Lanthanide CPs: the guest-tunable drastic changes of luminescent quantum yields, and two photon luminescence

Abstract

Four kinds of guest-driven lanthanide coordination polymers (CPs) have been synthesized. They have similar formula: [Tb(NPA)₃CH₃CN]_n (1, H-NPA = N-phenylanthranilic acid), {[Tb(NPA)₃CH₃OH]CH₃OH}_n (2), [Ln(NPA)₃DMF]_n (Ln = Tb (3a), Gd (3b), Eu (3c)), and [Tb(NPA)₃DMSO]_n (4). These complexes were characterized by single-crystal diffraction, PXRD, FT-IR, TGA, DTA, EA, UV-vis spectra and luminescence lifetime measurements. They are all highly thermostable, acid and base resistant. The luminescence quantum yields (QY) of Tb³⁺ complexes: 1, 2, 3a and 4 are 4.0%, 9.0%, 44% and 46% respectively. Interestingly, there is a drastic change from 4.0% to 46% in luminescence QY by exchanging the coordination solvent, the oscillation of small molecule near the Tb³⁺ causes the drastic change. Furthermore, the octupolar-like structure of 4 has a high two-photon luminescence.