Visible and ultraviolet spectra of tetraethylammonium tetrakis(β-diketonato) cerate(III) and tetrakis(β-diketonato)cerium(IV) complexes

Abstract

A number of β-diketonates of cerium(III), [NEt₄][Ce^IIIL₄], and cerium(IV), [Ce^IVL₄], have been prepared and their spectra have been recorded in the visible and u.v. regions. The spectra of the cerium(III) complexes show a group of two or three bands of moderate intensity at frequencies just below those of the strong intraligand transitions. Such bands are assigned as cerium(III)-to-ligand electron transitions or as 4f→5d transitions. For the cerium(IV) complexes a very broad absorption is found on the red side of the intraligand transitions, and is attributed to ligand-to-metal electron transfers.