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通过二乙三胺五乙酸单环酸酐(DTPA-MA)分别与L-赖氨酸的十八酯、十六酯、十四酯和十二酯的双酰化反应, 制得四种含有双DTPA螯合单元的新型配体. 它们与GdCl3·6H2O配合得到相应的双核钆(Ⅲ)配合物. 表征了配体和配合物的结构, 测试了配合物的纵向弛豫效能(R1). 结果表明: 这四种新钆配合物的R1都高于Gd-DTPA. 相似文献
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A novel ligand of DTPA-dihydropyridine derivative was synthesized by reaction of DTPA-dianhydride with 4-aniline-1,4-dihydropyridine. Its complexes of gadolinium, manganese and iron were prepared. Their spin-lattice relaxivities (T1) were investigated. The results show that the NMR T1 relaxivitives (R1) for complexes of Fe(Ⅲ), Mn(Ⅱ) are less than that of Gd(Ⅲ) complex,which has a high relaxivity (R1) on the surrounding water protons, indicating that the Gd(Ⅲ) complex possesses the precondition to be contrast agents for magnetic resonance imaging. 相似文献
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Macromolecular ligands with liver-targeting group (pyridoxamine, PM) PHEA-DTPA-PM and PAEA-DTPA-PM were prepared by the incorporation of different amount of diethylenetria-minepentaacetic acid monopyridoxamine group (DTPA-PM) into poly-cc, p-[N-(2-hydroxyethyl)-L-aspartamide] (PHEA) and poly-α, β-[N-(2-aminoethyl)-L-aspartamide] (PAEA). The macromolecular ligands thus obtained were further complexed with gadolinium chloride to give macromolecular MRI contrast agents with different Gd(Ⅲ) contents. These macromolecular ligands and their gadolinium complexes were characterized by 1H NMR, 1R, UV and elementary analysis. Relaxivity studies showed that these polyaspartamide gadolinium complexes possess higher relaxation effectiveness than that of the clinically used Gd-DTPA. Magnetic resonance imaging of the liver in rats and experimental data of biodistribution in mice indicate that these macromolecular MRI contrast agents containing pyridoxamine exhibit liver-targeting property. 相似文献
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《Angewandte Chemie (International ed. in English)》2017,56(20):5603-5606
Aqua ligands can undergo rapid internal rotation about the M−O bond. For magnetic resonance contrast agents, this rotation results in diminished relaxivity. Herein, we show that an intramolecular hydrogen bond to the aqua ligand can reduce this internal rotation and increase relaxivity. Molecular modeling was used to design a series of four Gd complexes capable of forming an intramolecular H‐bond to the coordinated water ligand, and these complexes had anomalously high relaxivities compared to similar complexes lacking a H‐bond acceptor. Molecular dynamics simulations supported the formation of a stable intramolecular H‐bond, while alternative hypotheses that could explain the higher relaxivity were systematically ruled out. Intramolecular H‐bonding represents a useful strategy to limit internal water rotational motion and increase relaxivity of Gd complexes. 相似文献
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Manyu Jin Yanqun Zhang Ge Gao Qiaoyue Xi Jie Tong Yongxia Zhao Cunqi Wu Hua Zhou Qiuxia Yang Wei Yang Jingwei Xu 《应用有机金属化学》2019,33(9)
A bimodal magnetic resonance imaging contrast agent, TPP‐M‐Gd, was developed by modifying tetraphenylporphyrin (TPP) with a small dendritic molecule as a ligand (M) to chelate gadolinium (Gd) ions. The ligand featured four carboxylate groups, which contributed to good water solubility and a strong combination with metal ions. The longitudinal relaxivity (R1) of the resulting agent was calculated to be 12.45 mM?1 s?1, which is much higher than that of DTPA‐Gd (4.49 mM?1 s?1). The magnetic resonance imaging experiments showed that the newly synthesized contrast agent could enhance T1‐weighted magnetic resonance imaging quality both in vitro and in vivo. In addition, TPP‐M‐Gd exhibited good fluorescent property as shown in cell imaging experiments. The cytotoxicity of TPP‐M‐Gd was even better than that of clinically approved DTPA‐Gd, which makes it a promising dual‐functional medical imaging agent to provide more detailed information about biological and disease‐related events. 相似文献
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Xu ZP Kurniawan ND Bartlett PF Lu GQ 《Chemistry (Weinheim an der Bergstrasse, Germany)》2007,13(10):2824-2830
In this paper we report the preparation and characterization of [Gd(dtpa)](2-) intercalated layered double hydroxide (LDH) nanomaterials. [Gd(dtpa)](2-) (gadolinium(III) diethylene triamine pentaacetate) was transferred into LDH by anionic exchange. The intercalation of [Gd(dtpa)](2-) into LDH was confirmed by X-ray diffraction for the new phase with the interlayer spacing of 3.5-4.0 nm and by FTIR for the characteristic vibration peaks of [Gd(dtpa)](2-). The morphology of the nanoparticles was influenced by the extent of [Gd(dtpa)](2-) loading, in which the poly-dispersity quality decreased as the [Gd(dtpa)](2-) loading was increased. Compared with the morphology of the original Mg(2)Al-Cl-LDH nanoparticles (hexagonal plate-like sheets of 50-200 nm), the modified LDH-Gd(dtpa) nanoparticles are bar-like with a width of 30-60 nm and a length of 50-150 nm. LDH-Gd(dtpa) was expected to have an increased water proton magnetic resonance relaxivity due to the intercalation of [Gd(dtpa)](2-) into the LDH interlayer that led to slower molecular anisotropic tumbling compared with free [Gd(dtpa)](2-) in solution. Indeed, LDH-nanoparticle suspension containing approximately 1.6 mM [Gd(dtpa)](2-) exhibits a longitudinal proton relaxivity r(1) of approximately 16 mM(-1) s(-1) and a transverse proton relaxivity r(2) of approximately 50 mM(-1) s(-1) at room temperature and a magnetic field of 190 MHz, which represents an enhancement four times (r(1)) and 12 times (r(2)) that of free [Gd(dtpa)](2-) in solution under the same reaction conditions. We have thus tailored LDH-nanoparticles into a novel contrast agent with strong relaxivity, promising for great potential applications in magnetic resonance imaging. 相似文献