Phase-Dependent Reactivity and Host-Guest Behaviors of a Metallo-Macrocycle in Liquid and Solid-State Photosensitized Oxygenation Reactions.

The photochemical oxygenation reactions of a host-guest complex, pCp⊂Ag (pCp = [2.2]paracyclophane) have been investigated in solution and in the solid state, using the macrocyclic ligand having four anthracene moieties in the framework. As a result, it was found that the reactivity and host-guest functions show remarkable phase dependence. In solution, the photosensitized oxygenation of all the anthracene moieties of resulted in a fully oxygenated macrocycle Ag as the final product, while simultaneously the guest molecule was dissociated from the macrocyclic cavity. On the other hand, in an amorphous solid of pCp⊂Ag prepared by decomposing single crystals through the removal of the crystalline solvent, the oxygenated site of was significantly controlled to provide a site-selectively oxygenated inclusion complex, pCp⊂Ag, possessing a mono-oxygenated -symmetrical macrocyclic skeleton.