Stereoelectronic Effects and Reactivity: Lone Pairs, Hydrogen Bonding, and Proton Transfer

在有机动力学项目的支持下，Perrin博士将利用核磁共振（NMR）光谱学来研究五个独立的问题：(i)将研究氨基酸阴离子的立体化学，以完成先前对酰胺和氨基酸中质子交换的研究。（ii）立体电子控制现象将通过评价一个或两个孤电子对与离开基团或进入的亲核试剂反周平面对反应性的影响来研究。（iii）平衡同位素摄动法将被用作研究氢键对称性的一种手段。通过测量离子对键旋转速率的影响，可以探测离子在水介质中溶剂化的程度。(v)将通过检查酰胺中的键旋转来研究大的次级动力学同位素效应现象。现代核磁共振（NMR）技术的应用增加了人们对分子结构和反应性的了解。Perrin博士的研究项目旨在利用这些新技术来研究有机分子中最简单的两种结构元素，即质子和电子对。将进行五个项目，以努力阐明诸如氢键和结构/构象对反应性的影响等基本现象的性质。这些结果可能会引起物理有机化学家、生物化学家和理论化学家的兴趣。

With support from the Organic Dynamics Program, Dr. Perrin will utilize nuclear magnetic resonance (NMR) spectroscopy to investigate five separate problems: (i) The stereochemistry of amidinate anions will be studied to complete previous investigations of proton exchange in amides and amidines. (ii) Stereoelectronic control phenomena will be studied by evaluating the effect on reactivity of having one or two lone electron pairs antiperiplanar to a leaving group or incoming nucleophile. (iii) The Method of Isotopic Perturbation of Equilibrium will be utilized as a means to investigate the symmetry of the hydrogen bond. (iv) The extent of solvation of ions in aqueous media will be probed by measuring the effect that these ions have upon bond rotation rates. (v) The phenomenon of large secondary kinetic isotope effects will be studied via examination of bond rotations in amides. %%% Applications of modern nuclear magnetic resonance (NMR) techniques have led to increased understanding of molecular structure and reactivity. Dr. Perrin's research program is designed to take advantage of these new techniques in order to study two of the simplest structural elements in organic molecules, i.e., protons and electron pairs. Five projects will be undertaken in an effort to elucidate the nature of such fundamental phenomena as hydrogen bonding and stuructural/conformational effects on reactivity. The results are likely to be of interest to physical-organic chemists, biochemists, and theoretical chemists.