Two polymer catalysts (Pd-OCMCS and Ni-OCMCS) with good reusability were synthesized by coordinating Pd and Ni ontoO-carboxymethyl chitosan (OCMCS). The chemical structure and thermal stability of prepared catalysts were determined by Fourier transform infrared (FT-IR) spectra, Energy Dispersive Spectrometer (EDS)analysis, X-ray diffraction (XRD), and thermogravimetric analyzer (TG-DTG), and the analysis results showed that the Pd and Ni ions coordinated onto the OCMCS and formed a ligand with the –COOH group, amino groups, and –OH group on the OCMCS, and the EDS and Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES) analysis results showed that the loading amounts of Pd and Ni were approximately 8.3% and 8.9%, respectively. In the Heck reaction between aryl halides andn-butyl acrylate catalyzed by the prepared catalyst, the test results showed that the product yield followed the order of aryl iodide > aryl bromide > aryl chloride. Additionally, the product yield for the aryl iodide and aryl bromide could reach up to 99% and 96%, respectively. Moreover, the electron-withdrawing and electron-donating property of the group on the aryl also affected the product yield, and the product yield for aryl halides with electron-withdrawing groupp-NO2,p-CH3CO, andp-CHO was higher than that with electron-donating groupp-CH3.Keywords:O-carboxymethyl chitosan;biopolymer-supported catalyst;Pd-OCMCS;Ni-OCMCS;heck reaction
Silicone-containing polymers have broad application prospects in the detection of many analytes due to their unique fluorescence properties. Environmental pollutants are very complex, which have prompted researchers to explore different detection methods. In this report, two kinds of polymers were synthesized via Heck-reaction between tetramethyltetravinylcyclotetrasiloxane (D 4 vi ) and carbazole derivatives. The polymers showed excellent fluorescent properties and exhibited high sensitivity to 4-nitrophenol (4-NP) and Fe 3+ in solution. Furthermore, the polymers still showed high sensitivity for Fe 3+ in living cells. We estimate that the cyclic structure of D 4 vi and carbazole structure will serve as responsive sites for Fe 3+ and 4-NP, respectively. The frontier molecular orbitals of polymers were calculated by Materials Studio and the effect of the cyclic structure of D 4 vi on their responsiveness had been discussed. The design idea of the polymer sensors can provide a new direction for the synthesis of multi-response polymer fluorescent probes.
Nitrogen doped mesoporous carbon (N-MPC)-supported monometallic and bimetallic catalysts were synthesized by using hydrothermal and impregnation method, and the catalytic activity of the catalyst to carbon–carbon bond-forming reactions (Suzuki, Heck and Sonogashira reactions) was studied. The bimetallic catalyst Pd-Ni@N-MPC with high Ni to Pd atomic ratios showed highly activity in the C–C coupling reactions of aryl halide under optimized condition. In contrast to their monometallic counterparts, such Pd-Ni@N-MPC catalyst not only show higher catalytic activity but also show more economic and stable. The catalysts were characterized by powder X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscope and transmission electron microscopy, which demonstrated that the Pd–Ni NPs highly dispersed and possessed uniform size.
Graphical abstract
危险品化学品经营许可证（带存储）