X-ray Diffraction and 13C Solid-State NMR Studies of the Dimethylformamide Solvate of Tetra(C-undecyl)calixresorcinarene
journal contributionposted on 09.02.2000, 00:00 by Marek Pietraszkiewicz, Oksana Pietraszkiewicz, Waclaw Kolodziejski, Krzysztof Wozniak, Neil Feeder, Francesca Benevelli, Jacek Klinowski
Lipophilic tetra(C-undecyl)calixresorcinarene obtained from resorcinol and lauryl aldehyde forms solvates with many organic solvents. Particularly good quality crystals are obtained from dimethylformamide. Single-crystal X-ray diffraction (XRD) analysis of the solvate shows that the calixresorcinarene molecules form centrosymmetric dimers held by van der Waals interactions of the C-undecyl aliphatic chains. The dimers are associated into layers with hydroxyl groups at the surfaces. Three types of solvent molecules are embedded in the crystal lattice: disordered isolated molecules located just above the cavities formed by the resorcinol units, clusters of four DMF molecules located between the calixarene layers, and single DMF molecules located inside the layers close to the alkyl chains. The solvent molecules join the layers of calixresorcinarenes by means of various hydrogen bonds. The 13C CP/MAS spectra are in agreement with the XRD results.