Main Group Cations, Radicals, Metal Complexes and Their Applications

作为我的研究小组正在进行的研究的一部分，在这项提案中，我们将重点关注以下跨越我们的专业领域的项目，包括主要组和过渡金属合成化学： 1.低价和/或低氧化态重族元素：由富电子配体稳定的阳离子和自由基 在第13族阳离子和自由基方面，我们的目标是开发适当的分子框架，这些框架是在电子和空间上稳定这些分子所必需的。对这些体系的全面了解将有助于我们深入了解Al与其他原子的成键过程，同时也使我们能够确定这些分子是否可以用作过渡金属上的配体。这项工作预计将在涉及这些金属的基本反应性和成键的领域产生很大影响。 2.主基和过渡金属络合物的Cp/芳基配体的络合作用 我们的目标是制备一系列类似于已知约束几何类型的配体的单阴离子配体，其中金属中心由一个环戊二烯(CP)阴离子环和一个中性芳基环螯合，这两个环都通过主链芳环附近的o-定位分开。改变(CP)环和芳环上的取代基将调节这些分子的电子和空间，从而允许研究成键。对于某些金属，例如铁，与二茂铁、Cp2Fe或[Cp-Fe-苯]阳离子相比，应变的Cp-芳基角将导致前线分子轨道的显著不稳定，从而允许发生前所未有的反应。 3.白磷(P4)与氢的化学 我们在P4化学方面的经验使我们研究了P4与质子和氢原子的基本反应活性。到目前为止，只有气相中存在[P4H]的证据。通过明智地选择“超强酸”和选择溶剂，我们计划在溶液中识别[P4H]，并在固态中将其分离。在类似的脉络中，P4与氢原子的反应性被建议用氢的一种轻同位素--钚来研究。 4.富含电子的有机和无机分子 最近，我们成功地制备了富含电子、高度不饱和的“有机”分子，其中许多分子的颜色很高。这些体系是高活性的丙烯酸阳离子[H_2C-CC-H]及其相关自由基的稳定衍生物。我们的目标是探索一个中心的高度不饱和片段[Para-CC-C6H4-CC]的各种取代模式。这些原始分子的“无机”类似物将通过用磷或硼分子取代[对位CC-C6H4-CC]的末端来制造。我们亦建议建立一个“推-拉”式的系统，一端是电子捐赠组，另一端是电子抽取组。这些取代将允许它们的性质和反应性的调节。

As part of the ongoing research within my research group, in this proposal we will be focusing on the following projects that span our areas of specialty including main group and transition metal synthetic chemistry: 1. Low-valent and/or low oxidation state heavy Group 13 elements: Cations and radicals stabilized by electron-rich ligands In the area of Group 13 cations and radicals we aim to develop the appropriate molecular frameworks that are necessary to electronically and sterically stabilize these molecules. A complete understanding of these systems will provide insight to the bonding of Al with other atoms and at the same time, allow us to determine if these molecules can be used as ligands on transition metals. This work is expected to have a high impact in the area involving fundamental reactivity and bonding in these metals. 2. Chelating Cp/aryl based ligands for main group and transition metal complexes We aim to prepare a suite of mono anionic ligands similar to known constrained geometry-type of ligands where the metal center is chelated by one cyclopentadienyl (Cp) anionic ring and one, neutral aryl ring, both separated by o-positioning about a backbone aryl ring. Altering the substituents on the (Cp) ring and the aryl ring will tune the electronics and sterics of these molecules, allowing for the studying of the bonding. In the case of some metals, for example iron, the strained Cp-Aryl angle will cause a significant destabilization of the frontier molecular orbitals when compared to ferrocene, Cp2Fe, or [Cp-Fe-Benzene] cations, allowing for unprecedented reactivity to take place. 3. The chemistry of white phosphorus (P4) with hydrogen Our experience in P4 chemistry has lead us to investigate the fundamental reactivity of P4 with both a proton and a hydrogen atom. To date, there is only evidence of the existence of [P4H]+ in the gas phase. Through judicious selection of a “super acid” and solvent choice we plan on identifying [P4H]+ in solution and isolating it in the solid state. In a similar vein, the reactivity of P4 with a hydrogen atom is proposed to be studied using muonium, a light isotope of hydrogen. 4. Electron-rich organic and inorganic molecules Recently we have had success in the preparation of electron rich, highly unsaturated "organic" molecules, many of them highly colored. These systems are stable derivatives of the highly reactive propargyl cation [H2C-CC-H]+ and its related radical. We aim to explore various substitution patterns about a central, highly unsaturated fragment [para-CC-C6H4-CC]. These "inorganic" analogues of our original molecules will be made by substituting the ends of the [para-CC-C6H4-CC] with phosphorus or boron-based molecules. We also propose making a "push-pull" type of system where an e- donating group is attached to one end and an e- withdrawing group is on the other. These substitutions will allow for the tuning of their properties and reactivity.