Chelating bis-N-heterocyclic carbene complexes of iron(ii) containing bipyridyl ligands as catalyst precursors for oxidation of alcohols. Issue 34 (10th August 2016)

• Record Type: Journal Article
• Authors: Pinto, Mara F.; Cardoso, Bernardo de P.; Barroso, Sónia; Martins, Ana M.; Royo, Beatriz
• Is Part Of: Dalton transactions. Volume 45:Issue 34(2016)
• Page Start: 13541
• Page End: 13546
• Publication Date: 2016-08-10
• Subjects: Chemistry, Inorganic -- Periodicals; Chemistry, Physical and theoretical -- Periodicals; Chemistry, Inorganic -- Periodicals; 546.05
• DOI: 10.1039/c6dt02718k
• Languages: English
• ISSNs: 1477-9226

Abstract

Abstract : Chelating bis-N-heterocyclic carbene (bis-NHC) complexes of iron(ii ) containing pyridyl ligands have been prepared by the reaction of [FeCl2 L] [L = bipy (1 ), phen (2 )] with [LiN(SiMe3 )2 ] and a bis(imidazolium) salt. Abstract : Chelating bis-N-heterocyclic carbene (bis-NHC) complexes of iron(ii ) containing pyridyl ligands have been prepared by the reaction of [FeCl2 L] [L = bipy (1 ), phen (2 )] with [LiN(SiMe3 )2 ] and a bis(imidazolium) salt. The [Fe(bis-NHC)L(I)2 ] complexes were active pre-catalysts in the oxidation of 1-phenylethanol with tert -butyl hydroperoxide in neat conditions, affording a quantitative yield of acetophenone in 4.5 h. The catalyst could be reused up to six cycles giving a turnover number (TON) of 1500. Various secondary alcohols, both aromatic and aliphatic were selectivity oxidised to the corresponding ketones in excellent yields. Compound1 is stable in acetonitrile solution for ca . 4 h, although after 16 h, it evolves to a mixture of [Fe(bis-NHC)(bipy)2 ]I2 (3 ), [Fe(bipy)3 ] 2+ and bis-imidazolium salt. The molecular structure of3 has been determined by X-ray diffraction studies.