Problems in Fluorocarbon Chemistry

在极端的键合情况下，氟化分子和它们的烃类似物之间的对比往往特别鲜明，从而导致碳氟化合物的新特性和反应性。该项目将探索高张力碳氟化合物- [2.2.2]螺桨烷，[2.2.1]螺桨烷，双环[2.1.0]戊烷，双环[1.1.0]丁烷和双环[2.2.0]烯烃-以及非苯型烃奥基的高度氟化衍生物的合成和性质。这些分子不仅因为它们的反应性而令人感兴趣，而且特别是因为它们的电子光谱和电子物理学，这将被合作探索。氟碳液体的官能化方法将应用于含氟聚合物表面。与使含氟聚合物表面官能化的其它方法（其本质上是非选择性的）相反，所使用的方法将在表面上的特定位点处引入特定官能团。结果应该是聚合物的新特性，包括螯合金属的能力。还将探索的是全氟化三重态卡宾的合成，其应显示出非凡的热稳定性，而没有唯一已知的稳定三重态卡宾的电子离域特性。该合成方案基于烷基和全氟烷基之间的尺寸差异以及碳氟键的巨大强度。氟碳化合物及其衍生材料在我们的社会中享有广泛的用途，其中许多用途是无与伦比的。它们的特殊性质是由于氟取代有机分子中的氢导致性质和化学行为的巨大变化。在有机和高分子化学项目的支持下，大卫M.达特茅斯学院化学系的Lemal正在扩展关于高度氟化分子的结构、反应性和合成的已知知识。通过这些研究，Lemal教授正在增强我们对这些分子与其更知名的碳氢化合物之间的对比的理解。

In extreme bonding situations the contrasts between fluorinated molecules and their hydrocarbon analogues are often especially sharp, resulting in novel properties and reactivity for the fluorocarbons. This project will explore the synthesis and properties of highly strained fluorocarbons - [2.2.2]propellanes, a [2.2.1]propellane, bicyclo[2.1.0]pentanes, bicyclo[1.1.0]butanes and a bicyclo[2.2.0]alkene - as well as highly fluorinated derivatives of an unusual aromatic system, the nonbenzenoid hydrocarbon azulene. These molecules are of interest not only for their reactivity, but especially for their electronic spectra and photophysics, which will be explored collaboratively. Methods for functionalization of fluorocarbon liquids will be applied to fluoropolymer surfaces. In contrast to other methods of functionalizing fluoropolymer surfaces, which are non-selective in nature, the approach to be used will introduce a specific functional group at specific sites on the surface. The result should be novel properties for the polymer, including the ability to chelate metals. Also to be explored is the synthesis of perfluorinated triplet carbenes that should display extraordinary thermal stability without the electron delocalization characteristic of the only known stable triplet carbenes. The synthetic plan is predicated on the size difference between alkyl and perfluoroalkyl groups, together with the great strength of carbon-fluorine bonds.Fluorocarbons and derived materials enjoy an wide variety of uses in our society, for many of which they are without equal. They owe their special character to the fact that substitution of fluorine for the hydrogens in organic molecules results in dramatic changes in properties and chemical behavior. With the support of the Organic and Macromolecular Chemistry Program, Professor David M. Lemal, of the Department of Chemistry at Dartmouth College, is extending what is known regarding the structure, reactivity and synthesis of highly fluorinated molecules. Through these studies, Professor Lemal is enhancing our understanding of the contrasts between these molecules and their better known hydrocarbon counterparts.