• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Chemistry: A European journal >Dissociation kinetics of open-chain and macrocyclic gadolinium(III)- aminopolycarboxylate complexes related to magnetic resonance imaging: Catalytic effect of endogenous ligands
【24h】

Dissociation kinetics of open-chain and macrocyclic gadolinium(III)- aminopolycarboxylate complexes related to magnetic resonance imaging: Catalytic effect of endogenous ligands

机译：与磁共振成像有关的开链和大环ado（III）-氨基聚羧酸盐配合物的解离动力学：内源性配体的催化作用

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

The kinetics of the metal exchange reactions between open-chain Gd(DTPA)~(2-) and Gd(DTPA-BMA), macrocyclic Gd(DOTA)~- and Gd(HP-DO3A) complexes, and Cu~(2+)ions were investigated in the presence of endogenous citrate, phosphate, carbonate and histidinate ligands in the pH range 6-8 in NaCl (0.15 M) at 25 °C. The rates of the exchange reactions of Gd(DTPA)~(2-) and Gd(DTPA-BMA) are independent of the Cu~(2+) concentration in the presence of citrate and the reactions occur via the dissociation of Gd~(3+)complexes catalyzed by the citrate ions. The HCO_3 ~-/CO_3 ~(2-) and H_2PO _4 ~- ions also catalyze the dissociation of complexes. The rates of the dissociation of Gd(DTPA-BMA), catalyzed by the endogenous ligands, are about two orders of magnitude higher than those of the Gd(DTPA) ~(2-). In fact near to physiological conditions the bicarbonate and carbonate ions show the largest catalytic effect, that significantly increase the dissociation rate of Gd(DTPA-BMA) and make the higher pHvalues (when the carbonate ion concentration is higher) a risk-factor for the dissociation of complexes in body fluids. The exchange reactions of Gd(DOTA)~- and Gd(HP-DO3A) with Cu~(2+) occur through the proton assisted dissociation of complexes in the pH range 3.5-5 and the endogenous ligands do not affect the dissociation rates of complexes. More insights into the interaction scheme between Gd(DTPA-BMA) and Gd(DTPA)~(2-) and endogenous ligands have been obtained by acquiring the ~(13)CNMR spectra of the corresponding diamagnetic Y(III)-complexes, indicating the increase of the rates of the intramolecular rearrangements in the presence of carbonate and citrate ions. The herein reported results may have implications in the understanding of the etiology of nephrogenic systemic fibrosis, a rare disease that has been associated to the administration of Gd-containing agents to patients with impaired renal function. Transmetalation reactions of Gd(DTPA)~(2-) and Gd(DTPA-BMA) with Cu~(2+) occur through the dissociation of complexes catalyzed by endogenous citrate, phosphate, and carbonate ions. The dissociation of Gd(DTPA-BMA) is catalyzed mainly by CO_3 ~(2-)ions. The reactions of Gd(DOTA)~- and Gd(HP-DO3A) with Cu~(2+) take place through the proton-assisted dissociation of complexes and the endogenous ligands do not affect the dissociation rates (see figure).
机译：开链Gd（DTPA）〜（2-）和Gd（DTPA-BMA），大环Gd（DOTA）〜和Gd（HP-DO3A）配合物和Cu〜（2+）之间的金属交换反应动力学在25°C的NaCl（0.15 M）中，在pH范围为6-8的内源性柠檬酸盐，磷酸盐，碳酸盐和组氨酸盐配体存在下，对离子进行了研究。在柠檬酸盐存在下，Gd（DTPA）〜（2-）和Gd（DTPA-BMA）的交换反应速率与Cu〜（2+）的浓度无关，并且反应通过Gd〜（柠檬酸根离子催化的3+）络合物。 HCO_3〜-/ CO_3〜（2-）和H_2PO_4〜-离子也催化配合物的离解。内源性配体催化的Gd（DTPA-BMA）的解离速率比Gd（DTPA）〜（2-）的解离速率高约两个数量级。实际上，在生理条件附近，碳酸氢根和碳酸根离子显示出最大的催化作用，这会显着增加Gd（DTPA-BMA）的解离速率，并使较高的pH值（当碳酸根离子浓度较高时）是导致Gd分解的危险因素。体液中复合物的解离。 Gd（DOTA）〜-和Gd（HP-DO3A）与Cu〜（2+）的交换反应是通过在pH范围为3.5-5的质子辅助的复合物解离而发生的，内源性配体不影响Pd的解离速率。复合体。 Gd（DTPA-BMA）与Gd（DTPA）〜（2-）与内源性配体之间的相互作用方案有了更深入的了解，这是通过获取相应的反磁性Y（III）配合物的〜（13）CNMR光谱获得的，表明碳酸根和柠檬酸根离子存在下分子内重排速率的增加。本文报道的结果可能对理解肾源性系统性纤维化的病因有影响，这是一种罕见疾病，与向肾功能受损的患者服用含Gd的药物有关。 Gd（DTPA）〜（2-）和Gd（DTPA-BMA）与Cu〜（2+）的金属转移反应是通过内源性柠檬酸根，磷酸根和碳酸根离子催化的配合物解离而发生的。 Gd（DTPA-BMA）的离解主要由CO_3〜（2-）离子催化。 Gd（DOTA）〜-和Gd（HP-DO3A）与Cu〜（2+）的反应是通过质子辅助的复合物解离而发生的，内源性配体不影响解离速率（见图）。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号