Pd nanosized particles supported on chitosan and 6-deoxy-6-amino chitosan as recyclable catalysts for Suzuki-Miyaura and Heck cross-coupling reactions

Banothile C.E. Makhubela, Anwar Jardine, Gregory S. Smith

Research output: Contribution to journalArticlepeer-review

125 Citations (Scopus)

Abstract

Several chitosan and 6-deoxy-6-amino chitosan-Schiff base ligands (1-4) were prepared by condensation of either 2-pyridinecarboxaldehyde or 2-(diphenylphosphino)benzaldehyde with the amino group(s) on chitosan and its derivative (6-deoxy-6-amino chitosan). The supported ligands were reacted with [PdCl2(COD)] to form chitosan-supported PdII catalysts (5-8). All the supported catalysts were air- and moisture-stable and have been characterized using elemental analysis, ICP-MS, UV-vis, FT-IR, PXRD, TGA, 31P solid state NMR and TEM. As models for the heterogenized catalysts (5 and 6), mononuclear PdII complexes (9 and 10) were also prepared via the Schiff-base condensation reaction of 1,3,4,6-tetra-O-acetyl- β-d-glucosamine hydrochloride to form 1,3,4,6-tetra-O-acetyl-β-d- glucos-2-pyridylimine and 1,3,4,6-tetra-O-acetyl-β-d-glucos-2- (diphenylphosphino)imine which were subsequently reacted with [PdCl 2(COD)]. Complexes (9 and 10) and their precursors were characterized by 1H and 31P NMR, UV-vis, FT-IR spectroscopy and elemental analysis. Catalytic Suzuki-Miyaura and Heck carbon-carbon cross-coupling reactions were carried out using the supported Pd catalysts and their mononuclear analogues. The immobilized and homogeneous catalysts showed high activity for both the Suzuki-Miyaura and Heck cross-coupling reactions in organic and aqueous media. Homogeneous catalysts (9 and 10) decomposed during the first run, while the supported catalysts could be recycled and reused up to five times.

Original languageEnglish
Pages (from-to)231-241
Number of pages11
JournalApplied Catalysis A: General
Volume393
Issue number1-2
DOIs
Publication statusPublished - 15 Feb 2011
Externally publishedYes

Keywords

  • Chitosan
  • Heck
  • Heterogeneous Pd catalysis
  • Schiff-base
  • Suzuki-Miyaura

ASJC Scopus subject areas

  • Catalysis
  • Process Chemistry and Technology

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