title: Synthesis and Characterization of Cobalt(III), Nickel(II) and Copper(II) Mononuclear Complexes with the Ligand 1,3-bis[(2-aminoethyl)amino]-2-propanol and Their Catalase-Like Activity.
abstract: In this work, we present the synthesis and characterization of two new mononuclear complexes with the ligand 1,3-bis[(2-aminoethyl)amino]-2-propanol (HL), [Co(L)(H2O)](ClO4)2 (1), [Ni(HL)](ClO4)2 (2), as well as the known complex [Cu(HL)](ClO4)2 (3) for comparison. Their abilities to catalyze the dismutation of H2O2 and the oxidation of cyclohexane were investigated. The complexes were characterized by X-ray diffraction, elemental analysis, electronic and infrared spectroscopy, cyclic voltammetry, electrospray ionization mass spectrometry (ESI-MS) and conductivity measurements. The X-ray structures showed that the nickel (2) and copper (3) complexes are tetracoordinated, with the metal ion bound to the nitrogen atoms of the ligand. On the other hand, the cobalt complex (1) is hexacoordinated, possessing additional bonds to the alkoxo group of the ligand and to a water molecule. Neither of the complexes was able to catalyze the oxidation of cyclohexane, but all of them exhibited catalase-like activity, following Michaelis-Menten kinetics, which suggest resemblance with the catalase natural enzymes. The catalytic activity followed the order: [Ni(HL)](ClO4)2 (2) > [Cu(HL)](ClO4)2 (3) > [Co(L)(H2O)](ClO4)2 (1). As far as we know, this is the first description of a nickel complex presenting a significant catalase-like activity.
authors.affiliation: Instituto de Química, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Rio de Janeiro, Brazil.
authors.forename: Bianca M
authors.initials: BM
authors.lastname: Pires
authors.affiliation: Instituto de Química, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Rio de Janeiro, Brazil.
authors.forename: Daniel M
authors.initials: DM
authors.lastname: Silva
authors.affiliation: NanoBusiness Informação e Inovação Ltda., Rio de Janeiro, Rio de Janeiro, Brazil.
authors.forename: Lorenzo C
authors.initials: LC
authors.lastname: Visentin
authors.affiliation: Departamento de Química, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil.
authors.forename: Bernardo L
authors.initials: BL
authors.lastname: Rodrigues
authors.affiliation: Instituto de Química, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Rio de Janeiro, Brazil.
authors.forename: Nakédia M F
authors.initials: NM
authors.lastname: Carvalho
authors.affiliation: Instituto de Química, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Rio de Janeiro, Brazil.
authors.forename: Roberto B
authors.initials: RB
authors.lastname: Faria
mesh_terms: D019840:2-Propanol / Q000737:chemistry*; D002374:Catalase / Q000737:chemistry*; D002384:Catalysis; D003035:Cobalt / Q000737:chemistry*; D056831:Coordination Complexes / Q000737:chemistry*; D003300:Copper / Q000737:chemistry*; D003510:Cyclohexanes / Q000737:chemistry; D006861:Hydrogen Peroxide / Q000737:chemistry; D007700:Kinetics; D008024:Ligands; D008670:Metals / Q000737:chemistry; D009532:Nickel / Q000737:chemistry*; D010084:Oxidation-Reduction; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods; D013055:Spectrophotometry, Infrared / Q000379:methods; D014961:X-Ray Diffraction / Q000379:methods
chemical_list: D056831:Coordination Complexes; D003510:Cyclohexanes; D008024:Ligands; D008670:Metals; D003035:Cobalt; C506365:Cyclohexane; D003300:Copper; D009532:Nickel; D006861:Hydrogen Peroxide; D002374:Catalase; D019840:2-Propanol