Synthesis, characterization, hydrolase and catecholase activity of a dinuclear iron(III) complex: Catalytic promiscuity

Camargo, Tiago P.; Maia, Fernanda F.; Chaves, Cláudia; Souza, Bernardo de; Bortoluzzi, Adaílton J.; Castilho, Nathalia; Bortolotto, Tiago; Terenzi, Hernán; Castellano, Eduardo E.; Haase, Wolfgang; Tomkowicz, Z.; Peralta, Rosely A.; Neves, Ademir

doi:10.1016/j.jinorgbio.2015.02.017

Cited by 49 publications

(29 citation statements)

References 41 publications

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“…To investigate the efficiency of the catalytic activity we draw a comparison between our complex 1 and some recently reported iron complexes which show efficient catecholase activity (Table ) . This comparison also indicates that complex 1 acts as a better and effective catalyst towards catecholase activity than the reported ones …”

Section: Resultsmentioning

confidence: 92%

Catalytic promiscuity of an iron(II)–phenanthroline complex

De¹,

Garai²,

Yadav

et al. 2016

Applied Organom Chemis

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A mononuclear iron(II) complex, [Fe(phen) 3 ]Cl 2 (1) (phen =1,10-phenanthroline), has been synthesized in crystalline phase and characterized using various spectroscopic techniques including single crystal X-ray diffraction. Crystal structure analysis revealed that 1 crystallizes in a monoclinic system with C2/m space group. Complex 1 acts as a functional model for a biomimetic catalyst promoting the aerobic oxidation of 3,5-di-tert-butylcatechol (3,5-DTBC) through radical pathways with a significant turnover number (k cat =3.55 × 10 3 h À1 ) and exhibits catechol dioxygenase activity towards the same 3,5-DTBC substrate at room temperature in oxygen-saturated ethanol medium. The existence of an isobestic point at 610 nm from spectrophotometric data indicates the presence of Fe 3+ À3,5-DTBC adduct favouring an enzyme-substrate binding phenomenon. Upon stoichiometric addition of 3,5-DTBC pretreated with two equivalents of triethylamine to the iron complex, two catecholate-to-iron(III) ligand-to-metal charge transfer bands (575 and 721 nm) are observed and the in situ generated catecholate intermediate reacts with dioxygen (k obs =9.89 × 10 À4 min À1 ) in ethanol medium to afford exclusively intradiol cleavage products along with a small amount of benzoquinone, and a small amount of extradiol cleavage products, which provide substantial evidence for a substrate activation mechanism.

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Section: Resultsmentioning

confidence: 92%

Catalytic promiscuity of an iron(II)–phenanthroline complex

De¹,

Garai²,

Yadav

et al. 2016

Applied Organom Chemis

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“…[1][2][3][4][5][6] In some cases, the presence of hydroxide and acetate ions may lead to further bridging and hence to doubly or triply bridged dinuclear metal complexes where the two metal centers are in close proximity in the range of 2.9-4.0 Å. [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21] Such coordination environments around the central metal ions together with the possible existence of the "coordinatively unsaturated" metal ion(s) and center with a "weakly bound" ligand(s) made these complexes attractive targets to mimic the active sites in the biological systems in order to elucidate the mechanism and the structural parameters of metalloproteins, e.g. hemocyanin, 12 metallo-β-lactamases (MβL), 13 catecholase oxidases, 8,14,15 Mn catalases, 16,17 and the phosphodiester hydrolysis of biomolecules such as purple acid phosphatases (PAPs), phosphoesterases and DNA nucleases.…”

Section: Introductionmentioning

confidence: 99%

“…[7][8][9][10][11][12][13][14][15][16][17][18][19][20][21] Such coordination environments around the central metal ions together with the possible existence of the "coordinatively unsaturated" metal ion(s) and center with a "weakly bound" ligand(s) made these complexes attractive targets to mimic the active sites in the biological systems in order to elucidate the mechanism and the structural parameters of metalloproteins, e.g. hemocyanin, 12 metallo-β-lactamases (MβL), 13 catecholase oxidases, 8,14,15 Mn catalases, 16,17 and the phosphodiester hydrolysis of biomolecules such as purple acid phosphatases (PAPs), phosphoesterases and DNA nucleases. 10,15,[18][19][20][21][22][23][24][25] In addition to the possible use of these compounds in modeling the biological systems, they provide a wide range of ferro-/antiferro-magnetic couplings between the two paramagnetic metallic centers (3d [5][6][7][8][9] ), bridged via the phenoxido group and through other ligands, which allows to probe the electronic structure of these compounds and compare them with the natural systems.…”

Section: Introductionmentioning

confidence: 99%

Dinuclear metal(ii)-acetato complexes based on bicompartmental 4-chlorophenolate: syntheses, structures, magnetic properties, DNA interactions and phosphodiester hydrolysis

et al. 2016

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A series of dinuclear metal(ii)-acetato complexes: [Ni2(μ-L(Cl)O)(μ2-OAc)2](PF6)·3H2O (1), [Ni2(μ-L(Cl)O)(μ2-OAc)2](ClO4)·CH3COCH3 (2), [Cu2(μ-L(Cl)O)(μ2-OAc)(ClO4)](ClO4) (3), [Cu2(μ-L(Cl)O)(OAc)2](PF6)·H2O (4), [Zn2(μ-L(Cl)O)(μ2-OAc)2](PF6) (5) and [Mn2(L(Cl)-O)(μ2-OAc)2](ClO4)·H2O (6), where L(Cl)O(-) = 2,6-bis[bis(2-pyridylmethyl)aminomethyl]-4-chlorophenolate, were synthesized. The complexes were structurally characterized by spectroscopic techniques and single crystal X-ray crystallography. Six-coordinate geometries with doubly bridged acetato ligands were found in Ni(ii), Zn(ii) and Mn(ii) complexes 1, 2, 5 and 6, whereas with Cu(ii) complexes a five-coordinate species was obtained with 4, and mixed five- and six-coordinate geometries with a doubly bridged dimetal core were observed in 3. The magnetic properties of complexes 1-4 and 6 were studied at variable temperatures and revealed weak to very weak antiferromagnetic interactions in 1, 2, 4 and 6 (J = -0.55 to -9.4 cm(-1)) and ferromagnetic coupling in 3 (J = 15.4 cm(-1)). These results are consistent with DFT calculations performed at the B3LYP/def2-TZVP(-f) level of theory. Under physiological conditions, the interaction of the dinculear complexes 1-5 with supercoiled plasmid ds-DNA did not show any pronounced nuclease activity, but Ni(ii) complexes 1 and 2 revealed a strong ability to unwind the supercoiled conformation of ds-DNA. The mechanistic studies performed on the interaction of the Ni(ii) complexes with DNA demonstrated the important impact of the nickel(ii) ion in the unwinding process. In combination with the DNA study, the phosphatase activity of complexes 1, 3, and 5 was examined by the phosphodiester hydrolysis of bis(2,4-dinitrophenol)phosphate (BDNPP) in the pH range of 5.5-10.5 at 25 °C. The Michaelis-Menten kinetics performed at pH 7 and 10.7 showed that catalytic efficiencies kcat/KM (kcat = catalytic rate constant, KM = substrate binding constant) decrease in the order: Ni(ii), 1 > Zn(ii), 5 > Cu(ii), 3. A similar trend was also observed with the turnover numbers at pH = 7. The results are discussed in relation to the coordination geometry and nature of the metal center as well as the steric environment imposed by the compartmental phenoxido ligand.

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“…1,2,[4][5][6][10][11][12][13] This property made this class of compounds to serve as good candidates to mimic biological systems and as a consequence they have been extensively employed to elucidate the structural spectroscopic parameters and to mimic the mechanism of metalloenzymes in catecholase oxidases, Mn catalases, metallo-b-lactamases (MbL) 7,13,[26][27][28][29][30] and particularly in the hydrolytic systems. 8,21,31,32 These includes phosphodiester bonds of biomolecules such as DNA, purple acid phosphatases and Zn phosphesterases. 8,21,[31][32][33] In addition to the advantages of the compartmental dinuclear metal(II) complexes which derived from phenolic compounds in enhancing our understanding for the role of metal ions in the active sides of metalloenzymes, the compounds could provide interesting magnetic properties as a result of the magnetic coupling between the two paramagnetic metal centers (3d [7][8][9] ) bridged via the phenoxido group.…”

Section: Introductionmentioning

confidence: 99%