Electron Spin Resonance in the Undergraduate Curriculum

本科生课程中对奇电子物种的处理包括有机化学中的自由基和无机和生物化学课程序列中的含过渡金属化合物的讨论。尽管讨论具有不成对电子的无机化合物是本科化学教学大纲的重要组成部分，但在本科有机化学课程中，自由基往往很快被视为短暂的中间体，忽视了稳定自由基的存在，并错过了加强结构和成键概念的机会。不幸的是，关于奇电子物种及其反应性的直接实验证据通常根本不被提出。该项目将购买一台电子自旋共振(ESR)光谱仪，用于本科课程。这将有助于物理化学(ESR和核磁共振之间的类比)、有机化学(将电子-核自旋耦合解释为核磁共振讨论中所涉及概念的扩展)、材料化学(未成对电子在导电聚合物和导电金属氧化物中的作用和性质)、无机化学(阐明分子结构、成键理论、稳定性和18电子规则)和生物化学(金属蛋白的氧化还原行为)中的重要概念的发展和演示。该仪器将允许我们开发和实施新的实验，这些实验将增强学生对结构和结合的基本概念的理解。每年将有300名学生在二年级的合成实验室课程中、化学专业的初级和高级学生以及本科生的研究中使用它。作为课程改革的一部分，正在为本科实验室开发新的实验，以应对从以季度为基础的制度到以学期为基础的学术日历的变化。在实验室序列中处理ESR提供了一个独特的机会来探索处理奇电子物种的新的教学方法，这是我们目前感到缺乏重点的一个领域。随着实验的发展，它们将被提供给其他地方采用。

The treatment of odd-electron species in the undergraduate curriculum includes discussion of radicals in organic chemistry and transition metal-containing compounds in both the inorganic and biochemistry lecture sequences. Although discussion of inorganic compounds with unpaired electrons is a vital component of the undergraduate chemistry syllabus, radicals are often quickly dismissed in the undergraduate organic chemistry curriculum as short-lived intermediates, ignoring the existence of stable radicals, and missing the opportunity to reinforce concepts in structure and bonding. Unfortunately, direct experimental evidence for odd-electron species and their reactivity are not usually presented at all. The project will purchase an Electron Spin Resonance (ESR) spectrometer for use in the undergraduate curriculum. This will facilitate the development and demonstration of important ideas in physical chemistry (analogy between ESR and NMR), organic chemistry (interpretation of electron-nuclear spin coupling as an extension of the concept covered in discussion of NMR), materials chemistry (role and nature of unpaired electrons in conducting polymers and conducting metal oxides), inorganic chemistry (elucidation of molecular structure, bonding theory, stability and the 18 electron rule) and biochemistry (redox behavior of metalloproteins). The instrument will allow us to develop and implement new experiments that will enhance students' understanding of fundamental ideas in structure and bonding. It will be used by 300 students per year in sophomore-level synthesis laboratory course, by junior and senior chemistry majors, and for undergraduate research. New experiments for the undergraduate laboratories are being developed as part of a curriculum reform in response to a change from a quarter based system to a semester based academic calendar. Treatment of ESR in the laboratory sequence offers a unique opportunity to explore new pedagogies for the treatment of odd-electron species, an area w hich we feel is currently lacking emphasis. As experiments are developed they will be made available for adoption elsewhere.