Highly Active, Selective, and Reusable RuO₂/SWCNT Catalyst for Heck Olefination of Aryl Halides

Abstract

Very fine RuO₂ nanoparticles (RuO₂NPs) with a mean diameter of about 0.9 nm were decorated on single-walled carbon nanotubes (SWCNTs) by a straightforward “dry synthesis” method. TEM images and the Raman spectrum of the resultant material (RuO₂/SWCNT) revealed excellent adhesion and homogeneous dispersion of the RuO₂NPs on anchoring sites of the SWCNTs. The surface area of RuO₂/SWCNT was found to be 416 m² g^–1. The SEM–EDS results showed that the weight percentage of Ru in RuO₂/SWCNT was 13.8%. The oxidation state of Ru in RuO₂/SWCNT was +4, as confirmed by XPS and XRD analyses. After the complete characterization, a 0.9 mol % loading of RuO₂/SWCNT was used as a nanocatalyst for the Heck olefination of a wide range of aryl halides to yield products in excellent yields with good turnover numbers and turnover frequencies. Less reactive bromo- and chloroarenes were also used for the formation of coupled products in good yields. RuO₂/SWCNT is regioselective, chemoselective, heterogeneous in nature, and reusable. The stability of RuO₂/SWCNT was also studied by means of TEM, ICP-MS, SEM–EDS, and XPS analyses