A Sustainable Heterogeneous Iron Catalyst Fe/SBA‐15 towards Direct Arylation of Unactivated C(sp3)−H and C(sp2)−H Bonds with Arenes. Issue 7 (1st March 2017)

• Record Type: Journal Article
• Authors: Rajendran, C.; Satishkumar, G.
• Is Part Of: ChemCatChem. Volume 9:Issue 7(2017)
• Page Start: 1284
• Page End: 1291
• Publication Date: 2017-03-01
• Subjects: C−H activation -- cross-coupling -- heterogeneous catalysis -- iron -- mesoporous materials; Catalysis -- Periodicals; 541.39505
• DOI: 10.1002/cctc.201601562
• Languages: English
• ISSNs: 1867-3880

Abstract

Abstract: Iron grafted over mesoporous silica (8 wt %Fe/SBA‐15) is a sustainable, efficient heterogeneous iron catalyst for direct arylation of biphenyl methane C(sp 3 )−H and benzene C(sp 2 )−H bonds. The selective extraction deposition (SED) technique was adopted to graft iron easily over the mesoporous support SBA‐15 by using LaFeO3 as an iron precursor. The synthesized catalyst has been characterized by EPR spectroscopy, diffuse reflectance UV/Vis spectroscopy, and temperature programmed reduction (TPR) analysis to understand the coordination environment and state of oxidic iron species grafted over the mesoporous SBA‐15. TPR results confirm the presence of isolated, clustered, oligomeric oxidic iron species in the catalyst. The adopted SED technique is highly successful for grafting 8 wt % iron into the mesopores of SBA‐15 without forming iron oxide particles. Unlike homogeneous iron, the 8 wt %Fe/SBA‐15 catalyst does not need support from an electron‐withdrawing group and additives to carry out arylation of benzene and could be successfully recycled five times. Abstract : Iron grafted over mesoporous silica (8 wt %Fe/SBA‐15) is a sustainable, efficient heterogeneous iron catalyst for direct arylation of biphenyl methane C(sp 3 )−H and benzene C(sp 2 )−H bonds (see scheme; DDQ=2, 3‐dichloro‐5, 6‐dicyano‐1, 4‐benzoquinone, DCE=dichloroethane; DTBP=di‐ tert ‐butyl peroxide). Unlike homogeneous iron, the 8 wt %Fe/SBA‐15 catalyst does not need support from an electron‐withdrawing group and additives to arylate benzene and could be successfully recycled five times.