Synthesis, Structures, and Thermal Behavior of Calcium, Strontium, Barium Bis(1-ferrocenyl-4,4,4-trifluorobutane-1,3-dionato) Complexes with Crown-Ethers

Abstract

The new ferrocenyl-containing β-diketonate complexes with crown-ethers [Ca(Fctfa)₂(15-crown-5)] (I), [Sr(Fctfa)₂(18-crown-6)] (II), [Sr(Fctfa)₂(18-crown-6)](CH₂Cl₂) (III), [Ba(Fctfa)₂(18-crown-6)] (IV) and [Ba(Fctfa)₂(18-crown-6)](CH₂Cl₂) (V) (Fctfa = 1-ferrocenyl-4,4,4-trifluorobutane-1,3-dionato), 15-crown-5 = 1,4,7,10,13-pentanoxacyclopentadecane; 18-crown-6 = 1,4,7,10,13,16-hexaoxacyclooctadecane) have been synthesized. The compounds are characterized by infrared and ¹H NMR spectroscopy and X-ray diffraction analysis. The thermal behavior of complexes I, II, IV was investigated by thermal analysis. It was found that complexes are thermally stable up to 150°C for I, 215°C for II 180°C for IV. The decomposition behavior of I, II, IV studied by ¹H nuclear magnetic resonance investigation of substances, formed at decomposition of I, II, IV in dynamic vacuum. It was found, that the heating of I, II, IV in the ranges 150–800°C for I, 215–800°C for II, 180–800°C for IV affords the solid substances, containing alkaline-earth metals fluorides and iron oxides. Using topological analysis of the electron density distribution in I, III, V, intra- and intermolecular interactions were quantitatively estimated within the framework of Bader’s atoms in molecules theory. According to Espinosa–Mollins–Lecomte correlation, energies of the intermolecular interactions for I, III, V are close to the experimentally measured enthalpies of sublimation of related complexes published previously.