Gas-Phase Studies of Organic Biradicals

有了这个更新奖，化学部的有机和高分子化学计划支持博士的工作。他是普渡大学化学系的教授。这项研究为难以捉摸的芳香族双自由基提供了长期寻求的反应性信息。有机双自由基在溶液中的高反应性和短寿命阻碍了其反应性研究。例如，目前对许多芳香族双自由基的反应动力学和选择性知之甚少，对控制这种反应性的因素知之更少。然而，它是非常可取的，以获得这样的信息，因为芳香族双自由基在许多反应中发挥关键作用，从有机合成的抗肿瘤抗生素的生物效应。在过去，PI和她的研究小组已经开发了气相方法来表征有机自由基。这种方法现在适用于双自由基的检查。动力学反应性的研究进行了孤立的双自由基在气相中，通过使用FT-ICR质谱。在质谱仪中，通过连接到自由基上的化学惰性带电基团（二阶离子方法）对自由基进行操作。许多不同反应体系的反应产物的鉴定和反应速率常数的测定产生了关于控制有机双自由基反应性的基本因素的新信息。独立探索带电基团的具体影响。热化学信息是使用流动余辉四极八极四极装置。该仪器也被用来详细研究一些在双自由基反应中形成的新型三电荷加成产物。与两位专家John Nash博士（普渡大学）和Chris Cramer教授（明尼苏达大学）合作进行分子轨道计算，从理论上研究该系统。化学系的有机和大分子化学项目支持Hilkka I博士。他将开发新的实验方法来表征难以捉摸的反应中间体，这将对实验物理有机化学产生影响。了解不多的有机双自由基的性质上获得的基本知识，将有助于合理设计的双自由基与定制的使用，例如，在有机合成和新的癌症治疗的性能。教授将继续她在促进研究和教育的融合的良好记录。以前的成就已经看到了20多名研究生和本科生进行研究的各个方面，并传播的结果下教授的监督。在上一个资助期内，有10名博士毕业，每个人都在工业、国家实验室或学术界找到了一份出色的工作。大约一半的参与学生是女性或属于代表性不足的群体（主要是非洲裔美国人）。地域多样性包括来自南非、加纳、尼日利亚、印度、中国、伯利兹、加拿大和美国的学生。Albertamaa教授的研究成果将继续在同行评审的化学期刊上发表，并通过Albertamaa教授及其学生在有关有机、生物和分析化学、质谱和气相离子化学的国家和国际会议上以及在本科和研究生院举办的研讨会传播。目前与礼来、路博润、埃克森的工业合作和访问将继续下去。

With this Renewal award, the Organic and Macromolecular Chemistry Program in the Chemistry Division supports the work of Dr. Hilkka I. Kenttamaa of the Department of Chemistry at Purdue University. This research provides long-sought-after reactivity information for elusive aromatic biradicals. Reactivity studies on organic biradicals are hindered by their high reactivity and short lifetime in solution. Very little is currently known, for example, about reaction kinetics and selectivity of many aromatic biradicals, and even less about the factors that control this reactivity. However, it is highly desirable to obtain such information since aromatic biradicals play a key role in many reactions, ranging from organic synthesis to the biological effects of antitumor antibiotics. In the past, the PI and her research group have developed gas- phase methodology for the characterization of organic radicals. This methodology is now adapted for the examination of biradicals. Kinetic reactivity studies are carried out on isolated biradicals in the gas phase by using FT-ICR mass spectrometry. The radicals are manipulated in the mass spectrometer via a chemically inert charged group attached to the radical (distonic ion approach). Identification of reaction products and determination of reaction rate constants for many different reaction systems yields new information on the fundamental factors that control organic biradicals reactivity. The specific effects of the charged group are independently explored. Thermochemical information is obtained using a flowing-afterglow quadrupole-octopole-quadrupole apparatus. This instrument is also used to study in detail some of the novel triply- charged addition products formed in the biradical reactions. Molecular orbital calculations are carried out to theoretically examine the systems in collaboration with two experts, Dr. John Nash (Purdue) and Professor Chris Cramer (U.Minnesota).The Organic and Macromolecular Chemistry Program in the Chemistry Division supports Dr. Hilkka I. Kenttamaa of the Department of Chemistry at Purdue University who will develop new experimental methodologies for characterization of elusive reaction intermediates that will have an impact on experimental physical organic chemistry. Fundamental knowledge obtained on the properties of poorly understood organic biradicals will facilitate the rational design of biradicals with properties tailored for use, for example, in organic synthesis and in new cancer treatments. Professor Kenttamaa will continue her excellent track record in promoting the integration of research and education. Previous accomplishments have seen more than 20 graduate and undergraduate students carry out all the aspects of the research and disseminate the results under Professor Kenttamaa's supervision. Ten PhD's graduated and each secured an excellent job in industry, national laboratories or academia during the last grant period. About half of the participating students are female or belong to underrepresented groups (mostly African-American). Geographic diversity includes, students from South Africa, Ghana, Nigeria, India, China, Belize, Canada and the US. Professor Kenttamaa's results will continue to be published in peer reviewed chemistry journals and disseminated via seminars given by Professor Kenttamaa and her students at national and international conferences on organic, biological and analytical chemistry, mass spectrometry and gas-phase ion chemistry, and in undergraduate and graduate colleges. Industrial collaborations and visits currently with Lilly, Lubrizol, Exxon, will continue.