Highly luminescent lanthanide CPs based on dinuclear cluster: crystal structure and sensitive Trp sensor

Abstract

Based on a ligand which contains methoxy and fluorine groups, a series of isostructural lanthanide coordination polymers (CPs) are synthesized, and they are characterized by FT-IR EA, PXRD, TGA and luminescence. Among these complexes, 1 is further characterized by single-crystal diffraction, it crystalizes in the triclinic space group P (no. 2), with a = 8.8577(8) Å, b = 12.0523(11) Å, c = 13.6494(13) Å, α = 114.2400(10)°, β = 96.3570(10)°, γ = 98.6170(10)°, V = 1289.5(2) ų and Z = 2. It is found that 1 and 2 are highly luminescent materials, which show high luminescence QY of 15.45% and 17.51%, respectively. TGA reveals that they are also highly thermostable materials. Sensing experiments reveal that 1 is a highly selective and sensitive tryptophan (Trp) sensor, the responsive behaviour shows excellent linearity in 2.5 × 10⁻⁵ – 2.5 × 10⁻⁴ M, the LOD is as low as 1.0 × 10⁻⁶ M. Further study reveals the sensor is applicable in real water sensing. The possible sensing mechanism is the coordination of Trp and Tb³⁺, which strengthens the antenna effect of 1.