Structural study of the novel deuterated calix[4]pyrrole complex d 12 -meso-tetrakis(4-methoxyphenyl)-meso-tetramethylcalix[4]pyrrole-pyridine N-oxide-acetonitrile (1/1/1).

Calix[4]pyrroles act as powerful receptors for electron-rich neutral guests and anionic guests in organic solvents. For the electron-rich neutral guest pyridine N-oxide, calix[4]pyrrole, with a deep cavity, provides an appropriate environment. The ability of calix[4]pyrrole to host binding guest molecules is the result of hydrogen bonding, π-π, C-H...π and hydrophobic interactions of the cavity. The novel title complex, C52 H40 D12 N4 O4 ·C5 H5 NO·C2 H3 N, based on d12 -meso-tetrakis(4-methoxyphenyl)-meso-tetramethylcalix[4]pyrrole, has been assembled using an excess of pyridine N-oxide and is the first deuterated complex of calix[4]pyrrole. A single-crystal X-ray study shows that the receptor adopts a cone conformation with the N-oxide fragment encapsulated deep within the cavity.1 H NMR spectroscopy was used to probe the molecular binding formation in CD3 CN. The results are consistent with the single-crystal X-ray study in identifying that the pyridine N-oxide molecule occupies the cavity of the calix[4]pyrrole molecule. UV-vis spectroscopy revealed that the calix[4]pyrrole receptor molecules are able to form 1:1 inclusion complexes in CH3 CN.