Low-Valent Chemistry: An Alternative Approach to Phosphorus-Containing Oligomers

A convenient
preparative approach to low-valent phosphorus-rich oligomers is presented.
Ligand substitution reactions involving anionic diphosphine ligands
of the form [(PR2)2N]− and
[(PPh2)2C5H3]− and a triphosphenium bromide PI precursor result in the
formation of phosphorus­(I)-containing heterocycles, several of which
are of types that have never been prepared before. The methodology
described also allows for the preparation of the known heterocycle cyclo-[P­(PPh2)­N­(PPh2)]2 in better yields and purity than the synthetic approach reported
previously. Preliminary reactivity studies demonstrate the viability
of such zwitterionic oligomers as multidentate ligands for transition
metals.

本文提出了一种便捷的合成低磷含量富磷寡聚物的制备方法。涉及阴离子双膦配体[(PR2)2N]−和[(PPh2)2C5H3]−以及三膦溴化物PI前体的配体取代反应，成功制备了含磷(I)杂环化合物，其中数种类型为前所未制。所述方法亦适用于已知杂环化合物环-[P(PPh2)N(PPh2)]2的制备，其在产率和纯度方面均优于先前报道的合成方法。初步的活性研究证实了此类两性离子寡聚物作为多齿配体在过渡金属领域的可行性。