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Synthesis and electron paramagnetic resonance studies of seven coordinated Mn(II) complexes with tridentate N-donor ligands. Polyhedron 2018. [DOI: 10.1016/j.poly.2018.08.014] [Citation(s) in RCA: 4] [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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Escriche-Tur L, Font-Bardia M, Albela B, Corbella M. Determination of ZFS parameters from the EPR spectra of mono-, di- and trinuclear Mn II complexes: impact of magnetic coupling. Dalton Trans 2017; 46:2699-2714. [PMID: 28170010 DOI: 10.1039/c6dt04012h] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A family of new MnII compounds, consisting of seven dinuclear, three mononuclear, and four trinuclear ones, were synthesised using benzoic acid derivatives n-RC6H4COOH, where n-R = 2-MeO, 3-MeO, 4-MeO, or 4-tBu, and 2,2'-bipyridine (bpy) or 1,10-phenantroline (phen) as blocking ligands. The crystal structures of nine of these compounds and the magnetic studies of all of them are reported here. Each type of compound was formed depending on the presence or absence of ClO4- ions, the solvent used, and/or the presence of a small amount of water in the reaction medium. The use of the tert-buthylbenzoate ligand gave unexpected results, very likely due to the steric hindrance caused by the voluminous tBu groups. The EPR spectra of each type of compound give some peculiar features that allow its identification. Attempts to fit these spectra have been made in order to determine the ZFS parameters, D and E, of the MnII ion (for mononuclear and dinuclear systems) or of the ground state (for trinuclear systems). For trinuclear systems, the single-ion ZFS parameters estimated from those of the ground state provided a good simulation of the EPR spectra of these compounds. The EPR signals observed in each case have been rationalised according to the energy level distribution and the plausible population in the excited states. In some particular situations, the sign of DMn could be determined from the fit of the EPR spectra of the antiferromagnetic dinuclear compounds, the source of the difference between the spectra lying in the second excited state.
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Affiliation(s)
- Luis Escriche-Tur
- Departament de Química Inorgànica i Orgànica (Secció inorgánica), Universitat de Barcelona, C/Martí i Franquès 1-11, 08028 Barcelona, Spain. and Laboratoire de Chimie, ENS de Lyon, Université de Lyon, 46 Allée d'Italie, 69364 Lyon Cedex 07, France
| | - Mercè Font-Bardia
- Cristal·lografia, Mineralogia i Dipòsits Minerals, Universitat de Barcelona, Martí i Franquès s/n, 08028 Barcelona, Spain
| | - Belén Albela
- Laboratoire de Chimie, ENS de Lyon, Université de Lyon, 46 Allée d'Italie, 69364 Lyon Cedex 07, France
| | - Montserrat Corbella
- Departament de Química Inorgànica i Orgànica (Secció inorgánica), Universitat de Barcelona, C/Martí i Franquès 1-11, 08028 Barcelona, Spain. and Institud de Nanociència i Nanotecnologia de la Universitat de Barcelona (IN2UB), Av. Joan XXIII s/n, 08028 Barcelona, Spain
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Saad A, Zhu W, Rousseau G, Mialane P, Marrot J, Haouas M, Taulelle F, Dessapt R, Serier-Brault H, Rivière E, Kubo T, Oldfield E, Dolbecq A. Polyoxomolybdate Bisphosphonate Heterometallic Complexes: Synthesis, Structure, and Activity on a Breast Cancer Cell Line. Chemistry 2015; 21:10537-47. [DOI: 10.1002/chem.201406565] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2014] [Revised: 03/12/2015] [Indexed: 01/15/2023]
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Palion-Gazda J, Machura B, Klemens T, Kłak J. Pseudohalide manganese(II) complexes of 2-hydroxymethylbenzimidazole – Synthesis, spectroscopy, X-ray structure and magnetic properties. Polyhedron 2014. [DOI: 10.1016/j.poly.2014.06.020] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Azarkh M, Penkova LV, Kats SV, Varzatskii OA, Voloshin YZ, Groenen EJJ. A Mononuclear Mn(II) Pseudoclathrochelate Complex Studied by Multi-Frequency Electron-Paramagnetic-Resonance Spectroscopy. J Phys Chem Lett 2014; 5:886-889. [PMID: 26274083 DOI: 10.1021/jz5000963] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Knowledge of the correlation between structural and spectroscopic properties of transition-metal complexes is essential to deepen the understanding of their role in catalysis, molecular magnetism, and biological inorganic chemistry. It provides topological and, sometimes, functional insight with respect to the active site properties of metalloproteins. The electronic structure of a high-spin mononuclear Mn(II) pseudoclathrochelate complex has been investigated by electron-paramagnetic-resonance (EPR) spectroscopy at 9.5 and 275.7 GHz. A substantial, virtually axial zero-field splitting with D = -9.7 GHz (-0.32 cm(-1)) is found, which is the largest one reported to date for a Mn(II) complex with six nitrogen atoms in the first coordination sphere.
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Affiliation(s)
- Mykhailo Azarkh
- †Huygens-Kamerlingh Onnes Laboratory, Department of Physics, Leiden University, P.O. Box 9504, 2300 RA Leiden, The Netherlands
| | - Larysa V Penkova
- ‡Department of Chemistry, Kyiv National Taras Shevchenko University, 01601 Kyiv, Ukraine
| | - Svitlana V Kats
- ‡Department of Chemistry, Kyiv National Taras Shevchenko University, 01601 Kyiv, Ukraine
| | - Oleg A Varzatskii
- §Vernadskii Institute of General and Inorganic Chemistry of the National Academy of Sciences of Ukraine, 03680 Kyiv, Ukraine
| | - Yan Z Voloshin
- ∥Nesmeyanov Institute of Organoelement Compounds of the Russian Academy of Sciences, 119991 Moscow, Russian Federation
| | - Edgar J J Groenen
- †Huygens-Kamerlingh Onnes Laboratory, Department of Physics, Leiden University, P.O. Box 9504, 2300 RA Leiden, The Netherlands
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Oliveira CG, da S Maia PI, Souza PC, Pavan FR, Leite CQF, Viana RB, Batista AA, Nascimento OR, Deflon VM. Manganese(II) complexes with thiosemicarbazones as potential anti-Mycobacterium tuberculosis agents. J Inorg Biochem 2013; 132:21-9. [PMID: 24188534 DOI: 10.1016/j.jinorgbio.2013.10.011] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2013] [Revised: 10/18/2013] [Accepted: 10/19/2013] [Indexed: 11/28/2022]
Abstract
Through a systematic variation on the structure of a series of manganese complexes derived from 2-acetylpyridine-N(4)-R-thiosemicarbazones (Hatc-R), structural features have been investigated with the aim of obtaining complexes with potent anti-Mycobacterium tuberculosis activity. The analytical methods used for characterization included FTIR, EPR, UV-visible, elemental analysis, cyclic voltammetry, magnetic susceptibility measurement and single crystal X-ray diffractometry. Density functional theory (DFT) calculations were performed in order to evaluate the contribution of the thiosemicarbazonate ligands on the charge distribution of the complexes by changing the peripheral groups as well as to verify the Mn-donor atoms bond dissociation predisposition. The results obtained are consistent with the monoanionic N,N,S-tridentate coordination of the thiosemicarbazone ligands, resulting in octahedral complexes of the type [Mn(atc-R)2], paramagnetic in the extension of 5 unpaired electrons, whose EPR spectra are consistent for manganese(II). The electrochemical analyses show two nearly reversible processes, which are influenced by the peripheral substituent groups at the N4 position of the atc-R(1-) ligands. The minimal inhibitory concentration (MIC) of these compounds against M. tuberculosis as well as their in vitro cytotoxicity on VERO and J774A.1 cells (IC50) was determined in order to find their selectivity index (SI) (SI=IC50/MIC). The results evidenced that the compounds described here can be considered as promising anti-M. tuberculosis agents, with SI values comparable or better than some commercial drugs available for the tuberculosis treatment.
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Affiliation(s)
- Carolina G Oliveira
- Instituto de Química de São Carlos, Universidade de São Paulo, 13566-590 São Carlos, SP, Brazil
| | - Pedro Ivo da S Maia
- Departamento de Química, Universidade Federal do Triângulo Mineiro, 38025-440 Uberaba, MG, Brazil
| | - Paula C Souza
- Faculdade de Ciências Farmacêuticas, Universidade Estadual Paulista, 14801-902 Araraquara, SP, Brazil
| | - Fernando R Pavan
- Faculdade de Ciências Farmacêuticas, Universidade Estadual Paulista, 14801-902 Araraquara, SP, Brazil
| | - Clarice Q F Leite
- Faculdade de Ciências Farmacêuticas, Universidade Estadual Paulista, 14801-902 Araraquara, SP, Brazil
| | - Rommel B Viana
- Instituto de Química de São Carlos, Universidade de São Paulo, 13566-590 São Carlos, SP, Brazil
| | - Alzir A Batista
- Departamento de Química, Universidade Federal de São Carlos, 13565-905 São Carlos, SP, Brazil
| | - Otaciro R Nascimento
- Instituto de Física de São Carlos, Universidade de São Paulo, CP 369, 13560-970 São Carlos, SP, Brazil
| | - Victor M Deflon
- Instituto de Química de São Carlos, Universidade de São Paulo, 13566-590 São Carlos, SP, Brazil.
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Gupta R, Taguchi T, Borovik AS, Hendrich MP. Characterization of monomeric Mn(II/III/IV)-hydroxo complexes from X- and Q-band dual mode electron paramagnetic resonance (EPR) spectroscopy. Inorg Chem 2013; 52:12568-75. [PMID: 24156406 DOI: 10.1021/ic401681r] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Manganese-hydroxo species have been implicated in C-H bond activation performed by metalloenzymes, but the electronic properties of many of these intermediates are not well characterized. The present work presents a detailed characterization of three Mn(n)-OH complexes (where n = II, III, and IV) of the tris[(N'-tert-butylureaylato)-N-ethylene]aminato ([H3buea](3-)) ligand using X- and Q-band dual mode electron paramagnetic resonance (EPR). Quantitative simulations for the [Mn(II)H3buea(OH)](2-) complex demonstrated the ability to characterize similar Mn(II) species commonly present in the resting states of manganese-containing enzymes. The spin states of the Mn(III) and Mn(IV) complexes determined from EPR spectroscopy are S = 2 and 3/2, respectively, as expected for the C3 symmetry imposed by the [H3buea](3-) ligand. Simulations of the spectra indicated the constant presence of two Mn(IV) species in solutions of [Mn(IV)H3buea(OH)] complex. The simulations of perpendicular- and parallel-mode EPR spectra allow determination of zero-field splitting and hyperfine parameters for all complexes. For the Mn(III) and Mn(IV) complexes, density functional theory calculations are used to determine the isotropic Mn hyperfine values, to compare the excited electronic state energies, and to give theoretical estimates of the zero-field energy.
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Affiliation(s)
- Rupal Gupta
- Department of Chemistry, University of California-Irvine , 1102 Natural Sciences II, Irvine, California 92697-2025, United States
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Wałęsa-Chorab M, Stefankiewicz AR, Ciesielski D, Hnatejko Z, Kubicki M, Kłak J, Korabik MJ, Patroniak V. New mononuclear manganese(II) and zinc(II) complexes with a terpyridine ligand: Structural, magnetic and spectroscopic properties. Polyhedron 2011. [DOI: 10.1016/j.poly.2010.12.032] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Rich J, Castillo CE, Romero I, Rodríguez M, Duboc C, Collomb MN. Investigation of the Zero-Field Splitting in Six- and Seven-Coordinate Mononuclear MnII Complexes with N/O-Based Ligands by Combining EPR Spectroscopy and Quantum Chemistry. Eur J Inorg Chem 2010. [DOI: 10.1002/ejic.201000373] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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