Consecutive N2 loss from a uranium diphosphazide complex

Abstract

A new ‘diphosphazidosalen’ ligand was synthesized and successfully transferred to uranium using salt metathesis strategies. The resultant 8-coordinate uranium(IV) diphosphazide complex [κ⁶-1,2-{(N₃)PPh₂(2-O-C₆H₄)}₂C₆H₄]UCl₂ (1) is unstable to consecutive N₂ loss, affording the asymmetric species [κ⁵-1-{(N₃)PPh₂(2-O-C₆H₄)}-2-{N=PPh₂(2-O-C₆H₄)}C₆H₄)]UCl₂ (2), defined by a phosphazide-phosphinimine mixed-ligand framework, and ultimately, the uranium(IV) phosphasalen complex [κ⁴-1,2-{N=PPh₂(2-O-C₆H₄)}₂C₆H₄]UCl₂(THF) (3).