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Levitskiy OA, Aglamazova OI, Dmitrieva AV, Magdesieva TV. Diastereomeric Ni(II) Schiff-base cysteine derivatives: Non-covalent interactions and redox activity. Electrochim Acta 2021. [DOI: 10.1016/j.electacta.2021.138537] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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2
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Das A, Hessin C, Ren Y, Desage-El Murr M. Biological concepts for catalysis and reactivity: empowering bioinspiration. Chem Soc Rev 2020; 49:8840-8867. [PMID: 33107878 DOI: 10.1039/d0cs00914h] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Biological systems provide attractive reactivity blueprints for the design of challenging chemical transformations. Emulating the operating mode of natural systems may however not be so easy and direct translation of structural observations does not always afford the anticipated efficiency. Metalloenzymes rely on earth-abundant metals to perform an incredibly wide range of chemical transformations. To do so, enzymes in general have evolved tools and tricks to enable control of such reactivity. The underlying concepts related to these tools are usually well-known to enzymologists and bio(inorganic) chemists but may be a little less familiar to organometallic chemists. So far, the field of bioinspired catalysis has greatly focused on the coordination sphere and electronic effects for the design of functional enzyme models but might benefit from a paradigm shift related to recent findings in biological systems. The goal of this review is to bring these fields closer together as this could likely result in the development of a new generation of highly efficient bioinspired systems. This contribution covers the fields of redox-active ligands, entatic state reactivity, energy conservation through electron bifurcation, and quantum tunneling for C-H activation.
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Affiliation(s)
- Agnideep Das
- Université de Strasbourg, Institut de Chimie, UMR CNRS 7177, 67000 Strasbourg, France.
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Llanos L, Vera C, Vega A, Aravena D, Lemus L. Reactivity of Cu IN 4 Flattened Complexes: Interplay between Coordination Geometry and Ligand Flexibility. Inorg Chem 2020; 59:15061-15073. [PMID: 33021785 DOI: 10.1021/acs.inorgchem.0c02037] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The relation between redox activity and coordination geometry in CuIN4 complexes indicates that more flattened structures tend to be more reactive. Such a preorganization of the ligand confers to the complex geometries closer to a transition state, which has been termed the "entatic" state in metalloproteins, more recently extending this concept for copper complexes. However, many aspects of the redox chemistry of CuI complexes cannot be explained only by flattening. For instance, the role of ligand flexibility in this context is an open debate nowadays. To analyze this point, we studied oxidation properties of a series of five monometallic CuI Schiff-base complexes, [CuI(Ln)]+, which span a range of geometries from a distorted square planar (n = 3) to a distorted tetrahedron (n = 6, 7). This stepped control of the structure around the CuI atom allows us to explore the effect of the flattening distortion on both the electronic and redox properties through the series. Experimental studies were complemented by a theoretical analysis based on density functional theory calculations. As expected, oxidation was favored in the flattened structures, spanning a broad potential window of 370 mV for the complete series. This orderly behavior was tested in the reductive dehalogenation reaction of tetrachloroethane (TCE). Kinetic studies show that CuI oxidation by TCE is faster as the flattening distortion is higher and the oxidation potentials of the metal are lower. However, the most reactive complex was not the more planar, contradicting the trend expected from oxidation potentials. The origin of this irregularity is related to ligand flexibility and its connection with the atom/electron transfer reaction path, highlighting the need to consider effects beyond flattening distortion to better understand the reactivity of this important class of complexes.
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Affiliation(s)
- Leonel Llanos
- Departamento de Química de los Materiales, Facultad de Química y Biología, Universidad de Santiago de Chile, Av. Libertador Bernardo O'Higgins 3363, Estacio'n Central, Santiago, Chile
| | - Cristian Vera
- Departamento de Química de los Materiales, Facultad de Química y Biología, Universidad de Santiago de Chile, Av. Libertador Bernardo O'Higgins 3363, Estacio'n Central, Santiago, Chile
| | - Andrés Vega
- Facultad de Ciencias Exactas, Departamento de Ciencias Químicas, Universidad Andrés Bello, Quillota 980, Viña del Mar, Chile.,Centro para el Desarrollo de Nanociencias y Nanotecnología, CEDENNA, Santiago, Chile
| | - Daniel Aravena
- Departamento de Química de los Materiales, Facultad de Química y Biología, Universidad de Santiago de Chile, Av. Libertador Bernardo O'Higgins 3363, Estacio'n Central, Santiago, Chile
| | - Luis Lemus
- Departamento de Química de los Materiales, Facultad de Química y Biología, Universidad de Santiago de Chile, Av. Libertador Bernardo O'Higgins 3363, Estacio'n Central, Santiago, Chile
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Milunović MNM, Palamarciuc O, Sirbu A, Shova S, Dumitrescu D, Dvoranová D, Rapta P, Petrasheuskaya TV, Enyedy EA, Spengler G, Ilic M, Sitte HH, Lubec G, Arion VB. Insight into the Anticancer Activity of Copper(II) 5-Methylenetrimethylammonium-Thiosemicarbazonates and Their Interaction with Organic Cation Transporters. Biomolecules 2020; 10:E1213. [PMID: 32825480 PMCID: PMC7565988 DOI: 10.3390/biom10091213] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Revised: 08/13/2020] [Accepted: 08/14/2020] [Indexed: 02/07/2023] Open
Abstract
A series of four water-soluble salicylaldehyde thiosemicarbazones with a positively charged trimethylammonium moiety ([H2LR]Cl, R = H, Me, Et, Ph) and four copper(II) complexes [Cu(HLR)Cl]Cl (1-4) were synthesised with the aim to study (i) their antiproliferative activity in cancer cells and, (ii) for the first time for thiosemicarbazones, the interaction with membrane transport proteins, specifically organic cation transporters OCT1-3. The compounds were comprehensively characterised by analytical, spectroscopic and X-ray diffraction methods. The highest cytotoxic effect was observed in the neuroblastoma cell line SH-5YSY after 24 h exposure and follows the rank order: 3 > 2 > 4 > cisplatin > 1 >>[H2LR]Cl. The copper(II) complexes showed marked interaction with OCT1-3, comparable to that of well-known OCT inhibitors (decynium 22, prazosin and corticosterone) in the cell-based radiotracer uptake assays. The work paves the way for the development of more potent and selective anticancer drugs and/or OCT inhibitors.
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Affiliation(s)
- Miljan N. M. Milunović
- Institute of Inorganic Chemistry, Faculty of Chemistry, University of Vienna, Währinger Strasse 42, A-1090 Vienna, Austria
| | - Oleg Palamarciuc
- Department of Chemistry, Moldova State University, A. Mateevici Street 60, MD-2009 Chisinau, Moldova; (O.P.); (A.S.)
| | - Angela Sirbu
- Department of Chemistry, Moldova State University, A. Mateevici Street 60, MD-2009 Chisinau, Moldova; (O.P.); (A.S.)
| | - Sergiu Shova
- Petru Poni Institute of Macromolecular Chemistry, Laboratory of Inorganic Polymers, Aleea Grigore Ghica Voda, Nr. 41A, 700487 Iasi, Romania;
| | - Dan Dumitrescu
- Elettra—Sincrotrone Trieste S.C.p.A, Strada Statale 14—km 163,5 in AREA Science Park, 34149 Basovizza, Trieste, Italy;
| | - Dana Dvoranová
- Institute of Physical Chemistry and Chemical Physics, Faculty of Chemical and Food Technology, Slovak University of Technology in Bratislava, Radlinského 9, SK-81237 Bratislava, Slovakia; (D.D.); (P.R.)
| | - Peter Rapta
- Institute of Physical Chemistry and Chemical Physics, Faculty of Chemical and Food Technology, Slovak University of Technology in Bratislava, Radlinského 9, SK-81237 Bratislava, Slovakia; (D.D.); (P.R.)
| | - Tatsiana V. Petrasheuskaya
- Department of Inorganic and Analytical Chemistry, Interdisciplinary Excellence Centre, University of Szeged, Dóm tér 7, H-6720 Szeged, Hungary; (T.V.P.); (E.A.E.)
- MTA-SZTE Lendület Functional Metal Complexes Research Group, University of Szeged, Dóm tér 7, H-6720 Szeged, Hungary;
| | - Eva A. Enyedy
- Department of Inorganic and Analytical Chemistry, Interdisciplinary Excellence Centre, University of Szeged, Dóm tér 7, H-6720 Szeged, Hungary; (T.V.P.); (E.A.E.)
- MTA-SZTE Lendület Functional Metal Complexes Research Group, University of Szeged, Dóm tér 7, H-6720 Szeged, Hungary;
| | - Gabriella Spengler
- MTA-SZTE Lendület Functional Metal Complexes Research Group, University of Szeged, Dóm tér 7, H-6720 Szeged, Hungary;
- Department of Medical Microbiology and Immunobiology, University of Szeged, Dóm tér 10, H-6720 Szeged, Hungary
| | - Marija Ilic
- Department of Pharmaceutical Chemistry, Faculty of Life Sciences, University of Vienna, A-1090 Vienna, Austria;
- Institute of Pharmacology, Centre for Physiology and Pharmacology, Medical University of Vienna, A-1090 Vienna, Austria;
- Neuroproteomics, Paracelsus Private Medical University, 5020 Salzburg, Austria;
| | - Harald H. Sitte
- Institute of Pharmacology, Centre for Physiology and Pharmacology, Medical University of Vienna, A-1090 Vienna, Austria;
| | - Gert Lubec
- Neuroproteomics, Paracelsus Private Medical University, 5020 Salzburg, Austria;
| | - Vladimir B. Arion
- Institute of Inorganic Chemistry, Faculty of Chemistry, University of Vienna, Währinger Strasse 42, A-1090 Vienna, Austria
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Harty ML, Sharma AN, Bearne SL. Catalytic properties of the metal ion variants of mandelate racemase reveal alterations in the apparent electrophilicity of the metal cofactor. Metallomics 2020; 11:707-723. [PMID: 30843025 DOI: 10.1039/c8mt00330k] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Mandalate racemase (MR) from Pseudomonas putida requires a divalent metal cation, usually Mg2+, to catalyse the interconversion of the enantiomers of mandelate. Although the active site Mg2+ may be replaced by Mn2+, Co2+, or Ni2+, substitution by these metal ions does not markedly (<10-fold) alter the kinetic parameters Kappm, kappcat, and (kcat/Km)app for the substrates (R)- and (S)-mandelate, and the alternative substrate (S)-trifluorolactate. Viscosity variation experiments with Mn2+-MR showed that the metal ion plays a role in the uniform binding of the transition states for enzyme-substrate association, the chemical step, and enzyme-product dissociation. Surprisingly, the competitive inhibition constants (Ki) for inhibition of each metalloenzyme variant by benzohydroxamate did not vary significantly with the identity of the metal ion unlike the marked variation of the stability constants (K1) observed for M2+·BzH complex formation in solution. A similar trend was observed for the inhibition of the metalloenzyme variants by F-, except for Mg2+-MR, which bound F- tighter than would be predicted based on the stability constants for formation of M2+·F- complexes in solution. Thus, the enzyme modifies the enatic state of the bound metal ion cofactor so that the apparent electrophilicity of Mg2+ is enhanced, while that of Ni2+ is attenuated, resulting in a levelling effect relative to the trends observed for the free metals in solution.
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Affiliation(s)
- Matthew L Harty
- Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, NS B3H 4R2, Canada.
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Levitskiy OA, Aglamazova OI, Magdesieva TV. Noncovalent interactions within 3D molecular structure of diastereoisomers: A background for stereodependent redox activity. Electrochim Acta 2019. [DOI: 10.1016/j.electacta.2019.03.143] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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Chaparro D, Alí-Torres J. Assessment of the isodesmic method in the calculation of standard reduction potential of copper complexes. J Mol Model 2017; 23:283. [PMID: 28936691 DOI: 10.1007/s00894-017-3469-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2017] [Accepted: 09/06/2017] [Indexed: 11/26/2022]
Abstract
Molecular phenomena involving electron transfer and reduction/oxidation processes are of the utmost importance in chemistry. However, accurate computational calculations of standard reduction potentials (SRPs) for transition metal complexes are still challenging. For this reason, some computational strategies have been proposed in order to overcome the main limitations in SRP calculations for copper complexes. However, these strategies are limited to particular coordination spheres and do not represent a general methodology. In this work, we present standard reduction potential calculations for copper complexes in aqueous solution covering a wide range of coordination spheres. These calculations were performed using the M06-2X density functional, and by employing the direct and isodesmic approaches. Result analysis reveals that values obtained with the use of the isodesmic method are in better agreement with experimental values than those obtained from the direct method (mean unsigned error 0.39 V with the direct and 0.08 V with the isodesmic method). This approach provides values with errors comparable to the experimental uncertainty due to the proper cancellation of computational errors. These results strongly suggest the isodesmic approach as an adequate methodology for the calculation of SRPs for copper complexes with diverse coordination spheres. Graphical Abstract Comparison between direct and isodesmic methods in the calculation of standard reduction potentials for copper complexes using DFT methods.
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Affiliation(s)
- Diego Chaparro
- Department of Chemistry, Universidad Nacional de Colombia, Av. Cra 30 # 45-03, Bogotá, Colombia
| | - Jorge Alí-Torres
- Department of Chemistry, Universidad Nacional de Colombia, Av. Cra 30 # 45-03, Bogotá, Colombia.
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Dahl EW, Szymczak NK. Hydrogen Bonds Dictate the Coordination Geometry of Copper: Characterization of a Square-Planar Copper(I) Complex. Angew Chem Int Ed Engl 2016; 55:3101-5. [PMID: 26822857 PMCID: PMC4804195 DOI: 10.1002/anie.201511527] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2015] [Indexed: 12/31/2022]
Abstract
6,6''-Bis(2,4,6-trimethylanilido)terpyridine (H2Tpy(NMes)) was prepared as a rigid, tridentate pincer ligand containing pendent anilines as hydrogen bond donor groups in the secondary coordination sphere. The coordination geometry of (H2 Tpy(NMes))copper(I)-halide (Cl, Br and I) complexes is dictated by the strength of the NH-halide hydrogen bond. The Cu(I)Cl and Cu(II)Cl complexes are nearly isostructural, the former presenting a highly unusual square-planar geometry about Cu(I) . The geometric constraints provided by secondary interactions are reminiscent of blue copper proteins where a constrained geometry, or entatic state, allows for extremely rapid Cu(I)/Cu(II) electron-transfer self-exchange rates. Cu(H2 Tpy(NMes))Cl shows similar fast electron transfer (≈10(5) m(-1) s(-1)) which is the same order of magnitude as biological systems.
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Affiliation(s)
- Eric W Dahl
- Department of Chemistry, University of Michigan, 930 N. University, Ann Arbor, MI, 48109, USA
| | - Nathaniel K Szymczak
- Department of Chemistry, University of Michigan, 930 N. University, Ann Arbor, MI, 48109, USA.
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Dahl EW, Szymczak NK. Hydrogen Bonds Dictate the Coordination Geometry of Copper: Characterization of a Square‐Planar Copper(I) Complex. Angew Chem Int Ed Engl 2016. [DOI: 10.1002/ange.201511527] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Eric W. Dahl
- Department of Chemistry University of Michigan 930 N. University Ann Arbor MI 48109 USA
| | - Nathaniel K. Szymczak
- Department of Chemistry University of Michigan 930 N. University Ann Arbor MI 48109 USA
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Magdesieva TV, Levitskiy OA, Grishin YK, Ambartsumyan AA, Kochetkov KA. New binuclear Ni(II)–glycinate homologues: electrochemically distinguishable diastereomers. Electrochim Acta 2015. [DOI: 10.1016/j.electacta.2015.04.040] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Kosman DJ. Iron metabolism in aerobes: managing ferric iron hydrolysis and ferrous iron autoxidation. Coord Chem Rev 2013; 257:210-217. [PMID: 23264695 PMCID: PMC3524981 DOI: 10.1016/j.ccr.2012.06.030] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Aerobes and anaerobes alike express a plethora of essential iron enzymes; in the resting state, the iron atom(s) in these proteins are in the ferrous state. For aerobes, ferric iron is the predominant environmental valence form which, given ferric iron's aqueous chemistry, occurs as 'rust', insoluble, bio-inert polymeric ferric oxide that results from the hydrolysis of [Fe(H(2)O)(6)](3+). Mobilizing this iron requires bio-ferrireduction which in turn requires managing the rapid autoxidation of the resulting Fe(II) which occurs at pH > 6. This review examines the aqueous redox chemistry of iron and the mechanisms evolved in aerobes to suppress the 'rusting out' of Fe(III) and the ROS-generating autoxidation of Fe(II) so as to make this metal ion available as the most ubiquitous prosthetic group in metallobiology.
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Affiliation(s)
- Daniel J. Kosman
- University at Buffalo, School of Medicine and Biomedical Sciences, Buffalo, NY, USA
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Turner SA, Remillard ZD, Gijima DT, Gao E, Pike RD, Goh C. Syntheses and Structures of Closely Related Copper(I) Complexes of Tridentate (2-Pyridylmethyl)imine and (2-Pyridylmethyl)amine Ligands and Their Use in Mediating Atom Transfer Radical Polymerizations. Inorg Chem 2012; 51:10762-73. [DOI: 10.1021/ic3011585] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Sara A Turner
- Department of Chemistry, Williams College, Williamstown, Massachusetts 01267, USA
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Levason W, Reid G. Hetero-Crown Ethers-Synthesis and Metal-Binding Properties of Macrocyclic Ligands Bearing Group 16 (S, Se, Te) Donor Atoms. Supramol Chem 2012. [DOI: 10.1002/9780470661345.smc049] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Magdesieva TV, Dolganov AV, Yakimansky AV, Goikhman MY, Podeshvo IV, Kudryavtsev VV. New Cu(I) complexes with biquinolyl-containing polymer ligands as electrocatalysts for O2 activation in the oxidation of alcohols. Electrochim Acta 2008. [DOI: 10.1016/j.electacta.2007.11.067] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Magdesieva TV, Dolganov AV, Yakimanskii AV, Goikhman MY, Podeshvo IV, Kudryavtsev VV. Electrochemical synthesis of Cu-containing polyheteroarylenes and study of their catalytic properties. RUSS J ELECTROCHEM+ 2007. [DOI: 10.1134/s1023193507100059] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Breza M, Májek P. DFT studies of copper complexes with biphenyldiimino dithioether. Part III: AIM analysis. Polyhedron 2007. [DOI: 10.1016/j.poly.2007.05.015] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Kulatilleke CP. Characterization and properties of the copper(II/I) complexes of macrocyclic hexathiaether ligand [21]aneS6. Polyhedron 2007. [DOI: 10.1016/j.poly.2006.09.085] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Chaka G, Kandegedara A, Heeg MJ, Rorabacher DB. Comparative study of donor atom effects on the thermodynamic and electron-transfer kinetic properties of copper(ii/i) complexes with sexadentate macrocyclic ligands. [CuII/I([18]aneS4N2)] and [CuII/I([18]aneS4O2)]. Dalton Trans 2007:449-58. [PMID: 17213930 DOI: 10.1039/b612252c] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Studies have been conducted on the copper complexes formed with two sexadentate macrocyclic ligands containing four thioether sulfur donor atoms plus either two nitrogen or two oxygen donor atoms on opposing sides of the ring. The resulting two ligands, L, designated as [18]aneS(4)N(2) and [18]aneS(4)O(2), respectively, represent homologues of the previously studied Cu(ii/i) system with a macrocycle having six sulfur donor atoms, [18]aneS(6). Crystal structures of [Cu(II)([18]aneS(4)O(2))](ClO(4))(2) and [Cu(I)([18]aneS(4)O(2))]ClO(4) have been determined in this work. Comparison of the structures of all three systems reveals that the oxidized complexes are six coordinate with two coordinate bonds undergoing rupture upon reduction. However, the geometric changes accompanying electron transfer appear to differ for the three systems. The stability constants and electrochemical properties of both of the heteromacrocyclic complexes have been determined in acetonitrile and the Cu(II/I)L electron-transfer kinetics have been studied in the same solvent using six different counter reagents for each system. The electron self-exchange rate constants have then been calculated using the Marcus cross relationship. The results are compared to other Cu(II/I)L systems in terms of the effect of ligand geometric changes upon the overall kinetic behavior.
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Affiliation(s)
- Gezahegn Chaka
- Department of Chemistry, Wayne State University, Detroit, Michigan 48202, USA
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Synthetic models for active sites of reduced blue copper proteins: minimal geometric change between two oxidation states for fast self-exchange rate constants. INORG CHEM COMMUN 2004. [DOI: 10.1016/j.inoche.2004.09.004] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Rapta P, Kožı́šek J, Breza M, Gembický M, Dunsch L. ESR/UV–Vis–NIR cyclovoltammetry of macrocyclic complex [CuI(bite)]BF4 at different temperatures. J Electroanal Chem (Lausanne) 2004. [DOI: 10.1016/j.jelechem.2003.11.019] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Coupled electron-transfer and spin-exchange reactions of metal–bis[tris(pyrazolyl)methane] complexes. Polyhedron 2004. [DOI: 10.1016/j.poly.2004.01.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Affiliation(s)
- David B Rorabacher
- Department of Chemistry, Wayne State University, Detroit, Michigan 48202, USA.
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Duhme-Klair AK, de Alwis DL, Schultz FA. Electrochemistry of molybdenum(VI)–catecholamide siderophore complexes in aqueous solution. Inorganica Chim Acta 2003. [DOI: 10.1016/s0020-1693(03)00210-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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De Alwis DCL, Schultz FA. Metal-bis[poly(pyrazolyl)borate] complexes. Electrochemical, magnetic, and spectroscopic properties and coupled electron-transfer and spin-exchange reactions. Inorg Chem 2003; 42:3616-22. [PMID: 12767201 DOI: 10.1021/ic034077a] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Electrochemical, magnetic, and spectroscopic properties are reported for homoleptic divalent (M = Mn, Fe, Co, Ni, Ru) and trivalent (M = Cr, Mn, Fe, Co) metal-bis[poly(pyrazolyl)borate] complexes, [M(pzb)(2)](+/0), where pzb(-) = hydrotris(pyrazolyl)borate (Tp), hydrotris(3,5-dimethylpyrazolyl)borate (Tp), or tetrakis(pyrazolyl)borate (pzTp). Ligand field strengths in metal-pzb complexes increase as Tp < Tp < pzTp, which reflects the importance of steric rather than electronic effects on spectroscopic properties. However, metal-centered redox potentials become more negative as pzTp < Tp < Tp, which follows the electron-donating ability of the ligands. Co(III)/Co(II) and Mn(III)/Mn(II) electrode reactions are accompanied by a change in metal atom spin-state; i.e., (S = 0) [Co(pzb)(2)](+) + e(-) <==> (S = 3/2) [Co(pzb)(2)] and (S = 1) [Mn(pzb)(2)](+) + e(-) <==> (S = 5/2) [Mn(pzb)(2)]. Apparent heterogeneous electron-transfer rate constants derived from sweep-rate dependent cyclic voltammetric peak potential separations in 1,2-dichloroethane are small and decrease as pzTp > Tp > Tp for the Co(III)/Co(II) couples. Slow electron transfer is characteristic of coupled electron transfer and spin exchange. [M(Tp)(2)](+/0) redox potentials relative to values for other homoleptic MN(6)(3+/2+) couples change as M varies from Cr to Ni. For early members of the series, [M(Tp)(2)](+/0) potentials nearly equal those of complexes with aliphatic N-donor ligands (e.g., triazacyclononane, sarcophagine). However, [M(Tp)(2)](+/0) potentials approach those of [M(bpy)(3)](3+/2+) for later members of the series. The variation suggests a change in the nature of the metal-pzb interaction upon crossing the first transition row.
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Affiliation(s)
- D Chanaka L De Alwis
- Department of Chemistry, Indiana University Purdue University Indianapolis, 402 North Blackford Street, Indianapolis, Indiana 46202-3274, USA
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