Synthesis and Structural Characterization of a Series of Carboxylic Acid Modified Cerium(III) Alkoxides

Abstract

AbstractA series of cerium alkoxides were synthesized from the reaction of Ce{N[Si(CH3)3]2}3 and the appropriate alcohol: neopentyl alcohol [H–OCH2C(CH3)3 = H‐ONep], tert‐butyl alcohol [H–OC(CH3)3 = H‐OtBu], o‐(tert‐butyl)phenol {H–OC6H4[C(CH3)3]‐2 = H‐oBP}, 2,6‐dimethylphenol [H–OC6H3(CH3)2‐2,6 = H‐DMP], 2,6‐diisopropylphenol {H–OC6H3[CH(CH3)2]2‐2,6 = H‐DIP}, 2,6‐di‐tert‐butylphenol {H–OC6H3[C(CH3)3]2‐2,6 = H‐DBP}, or 2,6‐diphenylphenol [H–OC6H3(C6H5)2‐2,6 = H‐DPP] using toluene (tol), tetrahydrofuran (THF) or pyridine (py). The precursors were characterized as [Ce(μ‐ONep)2(ONep)]4 (1), Ce4(μ3‐OtBu)3(μ‐OtBu)4(OtBu)5 (2), Ce3(μ3‐OtBu)3(μ‐OtBu)3(OtBu)3(H‐OtBu)2 (2a), Ce(oBP)3(THF)3 (3), [Ce(μ‐DMP)(DMP)2(solv)2]2 [solv = THF (4) and py (4a)], Ce(DIP)3(THF)3 (5), Ce(DPP)3(THF)2 (6). Once isolated, several of these species were further reacted with a series of sterically varied carboxylic acid modifiers including isobutyric acid [H–O2CCH(CH3)2 = H‐OPc] and trimethylacetic acid [H–O2CC(CH3)3 = H‐OBc]. The products were isolated as [Ce(OR)(μ‐ORc)(μc‐ORc)(py)]2 [OR = oBP, OBc: 7; DMP, OPc: 8; DMP, OBc: 9; DIP, OPc: 10]. These compounds were identified by single‐crystal X‐ray diffraction and powder XRD analyses. Several novel structure types are added to the cerium alkoxide family of compounds. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)