Actinide complexes with the Kläui tripodal oxygen ligand – crystal structure of [{η4-C5H5(CH2C(CH3)3)}Co{P(O)(OC2H5)2}3]2U

Reaction between [(C5H5)Co{P(O)(OEt)2}3]2UCl2 and neopentyl lithium affords the novel complex, [{η4-C5H5(CH2C(CH3)3)}Co{P(O)(OEt)2}3]2U, in which the uranium metal center has been dehalogenated and the neopentyl nucleophiles have attacked the cyclopentadienyl groups on the Kläui ([(C5H5)Co{P(O)(OEt)2}3]−) ligands. The uranium atom in the title compound possesses octahedral geometry defined by the oxygen atoms from two sets of tripodal oxygen ligands, while the cyclopentadienyl ligands are bound η4 to the cobalt atoms. The formation of this complex suggests that the Kläui ligand may not be a suitable ligand framework for supporting organometallic complexes of oxophilic early actinides.