Isolable f-element diphosphene complexes by phosphinidene group transfer and coupling at uranium

TL;DR

This paper reports the synthesis of f-element diphosphene complexes, expanding the field of f-element chemistry and offering new insights into diphosphene stabilization.

Contribution

The introduction of f-element diphosphene complexes and new synthetic methods for their preparation.

Findings

F-element diphosphene complexes were successfully synthesized using uranium(III) reagents.

Computed reaction profiles show radical intermediates and P-centered redox chemistry.

The study provides a foundation for future synthetic strategies in f-element diphosphene chemistry.

Abstract

The parent diphosphene (HPPH) molecule is of fundamental interest, but its reactive nature renders it challenging to isolate and study. Metal-stabilization is an attractive approach for studying HPPH, but molecular derivatives are limited to three complexes of p-/d-metals reflecting a scarcity of synthetic methods for rationally preparing HPPH complexes. Here, we introduce f-element HPPH complexes, adding to f-element diazenes (HNNH) that were first reported over thirty years ago. By utilizing 7λ3-phosphadibenzonorbornadiene and uranium(III) reagents we show how parent diphosphene, phosphinidiide, and diphosphorus motifs can all be constructed, developing synthetic approaches for this area. Computed reaction profiles reveal common, initial reaction steps that subsequently diverge depending on the ancillary ligands, radical nature of intermediates, and the 7λ3-phosphadibenzonorbornadiene P-substituent. Calculations demonstrate a surprising prevalence of open-shell radical intermediates, and that the redox chemistry is P-, not U-, centred. This work thus provides insights to inform future synthetic endeavours in this area.

The parent diphosphene molecule is of fundamental interest, but its reactive nature renders it challenging to isolate, and current metal-stabilized derivatives are limited to complexes of p-/d-metals. Here, the authors introduce f-element diphosphene complexes, adding to f-element diazenes that were first reported over thirty years ago.

Figures