Well-dispersed N-heterocyclic carbene-palladium complex anchored onto poly(acrylic acid)/poly(vinyl alcohol) nanofibers: Novel, superior and ecofriendly nanocatalyst for the Suzuki-Miyaura cross-coupling reaction

Polymeric nanocomposite@Pd is one of the crown jewels for the catalysis of cross-coupling reactions. This Pd nanocomposite on various polymeric supports has been well established to catalyze cross-coupling reactions, but its preparation supported on the surface of nanofibers has been largely overlooked. Herein, we report the preparation of a poly(acrylic acid) (PAA)/poly(vinyl alcohol) (PVA) nanofiber-supported N-heterocyclic carbene-Pd complex. The first step involves the preparation of PAA/PVA nanofibers using the electrospinning process. The second step comprises the reaction of water-soluble poly(ethylene glycol)-imidazole with modified PAA/PVA nanofibers followed by introduction of PdCl2 to achieve successfully the desired nanocomposite. The catalytic activity of this nanocomposite was examined in the expeditious synthesis of biaryl compounds using the Suzuki-Miyaura cross-coupling reaction under mild reaction conditions. The composite offers multiple features such as good hydrophilic properties, high surface area, admirable potential in repeatability tests and being recyclable for several runs without significant loss in its activity under the optimum reaction conditions. Our results showed the superior applicability of this novel nanocatalyst in terms of conversion reaction, yields and turnover frequencies. The structure of the catalyst was characterized using a variety of techniques.