A naphthalene-based heterobimetallic triazolylidene IrIII/PdII complex: regioselective to regiospecific C–H activation, tandem catalysis and a copper-free Sonogashira reaction.
- Resource Type
- Article
- Authors
- Majumder, Adhir; Naskar, Rajat; Roy, Pallabi; Mondal, Bhaskar; Garai, Somenath; Maity, Ramananda
- Source
- Dalton Transactions: An International Journal of Inorganic Chemistry. 2/28/2023, Vol. 52 Issue 8, p2272-2281. 10p.
- Subject
- *SONOGASHIRA reaction
*HETEROBIMETALLIC complexes
*TRANSFER hydrogenation
*CATALYSIS
*NUCLEAR magnetic resonance spectroscopy
*MASS spectrometry
- Language
- ISSN
- 1477-9226
Heterobimetallic complexes featuring mesoionic carbene (MIC) donor ligands are gaining enormous popularity in tandem catalysis owing to the combined action of two different metal centers during catalysis. A rare version of the heterobimetallic PdII/IrIII complex possessing a cyclometalated mesoionic carbene (MIC) ligand is presented along with the analogous homodinuclear PdII complex. A sterically controlled regiospecific cyclometalation towards the formation of a six-membered ring complex over a five-membered ring complex has been performed using a naphthalene-based bis-MIC ligand platform. The interplay between regioselective vs. regiospecific C–H bond activation for the synthesis of cyclometalated IrIII complexes has also been demonstrated using the corresponding naphthyl-derived mono-imidazolylidene ligand. Both homodinuclear PdII and heterobimetallic PdII/IrIII complexes have been characterized using standard spectroscopic techniques including 1H, 13C{1H}, 2D correlation NMR spectroscopy and ESI mass spectrometry. The structure of the cyclometalated heterobimetallic complex has been established by single crystal XRD. The heterobimetallic complex has been employed as a pre-catalyst in the tandem Suzuki–Miyaura/transfer hydrogenation reaction and the homobimetallic PdII complex has been successfully employed as a catalyst in both the Sonogashira coupling and α-arylation of 1-methyl-2-oxindole. [ABSTRACT FROM AUTHOR]