Mechanisms of Iron-Ligand Exchange Reactions and the Influence of Ionophore Hosts in the Second-Sphere

杜克大学的Alvin L. Crumbliss得到了无机、生物无机和有机金属化学计划的支持，研究了配体-金属交换反应的机制，重点是第二球体的影响。他是NSF在同一领域的9709105基金（36个月34.5万美元）的PI，早期的基金一直延续到1976年。本基金的目的包括阐明：铁（III）从螯合物中解离的动力学和机制，第二球体的主客体化学方面，配合物和第二球体聚集体的铁（III- ii）氧化还原电位，以及第二球体在各种环境中对铁（III）迁移率的影响。金属离子在包括地质学、生物学、医学和生态学在内的所有科学领域的重要变化中都起着重要作用。三铁——铁（III）——是最常见、用途最广、最重要的金属离子之一。由于它在替换其近邻（“第一配位球”）中的原子方面往往相当迟钝，因此选择该离子进行详细研究有许多优点。这个小组和其他人的研究结果表明，第一配位球（“第二配位球”）之外的原子影响、调节和控制金属离子附近发生的事情，从而对宏观系统（地质学、生物学、生态学）中可以观察到的整体化学产生巨大影响。这个项目在揭示控制这一重要化学类别的微妙因素方面取得了良好进展。

Alvin L. Crumbliss of Duke University is supported by the Inorganic, Bioinorganic, and Organometallic Chemistry Program for research on mechanisms of ligand-metal exchange reactions-- with emphasis on second sphere-influences. He is PI of NSF grant 9709105 ($345K for 36 months) in this same area, and earlier grants extending to 1976. Aims of the present grant include elucidation of: kinetics and mechanisms of dissociation of Fe(III) from chelate complexes, aspects of host-guest chemistry in the second sphere, Fe(III-II) redox potentials of complexes and second-sphere aggregates, and second-sphere effects on mobility of Fe(III) in various environments.Metal ions are centrally involved in important changes that figure in all areas of science, including geology, biology, medicine and ecology. Ferric iron -- Fe(III) -- is one of the most common, versatile, and important metal ions. Since it tends to be rather sluggish in regard to replacing atoms in its near neighborhood ("first coordination sphere") there are many advantages in selecting that ion for detailed study. Results of this group and others have shown that atoms beyond the first coordination sphere ("second coordination sphere") influence, modulate, and control what goes on near the metal ion, and thereby have dramatic effect on the overall chemistry that can be observed in macroscopic systems (geology, biology, ecology). This program is making good progress in unrraveling the subtle factors that govern this important class of chemistry.