Application of new Ru (II) pyridine‐based complexes in the partial oxidation of n‐octane. (13th December 2019)

• Record Type: Journal Article
• Authors: Chanerika, Revana; Friedrich, Holger B.; Shozi, Mzamo L.
• Is Part Of: Applied organometallic chemistry. Volume 34:Number 2(2020)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2019-12-13
• Subjects: alcohols -- bidentate -- NNN ligands -- oxidation -- ruthenium complexes; Organometallic chemistry -- Periodicals; Organometallic compounds -- Periodicals; 547.05
• DOI: 10.1002/aoc.5361
• Languages: English
• ISSNs: 0268-2605

Abstract

Abstract: Tridentate and bidentate Ru (II) complexes were prepared through reaction of four pyridine‐based ligands: pyCH2 N(R)CH2 py {R = propyl, tert‐ butyl, cyclohexyl and phenyl; py = pyridine} with the [(η 6 ‐C6 H6 )Ru(μ‐Cl)Cl]2 dimer. Crystal structures of the new terdentate Ru (II) complexes [Ru{pyCH2 N(R)CH2 py}C6 H6 ](PF6 )2 (R = C3 H7 (1 ), C (CH3 )3 (2 ), C6 H11 (3 ) and the bidentate Ru (II) complex [Ru{pyCH2 N(R)}C6 H6 ]PF6 (R = C6 H5 (4 )) are reported. It was found that complexes 1, 2, 3 and 4 crystallised as mono‐metallic species, with a piano stool geometry around each Ru centre. All complexes were active in the selective oxidation of n ‐octane using t ‐BuOOH and H2 O2 as oxidants. Complexes 2 and 4 reached a product yield of 12% with t ‐BuOOH as oxidant, however, superior yields (23–32%) were achieved using H2 O2 over all systems. The selectivity was predominantly towards alcohols (particularly 2‐octanol) over all complexes using t ‐BuOOH and H2 O2 after reduction of the formed alkylhydroperoxides in solution by PPh3 . High TONs of up to 2400 were achieved over the Ru/H2 O2 systems. Abstract : New Ru(II) catalysts with tridentate NNN ligands were synthesised and fully characterised. For the partial oxidation of n ‐octane, using H2 O2, TONS up to 2400 were obtained, with dominantly octanols forming.