Chemical and structural aspects of cyclopentadienyl uranium(IV) tetrahydroborato complexes

Several new or partially described complexes of uranium(IV) of the series Cp4-n U(BH4)n [Cp=?5- C5H5, ?5-C5H4CH3 or ?5-C5H4Si(CH3)3] are reported, mainly in order to systematically compare their physical, chemical and spectroscopic properties. X-ray data of the crystal structure of Cp3UBH4 are also reported.