Catechol‐Functionalized Carbon Nanotubes as Support for Pd Nanoparticles: a Recyclable System for the Heck Reaction. Issue 38 (17th August 2022)

• Record Type: Journal Article
• Authors: Mercadante, Alessandro; Campisciano, Vincenzo; Morena, Anthony; Valentino, Laura; La Parola, Valeria; Aprile, Carmela; Gruttadauria, Michelangelo; Giacalone, Francesco
• Is Part Of: European journal of organic chemistry. Volume 2022:Issue 38(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-08-17
• Subjects: Carbon nanotubes -- C−C coupling reactions -- Suzuki and Heck reactions -- Palladium nanoparticles -- Heterogeneous catalysis; Chemistry, Organic -- Periodicals; Organic compounds -- Synthesis -- Periodicals; Bioorganic chemistry -- Periodicals; Chemistry, Physical organic -- Periodicals; 547
• DOI: 10.1002/ejoc.202200497
• Languages: English
• ISSNs: 1434-193X

Abstract

Abstract: Carbon nanotubes have been covalently functionalized with catechol moieties through the formation of the corresponding aryl radicals obtained by reacting 4‐aminocatechol with isoamyl nitrite. The functionalized multiwalled carbon nanotubes have been in turn used to immobilize Pd(II) ions on its surface forming catechol‐Pd complexes, which were reduced to Pd nanoparticles (NPs). The so‐obtained hybrid material has been characterized by means of thermogravimetric analysis coupled with differential scanning calorimetry (TGA‐DSC), X‐ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM). This latter technique allowed to estimate the nanoparticle size (5.7±2.8 nm) whereas a palladium loading of 20.3 wt % has been found by inductively coupled plasma optical emission spectroscopy (ICP‐OES). The carbon nanotube‐catechol‐Pd hybrid was used as catalyst in two C−C coupling reactions, namely Suzuki and Heck reactions, resulting recyclable for at least 9 times in the latter process. During the reuse Pd nanoparticles increase their dimension to 19.3±11.7 nm. Abstract : Multiwalled carbon nanotubes were highly functionalized with catechol moieties by means of a simple procedure involving the in‐situ generation of the diazonium salt arising from the reaction between 4‐aminocatechol and isoamyl nitrite. The resulting material was used to immobilize Pd nanoparticles obtaining an active and recyclable catalyst for the Heck reaction between methyl acrylate/styrene and aryl iodides.