Synthesis and Characterization of the First Sandwich Complex of Trivalent Thorium:  A Structural Comparison with the Uranium Analogue

Abstract

Reduction of the bulky 8-annulene thorium complex [Th{COT(TBS) 2 } 2 ] (COT(TBS) 2 = η-C 8 H 6 ( t BuMe 2 Si) 2 -1,4) by potassium yields the anionic compound {Th[COT(TBS) 2 ] 2 }K·(DME) 2, which was crystallographically characterized and is the first sandwich complex of Th(III). EPR spectroscopy indicates that the molecule possesses a 6d 1 ground state. A structural comparison is made with the isostructural uranium(III) complex and the thorium(IV) parent compound.