A new approach to the cooperative activation and transformation of elementary phosphorus

元素磷是制备大多数有机磷化合物的起始材料，因此，探索从元素直接合成它们的可持续方法在学术和应用研究中都具有重要意义。在这个项目中，我们将进一步推进一个最近发现的反应，其中空间上不受阻碍的N-杂环卡宾（NHC）和弱酸的同时作用诱导P4-四面体在形式上的分解下分解成两个不同的P1-结构单元（“咪唑基膦”）。通过进行由机理研究结果指导的反应条件的优化，我们打算抑制副产物的形成并且优选接近磷的定量转化。此外，我们将开发允许将所得的P1-构建块转化为官能化的亲电有机磷化合物的反应（例如。G.有机磷卤化物），在回收所用NHC试剂的条件下进行。 由各种单独转化的连接产生的反应网络将建立合成有价值的目标化合物的新的简单途径，并将允许识别可作为催化反应变体的长期开发的基础的反应循环。在这些活动过程中研究的简单咪唑基膦的取代反应也将用于组装可能充当可能的多齿或大环配体的多官能衍生物。在配位化学的初步研究过程中，我们将探索使用这些配体来稳定动力学惰性的双金属或多金属络合物。

Elemental phosphorus is the starting material for the preparation of most organophosphorus compounds, and the exploration of sustainable methods for their straight synthesis from the element is consequently of paramount interest in both academic and applied research. In this project, we will further advance a recently discovered reaction in which the simultaneous action of a sterically unhindered N-heterocyclic carbene (NHC) and a weak acid induces dismantling of the P4-tetrahedron under formal disproportionation into two different P1-building blocks ("imidazoyl phosphinidenes"). By carrying out an optimization of the reaction conditions that is directed by the results of mechanistic studies, we intend to suppress the formation of side products and preferably approach quantitative conversion of the phosphorus. In addition, we will develop reactions which allow transformation of the resulting P1-building blocks into functionalized electrophilic organophosphorus compounds (e. g. organophosphorus halides), under recovery of the NHC reagents employed. The reaction network arising from the connection of the various individual transformations will establish novel simple access routes to synthetically valuable target compounds and will permit to identify reaction cycles which may serve as the basis for a long-term development of catalytic reaction variants. Substitution reactions at simple imidazoyl phosphinidines, which are studied in the course of these activities, will also be employed for the assembly of polyfunctional derivatives that may serve as possible multidentate or macrocyclic ligands. In the course of first studies of the coordination chemistry, we will explore the use of these ligands for the stabilization of kinetically inert bi- or multimetallic complexes.