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)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)2(pmdt)] (I) and [Ba(thd)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(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(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 BaTiO3 which has revealed that, compared to Ba(thd)2(tetraglyme), the polyamine adduct allows a larger temperature window for effective vapor transport.