Yttrium beta-diketonate glyme MOCVD precursors: Effects of the polyether length on stabilities, mass transport properties and coordination spheres

The glyme adducts of trishexafluoroacetylacetonato yttrium, [Y(hfa)(3)(.)monoglyme], [Y(hfa)(3)(.)diglyme], [Y(hfa)(3)(.)(H2O)(2)(.)triglyme] and [Y(hfa)(2)(.)tetraglyme](+)[Y(hfa)(4)](-) {CH3(OCH2CH2)(n)OCH3, n = 1 monoglyme, 2 diglyme, 3 triglyme and 4 tetraglyme}, were synthesized and characterized by elemental analysis, mass spectrometry, and IR, H-1 and C-13 NMR spectroscopy. Additionally, [Y(hfa)(3)(.)monoglyme] and [Y(hfa)(3)(.)diglyme] were characterized by single-crystal X-ray diffraction studies. The mass-transport properties of these adducts were investigated by thermogravimetric analysis, differential scanning calorimetry, evaporation-rate measurements and chemical vapour-deposition experiments. There is evidence of high volatility and very good thermal stabilities with a residue lower than 2-4%. Vaporization-rate experiments proved that all adducts are well-suited for metal-organic chemical vapour-deposition experiments. The [Y(hfa)(3)(.)monoglyme] complex was successfully applied in the low-pressure MOCVD process of YBaCuO HTc superconductor using a multimetal molten single source. (C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004.