Hydrothermal Heck reaction catalyzed by Ni nanoparticles

Abstract

A novel environmentally benign Heck reaction using Ni nanoparticles as catalysts under hydrothermal conditions has been developed in the absence of phosphine ligands without the protection of an inert atmosphere. The results showed that the aryl iodides and bromides could carry out the coupling reaction with a variety of alkenes by hydrothermal treatment. More importantly, the cheap catalysts are stable under the reaction conditions and retain good to moderate activity for at least six successive runs without any additional activation treatment. This approach would be very useful from a practical viewpoint.

Nanocatalysts for the Heck Coupling Reactions

“…[70][71][72][73][74] Discussion on other metal nanoparticles such as Ru, 75 Ni, 76 and trimetallic Au-Ag-Pd 77 , which have also been shown to catalyze the Heck reaction, is also included, though not in much detail.…”

“…Although the Heck reaction has been traditionally conducted using Pd-NPs, other transition metal nanoparticles such as Ru, 101 Ni, 102 and trimetallic Au-Ag-Pd 103 nanoparticles have also been shown to catalyze the reaction. This is mainly because many of these metals are also capable of inserting into the aryl halide bonds of the substrates during the Heck reaction.…”

“…The Ni(II)/silica gel was then dried with supercritical CO 2 to afford silica aerogels, and the Ni(II) ions were subsequently reduced into Ni(0) by heating the sample in a stream of hydrogen at 550 • C (heating rate 10 • C min −1 ), followed by keeping the sample at 550 • C for 2 h. In another example, Zhang et al reported a hydrothermal catalytic Heck reaction using Ni nanoparticles, which were prepared by direct reduction of NiCl 2 with NaBH 4 in aqueous medium under sonication in the absence of surfactants. 102 The resulting Ni nanoparticles catalyzed the Heck coupling reaction between aryl iodides or bromides and a variety of alkenes in the absence of phosphine ligands, giving the corresponding coupling products with moderate to good yields.…”

Synthesis of green nanocatalysts and industrially important green reactions

“…These palladium nanoparticles are used as catalysts for the Heck crosscoupling reaction in water. An environmentally benign Heck reaction using nickel nanoparticles as catalysts under hydrothermal conditions was found to be effective catalysts (75). Figure 20 shows SEM images of the nickel nanoparticles before the Heck reaction and after six cycles of the Heck reaction (75).…”

CuO nanoparticle‐catalyzed diaminations for synthesis of benzimidazole derivatives

“…Nanoparticles have emerged as robust and high‐surface‐area heterogeneous catalysts, which serve as sustainable alternatives to conventional materials . CuO nanoparticles have drawn attention due to their stability and availability .…”