Synthesis and Characterisation of Modified Germanium (IV) Isopropoxide with Internally Functionalised oximes: Soft Transformation of Some of These to Pure Nano-Sized Germania

Abstract

Reactions of [Ge(OPrⁱ)₄] with internally functionalised oximes in 1:1 and 1:2 molar ratios in refluxing anhydrous benzene yielded complexes of the type [Ge(OPrⁱ)_4-n{ONC(CH₃)C₄H₃O-2} _n ] (1, 2); [Ge(OPrⁱ)_4-n{ONC(CH₃)C₄H₃S-2} _n ] (3, 4); [Ge(OPrⁱ)_4-n{ONC(CH₃)C₅H₄N-2} _n ] (5, 6); [Ge(OPrⁱ)_4-n{ONC(H)C₄H₃O-2} _n ] (7, 8); [Ge(OPrⁱ)_4-n{ONC(H)C₄H₃S-2} _n ] (9, 10); [Ge(OPrⁱ)_4-n{ONC(H)C₅H₄N-2} _n ] (11, 12) (where n = 1 or 2), All the above monomeric complexes are soluble in organic solvents and have been characterised by elemental analyses and spectroscopy. Thermal and hydrolytic studies of complexes 2, 4 and 8 suggest them to be potential molecular precursors for the synthesis of pure GeO₂ at low temperatures by the sol-gel technique. Powder X-ray diffraction, IR spectral studies as well as SEM images of the GeO₂ indicate formation of pure nano-crystalline hexagonal (α-quartz) germania at 550°C.