Stable Pyrene-Based Metal-Organic Framework for Cyclization of Propargylic Amines with CO₂ and Detection of...

A pyrene-based metal-organic framework, Cd₂(PTTB)(H₂O)₂ (WYU-11), was synthesized from the tetracarboxylic pyrene ligand H₄PTTB (H₄PTTB = 1,3,6,8-tetrakis(3-carboxyphenyl)pyrene) and Cd(NO₃)₂·4H₂O. Powder X-ray diffraction analysis discloses that the framework is stable in acid, base, and various organic solvent environments. WYU-11 shows excellent catalytic performance on the cyclization reaction of propargylic amines with CO₂ into 2-oxazolidinones under mild conditions (60 °C, atmospheric CO₂). ¹H NMR studies unveiled that WYU-11 and 1,1,3,3-tetramethylguanidine (TMG) can synergistically activate the propargylic amine substrate and promote the reaction. Importantly, WYU-11 represents a rare example of noble metal-free heterogeneous catalyst that can catalyze the cyclization of CO₂ with propargylic amines. In addition, by virtue of the excellent water stability and luminescence properties, WYU-11 shows excellent detection performance for sulfathiazole (STZ) and ornidazole (ODZ) in water. Investigation reveals that the coexistence of photoinduced electron transfer and internal filtering effect could reasonably explain the luminescence quenching of WYU-11 by the antibiotics.