Caesium 18-crown[6] complexes with aromatic polycarboxylate anions: preparation, solid-state characterization and thermal behaviour

Abstract

18-Crown[6] has been used to prepare new organic–inorganic complexes with Cs₂CO₃ and aromatic mono-, di- and tricarboxylic acids (benzoic, isophthalic, terephthalic and trimesic acid). The complexes 18-crown[6]·Cs[trimH₂] (1), 18-crown[6]·Cs[isoH] (2), 18-crown[6]·Cs₂[isoH]₂·2H₂O (3), (18-crown[6])₃·Cs₃[trim]·9H₂O (4), 18-crown[6]·Cs[ben]·H₂O (5) and (18-crown[6])₆·Cs₄[tereH]₂[tere]·5H₂O (6) have been characterized by single-crystal X-ray diffraction. The thermal behaviour of 1, 2 and 4 has been investigated by a combination of solid-state techniques including differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and variable temperature X-ray powder diffraction (VT-XRPD); in the case of 2 hot stage microscopy was used to clarify its thermal behaviour.