Isotopic Perturbations in Aromatic Character and New Annulene Conformers

这个项目将探索环烯构象和芳香性之间的相互作用。具体地说，环烯的西格玛骨架的形态将通过用氢原子取代内部质子而被扰动。核磁共振波谱将监测发生的圆周率离域的变化。测量氢化和质子化的环烯及其相应的双阴离子中的相对环电流将有助于深入了解sigma和pi骨架在芳香性和抗芳香性方面的相对重要性。通过该Rui奖，有机和高分子化学计划支持伊利诺伊州立大学谢丽尔·D·史蒂文森教授的研究。史蒂文森教授的研究将探索一种被化学家称为芳香性的现象，指的不是嗅觉特征，而是一种特定分子的稳定性因其成键电子的特定排列而比预期更大的情况。为了进行这项研究，将合成被称为环烯的大环状分子，并在分子内的特定位置加入氢的同位素。这种氢同位素，氢，将表现出一定的行为取决于它在成键电子中的位置，以及是否满足芳香性的条件。一种被称为核磁共振的分子尺度核磁共振将被用来探测氚原子。

This project will explore the interplay between conformation and aromaticity in annulenes. Specifically, the morphology of the sigma framework of annulenes will be perturbed via replacement of the internal protons with deuterium atoms. The changes in pi-delocalization that takes place will be monitored by NMR spectroscopy. Measurements of the relative ring currents in deuterated and protiated annulenes and their respective dianions will lead to insight into the relative importance of the sigma and pi frameworks in terms of aromatic and antiaromatic character.With this RUI Award, the Organic and Macromolecular Chemistry Program supports the research of Professor Cheryl D. Stevenson of Illinois State University. Professor Stevenson's research will explore a phenomenon known to chemists as aromaticity, referring not to an olfactory characteristic but to a circumstance whereby the stability of a particular molecule is greater than expected due to a specific arrangement of its bonding electrons. In order to carry out this study, large ring-like molecules known as annulenes will be synthesized and an isotope of hydrogen incorporated at specific locations within the molecule. This hydrogen isotope, deuterium, will display certain behavior depending upon its location among the bonding electrons as well as whether the conditions for aromaticity are met. A molecular-scale MRI known as NMR will be used to probe the deuterium atoms.