1
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Doyle LM, Bienenmann RLM, Gericke R, Xu S, Farquhar ER, Que L, McDonald AR. Preparation and characterization of Mn IIMn III complexes with relevance to class Ib ribonucleotide reductases. J Inorg Biochem 2024; 257:112583. [PMID: 38733704 DOI: 10.1016/j.jinorgbio.2024.112583] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2024] [Revised: 04/26/2024] [Accepted: 04/30/2024] [Indexed: 05/13/2024]
Abstract
The Mn2 complex [MnII2(TPDP)(O2CPh)2](BPh4) (1, TPDP = 1,3-bis(bis(pyridin-2-ylmethyl)amino)propan-2-ol, Ph =phenyl) was prepared and subsequently characterized via single-crystal X-ray diffraction, X-ray absorption, electronic absorption, and infrared spectroscopies, and mass spectrometry. 1 was prepared in order to explore its properties as a structural and functional mimic of class Ib ribonucleotide reductases (RNRs). 1 reacted with superoxide anion (O2•-) to generate a peroxido-MnIIMnIII complex, 2. The electronic absorption and electron paramagnetic resonance (EPR) spectra of 2 were similar to previously published peroxido-MnIIMnIII species. Furthermore, X-ray near edge absorption structure (XANES) studies indicated the conversion of a MnII2 core in 1 to a MnIIMnIII state in 2. Treatment of 2 with para-toluenesulfonic acid (p-TsOH) resulted in the conversion to a new MnIIMnIII species, 3, rather than causing O-O bond scission, as previously encountered. 3 was characterized using electronic absorption, EPR, and X-ray absorption spectroscopies. Unlike other reported peroxido-MnIIMnIII species, 3 was capable of oxidative O-H activation, mirroring the generation of tyrosyl radical in class Ib RNRs, however without accessing the MnIIIMnIV state.
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Affiliation(s)
- Lorna M Doyle
- School of Chemistry, Trinity College Dublin, The University of Dublin, College Green, Dublin 2, Ireland
| | - Roel L M Bienenmann
- School of Chemistry, Trinity College Dublin, The University of Dublin, College Green, Dublin 2, Ireland
| | - Robert Gericke
- School of Chemistry, Trinity College Dublin, The University of Dublin, College Green, Dublin 2, Ireland
| | - Shuangning Xu
- Department of Chemistry and Centre for Metals in Biocatalysis, University of Minnesota, Minneapolis, 55455 MN, United States
| | - Erik R Farquhar
- Case Western Reserve University Center for Synchrotron Biosciences, National Synchrotron Light Source II, Brookhaven National Laboratory Upton, NY, 11973 New York, United States
| | - Lawrence Que
- Department of Chemistry and Centre for Metals in Biocatalysis, University of Minnesota, Minneapolis, 55455 MN, United States
| | - Aidan R McDonald
- School of Chemistry, Trinity College Dublin, The University of Dublin, College Green, Dublin 2, Ireland.
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2
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Luiz E, Farias G, Bortoluzzi AJ, Neves A, de Melo Mattos LM, Pereira MD, Xavier FR, Peralta RA. Hydrolytic activity of new bioinspired Mn IIIMn II and Fe IIIMn II complexes as mimetics of PAPs: Biological and environmental interest. J Inorg Biochem 2022; 236:111965. [PMID: 35988388 DOI: 10.1016/j.jinorgbio.2022.111965] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2022] [Revised: 08/01/2022] [Accepted: 08/10/2022] [Indexed: 12/15/2022]
Abstract
Coordination compounds that mimic Purple Acid Phosphatases (PAPs) have drawn attention in the bioinorganic field due to their capacity to cleave phosphodiester bonds. However, their catalytic activity upon phosphate triesters is still unexplored. Thus, we report the synthesis and characterization of two binuclear complexes, [MnIIMnIII(L1)(OAc)2]BF4 (1) and [MnIIFeIII(L1)(OAc)2]BF4 (2) (H2L1 = 2-[N,N-bis-(2- pyridilmethyl)aminomethyl]-4-methyl-6-[N-(2-hydroxy-3-formyl-5-methylbenzyl)-N-(2-pyridylmethyl)aminomethyl]phenol), their hydrolytic activity and antioxidant potential. The complexes were fully characterized, including the X-Ray diffraction (XRD) of 1. Density functional theory (DFT) calculations were performed to better understand their electronic and structural properties and phosphate conjugates. The catalytic activity was analyzed for two model substrates, a diester (BDNPP) and a triester phosphate (DEDNPP). The results suggest enhancement of the hydrolysis reaction by 170 to 1500 times, depending on the substrate and complex. It was possible to accompany the catalytic reaction of DEDNPP hydrolysis by phosphorus nuclear magnetic resonance (31P NMR), showing that both 1 and 2 are efficient catalysts. Moreover, we also addressed that 1 and 2 present a relevant antioxidant potential, protecting the yeast Saccharomyces cerevisiae, used as eukaryotic model of study, against the exposure of cells to acute oxidative stress.
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Affiliation(s)
- Edinara Luiz
- Departamento de Química, Universidade Federal de Santa Catarina, Florianópolis, Santa Catarina 88040-900, Brazil
| | - Giliandro Farias
- Departamento de Química, Universidade Federal de Santa Catarina, Florianópolis, Santa Catarina 88040-900, Brazil
| | - Adailton J Bortoluzzi
- Departamento de Química, Universidade Federal de Santa Catarina, Florianópolis, Santa Catarina 88040-900, Brazil
| | - Ademir Neves
- Departamento de Química, Universidade Federal de Santa Catarina, Florianópolis, Santa Catarina 88040-900, Brazil
| | - Larissa Maura de Melo Mattos
- Instituto de Química, Departamento de Bioquímica, Universidade Federal do Rio de Janeiro, 21941-909, Brazil; Rede Micologia RJ - FAPERJ
| | - Marcos Dias Pereira
- Instituto de Química, Departamento de Bioquímica, Universidade Federal do Rio de Janeiro, 21941-909, Brazil; Rede Micologia RJ - FAPERJ
| | - Fernando R Xavier
- Departamento de Química, Universidade do Estado de Santa Catarina, Joinville, Santa Catarina 89219-710, Brazil.
| | - Rosely A Peralta
- Departamento de Química, Universidade Federal de Santa Catarina, Florianópolis, Santa Catarina 88040-900, Brazil.
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3
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Elkurtehi AI, Kerton FM. Synthesis of amino-phenolate manganese complexes and their catalytic activity in carbon dioxide activation and oxidation reactions. CAN J CHEM 2021. [DOI: 10.1139/cjc-2020-0348] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Two manganese(III) compounds were studied as catalysts for the reaction of carbon dioxide with propylene oxide, styrene oxide, and cyclohexene oxide, and formed cyclic carbonate products selectively under solvent free conditions in the presence of an ionic co-catalyst such as TBAB or PPNCl. Variable temperature kinetic studies allowed the activation energy for propylene carbonate formation to be determined (64 kJ mol−1). The catalysts showed good stability in these reactions and overall turnover numbers (TON) of up to 6000 were observed. The complexes showed low activity for the aerobic oxidation of 4-methyoxybenzylalcohol to the corresponding aldehyde, achieving up to 40% conversion in 72 h. However, near quantitative conversion of 1,2-diphenyl-2-methoxyethanol to provide up to 90% yield of benzaldehyde could be achieved over the course of 5 days. Both complexes showed similar reactivity in the two catalytic processes, and this is likely due to the weakly coordinating nature of the pendant donor within the tetradentate ligand.
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Affiliation(s)
- Ali I. Elkurtehi
- Department of Chemistry, Memorial University of Newfoundland, St. John’s, NL, A1B 3X7, Canada
- Department of Chemistry, Memorial University of Newfoundland, St. John’s, NL, A1B 3X7, Canada
| | - Francesca M. Kerton
- Department of Chemistry, Memorial University of Newfoundland, St. John’s, NL, A1B 3X7, Canada
- Department of Chemistry, Memorial University of Newfoundland, St. John’s, NL, A1B 3X7, Canada
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4
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Mehrotra R, Richezzi M, Palopoli C, Hureau C, Signorella SR. Effect of coordination dissymmetry on the catalytic activity of manganese catalase mimics. J Inorg Biochem 2020; 213:111264. [PMID: 33045594 DOI: 10.1016/j.jinorgbio.2020.111264] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2020] [Revised: 09/09/2020] [Accepted: 09/21/2020] [Indexed: 11/15/2022]
Abstract
Two mixed-valence Mn(II)Mn(III) complexes, [Mn2L1(OAc)2(H2O)]BPh4·2.5H2O and [Mn2L2(OAc)2]·4H2O, obtained with unsymmetrical N4O2-hexadentate L1(2-) (H2L1 = 2-(N,N-bis(2-(pyridylmethyl)aminomethyl)-6-(N-(2-hydroxybenzyl)benzylaminomethyl)-4-methylphenol) and N4O3-heptadentate L2(3-) (NaH2L2 = 2-(N,N-bis(2-(pyridylmethyl)aminomethyl)-6-(N'-(2-hydroxybenzyl)(carboxymethyl)aminomethyl)-4-methylphenol sodium salt) ligands, have been prepared and characterized. Both complexes share a μ-phenolate-bis(μ-acetate)Mn(II)Mn(III) core and N3O3-coordination sphere around the Mn(II) ion, but differ in the donor groups surrounding Mn(III) (NO4(solvent) and NO5). In non-protic solvents, these two complexes are able to disproportionate at least 3600 equiv. of H2O2 without significant decomposition, with first-order dependence on catalyst and saturation kinetics on [H2O2]. Spectroscopic monitoring of the reaction mixtures revealed the two complexes disproportionate H2O2 employing a different redox cycle, with retention of dinuclearity. The higher catalytic efficiency of [Mn2L2(OAc)2] was rationalized in terms of the larger labilizing effect of the heptadentate ligand that favors the acetate-shift and the replacement of the non-coordinating benzyl arm of L1 by a carboxylate arm in L2 which facilitates the formation of the catalyst-H2O2 adduct, placing [Mn2L2(OAc)2] as the most efficient among the phenolate-bridged diMn catalysts based on the kcat/KM criterion.
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Affiliation(s)
- Ripul Mehrotra
- IQUIR (Instituto de Quimica Rosario), Consejo Nacional de Investigaciones Cientificas y Tecnicas (CONICET), Facultad de Ciencias Bioquimicas y Farmaceuticas, Universidad Nacional de Rosario, Suipacha 531, S2002LRK Rosario, Argentina
| | - Micaela Richezzi
- IQUIR (Instituto de Quimica Rosario), Consejo Nacional de Investigaciones Cientificas y Tecnicas (CONICET), Facultad de Ciencias Bioquimicas y Farmaceuticas, Universidad Nacional de Rosario, Suipacha 531, S2002LRK Rosario, Argentina
| | - Claudia Palopoli
- IQUIR (Instituto de Quimica Rosario), Consejo Nacional de Investigaciones Cientificas y Tecnicas (CONICET), Facultad de Ciencias Bioquimicas y Farmaceuticas, Universidad Nacional de Rosario, Suipacha 531, S2002LRK Rosario, Argentina
| | - Christelle Hureau
- CNRS, LCC (Laboratoire de Chimie de Coordination) and UPS, INPT, LCC, Université de Toulouse, 205 route de Narbonne, F-31077 Toulouse, France
| | - Sandra R Signorella
- IQUIR (Instituto de Quimica Rosario), Consejo Nacional de Investigaciones Cientificas y Tecnicas (CONICET), Facultad de Ciencias Bioquimicas y Farmaceuticas, Universidad Nacional de Rosario, Suipacha 531, S2002LRK Rosario, Argentina.
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5
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Ramadan AEM, Shaban SY, Ibrahim MM, Eissa H, Al‐Saidi HM, Fathy AM. Catechol oxidase and phenoxazinone synthase mimicking activity, X‐ray diffraction and density function theory study of pyridine and phenolate‐based manganese(II) and iron(III) complexes: Synthesis and spectroscopic characterization. J CHIN CHEM SOC-TAIP 2020. [DOI: 10.1002/jccs.201900383] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
| | - Shaban Y. Shaban
- Chemistry Department, Faculty of ScienceKafr El‐Sheikh University Egypt
| | - Mohamed M. Ibrahim
- Chemistry Department, Faculty of ScienceKafr El‐Sheikh University Egypt
- Chemistry Department, Faculty of ScienceTaif University Taif Saudi Arabia
| | - Hatem Eissa
- Chemistry Department, Faculty of ScienceKafr El‐Sheikh University Egypt
| | - Hamed M. Al‐Saidi
- Chemistry Department, University College in Al‐JamoumUmm Al‐Qura University Makkah Saudi Arabia
| | - Ahmad M. Fathy
- Chemistry Department, Faculty of ScienceZagazig University Zagazig Egypt
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6
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Ramadan AEMM, Shaban SY, Ibrahim MM, Abdel-Rahman AAH, Sallam SA, Al-Harbi SA, Omar W. Synthesis and spectroscopic characterization of ternary copper(ii) complexes containing nitrogen and oxygen donors as functional mimics of catechol oxidase and phenoxazinone synthase. NEW J CHEM 2020. [DOI: 10.1039/c9nj06131b] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Two ternary copper(ii) complexes 1 [(Cu2Me4en)4(EDTA)] and 2 [(CuMe4en)2(MIDA)] containing the mixed ligand system of 1,1′,4,4′-tetramethylethylenediamine (Me4en) (L) and N-methyliminodiacetic (MIDAH2) (L′) or ethylenediaminetetraacetic acid (EDTAH4) (L′) were synthesized.
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Affiliation(s)
| | - Shaban Y. Shaban
- Department of Chemistry
- Faculty of Science
- Kafr El-Sheikh University
- Kafr El-Sheikh
- Egypt
| | - Mohamed M. Ibrahim
- Department of Chemistry
- Faculty of Science
- Kafr El-Sheikh University
- Kafr El-Sheikh
- Egypt
| | | | - Shehab A. Sallam
- Department of Chemistry
- Faculty of Science
- Suez Canal University
- Ismailia
- Egypt
| | - Sami A. Al-Harbi
- Department of Chemistry
- University College in Al-Jamoum
- Umm Al-Qura University
- Makkah
- Saudi Arabia
| | - Walid Omar
- Department of Chemistry
- Faculty of Science
- Kafr El-Sheikh University
- Kafr El-Sheikh
- Egypt
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7
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Palopoli C, Ferreyra J, Conte-Daban A, Richezzi M, Foi A, Doctorovich F, Anxolabéhère-Mallart E, Hureau C, Signorella SR. Insights into Second-Sphere Effects on Redox Potentials, Spectroscopic Properties, and Superoxide Dismutase Activity of Manganese Complexes with Schiff-Base Ligands. ACS OMEGA 2019; 4:48-57. [PMID: 31459311 PMCID: PMC6649300 DOI: 10.1021/acsomega.8b03018] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Accepted: 12/20/2018] [Indexed: 05/04/2023]
Abstract
Six Mn-Schiff base complexes, [Mn(X-salpn)]0/+ (salpn = 1,3-bis(sal-ic-ylidenamino)propane, X = H [1], 5-Cl [2], 2,5-F2 [3], 3,5-Cl2 [4], 5-NO2 [5], 3,5-(NO2)2 [6]), were synthesized and characterized in solution, and second-sphere effects on their electrochemical and spectroscopic properties were analyzed. The six complexes catalyze the dismutation of superoxide with catalytic rate constants in the range 0.65 to 1.54 × 106 M-1 s-1 obtained through the nitro blue tetrazolium photoreduction inhibition superoxide dismutases assay, in aqueous medium of pH 7.8. In solution, these compounds possess two labile solvent molecules in the axial positions favoring coordination of the highly nucleophilic O2 •- to the metal center. Even complex 5, [Mn(5-(NO2)salpn) (OAc) (H2O)], with an axial acetate in the solid state, behaves as a 1:1 electrolyte in methanolic solution. Electron paramagnetic resonance and UV-vis monitoring of the reaction of [Mn(X-salpn)]0/+ with KO2 demonstrates that in diluted solutions these complexes behave as catalysts supporting several additions of excess O2 •-, but at high complex concentrations (≥0.75 mM) catalyst self-inhibition occurs by the formation of a catalytically inactive dimer. The correlation of spectroscopic, electrochemical, and kinetics data suggest that second-sphere effects control the oxidation states of Mn involved in the O2 •- dismutation cycle catalyzed by complexes 1-6 and modulate the strength of the Mn-substrate adduct for electron-transfer through an inner-sphere mechanism.
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Affiliation(s)
- Claudia Palopoli
- IQUIR
(Instituto de Química Rosario), Consejo Nacional de Investigaciones
Científicas y Técnicas (CONICET), Facultad de Ciencias
Bioquímicas y Farmacéuticas, Universidad Nacional de
Rosario, Suipacha 531, S2002LRK Rosario, Argentina
| | - Joaquín Ferreyra
- IQUIR
(Instituto de Química Rosario), Consejo Nacional de Investigaciones
Científicas y Técnicas (CONICET), Facultad de Ciencias
Bioquímicas y Farmacéuticas, Universidad Nacional de
Rosario, Suipacha 531, S2002LRK Rosario, Argentina
| | | | - Micaela Richezzi
- IQUIR
(Instituto de Química Rosario), Consejo Nacional de Investigaciones
Científicas y Técnicas (CONICET), Facultad de Ciencias
Bioquímicas y Farmacéuticas, Universidad Nacional de
Rosario, Suipacha 531, S2002LRK Rosario, Argentina
| | - Ana Foi
- Departamento
de Química Inorgánica, Analítica y Química
Física/INQUIMAE-CONICET, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pabellón 2, C1428EHA Buenos Aires, Argentina
| | - Fabio Doctorovich
- Departamento
de Química Inorgánica, Analítica y Química
Física/INQUIMAE-CONICET, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pabellón 2, C1428EHA Buenos Aires, Argentina
| | - Elodie Anxolabéhère-Mallart
- Laboratoire
d’Electrochimie Moléculaire UMR CNRS-P7 7591, Université
Paris Diderot-Paris, 15 rue Jean-Antoine de Baïf, 75205 Paris Cedex 13, France
| | - Christelle Hureau
- LCC-CNRS,
Université de Toulouse, 205 route de Narbonne, 31077 Toulouse, France
| | - Sandra R. Signorella
- IQUIR
(Instituto de Química Rosario), Consejo Nacional de Investigaciones
Científicas y Técnicas (CONICET), Facultad de Ciencias
Bioquímicas y Farmacéuticas, Universidad Nacional de
Rosario, Suipacha 531, S2002LRK Rosario, Argentina
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8
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Shova S, Vlad A, Cazacu M, Krzystek J, Ozarowski A, Malček M, Bucinsky L, Rapta P, Cano J, Telser J, Arion VB. Dinuclear manganese(iii) complexes with bioinspired coordination and variable linkers showing weak exchange effects: a synthetic, structural, spectroscopic and computation study. Dalton Trans 2019; 48:5909-5922. [DOI: 10.1039/c8dt04596h] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
High-resolution HFEPR indicates weak exchange interactions between MnIII ions in agreement with DFT calculations.
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Affiliation(s)
- Sergiu Shova
- Inorganic Polymers Department
- “Petru Poni” Institute of Macromolecular Chemistry
- Iasi 700487
- Romania
| | - Angelica Vlad
- Inorganic Polymers Department
- “Petru Poni” Institute of Macromolecular Chemistry
- Iasi 700487
- Romania
| | - Maria Cazacu
- Inorganic Polymers Department
- “Petru Poni” Institute of Macromolecular Chemistry
- Iasi 700487
- Romania
| | - J. Krzystek
- National High Magnetic Field Laboratory
- Florida State University
- Tallahassee
- USA
| | - Andrew Ozarowski
- National High Magnetic Field Laboratory
- Florida State University
- Tallahassee
- USA
| | - Michal Malček
- Institute of Physical Chemistry and Chemical Physics
- Slovak University of Technology in Bratislava
- 81237 Bratislava
- Slovak Republic
| | - Lukas Bucinsky
- Institute of Physical Chemistry and Chemical Physics
- Slovak University of Technology in Bratislava
- 81237 Bratislava
- Slovak Republic
| | - Peter Rapta
- Institute of Physical Chemistry and Chemical Physics
- Slovak University of Technology in Bratislava
- 81237 Bratislava
- Slovak Republic
| | - Joan Cano
- Institut de Ciència Molecular
- Universitat de València
- 46980 Paterna
- Spain
| | - Joshua Telser
- Department of Biological
- Physical and Health Sciences
- Roosevelt University
- Chicago
- USA
| | - Vladimir B. Arion
- Institute of Inorganic Chemistry of the University of Vienna
- A1090 Vienna
- Austria
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9
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Ledesma GN, Anxolabéhère-Mallart E, Sabater L, Hureau C, Signorella SR. Functional modeling of the MnCAT active site with a dimanganese(III) complex of an unsymmetrical polydentate N 3 O 3 ligand. J Inorg Biochem 2018; 186:10-16. [DOI: 10.1016/j.jinorgbio.2018.04.023] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2017] [Revised: 04/09/2018] [Accepted: 04/29/2018] [Indexed: 10/16/2022]
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10
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Solís V, Palopoli C, Daier V, Rivière E, Collin F, Moreno DM, Hureau C, Signorella S. Tuning the Mn II2/Mn III2 redox cycle of a phenoxo-bridged diMn catalase mimic with terminal carboxylate donors. J Inorg Biochem 2018; 182:29-36. [PMID: 29407867 DOI: 10.1016/j.jinorgbio.2018.01.013] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2017] [Revised: 01/14/2018] [Accepted: 01/21/2018] [Indexed: 11/27/2022]
Abstract
A new phenoxo-bridged diMnIII complex, Na[Mn2L(OH)2(H2O)2]·5H2O (1), obtained with the ligand L5- = 5‑methyl‑2‑hydroxo‑1,3‑xylene‑α,α‑diamine‑N,N,N',N'‑tetraacetato, has been prepared and characterized. Mass spectrometry, conductivity, UV-visible, EPR and 1H NMR spectroscopic studies showed that the complex exists in solution as a monoanionic diMnIII complex. Complex 1 catalyzes H2O2 disproportionation with second-order rate constant kcat = 305(9) M-1 min-1 and without a time-lag phase. Based on spectroscopic results, the catalase activity of complex 1 in methanol involves a MnIII2/MnII2 redox cycle, which distinguishes this catalyst from other phenoxo-bridged diMn complexes that cycle between MnIIMnIII/MnIIIMnIV species. Addition of base stabilizes the catalyst, restrains demetallation during catalysis and causes moderate enhancement of catalase activity. The terminal carboxylate donors of 1 not only contribute as internal bases to assist deprotonation of H2O2 but also favor the formation of active homovalent diMn species, just as observed for the enzyme.
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Affiliation(s)
- Verónica Solís
- IQUIR (Instituto de Química Rosario), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Suipacha 531, S2002LRK Rosario, Argentina
| | - Claudia Palopoli
- IQUIR (Instituto de Química Rosario), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Suipacha 531, S2002LRK Rosario, Argentina
| | - Verónica Daier
- IQUIR (Instituto de Química Rosario), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Suipacha 531, S2002LRK Rosario, Argentina
| | - Eric Rivière
- Institut de Chimie Moléculaire et des Matériaux d'Orsay, CNRS, Université Paris Sud, Université Paris Saclay, 91405 Orsay Cedex, France
| | - Fabrice Collin
- UPS, INPT, Université de Toulouse, 205 route de Narbonne, F-31077 Toulouse, France; CNRS, LCC (Laboratoire de Chimie de Coordination), France; UMR 152 Pharma Dev, Université de Toulouse, IRD, UPS, France
| | - Diego M Moreno
- IQUIR (Instituto de Química Rosario), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Suipacha 531, S2002LRK Rosario, Argentina
| | - Christelle Hureau
- UPS, INPT, Université de Toulouse, 205 route de Narbonne, F-31077 Toulouse, France; CNRS, LCC (Laboratoire de Chimie de Coordination), France
| | - Sandra Signorella
- IQUIR (Instituto de Química Rosario), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Suipacha 531, S2002LRK Rosario, Argentina.
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11
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Magherusan AM, Zhou A, Farquhar ER, García-Melchor M, Twamley B, Que L, McDonald AR. Mimicking Class I b Mn 2 -Ribonucleotide Reductase: A Mn II2 Complex and Its Reaction with Superoxide. Angew Chem Int Ed Engl 2017; 57:918-922. [PMID: 29165865 DOI: 10.1002/anie.201709806] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2017] [Revised: 11/02/2017] [Indexed: 02/05/2023]
Abstract
A fascinating discovery in the chemistry of ribonucleotide reductases (RNRs) has been the identification of a dimanganese (Mn2 ) active site in class I b RNRs that requires superoxide anion (O2.- ), rather than dioxygen (O2 ), to access a high-valent Mn2 oxidant. Complex 1 ([Mn2 (O2 CCH3 )(N-Et-HPTB)](ClO4 )2 , N-Et-HPTB=N,N,N',N'-tetrakis(2-(1-ethylbenzimidazolyl))-2-hydroxy-1,3-diaminopropane) was synthesised in high yield (90 %). 1 was reacted with O2.- at -40 °C resulting in the formation of a metastable species (2). 2 displayed electronic absorption features (λmax =460, 610 nm) typical of a Mn-peroxide species and a 29-line EPR signal typical of a MnII MnIII entity. Mn K-edge X-ray absorption near-edge spectroscopy (XANES) suggested a formal oxidation state change of MnII2 in 1 to MnII MnIII for 2. Electrospray ionisation mass spectrometry (ESI-MS) suggested 2 to be a MnII MnIII -peroxide complex. 2 was capable of oxidizing ferrocene and weak O-H bonds upon activation with proton donors. Our findings provide support for the postulated mechanism of O2.- activation at class I b Mn2 RNRs.
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Affiliation(s)
- Adriana M Magherusan
- School of Chemistry and CRANN/AMBER Nanoscience Institute, Trinity College Dublin, The University of Dublin, College Green, Dublin 2, Ireland
| | - Ang Zhou
- Department of Chemistry and Center for Metals in Biocatalysis, University of Minnesota, 207 Pleasant St. SE, Minneapolis, MN, 55455, USA
| | - Erik R Farquhar
- Case Western Reserve University Center for Synchrotron Biosciences, National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, NY, 11973, USA
| | - Max García-Melchor
- School of Chemistry and CRANN/AMBER Nanoscience Institute, Trinity College Dublin, The University of Dublin, College Green, Dublin 2, Ireland
| | - Brendan Twamley
- School of Chemistry and CRANN/AMBER Nanoscience Institute, Trinity College Dublin, The University of Dublin, College Green, Dublin 2, Ireland
| | - Lawrence Que
- Department of Chemistry and Center for Metals in Biocatalysis, University of Minnesota, 207 Pleasant St. SE, Minneapolis, MN, 55455, USA
| | - Aidan R McDonald
- School of Chemistry and CRANN/AMBER Nanoscience Institute, Trinity College Dublin, The University of Dublin, College Green, Dublin 2, Ireland
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12
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Magherusan AM, Zhou A, Farquhar ER, García-Melchor M, Twamley B, Que L, McDonald AR. Mimicking Class I b Mn2
-Ribonucleotide Reductase: A MnII
2
Complex and Its Reaction with Superoxide. Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201709806] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Adriana M. Magherusan
- School of Chemistry and CRANN/AMBER Nanoscience Institute; Trinity College Dublin; The University of Dublin; College Green Dublin 2 Ireland
| | - Ang Zhou
- Department of Chemistry and Center for Metals in Biocatalysis; University of Minnesota; 207 Pleasant St. SE Minneapolis MN 55455 USA
| | - Erik R. Farquhar
- Case Western Reserve University Center for Synchrotron Biosciences; National Synchrotron Light Source II, Brookhaven National Laboratory; Upton NY 11973 USA
| | - Max García-Melchor
- School of Chemistry and CRANN/AMBER Nanoscience Institute; Trinity College Dublin; The University of Dublin; College Green Dublin 2 Ireland
| | - Brendan Twamley
- School of Chemistry and CRANN/AMBER Nanoscience Institute; Trinity College Dublin; The University of Dublin; College Green Dublin 2 Ireland
| | - Lawrence Que
- Department of Chemistry and Center for Metals in Biocatalysis; University of Minnesota; 207 Pleasant St. SE Minneapolis MN 55455 USA
| | - Aidan R. McDonald
- School of Chemistry and CRANN/AMBER Nanoscience Institute; Trinity College Dublin; The University of Dublin; College Green Dublin 2 Ireland
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13
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Palopoli C, Duhayon C, Tuchagues JP, Signorella S. Synthesis, characterization, and reactivity studies of a water-soluble bis(alkoxo)(carboxylato)-bridged diMn(III) complex modeling the active site in catalase. Dalton Trans 2015; 43:17145-55. [PMID: 25315041 DOI: 10.1039/c4dt01907e] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A new diMn(III) complex, Na[Mn2(5-SO3-salpentO)(μ-OAc)(μ-OMe)(H2O)]·4H2O, where 5-SO3-salpentOH = 1,5-bis(5-sulphonatosalicylidenamino)pentan-3-ol, has been prepared and characterized. ESI-mass spectrometry, paramagnetic (1)H NMR, EPR and UV-visible spectroscopic studies on freshly prepared solutions of the complex in methanol and 9 : 1 methanol-water mixtures showed that the compound retains the triply bridged bis(μ-alkoxo)(μ-acetato)Mn2(3+) core in solution. In the 9 : 1 methanol-water mixture, slow substitution of acetate by water molecules took place, and after one month, the doubly bridged diMn(III) complex, [Mn2(5-SO3-salpentO)(μ-OMe)(H2O)3]·5H2O, formed and could be characterized by X-ray diffraction analysis. In methanolic or aqueous basic media, acetate shifts from a bridging to a terminal coordination mode, affording the highly stable [Mn2(5-SO3-salpentO)(μ-OMe)(OAc)](-) anion. The efficiency of the complex in disproportionating H2O2 depends on the solvent and correlates with the stability of the complex (towards metal dissociation) in each medium: basic buffer > aqueous base > water. The buffer preserves the integrity of the catalyst and the rate of O2 evolution remains essentially constant after successive additions of excess of H2O2. Turnovers as high as 3000 mol H2O2 per mol of catalyst, without significant decomposition and with an efficiency of k(cat)/K(M) = 1028 M(-1) s(-1), were measured for the complex in aqueous buffers of pH 11. Kinetic and spectroscopic results suggest a catalytic cycle that runs between Mn(III)2 and Mn(IV)2 oxidation states, which is consistent with the low redox potential observed for the Mn(III)2/Mn(III)Mn(IV) couple of the catalyst in basic medium.
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Affiliation(s)
- Claudia Palopoli
- IQUIR (Instituto de Química Rosario), CONICET, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Suipacha 531, (S2002LRK) Rosario, Argentina.
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14
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Singh R, Haukka M, McKenzie CJ, Nordlander E. High Turnover Catalase Activity of a Mixed-Valence MnIIMnIIIComplex with Terminal Carboxylate Donors. Eur J Inorg Chem 2015. [DOI: 10.1002/ejic.201500468] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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15
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Ledesma GN, Eury H, Anxolabéhère-Mallart E, Hureau C, Signorella SR. A new mononuclear manganese(III) complex of an unsymmetrical hexadentate N3O3 ligand exhibiting superoxide dismutase and catalase-like activity: synthesis, characterization, properties and kinetics studies. J Inorg Biochem 2015; 146:69-76. [PMID: 25771435 DOI: 10.1016/j.jinorgbio.2015.02.012] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Revised: 02/20/2015] [Accepted: 02/20/2015] [Indexed: 11/28/2022]
Abstract
A mononuclear Mn(III) complex MnL·4H2O (H3L=1-[N-(2-pyridylmethyl),N-(2-hydroxybenzyl)amino]-3-[N'-(2-hydroxybenzyl),N'-(4-methylbenzyl)amino]propan-2-ol) has been prepared and characterized. This complex catalyzes the dismutation of superoxide efficiently, with catalytic rate constant kcat=1.7×10(6)M(-1)s(-1) and IC50 1.26μM, obtained through the nitro blue tetrazolium photoreduction inhibition superoxide dismutase assay, in aqueous solution of pH7.8. MnL is also able to disproportionate more than 300 equivalents of H2O2 in CH3CN, with initial rate of H2O2 decomposition given by ri=kcat [MnL](2) [H2O2] and kcat=1.32(2)mM(-2)min(-1). The accessibility of the Mn(IV) state (E(p)=0.53V vs. saturated calomel electrode), suggests MnL employs a high-valent catalytic cycle to decompose O2(-) and H2O2.
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Affiliation(s)
- Gabriela N Ledesma
- IQUIR (Instituto de Química Rosario), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Suipacha 531, (S2002LRK), Rosario, Argentina
| | - Hélène Eury
- Laboratoire de Chimie de Coordination, UPR CNRS 8241, 205 Route de Narbonne, 31077 Toulouse Cedex 04, France; Université de Toulouse; UPS, INPT, LCC, F-31077 Toulouse, France
| | - Elodie Anxolabéhère-Mallart
- Laboratoire d'Electrochimie Moléculaire UMR CNRS-P7 7591 Université Paris Diderot-Paris, 15 rue Jean-Antoine de Baïf, 75205 Paris Cedex 13, France
| | - Christelle Hureau
- Laboratoire de Chimie de Coordination, UPR CNRS 8241, 205 Route de Narbonne, 31077 Toulouse Cedex 04, France; Université de Toulouse; UPS, INPT, LCC, F-31077 Toulouse, France
| | - Sandra R Signorella
- IQUIR (Instituto de Química Rosario), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Suipacha 531, (S2002LRK), Rosario, Argentina.
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16
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Gouré E, Carboni M, Dubourdeaux P, Clémancey M, Balasubramanian R, Lebrun C, Bayle PA, Maldivi P, Blondin G, Latour JM. Cis/trans isomerizations in diiron complexes involving aniline or anilide ligands. Inorg Chem 2014; 53:10060-9. [PMID: 25254906 DOI: 10.1021/ic501793v] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We have recently reported a deprotonation-induced valence inversion within a phenoxido-bridged mixed-valent diiron(II,III) complex. The initial aniline coordinated to the Fe(II) site reacts with triethylamine, and the resulting complex contains an anilide ligand coordinated to the Fe(III) ion. The behavior of these complexes in acetonitrile is indeed more intricate. Owing to the very distinctive spectroscopic signatures of the complexes, the conjunction of NMR, Mössbauer, and UV-visible absorption spectroscopies allows one to evidence two isomerization reactions, one involving the aniline linked to Fe(II) and the other the anilide on Fe(III). Theoretical calculations sustain this conclusion. Aniline in the cis position versus the bridging phenoxide is shown to be the most stable isomer while the anilide trans to the phenoxido bridge is favored. The trans isomer of the aniline complex is more acidic than the cis one by 1 pKa unit. Isomerization of the anilide complex is 10 times faster than the analogous isomerization of the aniline complex. Both reactions are proposed to proceed through a unique mechanism. This is the first time that such isomerization reactions are evidenced in dinuclear complexes.
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Affiliation(s)
- Eric Gouré
- CEA, iRTSV/LCBM, pmb , F-38000 Grenoble, France
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17
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Ledesma GN, Anxolabéhère-Mallart E, Rivière E, Mallet-Ladeira S, Hureau C, Signorella SR. Trinuclear Manganese Complexes of Unsymmetrical Polypodal Diamino N3O3 Ligands with an Unusual [Mn3(μ-OR)4]5+ Triangular Core: Synthesis, Characterization, and Catalase Activity. Inorg Chem 2014; 53:2545-53. [DOI: 10.1021/ic402843y] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Gabriela N. Ledesma
- IQUIR (Instituto de Química Rosario),
Consejo Nacional de Investigaciones Científicas y Técnicas
(CONICET), Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Suipacha 531, S2002LRK Rosario, Argentina
| | - Elodie Anxolabéhère-Mallart
- Laboratoire Electrochimie
Moléculaire-UMR CNRS 7591, University of Paris Diderot, Sorbonne
Paris Cité15 rue Jean de Baïf, 75251 Paris, Cedex 13, France
| | - Eric Rivière
- ICMMO-UMR 8182, Equipe Chimie Inorganique, Université Paris-Sud, 91405 Orsay, France
| | - Sonia Mallet-Ladeira
- Institut de Chimie de Toulouse, FR 2599, 118 Route de Narbonne, F-31062 Toulouse, France
| | - Christelle Hureau
- CNRS, LCC (Laboratoire
de Chimie de Coordination) and UPS, INPT,
LCC, Université de Toulouse, 205 route de Narbonne, F-31077 Toulouse, France
| | - Sandra R. Signorella
- IQUIR (Instituto de Química Rosario),
Consejo Nacional de Investigaciones Científicas y Técnicas
(CONICET), Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Suipacha 531, S2002LRK Rosario, Argentina
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18
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Daumann LJ, Schenk G, Ollis DL, Gahan LR. Spectroscopic and mechanistic studies of dinuclear metallohydrolases and their biomimetic complexes. Dalton Trans 2013; 43:910-28. [PMID: 24135968 DOI: 10.1039/c3dt52287c] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
An enhanced understanding of the metal ion binding and active site structural features of phosphoesterases such as the glycerophosphodiesterase from Enterobacter aerogenes (GpdQ), and the organophosphate degrading agent from Agrobacterium radiobacter (OpdA) have important consequences for potential applications. Coupled with investigations of the metalloenzymes, programs of study to synthesise and characterise model complexes based on these metalloenzymes can add to our understanding of structure and function of the enzymes themselves. This review summarises some of our work and illustrates the significance and contributions of model studies to knowledge in the area.
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Affiliation(s)
- Lena J Daumann
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD 4072, Australia.
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19
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Lin H, Wang JG, Shi HT, Chen Q, Zhang QF. Chlorido[2,2'-[1,2-phenyl-enebis(nitrilo-methanylyl-idyne)]diphenolato-κ(4) O,N,N',O']manganese(III) methanol monosolvate. Acta Crystallogr Sect E Struct Rep Online 2013; 69:m404. [PMID: 24046575 PMCID: PMC3772432 DOI: 10.1107/s1600536813016450] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2013] [Accepted: 06/13/2013] [Indexed: 12/01/2022]
Abstract
In the title complex, [Mn(C20H14N2O2)Cl]·CH3OH, the central MnIII atom displays a distorted square-pyramidal coordination by two N and two O atoms from the tetradentate 2,2′-[1,2-phenylenebis(nitrilomethanylylidyne)]diphenolate ligand and one chloride ligand. The MnIII atom is 0.525 (4) Å out of the square basal N2O2 least-squares plane. The complex molecule is hydrogen bonded to the methanol solvent molecule.
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Affiliation(s)
- Hui Lin
- Institute of Molecular Engineering and Applied Chemsitry, Anhui University of Technology, Ma'anshan, Anhui 243002, People's Republic of China
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20
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Jana A, Aliaga-Alcalde N, Ruiz E, Mohanta S. Structures, Magnetochemistry, Spectroscopy, Theoretical Study, and Catechol Oxidase Activity of Dinuclear and Dimer-of-Dinuclear Mixed-Valence MnIIIMnII Complexes Derived from a Macrocyclic Ligand. Inorg Chem 2013; 52:7732-46. [DOI: 10.1021/ic400916h] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Arpita Jana
- Department of Chemistry, University of Calcutta, 92 A. P. C. Road, Kolkata 700
009, India
| | - Núria Aliaga-Alcalde
- Institució Catalana de Recerca i Estudis Avançats (ICREA), Institut de Ciència de Materials de Barcelona (ICMAB-CSIC)
Campus de la UAB, 08193 Bellaterra, Spain
| | - Eliseo Ruiz
- Departament de Química Inorgànica and
Institut de Recerca de Química Teòrica i Computacional, Universitat de Barcelona, Diagonal 645, E-08028 Barcelona,
Spain
| | - Sasankasekhar Mohanta
- Department of Chemistry, University of Calcutta, 92 A. P. C. Road, Kolkata 700
009, India
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21
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Daumann LJ, Marty L, Schenk G, Gahan LR. Asymmetric zinc(ii) complexes as functional and structural models for phosphoesterases. Dalton Trans 2013; 42:9574-84. [DOI: 10.1039/c3dt50514f] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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22
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Tomter AB, Zoppellaro G, Andersen NH, Hersleth HP, Hammerstad M, Røhr ÅK, Sandvik GK, Strand KR, Nilsson GE, Bell CB, Barra AL, Blasco E, Le Pape L, Solomon EI, Andersson KK. Ribonucleotide reductase class I with different radical generating clusters. Coord Chem Rev 2013. [DOI: 10.1016/j.ccr.2012.05.021] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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23
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Carboni M, Clémancey M, Molton F, Pécaut J, Lebrun C, Dubois L, Blondin G, Latour JM. Biologically relevant heterodinuclear iron-manganese complexes. Inorg Chem 2012; 51:10447-60. [PMID: 22989001 DOI: 10.1021/ic301725z] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The heterodinuclear complexes [Fe(III)Mn(II)(L-Bn)(μ-OAc)(2)](ClO(4))(2) (1) and [Fe(II)Mn(II)(L-Bn)(μ-OAc)(2)](ClO(4)) (2) with the unsymmetrical dinucleating ligand HL-Bn {[2-bis[(2-pyridylmethyl)aminomethyl]]-6-[benzyl-2-(pyridylmethyl)aminomethyl]-4-methylphenol} were synthesized and characterized as biologically relevant models of the new Fe/Mn class of nonheme enzymes. Crystallographic studies have been completed on compound 1 and reveal an Fe(III)Mn(II)μ-phenoxobis(μ-carboxylato) core. A single location of the Fe(III) ion in 1 and of the Fe(II) ion in 2 was demonstrated by Mössbauer and (1)H NMR spectroscopies, respectively. An investigation of the temperature dependence of the magnetic susceptibility of 1 revealed a moderate antiferromagnetic interaction (J = 20 cm(-1)) between the high-spin Fe(III) and Mn(II) ions in 1, which was confirmed by Mössbauer and electron paramagnetic resonance (EPR) studies. The electrochemical properties of complex 1 are described. A quasireversible electron transfer at -40 mV versus Ag/AgCl corresponding to the Fe(III)Mn(II)/Fe(II)Mn(II) couple appears in the cyclic voltammogram. Thorough investigations of the Mössbauer and EPR signatures of complex 2 were performed. The analysis allowed evidencing of a weak antiferromagnetic interaction (J = 5.72 cm(-1)) within the Fe(II)Mn(II) pair consistent with that deduced from magnetic susceptibility measurements (J = 6.8 cm(-1)). Owing to the similar value of the Fe(II) zero-field splitting (D(Fe) = 3.55 cm(-1)), the usual treatment within the strong exchange limit was precluded and a full analysis of the electronic structure of the ground state of complex 2 was developed. This situation is reminiscent of that found in many diiron and iron-manganese enzyme active sites.
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Affiliation(s)
- Michaël Carboni
- Laboratoire de Chimie et Biologie des Métaux-pmb, UMR 5249, Université Joseph Fourier-Grenoble 1/CEA-DSV-iRTSV/CNRS, Grenoble F-38054, France
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24
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Wang RX, Gao DZ, Ye F, Wu YF, Zhu DR. 3-{[Bis(pyridin-2-ylmeth-yl)amino]-meth-yl}-2-hy-droxy-5-methyl-benz-aldehyde. Acta Crystallogr Sect E Struct Rep Online 2012; 68:o1672-3. [PMID: 22719467 PMCID: PMC3379269 DOI: 10.1107/s1600536812019940] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2012] [Accepted: 05/03/2012] [Indexed: 11/20/2022]
Abstract
In the title compound, C21H21N3O2, the pyridine rings and the benzene ring lie in a propeller arrangement around the central tertiary amine N atom. The dihedral angles formed by the benzene ring with the pyridine rings are 61.0 (3) and 49.6 (3)°, while the dihedral angle between the pyridine rings is 69.7 (3)°. The molecular conformation is stabilized by intramolecular bifurcated O—H⋯N hydrogen bonds. In the crystal, inversion dimers are formed via pairs of C—H⋯N hydrogen bonds.
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Affiliation(s)
- Ruo-Xu Wang
- College of Chemistry and Chemical Engineering, State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing University of Technology, Nanjing 210009, People's Republic of China
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25
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26
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Xie QW, Chen X, Hu KQ, Wang YT, Cui AL, Kou HZ. Mixed-valence trinuclear manganese(II/III) complexes of flexible tetradentate N2O2 ligands: Ferromagnetic versus antiferromagnetic coupling. Polyhedron 2012. [DOI: 10.1016/j.poly.2012.03.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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27
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Arora H, Barman SK, Lloret F, Mukherjee R. Isostructural Dinuclear Phenoxo-/Acetato-Bridged Manganese(II), Cobalt(II), and Zinc(II) Complexes with Labile Sites: Kinetics of Transesterification of 2-Hydroxypropyl-p-nitrophenylphosphate. Inorg Chem 2012; 51:5539-53. [DOI: 10.1021/ic201971t] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Himanshu Arora
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur 208 016, India
| | - Suman K. Barman
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur 208 016, India
| | - Francesc Lloret
- Departament de Quı́mica Inorgànica/Instituto de
Ciencia Molecular (ICMOL), Universitat de València, Polígono de la Coma, s/n, 46980-Paterna
(València), Spain
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28
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Palopoli C, Bruzzo N, Hureau C, Ladeira S, Murgida D, Signorella S. Synthesis, Characterization, and Catalase Activity of a Water-Soluble diMnIII Complex of a Sulphonato-Substituted Schiff Base Ligand: An Efficient Catalyst for H2O2 Disproportionation. Inorg Chem 2011; 50:8973-83. [DOI: 10.1021/ic2011452] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Affiliation(s)
- Claudia Palopoli
- Departamento de Química Física/IQUIR-CONICET, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Suipacha 531, S2002LRK Rosario, Argentina
| | - Natalia Bruzzo
- Departamento de Química Física/IQUIR-CONICET, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Suipacha 531, S2002LRK Rosario, Argentina
| | - Christelle Hureau
- CNRS, LCC (Laboratoire de Chimie de Coordination), 205, route de Narbonne, F-31077 Toulouse, France and Université de Toulouse, UPS, INPT, LCC, F-31077 Toulouse, France
| | - Sonia Ladeira
- CNRS, LCC (Laboratoire de Chimie de Coordination), 205, route de Narbonne, F-31077 Toulouse, France and Université de Toulouse, UPS, INPT, LCC, F-31077 Toulouse, France
- Institut de Chimie de Toulouse, FR2599, 118 route de Narbonne, F-31062 Toulouse, France
| | - Daniel Murgida
- Departamento de Química Inorgánica, Analítica y Química Física/INQUIMAE-CONICET, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pabellón 2, Buenos Aires C1428EHA, Argentina
| | - Sandra Signorella
- Departamento de Química Física/IQUIR-CONICET, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Suipacha 531, S2002LRK Rosario, Argentina
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29
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30
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Madhu V, Ekambaram B, Shimon LJW, Diskin Y, Leitus G, Neumann R. Structural diversity in manganese, iron and cobalt complexes of the ditopic 1,2-bis(2,2′-bipyridyl-6-yl)ethyne ligand and observation of epoxidation and catalase activity of manganese compounds. Dalton Trans 2010; 39:7266-75. [DOI: 10.1039/b925129d] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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31
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Berggren G, Huang P, Eriksson L, Styring S, Anderlund MF, Thapper A. Synthesis and characterisation of low valent Mn-complexes as models for Mn-catalases. Dalton Trans 2010; 39:11035-44. [DOI: 10.1039/c0dt00165a] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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32
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Smith SJ, Riley MJ, Noble CJ, Hanson GR, Stranger R, Jayaratne V, Cavigliasso G, Schenk G, Gahan LR. Structural and Catalytic Characterization of a Heterovalent Mn(II)Mn(III) Complex That Mimics Purple Acid Phosphatases. Inorg Chem 2009; 48:10036-48. [DOI: 10.1021/ic9005086] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
| | | | - Christopher J. Noble
- Centre for Magnetic Resonance, The University of Queensland, Brisbane 4072, Australia
| | - Graeme R. Hanson
- Centre for Magnetic Resonance, The University of Queensland, Brisbane 4072, Australia
| | - Robert Stranger
- Research School of Chemistry, Australian National University, Canberra 0200, Australia
| | - Vidura Jayaratne
- Research School of Chemistry, Australian National University, Canberra 0200, Australia
| | - Germán Cavigliasso
- Research School of Chemistry, Australian National University, Canberra 0200, Australia
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33
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Banerjee A, Ganguly S, Chattopadhyay T, Sabnam Banu K, Patra A, Bhattacharya S, Zangrando E, Das D. Metal-Assisted Oxazolidine/Oxazine Ring Formation in Dinuclear Zinc(II) Complexes: Synthesis, Structural Aspects, and Bioactivity. Inorg Chem 2009; 48:8695-702. [DOI: 10.1021/ic900643h] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Arpita Banerjee
- Department of Chemistry, University of Calcutta, 92 A. P. C. Road, Kolkata 700009, India
| | - Subhalakshmi Ganguly
- Chittaranjan National Cancer Institute, 37 S. P. Mukherjee Road, Kolkata 700026, India
| | - Tanmay Chattopadhyay
- Department of Chemistry, University of Calcutta, 92 A. P. C. Road, Kolkata 700009, India
| | - Kazi Sabnam Banu
- Department of Chemistry, University of Calcutta, 92 A. P. C. Road, Kolkata 700009, India
| | - Amarendra Patra
- Department of Chemistry, University of Calcutta, 92 A. P. C. Road, Kolkata 700009, India
| | - Santanu Bhattacharya
- Department of Chemistry, Maharaja Manindra Chandra College, Kolkata 700003, India
| | - Ennio Zangrando
- Dipartimento di Scienze Chimiche, University of Trieste, Via L. Giorgieri 1, 34127 Trieste, Italy
| | - Debasis Das
- Department of Chemistry, University of Calcutta, 92 A. P. C. Road, Kolkata 700009, India
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34
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Collomb M, Deronzier A. Electro‐ and Photoinduced Formation and Transformation of Oxido‐Bridged Multinuclear Mn Complexes. Eur J Inorg Chem 2009. [DOI: 10.1002/ejic.200801141] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Marie‐Noëlle Collomb
- Université Joseph Fourier Grenoble 1/CNRS, Département de Chimie Moléculaire, UMR‐5250, Institut de Chimie Moléculaire de Grenoble FR‐CNRS‐2607, Laboratoire de Chimie Inorganique Redox B. P. 53, 38041 Grenoble Cedex 9, France
| | - Alain Deronzier
- Université Joseph Fourier Grenoble 1/CNRS, Département de Chimie Moléculaire, UMR‐5250, Institut de Chimie Moléculaire de Grenoble FR‐CNRS‐2607, Laboratoire de Chimie Inorganique Redox B. P. 53, 38041 Grenoble Cedex 9, France
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35
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Biava H, Palopoli C, Duhayon C, Tuchagues JP, Signorella S. Synthesis, Structure, and Catalase-Like Activity of Dimanganese(III) Complexes of 1,5-Bis[(2-hydroxy-5-X-benzyl)(2-pyridylmethyl)amino]pentan-3-ol (X = H, Br, OCH3). Inorg Chem 2009; 48:3205-14. [DOI: 10.1021/ic8019793] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Hernán Biava
- Instituto de Química Rosario - CONICET, Universidad Nacional de Rosario, Suipacha 531, S2002LRK Rosario, Argentina, and Laboratoire de Chimie de Coordination, UPR CNRS 8241, 205 Route de Narbonne, 31077 Toulouse Cedex 04, France
| | - Claudia Palopoli
- Instituto de Química Rosario - CONICET, Universidad Nacional de Rosario, Suipacha 531, S2002LRK Rosario, Argentina, and Laboratoire de Chimie de Coordination, UPR CNRS 8241, 205 Route de Narbonne, 31077 Toulouse Cedex 04, France
| | - Carine Duhayon
- Instituto de Química Rosario - CONICET, Universidad Nacional de Rosario, Suipacha 531, S2002LRK Rosario, Argentina, and Laboratoire de Chimie de Coordination, UPR CNRS 8241, 205 Route de Narbonne, 31077 Toulouse Cedex 04, France
| | - Jean-Pierre Tuchagues
- Instituto de Química Rosario - CONICET, Universidad Nacional de Rosario, Suipacha 531, S2002LRK Rosario, Argentina, and Laboratoire de Chimie de Coordination, UPR CNRS 8241, 205 Route de Narbonne, 31077 Toulouse Cedex 04, France
| | - Sandra Signorella
- Instituto de Química Rosario - CONICET, Universidad Nacional de Rosario, Suipacha 531, S2002LRK Rosario, Argentina, and Laboratoire de Chimie de Coordination, UPR CNRS 8241, 205 Route de Narbonne, 31077 Toulouse Cedex 04, France
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36
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Castaman ST, Nakagaki S, Ribeiro RR, Ciuffi KJ, Drechsel SM. Homogeneous and heterogeneous olefin epoxidation catalyzed by a binuclear Mn(II)Mn(III) complex. ACTA ACUST UNITED AC 2009. [DOI: 10.1016/j.molcata.2008.10.037] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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37
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A novel (μ-OAc)2 bridged unsymmetric coordinated binuclear Mn(II) macrocyclic complex with ligating pendant-arm. INORG CHEM COMMUN 2008. [DOI: 10.1016/j.inoche.2008.09.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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38
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Lu YB, Wang MS, Zhou WW, Xu G, Guo GC, Huang JS. Novel 3-D PtS-like Tetrazolate-Bridged Manganese(II) Complex Exhibiting Spin-Canted Antiferromagnetism and Field-Induced Spin-Flop Transition. Inorg Chem 2008; 47:8935-42. [DOI: 10.1021/ic801026y] [Citation(s) in RCA: 92] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Ying-Bing Lu
- State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002, Peopleʼs Republic of China, and Graduate School of the Chinese Academy of Sciences, Beijing 100039, Peopleʼs Republic of China
| | - Ming-Sheng Wang
- State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002, Peopleʼs Republic of China, and Graduate School of the Chinese Academy of Sciences, Beijing 100039, Peopleʼs Republic of China
| | - Wei-Wei Zhou
- State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002, Peopleʼs Republic of China, and Graduate School of the Chinese Academy of Sciences, Beijing 100039, Peopleʼs Republic of China
| | - Gang Xu
- State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002, Peopleʼs Republic of China, and Graduate School of the Chinese Academy of Sciences, Beijing 100039, Peopleʼs Republic of China
| | - Guo-Cong Guo
- State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002, Peopleʼs Republic of China, and Graduate School of the Chinese Academy of Sciences, Beijing 100039, Peopleʼs Republic of China
| | - Jin-Shun Huang
- State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002, Peopleʼs Republic of China, and Graduate School of the Chinese Academy of Sciences, Beijing 100039, Peopleʼs Republic of China
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39
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Wang JP, Ma PT, Li J, Niu HY, Niu JY. Self-Assembly of [B-SbW9O33]9− Subunit with Transition Metal Ions (Mn2+, Cu2+, Co2+) in Aqueous Solution: Syntheses, Structures and Magnetic Properties of Sandwich Type Polyoxometalates with Subvalent SbIII Heteroatom. Chem Asian J 2008; 3:822-33. [DOI: 10.1002/asia.200700363] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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40
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Dubois L, Pécaut J, Charlot MF, Baffert C, Collomb MN, Deronzier A, Latour JM. Carboxylate Ligands Drastically Enhance the Rates of Oxo Exchange and Hydrogen Peroxide Disproportionation by Oxo Manganese Compounds of Potential Biological Significance. Chemistry 2008; 14:3013-25. [DOI: 10.1002/chem.200701253] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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41
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Dubois L, Jacquamet L, Pécaut J, Latour JM. X-ray photoreduction of a di(mu-oxo)Mn(III)Mn(IV) complex occurs at temperatures as low as 20 K. Chem Commun (Camb) 2007:4521-3. [PMID: 17283805 DOI: 10.1039/b609072a] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Full reduction of the Mn(III)(mu-O)2Mn(IV) core to Mn(II)(mu-OH2)2Mn(II) is observed upon irradiation by an X-ray beam at ca. 20 K.
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Affiliation(s)
- Lionel Dubois
- Laboratoire DRDCIPMB, UMR 5155 CEA-CNRS- UJF, CEA-Grenoble, 38054 Grenoble Cedex 9, France
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43
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Anderlund MF, Zheng J, Ghiladi M, Kritikos M, Rivière E, Sun L, Girerd JJ, Åkermark B. A new, dinuclear high spin manganese(III) complex with bridging phenoxy and methoxy groups. Structure and magnetic properties. INORG CHEM COMMUN 2006. [DOI: 10.1016/j.inoche.2006.07.025] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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44
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Anderlund MF, Högblom J, Shi W, Huang P, Eriksson L, Weihe H, Styring S, Åkermark B, Lomoth R, Magnuson A. Redox Chemistry of a Dimanganese(II,III) Complex with an Unsymmetric Ligand: Water Binding, Deprotonation and Accumulative Light-Induced Oxidation. Eur J Inorg Chem 2006. [DOI: 10.1002/ejic.200600676] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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45
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Structure and characterization of a μ-phenoxo-bis μ-acetato dinuclear Mn(II,II) complex [Mn2(LO)(μ-OAc)2](ClO4) (LOH=2,6-bis{bis(2-(2-pyridyl)ethyl)aminomethyl}-4-methylphenol): Substituent effects. Inorganica Chim Acta 2006. [DOI: 10.1016/j.ica.2006.05.040] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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46
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Moreno D, Palopoli C, Daier V, Shova S, Vendier L, Sierra MG, Tuchagues JP, Signorella S. Synthesis, structure and catalase-like activity of dimanganese(III) complexes of 1,5-bis(X-salicylidenamino)pentan-3-ol (X = 3- and 5-methyl). Influence of phenyl-ring substituents on catalytic activity. Dalton Trans 2006:5156-66. [PMID: 17077889 DOI: 10.1039/b609366c] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The diMn(III) complexes [Mn2(5-Me-salpentO)(mu-MeO)(mu-AcO)(H2O)Br] (1) and [Mn2(3-Me-salpentO)(mu-MeO)(mu-AcO)(MeOH)2]Br (2), where salpentOH = 1,5-bis(salicylidenamino)pentan-3-ol, were synthesised and structurally characterized. The two complexes include a bis(micro-alkoxo)(micro-acetato) triply-bridged diMn(III) core with an Mn...Mn separation of 2.93-2.94 A, the structure of which is retained upon dissolution. Complexes 1 and 2 show catalytic activity toward disproportionation of H2O2, with first-order dependence on the catalyst, and saturation kinetics on [H2O2], in methanol and DMF. In DMF, the two complexes are able to disproportionate at least 1500 eq. of H2O2 without significant decomposition, while in methanol, they rapidly lose activity with formation of a non-coupled Mn(II) species. Electrospray ionisation mass spectrometry, EPR and UV/vis spectroscopy used to monitor the reaction suggest that the major active form of the catalyst occurs in the Mn2(III) oxidation state during cycling. The correlation between log(k(cat)) and the redox potentials of 1, 2 and analogous complexes of other X-salpentOH derivatives indicates that, in this series, the oxidation of the catalyst is probably the rate-limiting step in the catalytic cycle. It is also noted that formation of the catalyst-peroxide adduct is more sensitive to steric effects in DMF than in methanol. Overall, kinetics and spectroscopic studies of H2O2 dismutation by these complexes converge at a catalytic cycle that involves the Mn2(III) and Mn2(IV) oxidation states.
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Affiliation(s)
- Diego Moreno
- Departamento de Química, Facultad de Ciencias Bioquímicas y Farmacéuticas, UNR, Suipacha 531, 2000, Rosario, Argentina
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47
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Larsen FB, Boisen A, Berry KJ, Moubaraki B, Murray KS, McKee V, Scarrow RC, McKenzie CJ. Identification of the Dinuclear and Tetranuclear Air‐Oxidized Products Derived from Labile Phenolate‐Bridged Dimanganese(II) Pyridyl‐Chelate Compounds. Eur J Inorg Chem 2006. [DOI: 10.1002/ejic.200600488] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Frank Bartnik Larsen
- Department of Physics and Chemistry, University of Southern Denmark, Odense Campus, 5230 Odense M, Denmark, Fax: +45‐6615‐8780
| | - Astrid Boisen
- Department of Physics and Chemistry, University of Southern Denmark, Odense Campus, 5230 Odense M, Denmark, Fax: +45‐6615‐8780
| | - Kevin J. Berry
- Westernport Secondary College, Hastings, Victoria 3915, Australia
| | - Boujemaa Moubaraki
- School of Chemistry, Building 23, Monash University, Clayton, Victoria 3800, Australia
| | - Keith S. Murray
- School of Chemistry, Building 23, Monash University, Clayton, Victoria 3800, Australia
| | - Vickie McKee
- Chemistry Department, Loughborough University, Loughborough, UK
| | - Robert C. Scarrow
- Department of Chemistry, Haverford College, 370 Lancaster Ave., Haverford, PA 19041‐1392, USA
| | - Christine J. McKenzie
- Department of Physics and Chemistry, University of Southern Denmark, Odense Campus, 5230 Odense M, Denmark, Fax: +45‐6615‐8780
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48
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Huang P, Shaikh N, Anderlund MF, Styring S, Hammarström L. Consistent simulation of X- and Q-band EPR spectra of an unsymmetric dinuclear Mn2II,III complex. J Inorg Biochem 2006; 100:1139-46. [PMID: 16574232 DOI: 10.1016/j.jinorgbio.2006.02.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2005] [Revised: 02/14/2006] [Accepted: 02/14/2006] [Indexed: 10/24/2022]
Abstract
Simulation of X- and Q-band electron paramagnetic resonance (EPR) spectra of an unsymmetric dinuclear [Mn(2)(II,III)L(mu-OAc)(2)]ClO(4) complex (1), (L is the dianion of 2-{[N,N-bis(2-pyridylmethyl)amino]methyl}-6-{[N-(3,5-di-tert-butyl-2-hydroxybenzyl)-N-(2-pyridylmethyl)amino]methyl}-4-methylphenol) was performed using one consistent set of simulation parameters. Rhombic g-tensors and hyperfine tensors were necessary to obtain satisfactory simulation of the EPR spectra. The anisotropy of the effective hyperfine tensors of each individual (55)Mn ion was further analyzed in terms of intrinsic hyperfine tensors. Detailed analysis shows that the hyperfine anisotropy of the Mn(III) ion is a result of the Jahn-Teller effect and thus an inherent character. In contrast, the anomalous hyperfine anisotropy of the Mn(II) ion is attributed as being transferred from the Mn(III) ion through the spin exchange interaction. The anisotropy parameter for the Mn(II) is deduced as D(II)=-1.26+/-0.2cm(-1). This is the first reported D(II) value for a Mn(II) ion in a weakly exchange coupled mixed-valence Mn(2)(II,III) complex with a bis-mu-acetato-bridge. The [see text] electronic configuration of the Mn(III) ion in 1 is revealed by the negative sign of its intrinsic hyperfine tensor anisotropy, Deltaa(III)=a(z)-a(x,y)=-46cm(-1). Lower spectral resolution of the Q-band EPR spectrum as compared to the X-band EPR spectrum is associated to large line width broadening of the x- and y-components in contrast to the z-component. The origins of the unequal distribution of line width between the z- and x-, y-components are discussed.
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Affiliation(s)
- Ping Huang
- Molecular Biomimetics, Department of Photochemistry and Molecular Science, Uppsala University, Villavägen 6, S-75236 Uppsala, Sweden.
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49
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Mitra K, Biswas S, Lucas CR, Adhikary B. Manganese(III) complexes of N2O2 donor 5-bromosalicylideneimine ligands: Combined effects of electron withdrawing substituents and chelate ring size variations on electrochemical properties. Inorganica Chim Acta 2006. [DOI: 10.1016/j.ica.2006.01.013] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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50
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Gultneh Y, Tesema YT, Yisgedu TB, Butcher RJ, Wang G, Yee GT. Studies of a Dinuclear Manganese Complex with Phenoxo and Bis-acetato Bridging in the Mn2(II,II) and Mn2(II,III) States: Coordination Structural Shifts and Oxidation State Control in Bridged Dinuclear Complexes. Inorg Chem 2006; 45:3023-33. [PMID: 16562958 DOI: 10.1021/ic060039q] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The dinucleating ligand, 2,6-bis{[(2-(2-pyridyl)ethyl)(2-pyridylmethyl)-amino]-methyl}-4-methylphenol) (L1OH) reacts with Mn(ClO4)2.6H2O to form the dinuclear complex [Mn2(II,II)(L1O)(mu-OOCCH3)2]ClO4 (1). The electrolytic oxidation of 1 at 0.7 V (vs Ag/AgCl) produces the mixed valent complex [Mn2(II,III)(L1O)(mu-OOCCH3)2](ClO4)2 (1ox) quantitatively, while electrolysis at 0.20 V converts 1ox back to 1. X-ray crystallographic structures show that both 1 and 1ox are dinuclear complexes in which the two manganese ions are each in distorted octahedral coordination environments bridged by the phenoxo oxygen and two acetate ions. The structural changes that occur upon the oxidation 1 to 1ox suggest an extended pi-bonding system involving the phenoxo ring C-O(phenoxo)-Mn(II)-N(pyridyl) chain. In addition, as 1 is oxidized to 1ox, the rearrangements in the coordination sphere resulting from the oxidation of one Mn(II) ion to Mn(III) are transmitted via the bridging Mn-O(phenoxo) bonds and cause structural changes that render the site of the second manganese ion unfit for the +3 state and hence unstable to reduction. Thus the electrolytic oxidation of 1ox in acetonitrile at 1.20 V takes up slightly greater than 1 F of charge/mol of 1ox, but the starting complex, 1ox, is recovered, showing the instability of the Mn2(III,III) state that is formed with respect to reduction to 1ox. Variable-temperature magnetic susceptibility measurements of 1 and 1ox over the temperature range from 1.8 to 300 K can be modeled with magnetic coupling constants J = -4.3 and -4.1 cm(-1), respectively showing the weak antiferromagnetic coupling between the two manganese ions in each dinuclear complex, which is commonly observed among similar phenoxo- and bis-1,3-carboxylato-bridged dinuclear Mn2(II,II) and Mn2(II,III) complexes.
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Affiliation(s)
- Yilma Gultneh
- Department of Chemistry, Howard University, Washington, DC 20059, USA.
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