Surprising robustness of a unit cell: isomorphism in caesium 18-crown[6] complexes with aromatic polycarboxylate anions

Abstract

Reaction in solution and in the solid state of 18-crown[6] with Cs₂CO₃ and 5-substituted isophthalic acids yields the new organic–inorganic complexes 18-crown[6]·Cs[OH-isoH] (2), 18-crown[6]·Cs[CH₃-isoH] (3), 18-crown[6]·Cs[Br-isoH] (4), 18-crown[6]·Cs[OCH₃-isoH] (5), 18-crown[6]·Cs[NO₂-isoH] (6) and 18-crown[6]·Cs[tert-Butyl-isoH] (8), which have all been characterized by X-ray diffraction. All compounds except the latter are isomorphous, in spite of the size, shape and chemical nature of the substituent and its ability to form hydrogen bonds.