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

Abstract

A 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)

Structurally Characterized Erbium Alkoxides for Use as an Amphoteric Dopant in PErZT Ceramic Thin Film and Nanoparticles

“…Those that were off slightly from expected values were solvated species and the high volatility of the bound solvent often causes significant problems in obtaining accurate analyses. [8,30] Due to the paramagnetic nature of the Er metal center, we were unable to get meaningful NMR spectroscopic data either in solution or solid-state. Therefore, single-crystal X-ray diffraction studies were undertaken to assist in elucidating the identity of the final products isolated.…”

“…The source of the oxo species is not known as of yet and typically not observed for the Onep derivatives, unless esterification mechanisms from side reactions with carboxylic acids occur but may be due to adventitious water in the solvent. [30][31][32] Increasing the steric bulk to the OtBu groups, led to crystallization of the trinuclear 4 which had additional HOtBu bound to it, as shown in Figure 2. Previously, we isolated a Ce/OtBu tetramer [30] that did not possess any Lewis basic solvents (i.e., thf, py, or HOtBu) however, the Er corollary could not be isolated without bound solvents as noted for the pyridine adduct, Er 3 (µ 3 -O)(µ-OtBu) 4 -(OtBu) 3 (py) 3 (7).…”

“…[30][31][32] Increasing the steric bulk to the OtBu groups, led to crystallization of the trinuclear 4 which had additional HOtBu bound to it, as shown in Figure 2. Previously, we isolated a Ce/OtBu tetramer [30] that did not possess any Lewis basic solvents (i.e., thf, py, or HOtBu) however, the Er corollary could not be isolated without bound solvents as noted for the pyridine adduct, Er 3 (µ 3 -O)(µ-OtBu) 4 -(OtBu) 3 (py) 3 (7). Again, the py adduct appears to produce the oxo which argues for water present in the py; however, numerous structures using the same solvent did not yield the oxide, so the origin of the oxo is still unproven.…”

“…Aryl oxides are often used to control nuclearity because the steric bulk around the metal center can be easily altered. [8,12,13,30,[33][34][35][36] We routinely use the most sterically demanding di-ortho-substituted phenoxide ligands to induce as large an effect as possible. The resulting products are again discussed in increasing steric demand (dmp, dip, dbp).…”

Novel mononuclear mixed ligand Ce(III) pivalate with protonated cationic form of monoethanolamine as ancillary ligand

“…The same coordination polyhedron was also found in monomeric lanthanide (III) 1-hydroxy-2-naphthoate hydrates [9,10] and dysprosium pivalate [12]. Only three structures of cerium(III) pivalates were described: [Ce(Piv) 3 (HPiv) 3 ] 2 [23], [Ce(Piv) 2 (Q)(Py) 2 ] 2 [24] (HQ = oBu t -C 6 H 4 OH, o-Me 2 -C 6 H 3 OH, Py = pyridine). These complexes have dimeric structure with four bridging pivalate ligands and the coordination polyhedron of cerium ions is described as a square antiprism (CN = 8).…”