Structural study of the novel deuterated calix[4]-pyrrole complex d_12-meso-tetrakis(4-methoxy-phenyl)-meso-tetramethylcalix[4]pyrrole-pyridine N-oxide-acetonitrile (1/1/1)

摘要

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, C_52H_40D_12N_4O_4?C_5H_5NO?C_2H_3N, based on d_12-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. ~1H NMR spectroscopy was used to probe the molecular binding formation in CD_3CN. 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 CH_3CN.