Alkaline Earth Titanate (AETiO₃) Perovskite Nanoparticles Synthesized from Structurally Characterized Single-Source Alkoxides

A series of alkaline earth modified titanium neo -pentoxide (OCH 2 CMe 3, ONep) derivatives were synthesized through the alcoholysis reaction of [Ti(μ-ONep)(ONep) 3 ] 2 and the respective alkaline earth alkoxide (A E (OR) 2 ), where A E (OR) 2 = “Ca(ONep) 2 ” ( 1 ), Sr 5 (μ 4 -O)(μ 3 -ONep) 4 (μ-ONep) 4 (HONep)(py) 4 ( 2 ), or [Ba 2 (μ 3 -ONep)(μ-ONep) 2 (ONep)(HONep) 3 (py)] 2 ( 3 ), in pyridine (py) in a 1:1 cation stoichiometry. For each A E cation, the following mixed-cation species were identified by single-crystal X-ray diffraction as (py) 2 A E [Ti(μ-ONep) 2 (ONep) 3 ] 2, where A E = Ca ( 1a ), Sr ( 2a ), and Ba ( 3a ). For each species, two square bipyramidal titanium moieties bridge to the single octahedrally bound A E metal center through four μ-ONep ligands. Two terminal py ligands on the A E and three terminal ONep ligands on Ti complete their coordination. Compounds 1a − 3a were used to synthesize nanoparticles of A E TiO 3 using solution precipitation (methyl-imidazole:water) and solvothermal (benzyl alcohol) routes. For comparison, we processed stoichiometeric mixtures of the individual precursors under identical conditions as noted for 1 − 3 . The nanoparticles (5−50 nm) synthesized varied in phase from carbonates to perovskites depending on the cation and the synthetic conditions used. On the basis of the comparison of routes, stoichiometric mixtures were better in generating single-phase A E TiO 3 from the MeIm/H 2 O route after calcination, whereas, through solovothermal synthesis routes, single-source and stoichiometric mixtures both gave favorable crystalline results for Sr and Ba.