Hydrogen-Bonded Aggregates of Scandium(III) Complexes

The influence of the concentration of halide ions and concentration of an organic component (Solv) in solutions on the composition, coordination number, and structure of the scandium(III) complexes in solutions and in crystal is studied. The 45Sc NMR data show that the main factor determining Cl– coordination in the Sc3+–Cl––H2O–Solv systems is the Solv concentration. According to the X-ray diffraction analysis data, at the molar ratios of X– : Sc3+ < 3 (X– = Cl, Br), the [Sc(OH)(H2O)5]2X4 · 2H2O salts with a coordination number of Sc 7 are isolated from solutions in H2O and alcohols (coordination core is ScO7 and X– ions are not involved in coordination). Supramolecular H-bonded aggregates containing the ScCl3(H2O)3 molecular complex with coordination number of Sc 6 and meridianal arrangement of analogous ligands are isolated from solutions with the Cl– : Sc3+ molar ratios from 3 to 20 (in concentrated HCl) using macrocyclic molecules (1,4,7,10,13,16-hexaoxocyclooctadecane (18C6) and 1,4,10,13-tetraoxo-7,16-diazacyclooctadecane (DA18C6)).