Tuning the Reactivity of ortho-, meta- and para- Benzyne Analogs and Releated Polyradicals in the Gas Phase

有机双自由基和多自由基的实验反应性研究由于难以在溶液中干净地生成，以及它们的高反应性和短寿命而受到阻碍。关于控制碳心sigma型双自由基化学性质的因素的信息是非常可取的，因为它可以允许人们通过改变结构细节来调节它们的反应性，从而设计具有定制性质的双自由基和多自由基。这项研究计划使用“远场离子方法”，通过傅里叶变换离子回旋共振质谱仪、流动余辉四极-八极-四极装置和最近的线性四极离子陷阱，通过带电模拟研究气态、碳心、Sigma型单、双和三自由基的反应性。这些研究表明，双自由基的电子亲和力和单重态-三重态能隙，以及间苯并类似物的脱氢原子分离，是可以用来“调节”其中一些物种的反应性的反应性控制因素。然而，到目前为止，只有很少的不同的邻苯并和间苯并类似物被研究，最值得注意的是，没有对苯并类似物进行研究。因此，这项研究现在将扩展到几个不同的和不同取代的邻苯并和间苯并类似物。有了在气相中产生对苯肼类似物的方法，计划对它们的反应进行检查。最后，还将探讨控制相关三和四元化合物的反应性的因素。预测、控制和合理化化学反应结果的能力经常需要关键反应中间体的知识。带有一个或多个未配对电子(多自由基)的芳香族化合物在有机合成和有机化合物的生物活性中发挥着重要作用。这项研究的重点是提高对这些活性中间体的化学性质的基本了解。最终，这项研究将导致改进合成包括药物和新材料在内的新有机化合物的方法，以及更合理的新药设计。为表征反应中间体而开发的新的实验方法将对实验物理和物理有机化学产生影响。更广泛的社会影响和基础设施的加强包括大量种族多样化、高素质的理科博士候选人、改进有机化合物(包括石油)的化学分析方法以及设计和合成新的有机材料和药物的更坚实的知识基础。

Experimental reactivity studies on organic bi- and polyradicals are hindered by the difficulty of generating them cleanly in solution, in addition to their high reactivity and short lifetime. Information on the factors that control the chemical properties of carbon-centered sigma-type biradicals, such as the benzynes and their analogs, is highly desirable since it may allow one to "tune" their reactivity by varying structural details, and hence design bi- and polyradicals with tailored properties. This research program uses the "distonic ion approach" to study the reactivity of gaseous, carbon-centered, sigma-type mono-, bi- and triradicals via their charged analogs by using Fourier-transform ion cyclotron resonance mass spectrometers, a flowing afterglow quadrupole-octapole-quadrupole apparatus, and most recently, a linear quadrupole ion trap. These studies have demonstrated that the electron affinity and singlet-triplet gap of biradicals, as well as dehydrocarbon atom separation for meta-benzyne analogs, are among the reactivity controlling factors that can be used to "tune" the reactivity of some of these species. However, only few different ortho- and meta-benzyne analogs, and most remarkably, no para-benzyne analogs, have been studied thus far. Hence, this research will now be extended to several different and differently substituted ortho- and meta-benzyne analogs. With the means to generate para-benzyne analogs in the gas phase, an examination of their reactions is planned. Finally, the factors that control the reactivity of related tri- and tetraradicals will also be explored.The ability to predict, control and rationalize the outcomes of chemical reactions frequently requires knowledge of key reaction intermediates. Aromatic compounds that carry one (monoradicals) or more unpaired electrons (polyradicals) play an important role, for example, in organic synthesis and the biological activity of organic compounds. This research focuses on improving fundamental understanding of the chemical properties of these reactive intermediates. Ultimately, this research will lead to improved methods to synthesize new organic compounds, including drugs and new materials, as well as more rational design of new drugs. The new experimental methodologies developed here for the characterization of reaction intermediates will have an impact on experimental physical and physical organic chemistry. The broader societal impacts and enhancement of infrastructure include a large number of ethnically diverse, highly qualified science Ph.D. candidates, improved methodology for chemical analysis of organic compounds (including petroleum), and a more solid knowledge base for the design and synthesis of new organic materials and drugs.