X-ray diffraction and 13C solid-state NMR studies of the solvate of tetra(C-undecyl) calix[4]resorcinarene with dimethylacetamide

Single crystal X-ray diffraction (XRD) analysis of the complex of calix [4]resorcinarene (CAV11) with dimethylacetamide (DMA) shows that the CAV11 molecules form centrosymmetric dimers, held by van der Waals interactions of the C-undecyl aliphatic chains. The dimers are associated in layers with hydroxyl groups at the surfaces. The DMA molecules are found between the CAV11 layers, above the cavities formed by the resorcine units and distant from them. They join the layers of CAV11 by molecular forces, in particular by various hydrogen bonds, and are relatively immobile. The C-13 CP/MAS spectra are in reasonable agreement with the XRD results.