Mononuclear barium diketonate polyamine adducts. Synthesis, structures, and use in MOCVD of barium titanate

Mononuclear barium {beta}-diketonate Lewis base adducts have been synthesized by reaction of Ba(thd){sub 2} (thd = 2,2,6,6-tetramethyl-3,5-heptanedionate) with polyamines 1,1,4,7,7-pentamethyldiethylenetriamine (pmdt) and 1,1,4,7,10,10-hexamethyltriethylenetetramine (hmtt). The adducts [Ba(thd){sub 2}(pmdt)] (I) and [Ba(thd){sub 2}(hmtt)] (II) have been characterized by NMR spectroscopy, elemental analyses and single-crystal X-ray diffraction. Compound I crystallizes in the space group P2{sub 1}/c with a = 10.577(3) {angstrom}, b = 23.547(7) {angstrom}, c = 15.963(5) {angstrom}, {beta} = 105.21(2){degrees}, and Z = 4. Compound II crystallizes in the space group P2{sub 1}/c with a = 10.833(6) {angstrom}, b = 20.442(12) {angstrom}, c = 19.404(9) {angstrom}, {beta} = 104.35(4){degrees}, and Z = 4. The adducts are seven- and eight-coordinate, respectively, with all nitrogen atoms of the polyamine bound to a single barium center. Compound I has been used for thin-film growth of BaTiO{sub 3} which has revealed that, compared to Ba(thd){sub 2}(tetraglyme), the polyamine adduct allows a larger temperature window for effective vapor transport. 10 refs., 2 figs., 2 tabs.