An Inverted-Sandwich Diuranium ?-?(5):?(5)-Cyclo-P5 Complex Supported by U-P5 ?-Bonding.

ABSTRACT: Reaction of [U(Tren(TIPS))] [1, Tren(TIPS)=N(CH2CH2NSiiPr3)3] with 0.25?equivalents of P4 reproducibly affords the unprecedented actinide inverted sandwich cyclo-P5 complex [{U(Tren(TIPS))}2(?-?(5):?(5)-cyclo-P5)] (2). All prior examples of cyclo-P5 are stabilized by d-block metals, so 2 shows that cyclo-P5 does not require d-block ions to be prepared. Although cyclo-P5 is isolobal to cyclopentadienyl, which usually bonds to metals via ?- and ?-interactions with minimal ?-bonding, theoretical calculations suggest the principal bonding in the U(P5)U unit is polarized ?-bonding. Surprisingly, the characterization data are overall consistent with charge transfer from uranium to the cyclo-P5 unit to give a cyclo-P5 charge state that approximates to a dianionic formulation. This is ascribed to the larger size and superior acceptor character of cyclo-P5 compared to cyclopentadienyl, the strongly reducing nature of uranium(III), and the availability of uranium ?-symmetry 5f orbitals.

SUBMITTER: Gardner BM 

PROVIDER: S-EPMC4517156 | biostudies-literature | 2015 Jun

REPOSITORIES: biostudies-literature