SGER: Phosphorus-Containing Diatomic Molecules as Reactive Intermediates in Solution

无机化学、生物无机化学和金属有机化学项目的SGER奖支持麻省理工学院的Christopher Cummins教授寻求形成P-P三键和将磷结合到有机分子中的新方法的研究。这项研究建立在最近开发的一种新的合成Nobaziridine氢化物体系的基础上，该体系允许激活元素P4分子，从而导致Nb-P三键。这为磷原子向主基受体的转移开辟了新的途径，例如在Nb的作用下合成了三键。本研究将Nb介导的磷三键形成化学扩展到元素磷本身，以便在温和的温压条件下和均相溶液中形成P2分子。通过对P2生成和俘获实验的机理和计算研究，建议确定自由双原子P2分子是否确实是中间体，因为这种化学可以用P2合成当量来解释，对于合成含有嵌入P2单元的分子很有价值。还建议生成一种W(CO)5保护的变体，它保留了游离P2的三键反应性，但寿命更长，更有效地被不饱和有机分子捕获，并且在室温下可用。三键生成反应的研究将扩展到目标双原子分子PAS和Pn，它们和P2一样是简单的三键系统，目前还没有已知的溶液化学。这一研究将对作为配体、催化或药效团的含磷有机分子的合成产生影响。在温和的条件下，PP三键倾向于充当积极的双亲双烯基团，应该能够一步构建四个P-C键和两个稠环体系。本科生、研究生和博士后将通过康明斯研究小组、麻省理工学院其他小组以及其他国内和国际合作者之间的互动进行培训。

This SGER award in the Inorganic, Bioinorganic and Organometallic Chemistry Program supports research by Professor Christopher Cummins at MIT to pursue new methods of forming P-P triple bonds and incorporating phosphorous into organic molecules. This research builds upon a recently developed new synthesis of niobaziridine hydride systems that permits activation of the elemental P4 molecule leading to niobium-phosphorus triple bonds. This paves new pathways for P-atom transfer to main-group acceptors, such as niobium-mediated synthesis of PCR (phosphaalkyne) triple bonds. This research extends the niobium-mediated phosphorus-triplebond-forming chemistry to the element phosphorus itself, so as to form the P2 molecule under mild conditions of temperature and pressure and in homogeneous solution. Through mechanistic and computational studies of the P2 generation and trapping experiments, it is proposed to determine if the free diatomic P2 molecule is indeed an intermediate, as the chemistry may be explicable in terms of a P2 synthetic equivalent valuable for the synthesis of molecules containing embedded P2 units. It is also proposed to generate a W(CO)5 protected variant that retains the triple bond reactivity of free P2 but is longer lived, more efficiently trapped by unsaturated organic molecules, and available at room temperature. The studies of triple-bond generating reactions will be extended to include the target diatomic molecules, PAs and PN, which, like P2, are simple triple bond systems with no presently known solution chemistry.This research will have an impact on the synthesis of phosphorus-containing organic molecules useful as ligands, in catalysis, or as pharmacophores. The propensity of the PP triple bond to serve as an aggressive double dienophile should enable the construction of four P-C bonds and two fused ring systems in a single step, under mild conditions. Undergraduate, graduate and postdoctoral students will be trained through interactions within the Cummins' research group, other groups at MIT, and other national and international collaborators.