Cerium(IV) Neopentoxide Complexes

Treatment of ceric ammonium nitrate (CAN) with varying amounts of sodium neopentoxide led to the isolation of crystalline cerium(IV) complexes [Ce(OCH 2 t Bu) 2 (NO 3 ) 2 (HOCH 2 t Bu) 2 ], [Ce(OCH 2 t Bu) 3 (NO 3 )-(NCCH 3 )] 2, [Ce 2 (OCH 2 t Bu) 7 (NO 3 )] 2, and [Ce 2 (OCH 2 t Bu) 9 Na-(THF)] featuring Ce IV /(OR) ratios of 1:2, 1:3, 1:3.5, and 1:4.5, respectively. The complexes are light-sensitive and prone to ligand redistribution as evidenced by multicomponent NMR spectra as well as the formation of [{Ce(OCH 2 t Bu) 4 } 2 (THF)] and the mixed-valent complex [Ce 3 (OCH 2 t Bu) 9 (NO 3 ) 2 ]. The CAN protocol also gave access to the isopropoxide derivative [Ce(O i Pr) 3 (NO 3 )(THF)] 2 . The reaction of [Et 4 N] 2 [CeCl 6 ] (CAC, ceric organoammonium chloride) with different equivalents of Na(OCH 2 t Bu) was also impaired by ligand reorganization and ate complexation as detected for the tetravalent cerium complex [Ce 2 (OCH 2 t Bu) 7 Cl 2 ][Et 4 N]. Protonolysis of [Ce{N(SiHMe 2 ) 2 } 4 ] with 4 equiv of HOCH 2 t Bu afforded donor-free homoleptic [Ce(OCH 2 t Bu) 4 ] 3 in quantitative yield. All complexes were characterized by NMR, DRIFT, and UV–vis spectroscopy, as well as paramagnetic susceptibility measurements, X-ray structure analysis, and elemental analysis.