Metal-Element Multiple Bonds Stabilized by Trisamidophosphines: Synthesis, Structure and Reactivity

许多化学转化，如烯烃或炔烃的歧化反应，依赖于具有多结合杂元素(E)的金属络合物，它们通常在这些转化中起关键作用。这里提出的研究集中在含有M=ER和ME构筑块(E=CR，N，P，As等)的(IV)和(V)族金属络合物。具有金属元素的双键和三键。为了稳定活性ME碎片，计划使用三胺基膦配体支架。由于后一类配体已经得到了详细的研究，因此拟进行的合成工作主要针对这类新配体的配位化学和ME基序的反应性。最初的目标是钛、锆和碲的阴离子亚烷基、亚胺和膦，随后的反应性研究旨在开发这些M=ER阴离子(M=Ti，Zr，Hf；E=N，P，As)的预期亲核性，以揭示这些化合物的潜在应用。含氮、磷、砷端基的阴离子钒、铌、钽配合物的合成也将发挥重要作用。开发合成含ME三键(M=V，Nb，Ta；E=N，P，As)的配合物的新合成途径具有根本意义，而反应性研究将在工作过程中变得越来越重要。从长远来看，后一种反应性研究旨在发现和建立这种金属络合物的应用，例如在均相催化中。由于在早期过渡金属的情况下，M=SiR_2和M=B_r的亚结构还没有被详细地研究过，所以我们将研究利用三胺基膦来稳定这些结构基序，并针对这些体系的可能应用进行研究。

Numerous chemical transformations, such as alkene or alkyne metathesis, rely on metal complexes with multiply-bound heteroelements (E), which often play key roles in these trans-formations. The studies proposed herein are focused on group (IV) and group (V) metal complexes that contain M=ER and ME building blocks (E = CR, N, P, As, etc.) with metal-element double and triple bonds. In order to stabilize the reactive ME fragments, the use of trisamidophosphine ligand scaffolds is planned. As the latter ligands have been studied in detail already, the intended synthetic efforts are directed mainly towards the coordination chemistry of this new class of ligands and the reactivity of ME motifs. Anionic alkylidenes, imides and phosphinidenes of titanium, zirconium and hafnium are targeted initially and subsequent reactivity studies are meant to exploit the expected nucleophilicity of such M=ER anions (M = Ti, Zr, Hf; E = N, P, As) in order to reveal potential applications of these compounds. The synthesis of anionic vanadium, niobium and tantalum complexes with terminal nitrido, phosphido and arsenido moieties is going to play a crucial role as well. The development of new synthetic pathways to complexes containing ME triple bonds (M = V, Nb, Ta; E = N, P, As) is of fundamental relevance, while reactivity studies will gain in importance over the course of the work. In the long term, the latter reactivity studies are meant to discover and establish applications of such metal complexes, for example in homogeneous catalysis. As M=SiR2 and M=BR substructures have not been studied in much detail in case of early transition metals, the frontier-crossing use of trisamidophosphins to stabilize such structural motifs will be examined and directed towards possible applications of these systems.