Fluorinated diarylamide complexes of uranium(iii, iv) incorporating ancillary fluorine-to-uranium dative interactions

Abstract

The fluorinated diarylamines HNPhPh^F, HNPh^F₂, HNPhAr^F, Ph^F = 2,3,4,5,6-pentafluorophenyl, Ar^F = 3,5-bis(trifluoromethyl)phenyl, are used to prepare complexes of uranium(III, IV) ions. Despite being electron-poor amines with little steric bulk, their coordinated amide ligands exhibit direct control over the coordination environment through a subtle, cooperative interplay of multiple labile F→U dative interactions and favorable arene–arene interactions. The C–F→U interactions, ∼8.9 kcal mol⁻¹ as determined by variable temperature NMR experiments, persist in solution and allow the isolation of otherwise unstable species as well as the first pseudo-square planar uranium complex.