Covalency in the f-element–chalcogen bond: Computational studies of [M(N(EPH2)2)3] (M = La, U, Pu; E = O, S, Se, Te)

The geometric and electronic structures of the title complexes have been studied using gradient corrected density functional theory. Excellent agreement is observed between computed r  (M–E) and experimental values in analogous Pri complexes. Natural charge analysis indicates that the M–E bond becomes less ionic in the order O>S>S>O>S>S> Te, and that this decrease is largest for U and smallest for La. Natural and Mulliken overlap populations suggest increasing M–E covalency as group 16 is descended, and also in the order La