Synthesis and catalytic application of new [{IrCl(cod)}₂(μ²-diNHC)] and [{Ir(cod)(sulfonated phosphine)}₂(μ²-diNHC)] complexes

Abstract

Four new dinuclear iridium(I) complexes were synthesized from the di(N-heterocyclic carbene) ligand precursors 1,1′-methylene-bis(3-benzyl-imidazolium)dichloride and 1,1′-methylene-bis(3-(2,4,6-trimethylbenzyl)imidazolium)dichloride. The complexes were fully characterized by spectroscopic methods, HR-MS (ESI) spectrometry, furthermore, the structure of complexes 1 and 2 were determined by single-crystal X-ray diffraction. Complexes 3a and 3b which have sulfonated triphenylphosphine ligands, were successfully used under mild conditions as catalysts in reduction reaction of ketones via hydrogen transfer from aqueous 2-propanol, and for hydrogenation of alkynes in aqueous-organic biphasic systems.

Graphical Abstract

Keywords:

• Alkyne
• hydrogenation
• iridium
• ketone
• N-heterocyclic carbene
• sulfonated phosphine

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

The research was supported by the EU and co-financed by the European Regional Development Fund under the projects GINOP 2.3.2-15-2016-00008 and GINOP-2.3.3-15-2016-00004. The financial support of the Hungarian National Research, Development and Innovation Office (FK-128333) is greatly acknowledged. Project no. TKP2020-NKA-04 has been implemented with the support provided from the National Research, Development and Innovation Fund of Hungary, financed under the 2020-4.1.1-TKP2020 funding scheme.