Metal-organic frameworks (MOFs) have attracted increased research attention in photocatalysis due to their great potential in light harvest and conversion. However, the organic transformations as photocatalyzed by MOFs under mild conditions yet remain a challenge. Herein, three bipyridyl-containing cadmium-organic frameworks Cd(dcbpy) (dcbpy = 2,2'-bipyridine-5,5'-dicarboxylate), Cd(bdc)(bpy) (bdc = 1,4-benzenedicarboxylate; bpy = 2,2'-bipyridyl), and Cd(bdc)(2Me-bpy) (2Me-bpy = 4,4'-dimethyl-2,2'-bipyridyl) were synthesized for the first time. The bpy-containing Cd-MOFs have strong light harvest abilities and suitable photocatalysis energy potentials, making them highly active and selective for the photo-oxidation of benzylamine to N-benzylbenzaldimine under mild conditions, i.e., using atmospheric air as oxidant, at room temperature, and in the absence of any photosensitizer or cocatalyst. It provides an efficient, economical, and green way for the direct oxidation of amines to produce imines.
Keywords: amine oxidation; bipyridyl-containing ligand; cadmium; metal−organic framework; photocatalysis.