Cationic iridium complexes bearing imidazol-2-ylidene ligands as transfer hydrogenation catalysts

A C Hillier, H M Lee, E D Stevens, Steven Patrick Nolan

Research output: Contribution to journalArticlepeer-review

205 Citations (Scopus)

Abstract

The synthesis and characterization by X-ray crystallography of the complexes [Ir(cod)-(py)(L)]PF6 (L = IMes, 1,3-bis(2,4,6-trimethylphenyl)imidazol-2-ylidene (2); L = IPr, 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene (3); L = ICy, 1,3-bis(cyclohexyl)imidazol-2-ylidene (4)) are reported. Complexes 2-4 have been employed as catalysts for transfer hydrogenation reactions from 2-propanol to a number of unsaturated substrates and their activity compared with that of the related cationic iridium(I) species [Ir(cod)(py)(SIMes)]-PF6 (1), [Ir(cod)(py)(PCy3)]PF6 (5), and complexes formed in situ from [Ir(cod)(py)(2)]PF6 and diazabutadienes (RN=CHCH=NR, DAB-R; R = cyclohexyl, DAB-Cy; R = 2,4,6-trimethylphenyl, DAB-Mes; R = adamantyl, DAB-Ad; R = 2,4,6-trimethoxyphenyl, DAB-trimethoxyphenyl). All complexes tested were found to be active catalysts for transfer hydrogenation of ketones, with complex 4 displaying the highest activity. Complex 4 also exhibits moderate activity toward simple olefins and an aromatic nitro compound.

Original languageEnglish
Pages (from-to)4246-4252
Number of pages7
JournalOrganometallics
Volume20
Issue number20
DOIs
Publication statusPublished - 1 Oct 2001

Keywords

  • ASYMMETRIC TRANSFER HYDROGENATION
  • ASTERISK = ETA(5)-C5ME5
  • ALPHA,BETA-UNSATURATED KETONES
  • TRANSFER REDUCTIONS
  • CARBONYL-COMPOUNDS
  • STABLE CARBENES
  • METAL-COMPLEXES
  • AMINODIPHOSPHINE LIGANDS
  • ALKANE DEHYDROGENATION
  • POLYDENTATE LIGANDS

Fingerprint

Dive into the research topics of 'Cationic iridium complexes bearing imidazol-2-ylidene ligands as transfer hydrogenation catalysts'. Together they form a unique fingerprint.

Cite this