BARIUM BETA-DIKETONATE DERIVATIVES WITH AMINOALCOHOLS - SYNTHESIS, MOLECULAR-STRUCTURE AND THERMAL-BEHAVIOR OF TA(2)-OCHMECH2NME2)4(MU,ETA(2)-THD)(4)(ETA(2)-THD) AND OF TA(2)-ETA(2)-THD)(ETA(2)-THD)(ETA(2)-OHCMECH2NME2)

The reaction between the barium derivative resulting from barium chips and 1-dimethylamino-2-propanol and 2,2,6,6-tetramethyl-3,5-heptanedio ne (thdH) in a 1:1 stoichiometry produced the beta-diketonatoalkoxide derivative 2 or [Ba(thd)2(OHCH MeCH2NMe2)]2 3, depending on the solven t, THF or hexane. Compounds 2 and 3 have been characterized by IR, H-1 and C-13 NMR, mass spectrometry as well as by single crystal X-ray di ffraction. Compound 2 is a pentanuclear hydroxo aggregate )(mu3,eta2-O CHMeCH2NMe2)4(mu,eta2-thd)4(eta2-thd), the metal framework correspondi ng to a square pyramid. Intramolecular coordination of the amino funct ions allows the metals to reach high coordination numbers-seven for th e basal ones without additional neutral ligands. The apical barium cen tre is only 6-coordinated. The barium centres are octacoordinated in t he centrosymmetric dimer, mu,eta2:eta2-thd)(eta2-thd)(eta2-OHCHMeCH2NM e2)]2. The Ba-O(thd) bond distances fall in the range 2.57(4)-2.88(1) angstrom, the Ba-N coordination bonds are slightly longer [2.96(4) ang strom]. Thermogravimetric analysis data and volatility are discussed f or both compounds.