31-Benz­yloxy-5,11,17,23,29-penta-tert-butyl­calix[5]arene-32,33,34,35-tetra­ol

Claudia Gargiulli; Giuseppe Gattuso; Anna Notti; Francesco Nicoló; Andrea Pappalardo

doi:10.1107/S1600536812047435

. 2012 Nov 24;68(Pt 12):o3423. doi: 10.1107/S1600536812047435

31-Benzyloxy-5,11,17,23,29-penta-tert-butylcalix[5]arene-32,33,34,35-tetraol

Claudia Gargiulli ^a, Giuseppe Gattuso ^a, Anna Notti ^a,^*, Francesco Nicoló ^a, Andrea Pappalardo ^b

PMCID: PMC3589006 PMID: 23476242

Abstract

The title compound, C₆₂H₇₆O₅, known to be one of the most versatile synthetic precursors/intermediates of calix[5]arene derivatives, adopts an approximate C _s-symmetric cone-in conformation. The aryloxybenzyl ring is tilted in such a way that the p-tert-butyl group fills the macrocycle cavity, while the benzyl group moves away from the cavity axis. In the crystal, this conformational arrangement is secured by intra- and intermolecular O—H⋯O hydrogen bonds forming inversion dimers. Four tert-butyl groups are disordered over two orientations, with occupancy ratios of 0.745 (6):0.255 (6), 0.837 (5):0.163 (5), 0.850 (5):0.150 (5) and 0.845 (8):0.155 (8).

Related literature

For the synthesis of the title compound, see: Stewart et al. (1995 ▶). For calix[5]arene molecules derived from the title compound, see: Garozzo et al. (2005 ▶); Capici et al. (2011 ▶); Pappalardo et al. (2012 ▶). For the structures of calix[5]arene/alkylammonium complexes, see: Gattuso et al. (2012 ▶).

Experimental

Crystal data

C₆₂H₇₆O₅
M _r = 901.23
Triclinic,
a = 14.1467 (8) Å
b = 14.3235 (9) Å
c = 15.2179 (9) Å
α = 70.653 (3)°
β = 78.776 (3)°
γ = 71.573 (3)°
V = 2746.3 (3) Å³
Z = 2
Mo Kα radiation
μ = 0.07 mm⁻¹
T = 296 K
0.38 × 0.18 × 0.10 mm

Data collection

Bruker APEXII CCD diffractometer
75089 measured reflections
10532 independent reflections
5343 reflections with I > 2σ(I)
R _int = 0.044

Refinement

R[F ² > 2σ(F ²)] = 0.052
wR(F ²) = 0.161
S = 0.96
10532 reflections
677 parameters
120 restraints
H-atom parameters constrained
Δρ_max = 0.45 e Å⁻³
Δρ_min = −0.16 e Å⁻³

Data collection: APEX2 (Bruker, 2007 ▶); cell refinement: SAINT (Bruker, 2007 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: XPW (Siemens, 1996 ▶); software used to prepare material for publication: SHELXTL (Sheldrick, 2008 ▶).

Supplementary Material

Click here for additional data file.^{(68.1KB, cif)}

Crystal structure: contains datablock(s) I, global. DOI: 10.1107/S1600536812047435/is5208sup1.cif

e-68-o3423-sup1.cif^{(68.1KB, cif)}

Click here for additional data file.^{(504.6KB, hkl)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536812047435/is5208Isup2.hkl

e-68-o3423-Isup2.hkl^{(504.6KB, hkl)}

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Table 1. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O3—H3⋯O5ⁱ	0.82	2.04	2.7197 (19)	140
O4—H4⋯O3	0.82	2.04	2.847 (2)	168
O5—H5⋯O4	0.82	2.00	2.803 (2)	168

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Symmetry code: (i) Inline graphic .

Acknowledgments

MIUR (PRIN-2009 A5Y3N9 project) is gratefully acknowledged for financial support.

supplementary crystallographic information

Comment

In the solid state the title compound adopts an approximate C_s-symmetric cone-in conformation, best described by (i) the leaning of the p-tert-butyl group of the benzylated ring inside the macrocycle cavity (defined by the four remaining p-tert-butylphenolic rings) and (ii) the concomitant tilting of the benzyl pendant group away from the cavity axis. The crystal packing shows the presence of pairs of centrosymmetric cone-shaped calix[5]arene molecules glued together –via their narrow rims– by several intra- and intermolecular hydrogen-bonding interactions involving the four hydroxyl groups present on each molecule. In addition, the benzyl (C22–C27) moiety and the p-tert-butylphenolic ring (C12–C14/C44/C43/C42) of each pair of centrosymmetric molecules lie on roughly parallel planes and their edges (C23/C24 and C12/C14, respectively) are seen at a spatial proximity of 3.5 Å (centroid-centroid = 4.47 (2) Å). In analogy with previously reported calixarene structures, collected at low temperature, four tert-butyl groups are disordered over two rotated orientations with refined occupancy factors.

Experimental

The title compound was prepared according to the procedure described by Stewart et al. (1995). p-tert-Butylcalix[5]arene (5.00 g, 6.17 mmol) and anhydrous KHCO₃ (1.23 g, 12.32 mmol) were suspended in anhydrous MeCN (125 ml). The mixture was heated at reflux for 1 h under an inert atmosphere. Benzyl chloride (0.262 g, 2.09 mmol) was added, and heating was continued for 24 h. The mixture was then allowed to cool, and the solvent was removed under reduced pressure. The resulting residue was partitioned between CHCl₃ (100 ml) and aqueous HCl (1 M, 75 ml). The organic layer was washed with H₂O (2 × 100 ml) and dried over anhydrous MgSO₄. The solvent was evaporated under reduced pressure, and the resulting residue was subjected to column chromatography (SiO₂, toluene/n-hexane 1:1 v/v), to yield the title compound (68%, 1.15 g). Single crystals were obtained by slow evaporation from a CHCl₃/MeOH solution. Spectral data are in full agreement with those reported in the literature (Stewart et al., 1995).