Synthesis and structure of mixed isopropoxide-beta-ketoester and beta-ketoamide zirconium complexes: Potential precursors for MOCVD of ZrO2

The reaction of [Zr(OPri)(4)-(HOPri)] with beta-ketoester and beta-ketoamide resulted in complexes having potential to serve as precursors for MOCVD of ZrO2 thin films. Zirconium bis(isopropoxide) bis(tert-butylacetoacetate) (1), zirconium tris(isopropoxide)(tert-butylacetoacetate) (2), zirconium tetrakis(tert-butylacetoacetate) (3) and zirconium bis(isopropoxide) bis(N,N-diethylacetoacetamide) (4) were synthesised and characterised by elemental analysis, NMR, IR and mass spectrometry. The molecular structure of the compounds as determined by single crystal X-ray diffraction revealed that compounds 1 and 4 exist as monomers while compound 2 exhibits a nearly symmetric dimeric structure. It is shown that by introducing small changes in the established key structures of the existing precursors, it is possible to tune the thermal properties. Compounds 1, 2 and 4 melt at low temperatures and possess thermal properties that are promising for MOCVD of ZrO2 and related oxide thin films. ZrO2 films grown using compound 1 as precursor in the absence of additional oxidant were characterised by X-ray powder diffraction, scanning electron microscopy and Rutherford back-scattering analysis.