1,3-alternate and partial cone conformers of tetramethyl (5,11,17,23-tetra-tert-butyl-2,8,14,20-tetrathiacalix[4]arene-25,26,27,28-tetrayltetraoxy)tetraacetate and tetramethyl (5,11,17,23-tetrabromo-2,8,14,20-tetrathiacalix[4]arene-25,26,27,28-tetrayltetraoxy)tetraacetate.

The crystal structures of the two title thiacalix[4]arene derivatives, C52H64O12S4, (I), and C36H28Br4O12S4, (II), are reported. Compound (I) has crystallographic C2 symmetry and adopts a 1,3-alternate conformation where the four -OCH2CO2Me groups are located alternately above and below the virtual plane (R) defined by the four bridging S atoms. The dihedral angles between the plane (R) and the aromatic rings are 87.17 (7) and 87.60 (8) degrees . Compound (II) has a partial cone conformation in which the pendant -OCH2CO2Me group of the rotated aryl ring is oriented away from the thiacalixarene cavity formed by the other three aryl rings. The dihedral angles between the plane (R) and the aryl rings range from 17.47 (10) to 85.98 (6) degrees . In the supramolecular structure of (II), the molecular components are linked into a two-dimensional framework by a combination of C-H...O hydrogen bonds and C-Br...C interactions. This study demonstrates the usefulness of these motif-generating interactions and thiacalix[4]arene derivatives in crystal engineering.