Gas-Phase Studies of Substituted Aromatic Radicals, Biradicals and Polyradicals

在有机动力学计划和数学和物理科学局多学科活动办公室的支持下，普渡大学化学系的Hilkka I.KentTamaa教授对取代的芳香族自由基、双自由基和多自由基进行了气相研究。通过产生含有正电荷基团的芳香族自由基，KentTamaa教授能够使用傅立叶变换离子回旋共振质谱仪来检测它们在清洁条件下的本征或无溶剂反应性，从而能够评估反应速率常数、产物支化比和键离解能等热化学参数。研究了苯基、苄基和其他带有中性取代基的芳香族单基和多基的取代基效应，并利用自由基捕获法探讨了极性效应在不同类型自由基反应中的重要性。对于双自由基，研究了反应性和预测的基态多重数之间的关系，并利用这些信息来寻找自旋选择性的气相反应。普渡大学化学系的Hilkka I.KentTamaa教授在有机动力学计划和数学和物理科学局多学科活动办公室的支持下，研究含有一个或多个未配对电子(‘自由基’)的分子的化学。通过适当地选择自由基，KentTamaa教授能够使用气相技术来研究它们的形成和反应活性，从而在没有溶剂或其他潜在活性物种的复杂影响的情况下评估它们的内在性质。通过这些研究，获得了有关缺电子分子化学的基础知识，促进了对取代基效应和极性效应在调节其反应活性中的作用的理解，并为基于自由基有机合成和有机材料研究领域提供了潜在的进展。

With the support of the Organic Dynamics Program and the Office of Multidisciplinary Activities of the Mathematical and Physical Sciences Directorate, Professor Hilkka I. Kenttamaa, of the Department of Chemistry at Purdue University, carries out gas-phase studies of substituted aromatic radicals, biradicals, and polyradicals. By generating aromatic radicals which incorporate a positively charged group, Professor Kenttamaa is able to employ Fourier-transform ion cyclotron resonance mass spectrometry to examine their intrinsic or solvent-free reactivity under clean conditions, permitting the assessment of reaction rate constants, product branching ratios, and thermochemical parameters such as bond dissociation energies. Substituent effects are explored for phenyl, benzyl, and other aromatic mono- and polyradicals carrying neutral substituents in addition to the remote charged groups, and radical traps are employed to probe the importance of polar effects in different types of radical reactions. For biradicals, the relationship between reactivity and predicted ground state multiplicity is examined, and this information is used to search for spin-selective gas-phase reactions. Professor Hilkka I. Kenttamaa, of the Department of Chemistry at Purdue University, with the support of the Organic Dynamics Program and the Office of Multidisciplinary Activities of the Mathematical and Physical Sciences Directorate, studies the chemistry of molecules containing one or more unpaired electrons (`radicals`). By appropriate choice of radicals, Professor Kenttamaa is able to employ gas-phase techniques to study their formation and reactivity, permitting an assessment of their intrinsic properties in the absence of the complicating influences of solvents or other potentially reactive species. Through these studies is gained fundamental knowledge regarding the chemistry of electron-deficient molecules, advancing the understanding of the roles of substituent effects and polar effects in governing their reactivity and offering potential advances in the areas of radical-based organic synthesis and organic materials research.