Synthesis and grafting of CAN-derived tetravalent cerium alkoxide silylamide precursors onto mesoporous silica MCM-41

Abstract

The heteroleptic tetravalent cerium complex [Ce(OiPr)₃{N(SiMe₃)₂}]₂ was synthesised by treating ceric ammonium nitrate (CAN) sequentially with sodium isopropoxide and lithium bis(trimethylsilyl)amide in THF. The trivalent ate complex [Ce(OiPr)₂{N(SiMe₃)₂]₂}][Li(thf)₂] was also isolated from these reaction mixtures. A transsilylamination reaction of [Ce(OiPr)₃{N(SiMe₃)₂}]₂ with tetramethyldisilazane produced a considerable amount of homoleptic Ce[N(SiHMe₂)₂]₄. The polymeric complex [Li₂Ce₂(OiPr)₁₀(1,4-dioxane)]_n was isolated as an additional ligand redistribution product. When tetravalent complexes Ce[N(SiHMe₂)₂]₄, Ce[N(SiMe₃)₂]₃Cl and Cp₃CeCl were allowed to react with samples of periodic mesoporous silica MCM-41, Ce(IV) hybrid materials were produced. All hybrid materials were characterised via N₂ physisorption, elemental analysis and DRIFT spectroscopy.