Polymer containing Pd(II) chelates grafted from SBA-15 for C–C bond formation via the Mizoroki–Heck reaction

The present work describes the grafting of a polymer-metal chelate (PMC) from mesoporous silica (SBA-15) via the Surface Initiated-Atom Transfer Radical Polymerization (SI-ATRP). SBA-15 was silylated by 2-bromo-2-methyl-N-(3-(trimethoxysilyl)propanamide (BTPAm) to give the surface-anchored ATRP initiator. The monomer, N-(4-(5-(pyridin-2-yl)-1,3,4-oxadiazol-2-yl)phenyl)acrylamide (POPA), was polymerized from the SBA-15 surface via the ATRP approach to give poly(POPA) -g- SBA-15. The grafted chelating polymer ligand (CPL) was treated with an ethanolic solution of PdCl 2 to afford the SBA-15 grafted PMC, poly(POPA) -g- SBA-15-Pd(II). The grafted PMC was characterized by FT-IR, CP/MAS 13 C NMR, thermo-gravimetric analysis (TGA), and Brunauer–Emmett–Teller (BET) analysis. X‐Ray photoelectron spectroscopy (XPS) corroborated that the major palladium species have the (+2) oxidation state. The catalytic activity of the grafted PMC was examined in the Heck reaction between haloarenes and olefins after establishing the optimal reaction conditions. Interestingly, chloroarenes exhibited enhanced activities than bromoarenes. Their activity was comparable to iodoarenes. The excellent recyclability of the catalyst was shown by negligible deactivation over six runs. Graphical Abstract