Zur Elektronenstruktur metallorganischer Komplexe der f-Elemente LXI. Welche Oxidationszahl hat Cer im tiefvioletten 1,1′,4,4′-Tetrakis(trimethylsilyl)cerocen?

Decamethylytterbocene Complexes of Bipyridines and Diazabutadienes: Multiconfigurational Ground States and Open-Shell Singlet Formation

“…These data therefore point to the formation of a multiconfigurational, open-shell singlet ground-state with anomalously strong antiferromagnetic coupling between the moments on the metal and the aromatic ligand. Similar behavior was predicted for cerocene [17][18][19] (Ce(cot) 2 , cot = cyclooctatetraene = C 8 H 8 ) and supported by experiments on cerocene, 16,20 substituted cerocenes, 21,22 the isoelectronic compounds Pn* 2 Ce (Pn* = permethylpentalene = C 8 25 Cp* 2 Yb(terpy = 2,2′:6′,2′′-terpyridine), 7 and Cp* 2 Yb(bipy). 16 This interpretation is further supported by a Complete Active Space Self-Consistent Yb L III -edge XANES and magnetic susceptibility measurements are reported below on several bipy and dad adducts of Cp* 2 Yb of the type Cp* 2 Yb(L) (Scheme 1), where L is either bipy, a 4,4′-disubstituted bipyridine, or a 1,4-diazabutadiene derivative, including purely di-and trivalent Yb complexes.…”

Electronic structures of organometallic complexes of f elements LXXIII: Parametric analysis of the crystal field splitting pattern of tris(η5-pentamethylcyclopentadienyl)cerium(III)

“…Hence, the bands at 13 700 and 11 800 cm À1 (with DE = 1900 cm À1 ) correspond most probably to the transitions initiating on the lowest d level 12e 1/2 and terminating on 2 F 5/2 and 2 F 7/2 , respectively. This pair of values is comparable with that of [Li(THF) 4 ][Ce(g 8 -C 8 H 8 ) 2 ] (13 310/11 920 cm À1 [39]), the Ce III compound with the strongest redshift of 5d ? 4f transitions found to date [9,.…”

“…However, in a number of cases these d ? f transitions are split into two components with the terminal multiplets 2 F 5/2 and 2 F 7/2 , respectively, which are separated in the case of Ce III organometallics between 1390 cm À1 ([Li(THF) 4 ][Ce(g 8 -C 8 H 8 ) 2 [39]) and 2330 cm À1 (LiCp* 2 CeCl 2 [40]) with 1900-1950 cm À1 being the most common values (see Ref. [9,).…”

All-electron CASPT2 study of Ce(η8–C8H6)2

“…This view has received (strong) experimental support via XANES measurements [20,21], and optical spectroscopic properties of substituted cerocenes have been shown to be more consistent with a bonding model based on Ce(III) than Ce(IV) [22].…”