Synthesis and crystal structure of the complex [Mg(H2O)6](bdc)CB[6]•14H2O and the inclusion compound [dmf@CB[6]]•3HCOOH•4H2O

A supramolecular adduct [Mg(H2O)(6)](bdc)CB[6]center dot 14H(2)O (1) and the inclusion compound [dmf@CB[6]]center dot 3HCOOH center dot 4H(2)O (2) were obtained from a mixture of magnesium chlorid (for compound 1) or magnesium sulfate (for compound 2), and cucurbit[6]uryl (CB[6]) in the presence of terephthalic or 4,4'-biphenildiarbonic acid in water. X-ray diffraction studies showed that magnesium cation in compound 1 form hydrogen bonds with oxygen atoms of the CB[6] molecule. When 4,4'-biphenildiarbonic acid was used instead of terephthalic acid under similar conditions of synthesis, no supramolecular adduct took place, rather an inclusion compound of DMF into the macrocyclic cavitand was formed. Compounds 1 and 2 were characterized by X-ray diffraction data, IR spectroscopy, and elemental analysis. Supramolecular adduct of hexaaqua magnesium cation with cucurbit[6]uril was isolated to the solid phase and structurally characterized for the first time.