Supramolecular architecture of crystals of perfluorinated 3-alkylphthalides

Abstract

The molecular and crystal structures of perfluoro-3-alkylphthalides (3-hydroxyperfluoro-3-methylphthalide and its hydrate, two polymorphs of 3-hydroxyperfluoro-3-ethylphthalide and 3-hydroxyperfluoro-3-isopropylphthalide) are determined by single crystal X-ray diffraction. In the crystals, the supramolecular O–Н…O=C synthon occurs leading, except the crystallohydrate, to the formation of C₁¹ (6) hydrogen bonded chains (supramolecular 1D motifs). According to the DFT/M06-2X/TZV calculations, the interaction energy of hydrogen bonded molecular pairs increases in this series, which can be explained by additional C=O…π, O…π, and C–F…π interactions.