X-ray crystal structures and isostructurality calculation of calix[4]arenes with lower rim propyl and carboxylic acid or mixed carboxylic acid and ester substituents involving solvent complexes with methanol and ethanol

X-ray crystal structures of two calix[4]arenes are reported. They feature aside from two distal n-propyl units, two ethyl acetate or mixed ethyl acetate and acetic acid groups as the characteristic substituents of the lower rim hydroxylic hydrogens. The structures are compared by making use of isostructurality calculations. In case of the semi-ester, solvates with methanol and ethanol as the guest solvents are involved. The carboxy function of the semi-ester does not form a dimer but an intramolecular hydrogen bond to a propoxy group. The solvates can be described as isostructural in spite of the different solvent molecules.