Volatile barium .beta.-diketonate polyether adducts. Synthesis, characterization, and metalloorganic chemical vapor deposition

The 2,5,8,11,14-pentaoxopentadecane (tetraglyme) adducts of barium complexes of 1,1,1,5,5,5-hexafluoro-2,4-pentanedione (H(hfacac)), 1,1,1-trifluoro-2,4-pentanedione (H(tfacac)), and 2,2,6,6-tetramethyl-3,5-heptanedione (H(thd)) have been prepared and characterized by X-ray crystallography, {sup 1}H and {sup 13}C NMR spectroscopies, melting and sublimation points, and elemental analysis. The thermal stability of the complexes is related to their solid-state structure in which the coordination number around the barium atom is nine with a monocapped, twisted square prism structure. Metalloorganic chemical vapor deposition experiments were performed using the 1,1,1,5,5,5-hexafluoro-2,4-pentanedionato and 1,1,1-trifluoro-2,4-pentanedionato complexes; the 2,2,6,6-tetramethyl-3,5-heptanedionate complex dissociated prior to sublimation. The as-deposited barium fluoride films were characterized by scanning electron microscopy and energy-dispersive X-ray spectroscopy.