Crystal structure of the inclusion complex 25-benzoylmethoxy-5,11,17,23-tetra-tert-butyl-26,27,28-trihydroxy-2,8,14,20-tetrathiacalix[4]arene–tetraethylammonium chloride (1/1)

The asymmetric unit of the title compound, C48H54O5S4·N(C2H5)4 +·Cl−, contains two tetra-tert-butyl-[(benzoyl)methoxy]-trihydroxy-tetrathiacalix[4]arene molecules, two tetraethylammonium cations and two chloride anions. The two calixarene molecules in the asymmetric unit each display a cone conformation. There are no significant differences between the two independent molecules. The guest species do not sit within the calixarene ‘buckets’. In the crystal, extensive O—H⋯O, O—H⋯S and O—H⋯Cl hydrogen bonds and weak C—H⋯O, C—H⋯S and C—H⋯Cl interactions link the thiacalixarene molecules, tetraethylammonium cations and chloride anions, forming a three-dimensional network encompassing channels running parallel to the a-axis direction. The structure contains a solvent-accessible void of 76 (3) Å3, but no solvent molecule could reasonably be located. The crystal studied was an inversion twin with a 0.57 (8):0.43 (8) domain ratio.

Two crystallographically independent molecules (A and B) in the asymmetric unit are shown in Figs 1 and 2, respectively, and together with two tetraethylammonium chloride molecules in Fig. 3. The bond lengths and bond angles of molecules A and B are within the normal ranges.

Figure 1
View of the molecule A of two molecules in the asymmetric unit with the atom-numbering scheme. Displacement ellipsoids for non-H atoms are drawn at the 30% probability level. All H atoms are omitted for clarity.

Figure 2
View of the molecule B of two molecules in the asymmetric unit with the atom-numbering scheme. Displacement ellipsoids for non-H atoms are drawn at the 30% probability level. All H atoms are omitted for clarity.

Figure 3
View of two molecules (A and B) with two solvent molecules in the asymmetric unit with the atom numbering scheme.

Special details
Geometry. Bond distances, angles etc. have been calculated using the rounded fractional coordinates. All su's are estimated from the variances of the (full) variance-covariance matrix. The cell e.s.d.'s are taken into account in the estimation of distances, angles and torsion angles Refinement. Refinement on F 2 for ALL reflections except those flagged by the user for potential systematic errors. Weighted R-factors wR and all goodnesses of fit S are based on F 2 , conventional R-factors R are based on F, with F set to zero for negative F 2 . The observed criterion of F 2 > σ(F 2 ) is used only for calculating -R-factor-obs etc. and is not relevant to the choice of reflections for refinement. R-factors based on F 2 are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger.