Sm and Eu(III) lanthanide triple helicate cages based on N,N′-methylene-bis(pyridin-4-one)

Presented here are Sm and Eu(III) lanthanide triple helicate cages with two distinct metal environments based on the N,N′-methylene-bis(pyridin-4-one) (MBP) ligand. Spontaneous resolution occurs in the crystallization of the Sm(III) complex. Luminescence is investigated by excitation of the metal ions with near-UV light. For the Sm(III) complex, close π–π stacking experienced by the pyridinone ring increases the sensitization of the Sm(III) ion, revealed by the appearance of ⁴G_5/2→⁶H_11/2 emission, the long luminescence lifetimes (35 and 18 μs) and the relatively high quantum yield (1.7%).