Synthesis and characterization of BaX2·18-crown-6 complexes. Barium bis(1,1,1,5,5,5-hexafluoropentane-2,4-dionate)·18-crown-6, a nonhygroscopic, thermally stable, volatile barium compound

Abstract The synthesis of a series of BaX 2 ·18-crown-6 complexes (X=hfac, tclac, tfac, thd, acac, O 2 CCF 3 , O 3 SCF 3 , O 2 CCH 3 , Cl, Br, I, NO3, OH and SCN) and BaX 2 compounds (X=tclac, tfac, O 2 CCF 3 and O 3 SCF 3 ) is described. The BaX 2 ·18-crown-6 complexes have been characterized by melting point determinations, elemental analysis and NMR spectroscopy. Their thermal stability and volatility at reduced pressure have been investigated. Barium bis(1,1,1,5,5,5-hexafluoropentane-2,4-dionato)·18- crown-6, Ba(hfac) 2 ·18-crown-6, appears to be a non-hygroscopic, thermally stable, sublimable solid. This compound has also been characterized by mass spectrometry. The 18-crown-6 complexes of BaI 2 , Ba(SCN) 2 , Ba(O 2 CCF 3 ) 2 and Ba(O 3 SCF 3 ) 2 are involatile and thermally stable up to 200 °C. The 18- crown-6 complexes of BaX 2 with X=Cl, Br, OH, NO 3 , O 2 CCH 3 , acac, tclac, tfac and thd dissociate upon heating between 80 and 200 °C. In the complexes, with X=Cl, Br, NO 3 , OH and tfac, loss of 18-crown-6 is accompanied by some co-evaporation of the barium compound.