Structure and Reactivity of Transient Carbenes

瞬态卡宾的结构和反应性

• 批准号: 1261862
• 负责人: Robert Moss
• 金额: $ 37.5万
• 依托单位: Rutgers University New Brunswick
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-06-01 至 2017-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1261862&HistoricalAwards=false
• 关键词: Structure; Reactivity; Transient; Carbenes

The Chemical Structure, Dynamics, and Mechanisms B Program supports Professor Robert A. Moss of Rutgers University to investigate the structure and reactivity of transient carbenes. The scientific objective of this work is to engage in mechanistic characterization of reactive intermediates, especially the chemistry of carbenes and carbanions. Its unifying theme is the correlation of structure with reactivity for highly reactive, short-lived intermediates. Activation parameters will be determined for carbene-alkene additions of the highly reactive carbenes Cl-C-CN, F-C-CN, Cl-C-CF3, and F-C-CF3. The results will bear upon the operation of enthalpy/entropy compensation in carbene/alkene addition reactions. Equilibrium constants and thermodynamic parameters will be measured for [PhCX + Y- = PhCXY-], where X,Y = F, Cl, and Br. Transient complexes of alkylchlorocarbenes with aromatic partners will be spectroscopically and computationally characterized. Modulation of carbenic reactivity by complexation will be probed. The chemistry of F-C-OPh encapsulated in a water-compatible hemicarcerand will be explored. Finally, the "umpolung" or philicity alteration of nucleophilic and ambiphilic carbenes by reaction with lithium salts will be studied.Carbenes are very unusual carbon-based molecules that are extremely reactive, living only billionths of a second in solution at room temperature. Carbenes can exist in different geometries with different arrangements of their outer electrons and this can lead to different reactivities. In this research project, a detailed set of fast spectroscopic measurements is made to determine the relationship between the geometry changes and the reactivity of these interesting molecules. Professor Moss is the Chair of the Coordinating Committee of the International Symposium on Reactive Intermediates and Unusual Molecules (ISRIUM), meeting in Mexico in 2014.

化学结构、动力学和机制B项目支持罗格斯大学的罗伯特·A·莫斯教授研究瞬时卡宾的结构和反应活性。这项工作的科学目标是从事活性中间体的机械表征，特别是卡宾和碳负离子的化学。其统一的主题是高活性、寿命短的中间体的结构与反应性的关联。将确定高活性卡宾Cl-C-CN、F-C-CN、Cl-C-CF3和F-C-CF3的卡宾-烯烃加成反应的活化参数。这一结果将对卡宾/烯烃加成反应中的焓/熵补偿操作具有指导意义。将测量[PhCX+Y-=PhCXY-]的平衡常数和热力学参数，其中X、Y=F、Cl和Br.烷基氯卡宾与芳香族配对的瞬时络合物将被光谱和计算表征。将探讨络合对卡宾反应性的调节作用。将探索F-C-Oph在水相容的半碳酸盐中的化学。最后，我们将研究亲核性和双亲性卡宾与锂盐反应后的亲水性变化。卡宾是一种非常不寻常的碳基分子，活性极强，在室温下只存在十亿分之一秒的溶液中。卡宾可以以不同的几何构型存在，其外层电子的排列也不同，这会导致不同的反应活性。在这个研究项目中，我们进行了一套详细的快速光谱测量，以确定这些感兴趣的分子的几何变化和反应活性之间的关系。莫斯教授是活性中间体和特殊分子国际研讨会(ISRIUM)协调委员会主席，该研讨会于2014年在墨西哥举行。