Syntheses, characterisation and vapour pressure of metallo-organic titanium precursor for MOCVD applications

摘要

Metallo-organic complexes of titanium such as [Ti(bzac)_2(O ~iPr)_2] (1) and [Ti(bzac)_2en(O ~iPr)_2] (2) were synthesised using 1-phenyl-1,3-butanedione (bzac) and the Schiff's base ligand N,N′-ethylene-bis(1-phenyl-1,3- butanediimine) [(bzac)_2en]. A novel ligand 1-phenyl-3-N-(2-hydroxy-2- methylethylimino)-1-butanone (bzac1a2pol, 3) synthesised by condensing benzoylacetone (bzac) with 1-amino-2-propanol (1a2pol) was used in the synthesis of the complex bis(1-phenyl-3-N-(2-hydroxy-2-methylethylimino)-1-butanoato) titanium (IV), [Ti(bzac1a2pol)_2, 4]. These complexes were synthesised by replacing the isopropoxy group (O~iPr) of titanium tetra-isopropoxide, Ti(O~iPr)_4 by the appropriate ligands. Complexes 1, 2 and 4 were characterised for their volatility/thermal stability using TG/DTA and complex 4 was found to be volatile giving a residue of ～5.0% (TG) at 377 °C and ～3.0% (reduced pressure, 1 mbar) at 285 °C. Ligand 3 and its Ti complex 4 were characterised by ~1H NMR, ~(13)C NMR, elemental analysis, mass spectrometry and single crystal XRD. A value of 164.2 ± 5.2 kJ mol~(-1) for the standard enthalpy of sublimation (ΔHsubo) was evaluated for 4 from its vapour pressure.