Home – Home – Jornals – Journal of Structural Chemistry 2012 number 4

Single crystal X-ray diffraction is used for the first time to study the structure of the ionic clathrate hydrate of tetrabutyl ammonium propionate (C₄H₉)₄NC₂H₅COO·27.0H₂O with the host framework based on cubic arrangement I. The structural model is characterized by a high degree of disordering in both guest and host subsystems. The structural features indicate a colocation of cations and anions in multicell 4T·nD cavities with n = 0-4; the simplest option is a pairwise location of cations and anions in combined five-cell 4T·D cavities. The positional ordering of cations leads to the formation of a 2×2×2 supercell (space group I3d, a = 24.312(6) Å). The resulting model confirms the characteristic features of ionic clathrate hydrates of tetrabutyl and tetraisoamyl ammonium carboxylates. Non-standard refinement techniques are described, which may be of interest for other structures with a high degree of disordering. The proposed structural interpretation can serve as a basis for a further investigation of this class of compounds by other methods.