In situ growth of Cu(BDC) on microscale Cu‐based carboxymethylcellulose fibers: A new strategy for constructing efficient catalysts for A3‐coupling reactions

Abstract

Based on the coordination properties of carboxylates in carboxymethylcellulose (CMC) and metal ions, we have prepared microscale Cu‐based carboxymethylcellulose fibers (Cu(II)/CMC) by extruding the CMC‐Na solution into a Cu(II) ions coagulation bath. We found that the as‐obtained microscale Cu(II)/CMC fibers are well suitable for the in situ growth of the copper terephthalate (Cu(BDC)) MOFs directly from the coordinated Cu(II) sites enriched on the surface of fibers (Cu(BDC)@Cu(II)/CMC) in the terephthalic acid solution. The composition and structure of Cu(BDC)@Cu(II)/CMC composite fibers were verified using various FTIR, XRD, SEM, EDX, elemental mapping, XPS, TGA, and BET tools. The characterized data revealed that well‐defined Cu(BDC) particles were distributed uniformly on the surface of the microscale Cu‐based fibers. The resulting Cu(BDC)@Cu(II)/CMC fibers were used as an effective and retrievable heterogeneous catalyst for the aldehyde‐alkyne‐amine (A3) coupling reactions. The superior catalytic activity is attributed to the excellent dispersion and stability of the Cu(BDC) MOFs crystallites containing the numerous active Cu(II) sites on the microscale fibers. In addition, the microscale fibrous catalyst can be conveniently retrieved with tweezers after each cycle and reused at least six times without a significant drop in its activity.