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Wang Z, Zhang H, Zhang P, Di K, Zhao J, Wang B, Qu J, Ye S, Yang D. Stepwise Reduction of Redox Noninnocent Nitrosobenzene to Aniline via a Rare Phenylhydroxylamino Intermediate on a Thiolate-Bridged Dicobalt Scaffold. J Am Chem Soc 2024; 146:19737-19747. [PMID: 39008833 DOI: 10.1021/jacs.4c01691] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/17/2024]
Abstract
Nitrosobenzene (PhNO) and phenylhydroxylamine (PhNHOH) are of paramount importance because of their involvement as crucial intermediates in the biological metabolism and catalytic transformation of nitrobenzene (PhNO2) to aniline (PhNH2). However, a complete reductive transformation cycle of PhNO to PhNH2 via the PhNHOH intermediate has not been reported yet. In this context, we design and construct a new thiolate-bridged dicobalt scaffold that can accomplish coordination activation and reductive transformation of PhNO. Notably, an unprecedented reversible ligand-based redox sequence PhNO0 ↔ PhNO•- ↔ PhNO2- can be achieved on this well-defined {CoIII(μ-SPh)2CoIII} functional platform. Further detailed reactivity investigations demonstrate that the PhNO0 and PhNO•- complexes cannot react with the usual hydrogen and hydride donors to afford the corresponding phenylhydroxylamino (PhNHO-) species. However, the double reduced PhNO2- complex can readily undergo N-protonation with an uncommon weak proton donor PhSH to selectively yield a stable dicobalt PhNHO- bridged complex with a high pKa value of 13-16. Cyclic voltammetry shows that there are two successive reduction events at E1/2 = -0.075 V and Ep = -1.08 V for the PhNO0 complex, which allows us to determine both bond dissociation energy (BDEN-H) of 59-63 kcal·mol-1 and thermodynamic hydricity (ΔGH-) of 71-75 kcal·mol-1 of the PhNHO- complex. Both values indicate that the PhNO•- complex is not a potent hydrogen abstractor and the PhNO0 complex is not an efficient hydride acceptor. In the presence of BH3 as a combination of protons and electrons, facile N-O bond cleavage of the coordinated PhNHO- group can be realized to generate PhNH2 and a dicobalt hydroxide-bridged complex. Overall, we present the first stepwise reductive sequence, PhNO0 ↔ PhNO•- ↔ PhNO2- ↔ PhNHO- → PhNH2.
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Affiliation(s)
- Zhijie Wang
- State Key Laboratory of Fine Chemicals, Frontier Science Center for Smart Materials, Dalian University of Technology, Dalian 116024, P. R. China
| | - Haoyan Zhang
- State Key Laboratory of Fine Chemicals, Frontier Science Center for Smart Materials, Dalian University of Technology, Dalian 116024, P. R. China
| | - Peng Zhang
- State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, P. R. China
| | - Kai Di
- State Key Laboratory of Fine Chemicals, Frontier Science Center for Smart Materials, Dalian University of Technology, Dalian 116024, P. R. China
| | - Jinfeng Zhao
- State Key Laboratory of Fine Chemicals, Frontier Science Center for Smart Materials, Dalian University of Technology, Dalian 116024, P. R. China
| | - Baomin Wang
- State Key Laboratory of Fine Chemicals, Frontier Science Center for Smart Materials, Dalian University of Technology, Dalian 116024, P. R. China
| | - Jingping Qu
- State Key Laboratory of Fine Chemicals, Frontier Science Center for Smart Materials, Dalian University of Technology, Dalian 116024, P. R. China
- State Key Laboratory of Bioreactor Engineering, Collaborative Innovation Centre for Biomanufacturing, Frontiers Science Center for Materiobiology and Dynamic Chemistry, East China University of Science and Technology, Shanghai 200237, P. R. China
| | - Shengfa Ye
- State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, P. R. China
| | - Dawei Yang
- State Key Laboratory of Fine Chemicals, Frontier Science Center for Smart Materials, Dalian University of Technology, Dalian 116024, P. R. China
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Silva TL, Do Nascimento TA, De Almeida AKA, Melo SMG, Da Silva JCS, Xavier JA, Xavier AFA, Santos DC, Wadhawan J, Emery FS, Goulart MOF. Decorating BODIPY with Electron‐Withdrawing NO Group: Spectroelectrochemical Consequences and Computational Investigation. ChemElectroChem 2021. [DOI: 10.1002/celc.202100609] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Thaissa L. Silva
- Instituto de Química e Biotecnologia Universidade Federal de Alagoas Avenida Lourival Melo Mota, s/n, Tabuleiro dos Martins 57072-970 Maceió, AL Brazil
- Núcleo de Ciências Exatas – NCEx Universidade Federal de Alagoas Campus de Arapiraca Arapiraca – AL 57309-005 Brazil
| | - Tamires A. Do Nascimento
- Instituto de Química e Biotecnologia Universidade Federal de Alagoas Avenida Lourival Melo Mota, s/n, Tabuleiro dos Martins 57072-970 Maceió, AL Brazil
| | - Andresa K. A. De Almeida
- Instituto de Química e Biotecnologia Universidade Federal de Alagoas Avenida Lourival Melo Mota, s/n, Tabuleiro dos Martins 57072-970 Maceió, AL Brazil
| | - Shaiani M. G. Melo
- Departamento de Ciências Farmacêuticas Faculdade de Ciências Farmacêuticas de Ribeirão Preto Universidade de São Paulo Ribeirão Preto SP, 14040-903 Brazil
| | - Julio C. S. Da Silva
- Instituto de Química e Biotecnologia Universidade Federal de Alagoas Avenida Lourival Melo Mota, s/n, Tabuleiro dos Martins 57072-970 Maceió, AL Brazil
| | - Jadriane A. Xavier
- Instituto de Química e Biotecnologia Universidade Federal de Alagoas Avenida Lourival Melo Mota, s/n, Tabuleiro dos Martins 57072-970 Maceió, AL Brazil
| | - André F. A. Xavier
- Instituto de Química e Biotecnologia Universidade Federal de Alagoas Avenida Lourival Melo Mota, s/n, Tabuleiro dos Martins 57072-970 Maceió, AL Brazil
| | - Danyelle C. Santos
- Instituto de Química e Biotecnologia Universidade Federal de Alagoas Avenida Lourival Melo Mota, s/n, Tabuleiro dos Martins 57072-970 Maceió, AL Brazil
| | - Jay Wadhawan
- Hull University Department of Chemical Engineering Cottingham Road Hull HU6 7RX United Kingdom
| | - Flavio S. Emery
- Departamento de Ciências Farmacêuticas Faculdade de Ciências Farmacêuticas de Ribeirão Preto Universidade de São Paulo Ribeirão Preto SP, 14040-903 Brazil
| | - Marilia O. F. Goulart
- Instituto de Química e Biotecnologia Universidade Federal de Alagoas Avenida Lourival Melo Mota, s/n, Tabuleiro dos Martins 57072-970 Maceió, AL Brazil
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Askari MS, Effaty F, Gennarini F, Orio M, Le Poul N, Ottenwaelder X. Tuning Inner-Sphere Electron Transfer in a Series of Copper/Nitrosoarene Adducts. Inorg Chem 2020; 59:8678-8689. [PMID: 32073833 DOI: 10.1021/acs.inorgchem.9b03175] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
A series of copper/nitrosoarene complexes was created that mimics several steps in biomimetic O2 activation by copper(I). The reaction of the copper(I) complex of N,N,N',N'-tetramethypropylenediamine with a series of para-substituted nitrosobenzene derivatives leads to adducts in which the nitrosoarene (ArNO) is reduced by zero, one, or two electrons, akin to the isovalent species dioxygen, superoxide, and peroxide, respectively. The geometric and electronic structures of these adducts were characterized by means of X-ray diffraction, vibrational analysis, ultraviolet-visible spectroscopy, NMR, electrochemistry, and density functional theory (DFT) calculations. The bonding mode of the NO moiety depends on the oxidation state of the ArNO moiety: κN for ArNO, mononuclear η2-NO and dinuclear μ-η2:η1 for ArNO•-, and dinuclear μ-η2:η2 for ArNO2-. 15N isotopic labeling confirms the reduction state by measuring the NO stretching frequency (1392 cm-1 for κN-ArNO, 1226 cm-1 for η2-ArNO•-, 1133 cm-1 for dinuclear μ-η2:η1-ArNO•-, and 875 cm-1 for dinuclear μ-η2:η2 for ArNO2-). The 15N NMR signal disappears for the ArNO•- species, establishing a unique diagnostic for the radical state. Electrochemical studies indicate reduction waves that are consistent with one-electron reduction of the adducts and are compared with studies performed on Cu-O2 analogues. DFT calculations were undertaken to confirm our experimental findings, notably to establish the nature of the charge-transfer transitions responsible for the intense green color of the complexes. In fine, this family of complexes is unique in that it walks through three redox states of the ArNO moiety while keeping the metal and its supporting ligand the same. This work provides snapshots of the reactivity of the toxic nitrosoarene molecules with the biologically relevant Cu(I) ion.
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Affiliation(s)
- Mohammad S Askari
- Department of Chemistry and Biochemistry, Concordia University, Montreal, Quebec H4B 1R6, Canada
| | - Farshid Effaty
- Department of Chemistry and Biochemistry, Concordia University, Montreal, Quebec H4B 1R6, Canada
| | - Federica Gennarini
- Department of Chemistry and Biochemistry, Concordia University, Montreal, Quebec H4B 1R6, Canada.,Laboratoire de Chimie, Électrochimie Moléculaires et Chimie Analytique, UMR, CNRS 6521, Université de Bretagne Occidentale, Brest 29238, France
| | - Maylis Orio
- Aix Marseille Université, CNRS, Centrale Marseille, iSm2, Marseille 13007, France
| | - Nicolas Le Poul
- Laboratoire de Chimie, Électrochimie Moléculaires et Chimie Analytique, UMR, CNRS 6521, Université de Bretagne Occidentale, Brest 29238, France
| | - Xavier Ottenwaelder
- Department of Chemistry and Biochemistry, Concordia University, Montreal, Quebec H4B 1R6, Canada
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Shemer B, Shpigel E, Glozman A, Yagur-Kroll S, Kabessa Y, Agranat AJ, Belkin S. Genome-wide gene-deletion screening identifies mutations that significantly enhance explosives vapor detection by a microbial sensor. N Biotechnol 2020; 59:65-73. [PMID: 32622861 DOI: 10.1016/j.nbt.2020.06.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2020] [Revised: 06/25/2020] [Accepted: 06/26/2020] [Indexed: 12/16/2022]
Abstract
Genetically engineered microbial biosensors, capable of detecting traces of explosives residues above buried military ordnance and emitting an optical signal in response, may potentially serve for the standoff detection of buried landmines. A promising candidate for such an application is a previously reported Escherichia coli-based reporter strain that employs the yqjF gene promoter as its sensing element; however, for this sensor to be able to detect actual landmines reliably, it was necessary for its detection sensitivity and signal intensity to be enhanced. In this study, a high-throughput approach was employed to screen the effects of individual gene deletions on yqjF activation by 2,4-dinitrotoluene (DNT). Several genes were identified, the deletion of which elicited a significant enhancement of yqjF induction by DNT. The most promising of these mutations were introduced into the sensor strain, individually or in pairs, yielding a considerable increase in signal intensity and a lowering of the detection threshold. A strain harboring two of the identified mutations, ygdD and eutE, appears to be the most sensitive microbial biosensor currently described for the detection of traces of landmine explosives.
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Affiliation(s)
- Benjamin Shemer
- Department of Plant and Environmental Sciences, Institute of Life Sciences, The Hebrew University of Jerusalem, Israel
| | - Etai Shpigel
- Department of Plant and Environmental Sciences, Institute of Life Sciences, The Hebrew University of Jerusalem, Israel
| | - Anat Glozman
- Department of Plant and Environmental Sciences, Institute of Life Sciences, The Hebrew University of Jerusalem, Israel
| | - Sharon Yagur-Kroll
- Department of Plant and Environmental Sciences, Institute of Life Sciences, The Hebrew University of Jerusalem, Israel
| | - Yosssef Kabessa
- Department of Applied Physics and the Brojde Center for Innovative Engineering and Computer Science, The Hebrew University of Jerusalem, Israel
| | - Aharon J Agranat
- Department of Applied Physics and the Brojde Center for Innovative Engineering and Computer Science, The Hebrew University of Jerusalem, Israel
| | - Shimshon Belkin
- Department of Plant and Environmental Sciences, Institute of Life Sciences, The Hebrew University of Jerusalem, Israel.
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5
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Gao Y, Yang S, Xiao W, Nie J, Hu XQ. Radical chemistry of nitrosoarenes: concepts, synthetic applications and directions. Chem Commun (Camb) 2020; 56:13719-13730. [DOI: 10.1039/d0cc06023b] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The radical chemistry of nitrosoarenes has recently emerged as an attractive and important topic in organic chemistry.
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Affiliation(s)
- Yang Gao
- School of Chemical Engineering and Light Industry
- Guangdong University of Technology
- Guangzhou
- China
| | - Simin Yang
- School of Chemical Engineering and Light Industry
- Guangdong University of Technology
- Guangzhou
- China
| | - Wenping Xiao
- School of Chemical Engineering and Light Industry
- Guangdong University of Technology
- Guangzhou
- China
| | - Jianhong Nie
- School of Chemical Engineering and Light Industry
- Guangdong University of Technology
- Guangzhou
- China
| | - Xiao-Qiang Hu
- Key Laboratory of Catalysis and Energy Materials Chemistry of Ministry of Education & Hubei Key Laboratory of Catalysis and Materials Science
- School of Chemistry and Materials Science
- South-Central University for Nationalities
- Wuhan 430074
- China
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6
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Preiß S, Förster C, Otto S, Bauer M, Müller P, Hinderberger D, Hashemi Haeri H, Carella L, Heinze K. Structure and reactivity of a mononuclear gold(II) complex. Nat Chem 2017; 9:1249-1255. [PMID: 29168491 DOI: 10.1038/nchem.2836] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2017] [Accepted: 06/27/2017] [Indexed: 01/08/2023]
Abstract
Mononuclear gold(II) complexes are very rare labile species. Transient gold(II) species have been suggested in homogeneous catalysis and in medical applications, but their geometric and electronic structures have remained essentially unexplored: even fundamental data, such as the ionic radius of gold(II), are unknown. Now, an unprecedentedly stable neutral gold(II) complex of a porphyrin derivative has been isolated, and its structural and spectroscopic features determined. The gold atom adopts a 2+2 coordination mode in between those of gold(III) (four-coordinate square planar) and gold(I) (two-coordinate linear), owing to a second-order Jahn-Teller distortion enabled by the relativistically lowered 6s orbital of gold. The reactivity of this gold(II) complex towards dioxygen, nitrosobenzene and acids is discussed. This study provides insight on the ionic radius of gold(II), and allows it to be placed within the homologous series of nd9 Cu/Ag/Au divalent ions and the 5d8/9/10 Pt/Au/Hg 'relativistic' triad in the periodic table.
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Affiliation(s)
- Sebastian Preiß
- Institute of Inorganic Chemistry and Analytical Chemistry, Johannes Gutenberg-University, Duesbergweg 10-14, D-55128 Mainz, Germany
| | - Christoph Förster
- Institute of Inorganic Chemistry and Analytical Chemistry, Johannes Gutenberg-University, Duesbergweg 10-14, D-55128 Mainz, Germany
| | - Sven Otto
- Institute of Inorganic Chemistry and Analytical Chemistry, Johannes Gutenberg-University, Duesbergweg 10-14, D-55128 Mainz, Germany.,Graduate School Materials Science in Mainz, Staudingerweg 9, D-55128 Mainz, Germany
| | - Matthias Bauer
- Department Chemie, University of Paderborn, Warburger Straße 100, D-33098 Paderborn, Germany
| | - Patrick Müller
- Department Chemie, University of Paderborn, Warburger Straße 100, D-33098 Paderborn, Germany
| | - Dariush Hinderberger
- Institute of Chemistry, Martin-Luther-Universität Halle-Wittenberg, von-Danckelmann-Platz 4, D-06120 Halle (Saale), Germany
| | - Haleh Hashemi Haeri
- Institute of Chemistry, Martin-Luther-Universität Halle-Wittenberg, von-Danckelmann-Platz 4, D-06120 Halle (Saale), Germany
| | - Luca Carella
- Institute of Inorganic Chemistry and Analytical Chemistry, Johannes Gutenberg-University, Duesbergweg 10-14, D-55128 Mainz, Germany
| | - Katja Heinze
- Institute of Inorganic Chemistry and Analytical Chemistry, Johannes Gutenberg-University, Duesbergweg 10-14, D-55128 Mainz, Germany
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7
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Wallace GC, Sander M, Chin YP, Arnold WA. Quantifying the electron donating capacities of sulfide and dissolved organic matter in sediment pore waters of wetlands. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2017; 19:758-767. [PMID: 28466914 DOI: 10.1039/c7em00060j] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Electron donating capacity (EDC) values were determined for a set of pore water samples collected from the sediments of four separate wetlands in the Cottonwood Lakes Study Area in Jamestown, ND by mediated electrochemical analysis, reaction with substituted nitro(so)benzenes, and calculation based on measured organic carbon and sulfide concentrations. The samples were taken from four hydrologically connected and increasingly sulfidic wetlands within the study site. Parallel trends in EDC values related to hydrologic conditions and to in situ reduced sulfur content were observed by all three methodologies. In particular, it was found that sulfide and dissolved organic matter (DOM) are the primary and secondary reductants, respectively, in these systems. The efficacy of these reductants in transforming organic contaminants, however, is largely driven by native pore water reduced sulfur content. Manipulation of the systems demonstrate that while DOM is capable of reducing highly oxidized contaminants or reactive intermediates, this likely only occurs once the reducing capacity of the sulfide is exhausted. Sulfide therefore was the dominant electron donor in the pore water samples.
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Affiliation(s)
- Grant C Wallace
- Department of Civil, Environmental, and Geo- Engineering, University of Minnesota, 500 Pillsbury Drive Southeast, Minneapolis, MN 55455, USA.
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Garcia-Amorós J, Swaminathan S, Zhang Y, Nonell S, Raymo FM. Optical writing and reading with a photoactivatable carbazole. Phys Chem Chem Phys 2015; 17:11140-3. [PMID: 25855103 DOI: 10.1039/c5cp01336d] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
The fluorescence of a carbazole chromophore can be activated irreversibly under optical control with the photoinduced opening of an oxazine ring. In proximity to silver nanoparticles, the quantum efficiency of this photochemical transformation and that of the emissive process increase significantly. The plasmonic effects responsible for such enhancements, together with the photochemical and photophysical properties engineered into this particular photoactivatable fluorophore, permit the optical writing and reading of microscaled patterns at low illumination intensities.
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Affiliation(s)
- Jaume Garcia-Amorós
- Laboratory for Molecular Photonics, Department of Chemistry, University of Miami, 1301 Memorial Drive, Coral Gables, Florida 33146-0431, USA.
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9
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Díaz-Urrutia CA, Olea-Azar CA, Zapata GA, Lapier M, Mura F, Aguilera-Venegas B, Arán VJ, López-Múñoz RA, Maya JD. Biological and chemical study of fused tri- and tetracyclic indazoles and analogues with important antiparasitic activity. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2012; 95:670-678. [PMID: 22584127 DOI: 10.1016/j.saa.2012.04.076] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2011] [Revised: 04/05/2012] [Accepted: 04/18/2012] [Indexed: 05/31/2023]
Abstract
A series of fused tri- and tetracyclic indazoles and analogues compounds (NID) with potential antiparasitic effects were studied using voltamperometric and spectroscopic techniques. Nitroanion radicals generated by cyclic voltammetry were characterized by electron spin resonance spectroscopy (ESR) and their spectral lines were explained and analyzed using simulated spectra. In addition, we examined the interaction between radical species generated from nitroindazole derivatives and glutathione (GSH). Biological assays such as activity against Trypanosoma cruzi and cytotoxicity against macrophages were carried out. Finally, spin trapping and molecular modeling studies were also done in order to elucidate the potentials action mechanisms involved in the trypanocidal activity.
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Affiliation(s)
- Christian A Díaz-Urrutia
- Departamento de Química Inorgánica y Analítica, Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, Casilla 233, Santiago 1, Chile
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10
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Mikhal’chenko LV, Syroeshkin MA, Leonova MY, Mendkovich AS, Rusakov AI, Gul’tyai VP. Dimerization and protonation reactions of nitrosonitrobenzenes radical anions. RUSS J ELECTROCHEM+ 2011. [DOI: 10.1134/s1023193511110127] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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11
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Aravena CM, Olea AC, Cerecetto H, González M, Maya JD, Rodríguez-Becerra J. Potent 5-nitrofuran derivatives inhibitors of Trypanosoma cruzi growth: electrochemical, spectroscopic and biological studies. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2011; 79:312-319. [PMID: 21470905 DOI: 10.1016/j.saa.2011.02.007] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2010] [Revised: 01/26/2011] [Accepted: 02/07/2011] [Indexed: 05/30/2023]
Abstract
Cyclic voltammetry and electron spin resonance techniques were used in the investigation of several potential antiprotozoal containing thiosemicarbazone and carbamate nitrofurans. In the electrochemical behaviour, a self-protonation process involving the nitro group was observed. The reactivity of the nitro anion radical for these derivatives with glutathione, a biological relevant thiol, was also studied in means of cyclic voltammetry. These studies demonstrated that glutathione could react with radical species from 5-nitrofuryl system. Furthermore, from the voltammetric results, some parameters of biological significance as E(7)(1) (indicative of the biological nitro anion radical formation), and [Formula: see text] (thermodynamic indicator the of oxygen redox cycling) have been calculated. We also evaluated the stability of the nitro anion radical in terms of the dimerization constant (k(d)). The nitrofuran-free radicals from cyclic voltammetry were characterized by electron spin resonance. A clear dependence between both the thiosemicarbazone or carbamate substructure and the length of the linker, furyl- or furylpropenyl-spacer, and the delocalization of the unpaired electron was observed. Through of biological assays we obtained important parameters that account for the selective anti-trypanosomal activity of these derivatives. The trypomastigote viability study showed that all derivatives are as active as in the epimastigote form of the parasite in a doses dependent manner.
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Affiliation(s)
- C Maria Aravena
- Departamento de Química Inorgánica y Analítica, Facultad de Ciencias Quimicas y Famacéuticas, Universidad de Chile, Olivos 1007, Independencia, Santiago, Chile
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12
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Mendkovich AS, Syroeshkin MA, Mikhalchenko LV, Mikhailov MN, Rusakov AI, Gul'tyai VP. Integrated Study of the Dinitrobenzene Electroreduction Mechanism by Electroanalytical and Computational Methods. INTERNATIONAL JOURNAL OF ELECTROCHEMISTRY 2011. [DOI: 10.4061/2011/346043] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Electroreduction of 1,2-, 1,3-, and 1,4-dinitrobenzenes in DMF has been investigated by a set of experimental (cyclic voltammetry, chronoamperometry, and controlled potential electrolysis) and theoretical methods (digital simulation and quantum chemical calculations). The transformation of only one nitro group is observed in the presence of proton donors. The process selectivity is provided by reactions of radical anions' intermediate products. The key reactions here are protonation of radical anions of nitrosonitrobenzenes and N-O bond cleavage in radical anions of N-(nitrophenyl)-hydroxylamines.
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Affiliation(s)
- Andrey S. Mendkovich
- N.D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Moscow 199991, Russia
| | - Mikhail A. Syroeshkin
- N.D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Moscow 199991, Russia
| | - Ludmila V. Mikhalchenko
- N.D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Moscow 199991, Russia
| | - Mikhail N. Mikhailov
- N.D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Moscow 199991, Russia
| | | | - Vadim P. Gul'tyai
- N.D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Moscow 199991, Russia
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Gómez-Vidales V, Vargas M, Meléndez I, Salmón M, Sansón-O C, Zaragoza I, Zolotukhin M, Salcedo R. Basic medium oxidation of aromatic α-hydroxy-ketones: A free radical mechanism. J Mol Struct 2010. [DOI: 10.1016/j.molstruc.2009.10.022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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14
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Rodríguez J, Olea-Azar C, Barriga G, Folch C, Gerpe A, Cerecetto H, González M. Comparative spectroscopic and electrochemical study of nitroindazoles: 3-alcoxy, 3-hydroxy and 3-oxo derivatives. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2008; 70:557-63. [PMID: 17855162 DOI: 10.1016/j.saa.2007.07.052] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2007] [Revised: 07/26/2007] [Accepted: 07/31/2007] [Indexed: 05/17/2023]
Abstract
Cyclic voltammetry and electron spin resonance techniques were used in the investigation of novel 3-alkoxy- and 3-hydroxy-1-[omega-(dialkylamino)alkyl]-5-nitroindazole derivatives. A self-protonation process involving the protonation of the nitro group was observed. The reactivity of the nitro-anion radical for these derivatives with glutathione, a biological relevant thiol, was also studied by cyclic voltammetry. These studies demonstrated that glutathione could react with radical species from 5-nitroindazole system. Also we demonstrated that nitro-anion radicals show three different patterns of delocalization where the indazole 1-lateral chain does not have major influence.
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Affiliation(s)
- Jorge Rodríguez
- Departamento de Química Inorgánica y Analítica, Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, Chile
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16
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Rawling T, Xiao H, Lee ST, Colbran SB, McDonagh AM. Optical and redox properties of ruthenium phthalocyanine complexes tuned with axial ligand substituents. Inorg Chem 2007; 46:2805-13. [PMID: 17330967 DOI: 10.1021/ic061866u] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The optical and electrochemical properties of the ruthenium phthalocyanine complexes [[(t-Bu)4Pc]Ru(4-Rpy)2], where R = NO2, Me, NH2, and NMe2, are reported. The electron density at the macrocycle may be adjusted using the axial ligand substituents, which have varying electron-donating/withdrawing strengths. Electrochemical data show that the axial pyridine ligand substituents exert significant influence over the phthalocyanine ring-based redox processes. The axial ligands also influence the electronic absorption properties of the complexes with influence also being observed in the electrogenerated oxidized and reduced species.
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Affiliation(s)
- Tristan Rawling
- Institute of Nanoscale Technology, University of Technology Sydney, Sydney, NSW 2007, Australia
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Gerpe A, Aguirre G, Boiani L, Cerecetto H, González M, Olea-Azar C, Rigol C, Maya JD, Morello A, Piro OE, Arán VJ, Azqueta A, de Ceráin AL, Monge A, Rojas MA, Yaluff G. Indazole N-oxide derivatives as antiprotozoal agents: Synthesis, biological evaluation and mechanism of action studies. Bioorg Med Chem 2006; 14:3467-80. [PMID: 16483783 DOI: 10.1016/j.bmc.2006.01.007] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2005] [Revised: 12/30/2005] [Accepted: 01/03/2006] [Indexed: 11/17/2022]
Abstract
A series of indazole N-oxide derivatives have been synthesized and their antichagasic and leishmanocidal properties studied. 3-Cyano-2-(4-iodophenyl)-2H-indazole N1-oxide exhibited interesting antichagasic activity on the two parasitic strains and the two parasitic stages evaluated. Furthermore, besides its trypanocidal activity, 3-cyano-2-(4-nitrophenyl)-2H-indazole N1-oxide showed leishmanocidal activity in the three parasitic strains evaluated. To gain insight into the mechanism of action, electrochemical behaviour, ESR experiment, inhibition of parasitic respiration and QSAR were performed.
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Affiliation(s)
- Alejandra Gerpe
- Departamento de Química Orgánica, Facultad de Química-Facultad de Ciencias, Universidad de la República, Iguá 4225, Montevideo 11400, Uruguay
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Olea-Azar C, Cerecetto H, Gerpe A, González M, Arán VJ, Rigol C, Opazo L. ESR and electrochemical study of 5-nitroindazole derivatives with antiprotozoal activity. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2006; 63:36-42. [PMID: 16344240 DOI: 10.1016/j.saa.2005.04.011] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2005] [Accepted: 04/19/2005] [Indexed: 05/05/2023]
Abstract
The electrochemistry of 3-alkoxy- and 3-hydroxy-1-[omega-(dialkylamino)alkyl]-5-nitroindazole derivatives were characterized using cyclic voltammetry in DMSO. The nitro reduction process was studied and this was affected by the acid moieties present in these compounds. A nitro anion self-protonation process was observed. This phenomenon was studied by cyclic voltammetry in presence of increasing amount of NaOH. The reactivity of the nitro anion radical of these derivatives with glutathione was also studied by cyclic voltammetry. The oxidizing effect of glutathione is supported by the parallel decrease of the anodic peak current and increase of the cathodic peak in the cyclic voltammograms, corresponding to the wave of the nitro anion radical from uncharged species with the addition of glutathione. Nitro anion radicals obtained by electrolytic reduction of these derivatives were measured and analyzed in DMSO using electron spin resonance spectroscopy.
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Affiliation(s)
- Claudio Olea-Azar
- Departamento de Química Inorgánica y Analítica, Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, Chile.
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Liu A, Jin Y, Zhang J, Brazeau BJ, Lipscomb JD. Substrate radical intermediates in soluble methane monooxygenase. Biochem Biophys Res Commun 2005; 338:254-61. [PMID: 16165086 DOI: 10.1016/j.bbrc.2005.08.216] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2005] [Accepted: 08/30/2005] [Indexed: 11/30/2022]
Abstract
EPR spin-trapping experiments were carried out using the three-component soluble methane monooxygenase (MMO). Spin-traps 5,5-dimethyl-1-pyrroline N-oxide (DMPO), alpha-4-pyridyl-1-oxide N-tert-butylnitrone (POBN), and nitrosobenzene (NOB) were used to investigate the possible formation of substrate radical intermediates during catalysis. In contrast to a previous report, the NADH-coupled oxidations of various substrates did not produce any trapped radical species when DMPO or POBN was present. However, radicals were detected by these traps when only the MMO reductase component and NADH were present. DMPO and POBN were found to be weak inhibitors of the MMO reaction. In contrast, NOB is a strong inhibitor for the MMO-catalyzed nitrobenzene oxidation reaction. When NOB was used as a spin-trap in the complete MMO system with or without substrate, EPR signals from an NOB radical were detected. We propose that a molecule of NOB acts simultaneously as a substrate and a spin-trap for MMO, yielding the long-lived radical and supporting a stepwise mechanism for MMO.
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Affiliation(s)
- Aimin Liu
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA
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Núñez-Vergara LJ, Santander P, Navarrete-Encina P, Squella J. Electrochemical reduction of C-4 nitrosophenyl 1,4-dihydropyridines and their parent C-4 nitrophenyl derivatives in protic media. J Electroanal Chem (Lausanne) 2005. [DOI: 10.1016/j.jelechem.2005.03.022] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Brezová V, Tarábek P, Dvoranová D, Staško A, Biskupič S. EPR study of photoinduced reduction of nitroso compounds in titanium dioxide suspensions. J Photochem Photobiol A Chem 2003. [DOI: 10.1016/s1010-6030(02)00357-x] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Miller C, Folkes LK, Mottley C, Wardman P, Mason RP. Revisiting the interaction of the radical anion metabolite of nitrofurantoin with glutathione. Arch Biochem Biophys 2002; 397:113-8. [PMID: 11747317 DOI: 10.1006/abbi.2001.2670] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
There have been several conflicting reports as to the scavenging nature of glutathione toward the nitro radical anion of the drug nitrofurantoin. We produced the radical anion enzymatically using the xanthine oxidase/hypoxanthine system at pH 7.4 and pH 9.0 in the presence of various levels of glutathione from 10 to 100 mM and monitored any changes in the radical concentration via electron spin resonance spectroscopy. Independent of glutathione concentration, there was no decrease in the steady-state concentration of the radical. In fact, there was an average 30% increase in the concentration of the radical anion, which suggests enhanced enzyme activity in the presence of glutathione (GSH). These results, together with observations of the effects of glutathione on the stability of the radical anion generated by radiolysis or dithionite, rule out any detectable reaction between the nitrofurantoin radical anion and GSH under physiologically relevant conditions.
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Affiliation(s)
- Catherine Miller
- Department of Chemistry, John Carroll University, Cleveland, Ohio 44118, USA.
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Núñez-Vergara LJ, Bontá M, Sturm J, Navarrete P, Bollo S, Squella J. Electrochemical reduction of nitroso compounds: voltammetric, UV–vis and EPR characterization of ortho- and meta-nitrosotoluene derivatives. J Electroanal Chem (Lausanne) 2001. [DOI: 10.1016/s0022-0728(01)00407-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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