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

单质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是学术和应用研究的首要兴趣。在这个项目中，我们将进一步推进一个最近发现的反应，在这个反应中，一个无位阻的n -杂环碳烯（NHC）和弱酸的同时作用诱导p4 -四面体在形式歧化下分解成两个不同的p1构建块（“咪唑酰膦烯”）。根据机理研究结果对反应条件进行优化，抑制副产物的生成，优选磷的定量转化。此外，我们将开发的反应，使所得到的p1构建块转化为功能化的亲电有机磷化合物（如有机磷卤化物），在回收NHC试剂使用。由各种单独转化的连接产生的反应网络将建立新的简单途径来合成有价值的目标化合物，并将允许确定反应周期，这可能作为催化反应变体长期发展的基础。在这些活性过程中所研究的简单咪唑酰膦的取代反应也将用于组装可能作为多齿或大环配体的多官能团衍生物。在配位化学的初步研究中，我们将探讨这些配体在稳定动力学惰性双金属或多金属配合物中的应用。

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.