Hydrogenation of CO2, carbonyl and imine substrates catalyzed by [IrH3(PhPNHP)] complex

Publication date: Available online 31 December 2018Source: Journal of Organometallic ChemistryAuthor(s): Ayyappan Ramaraj, Munirathinam Nethaji, Balaji R. JagirdarAbstractA series of iridium and rhodium complexes [M(COD)(PhPNHP)]Cl {M = Ir (1), Rh (2)}, [MH2Cl(PhPNHP)] {M = Ir (3), Rh (4)} and [IrH3(PhPNHP)] (6) supported by pincer ligand H-N(CH2CH2PPh2)2 {PhPNHP} have been synthesized and characterized. All complexes were isolated in good yields. The iridium trihydride complex [IrH3(PhPNHP)] (6) was found to be an active catalyst for the hydrogenation of CO2 in 1 M aqueous KOH solution. It also acts as a catalyst for the base-free hydrogenation of carbonyl and imine substrates in MeOH. Under similar hydrogenation conditions, 2-cyclohexen-1-one undergoes solvent assisted tandem Michael addition-reduction mediated by bifunctional Lewis-acid-catalyst [IrH3(PhPNHP)] in ROH (R = Me, Et) at room temperature. The complexes 1, 3, 4, and 6 were characterized by X-ray crystallography. Extensive hydrogen bonding interactions N−H···H−Ir (2.15 Å), N−H···Cl (2.370 Å) were noted in the crystal structures of these complexes.Graphical abstract

Source: Journal of Organometallic Chemistry - January 1, 2019 Category: Chemistry Source Type: research