| Popis: |
The reaction between the barium derivative resulting from barium chips and 1-dimethylamino-2-propanol and 2,2,6,6-tetramethyl-3,5-heptanedione (thdH) in a 1 : 1 stoichiometry produced the β-diketonatoalkoxide derivative 2 or [Ba(thd)2(OHCH MeCH2NMe2)]2 3, depending on the solvent, THF or hexane. Compounds 2 and 3 have been characterized by IR, 1H and 13C NMR, mass spectrometry as well as by single crystal X-ray diffraction. Compound 2 is a pentanuclear hydroxo aggregate Ba5(μ4-OH)(μ3,η2-OCHMeCH2NMe2)4(μ,η2-thd)4(η2-thd), the metal framework corresponding to a square pyramid. Intramolecular coordination of the amino functions allows the metals to reach high coordination numbers—seven for the basal ones—without additional neutral ligands. The apical barium centre is only 6-coordinated. The barium centres are octacoordinated in the centrosymmetric dimer, [Ba(μ,η2 : η2-thd)(η2-thd)(η2-OHCHMeCH2NMe2)]2. The BaO(thd) bond distances fall in the range 2.57(4)–2.88(1) A, the BaN coordination bonds are slightly longer [2.96(4) A]. Thermogravimetric analysis data and volatility are discussed for both compounds. |
