Dipnictogen f-Element Chemistry: A Diphosphorus Uranium Complex

Abstract

The first isolation and structural characterization of an f-element dinitrogen complex was reported in 1988, but an f-element complex with the first heavier group 15 homologue diphosphorus has to date remained unknown. Here, we report the synthesis of a side-on bound diphosphorus complex of uranium(IV) using a 7λ³-(dimethylamino)phosphadibenzonorbornadiene-mediated P atom transfer approach. Experimental and computational characterization reveals that the diphosphorus ligand is activated to its dianionic (P₂)^2- form and that in-plane U-P π-bonding dominates the bonding of the U(μ-η²:η²-P₂)U unit, which is supplemented by a weak U-P interaction of δ symmetry. A preliminary reactivity study demonstrates conversion of this diphosphorus complex to unprecedented uranium <i>cyclo</i>-P₃ complexes, suggesting <i>in situ</i> generation of transient, reactive phosphido species.