• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>The journal of physical chemistry, A. Molecules, spectroscopy, kinetics, environment, & general theory >Toward a better understanding of the regioselectivity of the AI(III) - Protocatechuic acid complexation reaction
【24h】

Toward a better understanding of the regioselectivity of the AI(III) - Protocatechuic acid complexation reaction

机译：为了更好地理解AI（III）-原儿茶酸络合反应的区域选择性

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

Protocatechuic acid presents two complexing sites in competition to fix metal: the carboxylic and catechol functions. Even in acidic aqueous medium, where the free ligand is fully protonated, Al(III) forms a chelate with the doubly deprotonated catechol group. To gain a better understanding of the complexation mechanism and to explain the regioselectivity of the reaction, reaction pathways involving either the catechol group or the carboxylic one have been calculated at the B3LYP/6-31G(d,p) level of theory. All the intermediate species have been identified, and both processes present the following different steps: metal attack with the coordination of Al(III) to an oxygen atom; deprotonation of hydroxyl groups; ring closure to form a chelate. Whatever the complexing site, a bidentate complex is more stable than a monodentate one. From an energetic point of view, the reaction pathway corresponding to a chelate formation with the catechol function is favored; notably the energy barrier necessary to close the ring involving the metal ion is calculated to be lower than that of carboxyl function.
机译：原儿茶酸在固定金属的竞争中表现出两个络合位点：羧酸和邻苯二酚功能。即使在酸性水介质中，游离配体被完全质子化，Al（III）也会与双去质子化的邻苯二酚基团形成螯合物。为了更好地理解络合机理并解释反应的区域选择性，已在理论上以B3LYP / 6-31G（d，p）水平计算了涉及邻苯二酚基或羧基的反应途径。已经鉴定了所有的中间物种，并且两个过程都呈现以下不同的步骤：金属与Al（III）配位到氧原子上;羟基去质子化;闭环形成螯合物。无论复杂的站点如何，双齿复合物都比单齿复合物更稳定。从能量的观点来看，对应于具有邻苯二酚功能的螯合物形成的反应途径是有利的。值得注意的是，将涉及金属离子的环封闭所需的能垒被计算为低于羧基官能的能垒。

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