety [Na2Cu2Gd2(pdc)4(H2O)14], which can be regarded as a centrosymmetric dimmer of [NaCuGd(pdc)2(H2O)7]. Many hydrogen bonds exist in the complex to build a 3D supramolecular framework.
文摘The heteronuclear gadolinium copper complex was synthesized. Its crystal structure was determined by single crystal diffraction. The crystal crystallizes in triclinic, space group P 1, a=0 8483(1) nm, b =0 9642(2) nm, c =1 2838(2) nm, α =111 17(1)°, β = 93 52(1)°, γ =100 89(1)°, Z =2, D c=2 335 g·cm -3 . The complex appears as a zigzag 1D chain. Each gadolinium ion is coordinated by three carboxylic oxygen atoms and six oxygen atoms from H 2O. Each copper ion is chelated by NTA with its nitrogen atom and three oxygen atoms of three carboxyl groups, and coordinated by a chlorine ion. The ClO 4 - is located between the chains as a counter ion.
