Generation of a π‐Bonded Isomer of [P<sub>4</sub>]<sup>4−</sup>by Aluminyl Reduction of White Phosphorus and its Ammonolysis to PH<sub>3</sub>
Matthew M. D. Roy, Andreas Heilmann, Mathias A. Ellwanger, Simon Aldridge
Abstract
Abstract By employing the highly reducing aluminyl complex [K{(NON)Al}] 2 (NON=4,5‐ bis (2,6‐diisopropylanilido)‐2,7‐di‐ tert ‐butyl‐9,9‐dimethylxanthene), we demonstrate the controlled formation of P 4 2− and P 4 4− complexes from white phosphorus, and chemically reversible inter‐conversion between them. The tetra‐anion features a unique planar π‐bonded structure, with the incorporation of the K + cations implicit in the use of the anionic nucleophile offering additional stabilization of the unsaturated isomer of the P 4 4− fragment. This complex is extremely reactive, acting as a source of P 3− : exposure to ammonia leads to the release of phosphine (PH 3 ) under mild conditions (room temperature and pressure), which contrast with those necessitated for the direct combination of P 4 and NH 3 (>5 kbar and >250 °C).