title: Synthesis and Characterization of Fe0(2,2'-bipyridine) (2-aminoethyl-pyridine) and its Reaction with Dihydrogen.
abstract: Fe0(bpy)(pyea) (2; bpy=2,2'-bipyridine, pyea=2-aminoethyl-pyridine), a 16-electron species, was synthesized by reduction of FeCl2(bpy)(pyea) (1) using Na-strips. It is a diamagnetic low-melting solid (m.p. 295 K) stable under N2and easily decomposed by radiations even at low temperature. It was fully characterized by elemental analyses and multinuclear NMR. Complex 2 acts as an active hydrogenation catalyst, but has a very short lifetime. In fact, it reacts with H2(0.1-1 MPa) at room temperature in toluene and affords in a few minutes a new Fe0complex characterized as Fe0(bpy)(η6-picoline) (3), inactive to hydrogenation. Picoline is derived from the sp3-sp3C-C bond cleavage of the aminoethyl arm of the pyea ligand. The rapid evolution of the putative intermediate FeH2(bpy)(pyea) (4) has not allowed the isolation such Fe-hydrido species. The interaction of H2with 2 has been studied by DFT, which has allowed to demonstrate that 3 is lower in energy than 2+H2, justifying the fact that the intermediate dihydride was not isolated. Interestingly, 3 was also obtained by reaction of 1 with NaBH4or with glycerol-KOH. Complex 2 is one of the rare examples of Fe0complex stabilized by a set of only N-donor atoms. The reaction with glycerol confirms the potential role of Fe in catalytic hydrogenation reactions using bio-glycerol as a H-source.
authors.affiliation: Interuniversity Consortium Chemical Reactivity and Catalysis (CIRCC), via Celso Ulpiani 27, 70126, Bari, Italy.|Department of Chemistry, University of Bari, Campus Universitario, 70125, Bari, Italy.
authors.forename: Angela
authors.identifier: http://orcid.org/0000-0003-4428-8256
authors.initials: A
authors.lastname: Dibenedetto
authors.affiliation: Interuniversity Consortium Chemical Reactivity and Catalysis (CIRCC), via Celso Ulpiani 27, 70126, Bari, Italy.
authors.forename: Cristina E
authors.initials: CE
authors.lastname: Roth
authors.affiliation: Interuniversity Consortium Chemical Reactivity and Catalysis (CIRCC), via Celso Ulpiani 27, 70126, Bari, Italy.|Department of Chemical and Biomolecular Engineering, National University of Sinapore, Engineering Drive 4, Singapore, 117585, SG, Singapore.
authors.forename: Michele
authors.initials: M
authors.lastname: Aresta
authors.affiliation: Hungarian Academy of Sciences, Budapest, Hungary.
authors.forename: Imre
authors.initials: I
authors.lastname: Pápai
mesh_terms: D015082:2,2'-Dipyridyl / Q000737:chemistry*; D002384:Catalysis; D060326:Chemistry Techniques, Synthetic; D006859:Hydrogen / Q000737:chemistry*; D058085:Iron Compounds / Q000737:chemistry*; D008958:Models, Molecular; D008968:Molecular Conformation; D011789:Quantum Theory
chemical_list: D058085:Iron Compounds; D015082:2,2'-Dipyridyl; D006859:Hydrogen
keywords: density functional theory; glycerol; hydrogenation; iron; sp3-sp3 cleavage