Porous Organic Polymers with Thiourea Linkages (POP-TUs): Effective and Recyclable Organocatalysts for the Michael Reaction

Weak Coupling Strategy to Construct High-Performance Sm/Tb-Doped Lanthanide Coordination Polymer Luminescent Sensor for D2O Detection

Accurate measurement of the purity and content of heavy water is of great concern in nuclear energy, the chemical industry, and biomedicine. Since the physical and chemical properties of D2O and H2O are very similar, achieving luminescent detection is challenging. Due to the difference in the vibrational frequency of the O-D and the O-H bonds, the quenching efficiency of the excited state of Ln3+ is different, which leads to a significant difference in the optical properties of Ln3+. Based on this theory, we composed a weak coupling strategy to strengthen the luminescence difference of Ln3+. Then, we demonstrated the weak coupling effect and how to improve detection performance by analyzing L1-Eu0.14Tb0.86(C22H20Eu0.14Tb0.86N3O10) and L1-Sm0.45Tb0.55(C22H20Sm0.45Tb0.55N3O10). The structure and performance of the two sensors were characterized in detail. A series of heavy water detection luminescence sensing experiments show that L1-Sm0.45Tb0.55 and L1-Eu0.14Tb0.86 can not only qualitatively distinguish D2O and H2O with the naked eye but also quantitatively detect any concentration of H2O in D2O. The prepared composite films L1-Sm0.45Tb0.55@PMMA and L1-Eu0.14Tb0.86@PMMA have practical application value. The application of Sm/Tb-doped lanthanide coordination polymers for detecting the H2O content in D2O has not been reported.

Dual Brønsted acidic-basic function immobilized on the 3D mesoporous polycalix [4]resorcinarene: As a highly recyclable catalyst for the synthesis of spiro acenaphthylene/indene heterocycles

In this study, a novel dual Brønsted acidic-basic nano-scale porous organic polymer catalyst, PC4RA@SiPr-Pip-BuSO3H, was synthesized through various steps: preparation of a 3D network of polycalix, modification with (3-chloropropyl)-trimethoxysilane, then functionalization of polymer with piperazine and n-butyl sulfonic acid under the provided conditions. The catalyst characterization was performed by FT-IR, TGA, EDS, elemental mapping, PXRD, TEM, and FE-SEM analyses, confirming high chemical stability, activity, recoverability, and excellent covalent anchoring of functional groups. So, the designed catalyst was utilized for preparing spiro-acenaphthylene and amino-spiroindene heterocycles, providing good performance with a high yield of the corresponding products. Accordingly, this catalyst can be used in different organic transformations. Necessary experiments were conducted for the recyclability test of the polymeric catalyst, and the results showed the PC4RA@SiPr-Pip-BuSO3H catalyst can be reused 10 times without any decrease in its activity or quality with excellent stability. The structure of resultant spiro heterocycles was confirmed using 1H NMR, 13C NMR, and FT-IR.