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Miller PD, Mengell J, Shultz DA, Kirk ML. Metal-Ligand Exchange Coupling Alters the Open-Shell Ligand Electronic Structure in a Bis(semiquinone) Complex. Inorg Chem 2024; 63:6493-6499. [PMID: 38517353 DOI: 10.1021/acs.inorgchem.4c00380] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/23/2024]
Abstract
The electronic structure of the bis(dioxolene) bridging ligand -SQ2Th2- is responsive to metal-ligand magnetic exchange coupling. Comparison of the crystal structure of (NiSQ)2Th2 to that of (ZnSQ)2Th2 indicates an open-shell biradical ground state for the dinuclear Ni(II) complex compared to the closed-shell quinoidal character found in the dinuclear Zn(II) complex. Consistent with a comparison of bond lengths obtained by X-ray diffraction, the analysis of the variable-temperature magnetic susceptibility data for crystalline (NiSQ)2Th2 yields reduced SQ-SQ radical-radical magnetic exchange coupling (JSQ-SQ = -203 cm-1) compared to that of (ZnSQ)2Th2 (JSQ-SQ = -321 cm-1). The reduced SQ-SQ exchange coupling in (NiSQ)2Th2 derives from an attenuation of the SQ spin densities, which in turn is derived from the Ni-SQ antiferromagnetic exchange interactions. This reduction in SQ--SQ exchange that we observe for (NiSQ)2Th2 correlates with an effective lengthening of the bridge unit by ∼2.1 Å relative to that of (ZnSQ)2Th2. This magnitude of the effective increase in the bridge distance is consistent with the (NiSQ)2Th2 JSQ-SQ value lying between those of (ZnSQ)2Th2 and (ZnSQ)2Th3. The ability to modulate spin populations on an organic radical via pairwise Ni-SQ magnetic exchange interactions is a general way to affect electronic coupling in the Th-Th bridge. Our results suggest that metal-radical exchange coupling represents a powerful mechanism for tuning organic molecular electronic structure, with important implications for molecular electronics and molecular electron transport.
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Affiliation(s)
- Paul D Miller
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, United States
| | - Joshua Mengell
- Department of Chemistry and Chemical Biology, The University of New Mexico, MSC03 2060, 1 University of New Mexico, Albuquerque, New Mexico 87131-0001, United States
| | - David A Shultz
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, United States
| | - Martin L Kirk
- Department of Chemistry and Chemical Biology, The University of New Mexico, MSC03 2060, 1 University of New Mexico, Albuquerque, New Mexico 87131-0001, United States
- The Center for High Technology Materials, The University of New Mexico, Albuquerque, New Mexico 87106, United States
- Center for Quantum Information and Control (CQuIC), The University of New Mexico, Albuquerque, New Mexico 87131-0001, United States
- Center for Computational Chemistry, The University of New Mexico, Albuquerque, New Mexico 87131-0001, United States
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Miller PD, Shultz DA, Mengell J, Kirk ML, Wojtas L. Variation from closed-shell to open shell electronic structures in oligothiophene bis(dioxolene) complexes. Chem Sci 2023; 14:12264-12276. [PMID: 37969598 PMCID: PMC10631215 DOI: 10.1039/d3sc02341a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Accepted: 10/07/2023] [Indexed: 11/17/2023] Open
Abstract
A series of oligothiophene bis(dioxolene) complexes, SQ-Thn-SQ (SQ = S = ½TpCum,MeZnII(3-tert-butyl-orthosemiquinonate); TpCum,Me = tris(5-cumenyl-3-methylpyrazolyl)borate anion) have been synthesized, structurally characterized, and studied as a function of the number of thiophene bridging units, n (n = 0-3) using a combination of variable-temperature (VT) electronic absorption and EPR spectroscopies, and VT magnetic susceptibility measurements. The thiophene bridge bond lengths determined by X-ray crystallography display dramatic differences across the SQ-Thn-SQ series. Bridge bond deviation values (Σ|Δi|) display a progressive change in the nature of the bridge fragment bonding as the number of thiophene groups increases, with quinoidal bridge character for n = 1 (SQ-Th-SQ) and biradical character with "aromatic" bridge bond lengths for n = 3 (SQ-Th3-SQ). Remarkably, for n = 2 (SQ-Th2-SQ) the nature of the bridge fragment is intermediate between quinoid and biradical aromatic, which we describe as having open-shell character as opposed to biradicaloid since the open-shell biradical configuration does not have the correct symmetry to mix with the quinoidal ground-state configuration. This bridge bonding character is reflected in the energies of the lowest lying open-shell states for these three molecules. The SQ-Th-SQ molecule is diamagnetic at all temperatures studied, and we provide evidence for SQ-SQ antiferromagnetic exchange coupling and population of triplet states in SQ-Th2-SQ and SQ-Th3-SQ, with JSQ-SQ(ave) = -279 cm-1 (VT EPR/electronic absorption/magnetic susceptibility) and JSQ-SQ = -117 cm-1 (VT EPR/electronic absorption/magnetic susceptibility), respectively. The results have been interpreted in the context of state configurational mixing within a simplified 4-electron, 3-orbital model that explicitly contains contributions of a bridge fragment. Variable-temperature spectroscopic- and magnetic susceptibility data are consistent with two low-lying open-shell states for SQ-Th3-SQ, but three low-lying states (one closed-shell and two open-shell) for SQ-Th2-SQ. This model provides a simple symmetry-based framework to understand the continuum of electronic and geometric structures of this class of molecules as a function of the number of thiophene units in the bridge.
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Affiliation(s)
- Paul D Miller
- Department of Chemistry, North Carolina State University Raleigh North Carolina 27695-8204 USA
| | - David A Shultz
- Department of Chemistry, North Carolina State University Raleigh North Carolina 27695-8204 USA
| | - Joshua Mengell
- Department of Chemistry and Chemical Biology, The University of New Mexico MSC03 2060, 1 University of New Mexico Albuquerque NM 87131-0001 USA
| | - Martin L Kirk
- Department of Chemistry and Chemical Biology, The University of New Mexico MSC03 2060, 1 University of New Mexico Albuquerque NM 87131-0001 USA
- The Center for High Technology Materials, The University of New Mexico Albuquerque New Mexico 87106 USA
- Center for Quantum Information and Control (CQuIC), The University of New Mexico Albuquerque New Mexico 87131-0001 USA
| | - Lukasz Wojtas
- Department of Chemistry, University of South Florida 4202 E. Fowler Avenue, CHE 205 Tampa FL 33620-5250 USA
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Kumar P, Devkota L, Casey MC, Fischer AA, Lindeman SV, Fiedler AT. Reversible Dioxygen Binding to Co(II) Complexes with Noninnocent Ligands. Inorg Chem 2022; 61:16664-16677. [PMID: 36206536 PMCID: PMC11218047 DOI: 10.1021/acs.inorgchem.2c02246] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A series of mononuclear Co(II) complexes with noninnocent (redox-active) ligands are prepared that exhibit metal-ligand cooperativity during the reversible binding of O2. The complexes have the general formula, [CoII(LS,N)(TpR2)] (R = Me, Ph), where LS,N is a bidentate o-aminothiophenolate and TpR2 is a hydrotris(pyrazol-1-yl)borate scorpionate with R-substituents at the 3- and 5-positions. Exposure to O2 at room temperature results in one-electron oxidation and deprotonation of LS,N. The oxidized derivatives possess substantial "singlet diradical" character arising from antiferromagnetic coupling between an iminothiosemiquinonate (ITSQ•-) ligand radical and a low-spin Co(II) ion. The [CoII(TpMe2)(X2ITSQ)] complexes, where X = H or tBu, coordinate O2 reversibly at reduced temperatures to provide Co/O2 adducts. The O2 binding reactions closely resemble those previously reported by our group (Kumar et al., J. Am. Chem. Soc. 2019,141, 10984-10987) for the related complexes [CoII(TpMe2)(tBu2SQ)] and [CoII(TpMe2)(tBu2ISQ)], where tBu2(I)SQ represents 4,6-di-tert-butyl-(2-imino)semiquinonate radicals. In each case, the oxygenation reaction proceeds via the addition of O2 to both the cobalt ion and the ligand radical, generating metallocyclic cobalt(III)-alkylperoxo structures. Thermodynamic measurements elucidate the relationship between O2 affinity and redox potentials of the (imino)(thio)semiquinonate radicals, as well as energetic differences between these reactions and conventional metal-based oxygenations. The results highlight the utility and versatility of noninnocent ligands in the design of O2-absorbing compounds.
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Affiliation(s)
- Praveen Kumar
- Department of Chemistry, Marquette University, 1414 W. Clybourn Street, Milwaukee, Wisconsin53233, United States
| | - Laxmi Devkota
- Department of Chemistry, Marquette University, 1414 W. Clybourn Street, Milwaukee, Wisconsin53233, United States
| | - Maximilian C Casey
- Department of Chemistry, Marquette University, 1414 W. Clybourn Street, Milwaukee, Wisconsin53233, United States
| | - Anne A Fischer
- Department of Chemistry, Marquette University, 1414 W. Clybourn Street, Milwaukee, Wisconsin53233, United States
| | - Sergey V Lindeman
- Department of Chemistry, Marquette University, 1414 W. Clybourn Street, Milwaukee, Wisconsin53233, United States
| | - Adam T Fiedler
- Department of Chemistry, Marquette University, 1414 W. Clybourn Street, Milwaukee, Wisconsin53233, United States
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Tripathy RR, Singha S, Sarkar S. A review on bio-functional models of catechol oxidase probed by less explored first row transition metals. J COORD CHEM 2022. [DOI: 10.1080/00958972.2022.2122053] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
Affiliation(s)
| | - Shuvendu Singha
- Department of Chemistry, SAS, KIIT University, Bhubaneswar, Odisha, India
| | - Sohini Sarkar
- Department of Chemistry, SAS, KIIT University, Bhubaneswar, Odisha, India
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Mondal R, Guin AK, Chakraborty G, Paul ND. Metal-ligand cooperative approaches in homogeneous catalysis using transition metal complex catalysts of redox noninnocent ligands. Org Biomol Chem 2022; 20:296-328. [PMID: 34904619 DOI: 10.1039/d1ob01153g] [Citation(s) in RCA: 26] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Catalysis offers a straightforward route to prepare various value-added molecules starting from readily available raw materials. The catalytic reactions mostly involve multi-electron transformations. Hence, compared to the inexpensive and readily available 3d-metals, the 4d and 5d-transition metals get an extra advantage for performing multi-electron catalytic reactions as the heavier transition metals prefer two-electron redox events. However, for sustainable development, these expensive and scarce heavy metal-based catalysts need to be replaced by inexpensive, environmentally benign, and economically affordable 3d-metal catalysts. In this regard, a metal-ligand cooperative approach involving transition metal complexes of redox noninnocent ligands offers an attractive alternative. The synergistic participation of redox-active ligands during electron transfer events allows multi-electron transformations using 3d-metal catalysts and allows interesting chemical transformations using 4d and 5d-metals as well. Herein we summarize an up-to-date literature report on the metal-ligand cooperative approaches using transition metal complexes of redox noninnocent ligands as catalysts for a few selected types of catalytic reactions.
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Affiliation(s)
- Rakesh Mondal
- Department of Chemistry, Indian Institute of Engineering Science and Technology, Shibpur Botanic Garden, Howrah 711103, India.
| | - Amit Kumar Guin
- Department of Chemistry, Indian Institute of Engineering Science and Technology, Shibpur Botanic Garden, Howrah 711103, India.
| | - Gargi Chakraborty
- Department of Chemistry, Indian Institute of Engineering Science and Technology, Shibpur Botanic Garden, Howrah 711103, India.
| | - Nanda D Paul
- Department of Chemistry, Indian Institute of Engineering Science and Technology, Shibpur Botanic Garden, Howrah 711103, India.
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Hewitt P, Shultz DA, Kirk ML. Rules for Magnetic Exchange in Azulene-Bridged Biradicals: Quo Vadis? J Org Chem 2021; 86:15577-15587. [PMID: 34644082 DOI: 10.1021/acs.joc.1c02085] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Electronic coupling through organic bridges facilitates magnetic exchange interactions and controls electron transfer and single-molecule device electron transport. Electronic coupling through alternant π-systems (e.g., benzene) is better understood than the corresponding coupling through nonalternant π-systems (e.g., azulene). Herein, we examine the structure, spectroscopy, and magnetic exchange coupling in two biradicals (1,3-SQ2Az and 1,3-SQ-Az-NN; SQ = the zinc(II) complex of spin-1/2 semiquinone radical anion, NN = spin-1/2 nitronylnitroxide; Az = azulene) that possess nonalternant azulene π-system bridges. The SQ radical spin density in both molecules is delocalized into the Az π-system, while the NN spin is effectively localized onto the five-atom ONCNO π-system of NN radical. The spin distributions and interactions are probed by EPR spectroscopy and magnetic susceptibility measurements. We find that J = +38 cm-1 for 1,3-SQ2Az and J = +9 cm-1 for 1,3-SQ-Az-NN (H=-2JS^SQ·S^SQorNN). Our results highlight the differences in exchange coupling mediated by azulene compared to exchange coupling mediated by alternant π-systems.
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Affiliation(s)
- Patrick Hewitt
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, United States
| | - David A Shultz
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, United States
| | - Martin L Kirk
- Department of Chemistry, The University of New Mexico, MSC03 2060, 1 University of New Mexico, Albuquerque, New Mexico 87131-0001, United States
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Rakshit T, Mandal B, Alenezi KM, Ganguly R, Mandal D. Synthesis, structure, luminescent properties and catecholase activity of Zn(II) complex with N, O chelating agent. J Mol Struct 2021. [DOI: 10.1016/j.molstruc.2020.129544] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Kumar P, SantaLucia DJ, Kaniewska-Laskowska K, Lindeman SV, Ozarowski A, Krzystek J, Ozerov M, Telser J, Berry JF, Fiedler AT. Probing the Magnetic Anisotropy of Co(II) Complexes Featuring Redox-Active Ligands. Inorg Chem 2020; 59:16178-16193. [DOI: 10.1021/acs.inorgchem.0c01812] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Praveen Kumar
- Department of Chemistry, Marquette University, Milwaukee, Wisconsin 53201, United States
| | - Daniel J. SantaLucia
- Department of Chemistry, University of Wisconsin−Madison, Madison, Wisconsin 53706, United States
| | - Kinga Kaniewska-Laskowska
- Department of Inorganic Chemistry, Faculty of Chemistry, Gdańsk University of Technology, Gdańsk PL-80-233, Poland
| | - Sergey V. Lindeman
- Department of Chemistry, Marquette University, Milwaukee, Wisconsin 53201, United States
| | - Andrew Ozarowski
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, United States
| | - J. Krzystek
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, United States
| | - Mykhaylo Ozerov
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, United States
| | - Joshua Telser
- Department of Biological, Chemical and Physical Sciences, Roosevelt University, Chicago, Illinois 60605, United States
| | - John F. Berry
- Department of Chemistry, University of Wisconsin−Madison, Madison, Wisconsin 53706, United States
| | - Adam T. Fiedler
- Department of Chemistry, Marquette University, Milwaukee, Wisconsin 53201, United States
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9
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Hens A. A combined experimental and theoretical study to explore the catecholase-like activity of a hepta coordinated dinuclear Zn(II) complex. INORG CHEM COMMUN 2020. [DOI: 10.1016/j.inoche.2020.108144] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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10
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Synthesis and Characterization of Catecholato Copper(II) Complexes with Sterically Hindered Neutral and Anionic N3 Type Ligands: Tris(3,5-diisopropyl-1-pyrazolyl)methane and Hydrotris(3,5-diisopropyl-1-pyrazolyl)borate. INORGANICS 2020. [DOI: 10.3390/inorganics8050037] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Three catecholato copper(II) complexes, [Cu(catCl4)(L1′)], [Cu(catBr4)(L1′)], and [Cu(catCl4)(L1H)], supported by sterically hindered neutral and anionic N3 type ligands: tris(3,5-diisopropyl-1-pyrazolyl)methane (referred to as L1′) and hydrotris(3,5-diisopropyl-1-pyrazolyl)borate (referred to as L1−), are synthesized and characterized in detail. Their X-ray structures reveal that both [Cu(catCl4)(L1′)] and [Cu(catBr4)(L1′)] complexes have a five-coordinate square-pyramidal geometry and [Cu(catCl4)(L1H)] complex has a four-coordinate square-planar geometry. The L1H is unusual protonated ligand that controls its overall charge. For the three catecholato copper(II) complexes, the oxidation state of copper is divalent, and catechol exists in catecholate as two minus anion. This difference in coordination geometry affects their d-d and CT transitions energy and ESR parameters.
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Shultz DA, Kirk ML, Zhang J, Stasiw DE, Wang G, Yang J, Habel-Rodriguez D, Stein BW, Sommer RD. Spectroscopic Signatures of Resonance Inhibition Reveal Differences in Donor-Bridge and Bridge-Acceptor Couplings. J Am Chem Soc 2020; 142:4916-4924. [PMID: 32069027 DOI: 10.1021/jacs.0c00326] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
The torsional dependence of the ground state magnetic exchange coupling (J) and the corresponding electronic coupling matrix element (HDA) for eight transition metal complexes possessing donor-acceptor (D-A) biradical ligands is presented. These biradical ligands are composed of an S = 1/2 metal semiquinone (SQ) donor and an S = 1/2 nitronylnitroxide (NN) acceptor, which are coupled to each other via para-phenylene, methyl-substituted para-phenylenes, or a bicyclo[2.2.2]octane ring. The observed trends in electronic absorption and resonance Raman spectral features are in accord with a reduction in electronic and magnetic coupling between D and A units within the framework of our valence bond configuration interaction model. Moreover, our spectroscopic results highlight different orbital mechanisms that modulate coupling in these complexes, which is not manifest in the ferromagnetic JSQ-B-NN values. The work provides new detailed insight into the effects of torsional rotations which contribute to inhomogeneities in experimentally determined exchange couplings, electron transfer rates, and electron transport conductance measurements.
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Affiliation(s)
- David A Shultz
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, United States
| | - Martin L Kirk
- Department of Chemistry and Chemical Biology, The University of New Mexico, MSC03 2060, 1 University of New Mexico, Albuquerque, New Mexico 87131-0001, United States.,Center for High Technology Materials, The University of New Mexico, Albuquerque, New Mexico 87106, United States
| | - Jinyuan Zhang
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, United States
| | - Daniel E Stasiw
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, United States
| | - Guangbin Wang
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, United States
| | - Jing Yang
- Department of Chemistry, The University of New Mexico, MSC03 2060, 1 University of New Mexico, Albuquerque, New Mexico 87131-0001, United States
| | - Diana Habel-Rodriguez
- Department of Chemistry, The University of New Mexico, MSC03 2060, 1 University of New Mexico, Albuquerque, New Mexico 87131-0001, United States
| | - Benjamin W Stein
- Department of Chemistry, The University of New Mexico, MSC03 2060, 1 University of New Mexico, Albuquerque, New Mexico 87131-0001, United States
| | - Roger D Sommer
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, United States
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12
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Synthesis and characterization of a hydro tris(3-phenylpyrazolyl)borato nickel(II) semiquinonate adduct. Polyhedron 2019. [DOI: 10.1016/j.poly.2019.01.042] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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13
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Wang P, Yap GP, Riordan CG. Synthesis, characterization and O2 reactivity of a bioinspired cobalt(II)-catecholate complex. Inorganica Chim Acta 2019. [DOI: 10.1016/j.ica.2019.01.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
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14
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Yang M, Xie S, Liang X, Zhang Y, Dong W. A novel functional nitronyl nitroxide and its manganese and cobalt complexes: Synthesis, structures and magnetic properties. Polyhedron 2019. [DOI: 10.1016/j.poly.2019.01.015] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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15
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Robole ZM, Rahn KL, Lampkin BJ, Anand RK, VanVeller B. Tuning the Electrochemical Redox Potentials of Catechol with Boronic Acid Derivatives. J Org Chem 2019; 84:2346-2350. [DOI: 10.1021/acs.joc.8b03087] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Zachary M. Robole
- Department of Chemistry, Iowa State University, Ames, Iowa 50011, United States
| | - Kira L. Rahn
- Department of Chemistry, Iowa State University, Ames, Iowa 50011, United States
| | - Bryan J. Lampkin
- Department of Chemistry, Iowa State University, Ames, Iowa 50011, United States
| | - Robbyn K. Anand
- Department of Chemistry, Iowa State University, Ames, Iowa 50011, United States
| | - Brett VanVeller
- Department of Chemistry, Iowa State University, Ames, Iowa 50011, United States
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16
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Anitha N, Saravanan N, Ajaykamal T, Suresh E, Palaniandavar M. Catecholase activity of mononuclear copper(II) complexes of tridentate 3N ligands in aqueous and aqueous micellar media: Influence of stereoelectronic factors on catalytic activity. Inorganica Chim Acta 2019. [DOI: 10.1016/j.ica.2018.09.069] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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17
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A monomeric manganese(II) catecholato complex: Synthesis, crystal structure, and reactivity toward molecular oxygen. Inorganica Chim Acta 2019. [DOI: 10.1016/j.ica.2018.09.013] [Citation(s) in RCA: 3] [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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18
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Wang P, Killian MM, Saber MR, Qiu T, Yap GPA, Popescu CV, Rosenthal J, Dunbar KR, Brunold TC, Riordan CG. Electronic, Magnetic, and Redox Properties and O 2 Reactivity of Iron(II) and Nickel(II) o-Semiquinonate Complexes of a Tris(thioether) Ligand: Uncovering the Intradiol Cleaving Reactivity of an Iron(II) o-Semiquinonate Complex. Inorg Chem 2017; 56:10481-10495. [PMID: 28809555 PMCID: PMC6200398 DOI: 10.1021/acs.inorgchem.7b01491] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The iron(II) semiquinonate character within the iron(III) catecholate species has been proposed by numerous studies to account for the O2 reactivity of intradiol catechol dioxygenases, but a well-characterized iron(II) semiquinonate species that exhibits intradiol cleaving reactivity has not yet been reported. In this study, a detailed electronic structure description of the first iron(II) o-semiquinonate complex, [PhTttBu]Fe(phenSQ) [PhTttBu = phenyltris(tert-butylthiomethyl)borate; phenSQ = 9,10-phenanthrenesemiquinonate; Wang et al. Chem. Commun. 2014, 50, 5871-5873], was generated through a combination of electronic and Mössbauer spectroscopies, SQUID magnetometry, and density functional theory (DFT) calculations. [PhTttBu]Fe(phenSQ) reacts with O2 to generate an intradiol cleavage product, diphenic anhydride, in 16% yield. To assess the dependence of the intradiol reactivity on the identity of the metal ion, the nickel analogue, [PhTttBu]Ni(phenSQ), and its derivative, [PhTttBu]Ni(3,5-DBSQ) (3,5-DBSQ = 3,5-di-tert-butyl-1,2-semiquinonate), were prepared and characterized by X-ray crystallography, mass spectrometry, 1H NMR and electronic spectroscopies, and SQUID magnetometry. DFT calculations, evaluated on the basis of the experimental data, support the electronic structure descriptions of [PhTttBu]Ni(phenSQ) and [PhTttBu]Ni(3,5-DBSQ) as high-spin nickel(II) complexes with antiferromagnetically coupled semiquinonate ligands. Unlike its iron counterpart, [PhTttBu]Ni(phenSQ) decomposes slowly in an O2 atmosphere to generate 14% phenanthrenequinone with a negligible amount of diphenic anhydride. [PhTttBu]Ni(3,5-DBSQ) does not react with O2. This dramatic effect of the metal-ion identity supports the hypothesis that a metal(III) alkylperoxo species serves as an intermediate in the intradiol cleaving reactions. The redox properties of all three complexes were probed using cyclic voltammetry and differential pulse voltammetry, which indicate an inner-sphere electron-transfer mechanism for the formation of phenanthrenequinone. The lack of O2 reactivity of [PhTttBu]Ni(3,5-DBSQ) can be rationalized by the high redox potential of the metal-ligated 3,5-DBSQ/3,5-DBQ couple.
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Affiliation(s)
- Peng Wang
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, United States
| | - Michelle M. Killian
- Department of Chemistry, University of Wisconsin—Madison, Madison, Wisconsin 53706, United States
| | - Mohamed R. Saber
- Department of Chemistry, Texas A&M University, College Station, Texas 77842-3012, United States
| | - Tian Qiu
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, United States
| | - Glenn P. A. Yap
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, United States
| | - Codrina V. Popescu
- Department of Chemistry, Colgate University, 13 Oak Drive, Hamilton, New York 13346, United States
| | - Joel Rosenthal
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, United States
| | - Kim R. Dunbar
- Department of Chemistry, Texas A&M University, College Station, Texas 77842-3012, United States
| | - Thomas C. Brunold
- Department of Chemistry, University of Wisconsin—Madison, Madison, Wisconsin 53706, United States
| | - Charles G. Riordan
- Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, United States
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Al-Saidi HM. Biosorption using chitosan thiourea polymer as an extraction and preconcentration technique for copper prior to its determination in environmental and food samples by flame atomic absorption spectrometry: Synthesis, characterization and analytical applications. Int J Biol Macromol 2016; 93:390-401. [PMID: 27565297 DOI: 10.1016/j.ijbiomac.2016.08.060] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2016] [Revised: 08/05/2016] [Accepted: 08/22/2016] [Indexed: 10/21/2022]
Abstract
The present work describes the synthesis and use of the chitosan thiourea polymer (CT polymer) as a novel biosorbent for copper preconcentration prior to its determination by flame atomic absorption spectrometry (FAAS). CT polymer submitted in the present study was synthesized by the direct reaction between chitosan isolated from penaeus monodon chitin and ammonium thiocyanate, then the chemical structure and morphology of polymer were investigated by spectroscopic measurements, thermal analysis, X-ray diffraction (XRD) and scanning electron microscope (SEM). The results of SEM and XRD show that the prepared CT polymer has rough and hard surface with pores and nanofibers structure in the α-form. The height equivalent to the theoretical plates (HETP), the plates number (N), LOD and LOQ of CT polymer packed column were calculated to be 0.10±0.04mm, 100±2.02, 0.3μgL-1and 0.99μgL-1, respectively. The developed column was employed in combination with FAAS for the analysis of copper in a certified reference material (NRCC-SLRS-4 Riverine water), potato, tea, and rice. Furthermore, the structure of the copper complex with CT polymer was proven with the aid of different spectroscopic and magnetic measurements.
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Affiliation(s)
- H M Al-Saidi
- Department of Chemistry, University College in Al-Jamoum, Umm Al-Qura University, 21955 Makkah, Saudi Arabia.
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20
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Rakshit R, Mukherjee C. Secondary Interactions versus Intramolecular π–π Interactions in CuII–Diradical Complexes. Eur J Inorg Chem 2016. [DOI: 10.1002/ejic.201600019] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Richa Rakshit
- Department of Chemistry Indian Institute of Technology Guwahati 781029 Guwahati Assam India
| | - Chandan Mukherjee
- Department of Chemistry Indian Institute of Technology Guwahati 781029 Guwahati Assam India
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21
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Ghorai S, Sarmah A, Roy RK, Tiwari A, Mukherjee C. Effect of Geometrical Distortion on the Electronic Structure: Synthesis and Characterization of Monoradical-Coordinated Mononuclear Cu(II) Complexes. Inorg Chem 2016; 55:1370-80. [PMID: 26812584 DOI: 10.1021/acs.inorgchem.5b01257] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Ligand H3Sami(Mixed(tBu)) was composed of two different compartments, a redox-active 2-aminophenol and a salen salicylidene. Both compartments were linked via a benzyl linker. The ligand reacted with CuCl2·2H2O under air in the presence of Et3N and provided the corresponding monoradical-coordinated mononuclear Cu(II) complex (1). Complex 1, in solution, reacted with air and provided complex 2 via ligand-centered oxygenation at the benzyl-CH2 position. Both complexes were characterized via IR, mass spectrometry, X-ray single-crystal diffraction, variable-temperature magnetic susceptibility, cyclic voltammograms (CVs), and UV-vis/NIR spectroscopic techniques. X-ray crystallographic analyses clearly showed almost equally distorted square planar geometry around the Cu(II) atom in both complexes. However, the bending of the radical-containing C6 ring compared to the N1-Cu1-O1 plane was different in both complexes. While complex 1 was paramagnetic and showed a ferromagnetic coupling between the d(x(2)-y(2)) magnetic orbital of Cu(II) ion and the p(z) orbital of coordinated π-radical, complex 2 was diamagnetic by experiencing a strong antiferromagnetic coupling between the two magnetic orbitals. UV-vis/NIR spectra of the complexes were dominated by charge-transfer transitions. CVs of the complexes showed two reversible one-electron oxidations and one reversible one-electron reduction. E(1/2)(ox2) and E(1/2)(red1) potentials were different in both complexes, while E(1/2)(ox1) values were almost the same and the process corresponded to the formation of phenoxyl radical. Theoretical studies were also performed to understand the magnetic coupling phenomena, and TD-DFT calculations were employed for the assignment of charge-transfer absorption bands.
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Affiliation(s)
- Samir Ghorai
- Department of Chemistry, Indian Institute of Technology Guwahati , Guwahati, 781039 Assam, India
| | - Amrit Sarmah
- Department of Chemistry, Birla Institute of Technology and Science (BITS) , Pilani, 333031 Rajasthan, India
| | - Ram Kinkar Roy
- Department of Chemistry, Birla Institute of Technology and Science (BITS) , Pilani, 333031 Rajasthan, India
| | - Archana Tiwari
- Department of Physics, School of Physical Sciences, Sikkim University , Gangtok 737102 Sikkim, India
| | - Chandan Mukherjee
- Department of Chemistry, Indian Institute of Technology Guwahati , Guwahati, 781039 Assam, India
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22
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Dhara AK, Singh UP, Ghosh K. Radical pathways and O2 participation in benzyl alcohol oxidation, and catechol and o-aminophenol oxidase activity studies with novel zinc complexes: an experimental and theoretical investigation. Inorg Chem Front 2016. [DOI: 10.1039/c6qi00356g] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Diphenoxo bridged dinuclear zinc complexes were found to be capable of oxidation of benzyl alcohol, catechol and o-aminophenol.
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Affiliation(s)
- Ashish Kumar Dhara
- Department of Chemistry
- Indian Institute of Technology Roorkee
- Uttrakhand
- India
| | - Udai P. Singh
- Department of Chemistry
- Indian Institute of Technology Roorkee
- Uttrakhand
- India
| | - Kaushik Ghosh
- Department of Chemistry
- Indian Institute of Technology Roorkee
- Uttrakhand
- India
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23
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Sanyal R, Dash SK, Das S, Chattopadhyay S, Roy S, Das D. Catecholase activity, DNA cleavage and cytotoxicity of six Zn(II) complexes synthesized from designed Mannich ligands: higher reactivity of mononuclear over dinuclear. J Biol Inorg Chem 2014; 19:1099-111. [DOI: 10.1007/s00775-014-1148-z] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2014] [Accepted: 05/17/2014] [Indexed: 10/25/2022]
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24
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Patra A, Giri GC, Sen TK, Carrella L, Mandal SK, Bera M. Bis(μ-alkoxo) bridged dinuclear CuII2 and ZnII2 complexes of an isoindol functionality based new ligand: Synthesis, structure, spectral characterization, magnetic properties and catechol oxidase activity. Polyhedron 2014. [DOI: 10.1016/j.poly.2013.09.034] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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25
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Wang P, Yap GPA, Riordan CG. Five-coordinate MII-semiquinonate (M = Fe, Mn, Co) complexes: reactivity models of the catechol dioxygenases. Chem Commun (Camb) 2014; 50:5871-3. [DOI: 10.1039/c3cc49143a] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The first mononuclear iron(ii)-semiquinonate has been prepared. Analogous manganese and cobalt adducts are reported, including a cobalt(ii)-semiquinonate that exhibits O2-mediated intradiol oxidation.
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Affiliation(s)
- Peng Wang
- Department of Chemistry & Biochemistry
- University of Delaware
- Newark, USA
| | - Glenn P. A. Yap
- Department of Chemistry & Biochemistry
- University of Delaware
- Newark, USA
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26
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El-Metwally NM. Spectral and Biological Investigation for Cr(III), Mn(II), Co(II), Ni(II), Cu(II), Zn(II), and Cd(II) Complexes With Optically Active Compound. ACTA ACUST UNITED AC 2013. [DOI: 10.1080/15533174.2013.776601] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Affiliation(s)
- Nashwa M. El-Metwally
- a Department of Chemistry, Faculty of Science , Mansoura University , Egypt
- b Department of Chemistry, Faculty of Science of girls, Abha , King Khalid University , Saudi Arabia
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27
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Kirk ML, Shultz DA, Stasiw DE, Lewis GF, Wang G, Brannen CL, Sommer RD, Boyle PD. Superexchange Contributions to Distance Dependence of Electron Transfer/Transport: Exchange and Electronic Coupling in Oligo(para-Phenylene)- and Oligo(2,5-Thiophene)-Bridged Donor–Bridge–Acceptor Biradical Complexes. J Am Chem Soc 2013; 135:17144-54. [DOI: 10.1021/ja4081887] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Affiliation(s)
- Martin L. Kirk
- Department
of Chemistry and Chemical Biology, The University of New Mexico, MSC03
2060, 1 University of New Mexico, Albuquerque, New Mexico 87131-0001, United States
| | - David A. Shultz
- Department
of Chemistry, North Carolina State University, 2200 Hillsborough, Raleigh, North Carolina 27695-8204, United States
| | - Daniel E. Stasiw
- Department
of Chemistry, North Carolina State University, 2200 Hillsborough, Raleigh, North Carolina 27695-8204, United States
| | - Geoffrey F. Lewis
- Department
of Chemistry, North Carolina State University, 2200 Hillsborough, Raleigh, North Carolina 27695-8204, United States
| | - Guangbin Wang
- Department
of Chemistry, North Carolina State University, 2200 Hillsborough, Raleigh, North Carolina 27695-8204, United States
| | - Candice L. Brannen
- Department
of Chemistry, North Carolina State University, 2200 Hillsborough, Raleigh, North Carolina 27695-8204, United States
| | - Roger D. Sommer
- Department
of Chemistry, North Carolina State University, 2200 Hillsborough, Raleigh, North Carolina 27695-8204, United States
| | - Paul D. Boyle
- Department
of Chemistry, North Carolina State University, 2200 Hillsborough, Raleigh, North Carolina 27695-8204, United States
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28
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Kirk ML, Shultz DA, Stasiw DE, Habel-Rodriguez D, Stein B, Boyle PD. Electronic and Exchange Coupling in a Cross-Conjugated D–B–A Biradical: Mechanistic Implications for Quantum Interference Effects. J Am Chem Soc 2013; 135:14713-25. [DOI: 10.1021/ja405354x] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Affiliation(s)
- Martin L. Kirk
- Department of
Chemistry, The University of New Mexico, MSC03 2060, Albuquerque, New Mexico 87131-0001, United States
| | - David A. Shultz
- Department of
Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, United States
| | - Daniel E. Stasiw
- Department of
Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, United States
| | - Diana Habel-Rodriguez
- Department of
Chemistry, The University of New Mexico, MSC03 2060, Albuquerque, New Mexico 87131-0001, United States
| | - Benjamin Stein
- Department of
Chemistry, The University of New Mexico, MSC03 2060, Albuquerque, New Mexico 87131-0001, United States
| | - Paul D. Boyle
- Department of
Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, United States
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29
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Redox-active metal(II) complexes of sterically hindered phenolic ligands: Antibacterial activity and reduction of cytochrome c. Part III. Copper(II) complexes of cycloaminomethyl derivatives of o-diphenols. Polyhedron 2013. [DOI: 10.1016/j.poly.2013.04.015] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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30
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Abou-Melha KS. Spectral and Eukaryotic DNA degradation studies for Ni(II), Pd(II), Pt(IV), Cu(II) and UO2(2+) complexes derived from thiouracil derivative. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2013; 109:146-154. [PMID: 23518511 DOI: 10.1016/j.saa.2013.01.030] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2012] [Revised: 01/08/2013] [Accepted: 01/10/2013] [Indexed: 06/01/2023]
Abstract
A derivative of thiouracil ligand was prepared. Ni(II), Pd(II), Pt(IV), Cu(II) and UO2(2+) complexes were prepared. The elemental and different spectral tools were used for their characterization. A binegative tetradentate mode is the general coordination behavior of the ligand towards all metal ions used. The structural geometries were varied from square-planer (Pt, Pd(II)), square-pyramidal (Cu(II)) and octahedral (UO2(2+)). The geometry optimization implementing the hyperChem reveals that the Cu(II) complex is the most stable one. The thermogravimetric analysis supports the presence of solvent molecules attached with most complexes. The biological investigation was studied on different microorganisms as gram-positive, gram-negative and fungia. The Ni(II) complex shows the most toxic activity towards most organisms used. The degradation effect of DNA was studied by the use of investigated compounds and reveal that the Ni(II) and Pd(II) complexes are the most effective on the DNA degradation.
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Affiliation(s)
- Khlood S Abou-Melha
- Chemistry Department, Faculty of Science, King Khalid University, Abha, Saudi Arabia.
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31
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Komatsuzaki H, Shiota A, Hazawa S, Itoh M, Miyamura N, Miki N, Takano Y, Nakazawa J, Inagaki A, Akita M, Hikichi S. Manganese(II) semiquinonato and manganese(III) catecholato complexes with tridentate ligand: modeling the substrate-binding state of manganese-dependent catechol dioxygenase and reactivity with molecular oxygen. Chem Asian J 2013; 8:1115-9. [PMID: 23512755 DOI: 10.1002/asia.201300029] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2013] [Revised: 02/19/2013] [Indexed: 11/06/2022]
Abstract
Catecholate catwalk: Monomeric manganese(III) catecholato and manganese(II) semiquinonato complexes as the substrate-binding model of catechol dioxygenase have been synthesized and structurally characterized. The semiquinonato complex reacted with molecular oxygen to give ring-cleaved products and benzoquinone in the catalytic condition.
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Affiliation(s)
- Hidehito Komatsuzaki
- Department of Chemistry and Material Engineering, Ibaraki National College of Technology, 866 Nakane, Hitachinaka, 312-8508, Japan.
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32
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33
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Ikeda A, Hoshino K, Komatsuzaki H, Satoh M, Nakazawa J, Hikichi S. O2 activation and external substrate oxidation capability of a Co(ii)–semiquinonato complex. NEW J CHEM 2013. [DOI: 10.1039/c3nj00215b] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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34
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Yu F, Li B. The effects of tripodal ligands on charge distribution in cobalt(III)-catecholate and cobalt(II)-semiquinonate compounds. Inorganica Chim Acta 2012. [DOI: 10.1016/j.ica.2012.06.023] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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35
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Guha A, Chattopadhyay T, Paul ND, Mukherjee M, Goswami S, Mondal TK, Zangrando E, Das D. Radical Pathway in Catecholase Activity with Zinc-Based Model Complexes of Compartmental Ligands. Inorg Chem 2012; 51:8750-9. [DOI: 10.1021/ic300400v] [Citation(s) in RCA: 96] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Averi Guha
- Department
of Chemistry, University of Calcutta, 92,
A. P. C. Road, Kolkata
700 009, India
| | | | - Nanda Dulal Paul
- Department
of Inorganic Chemistry, Indian Association for the Cultivation of Science,
Jadavpur, Kolkata 700 032, India
| | - Madhuparna Mukherjee
- Department
of Chemistry, University of Calcutta, 92,
A. P. C. Road, Kolkata
700 009, India
| | - Somen Goswami
- Department
of Chemistry, University of Calcutta, 92,
A. P. C. Road, Kolkata
700 009, India
| | - Tapan Kumar Mondal
- Department of Chemistry, Jadavpur University, Jadavpur, Kolkata 700 032, India
| | - Ennio Zangrando
- Dipartimento di Scienze Chimiche
e Farmaceutiche, University of Trieste,
Via L. Giorgieri 1, 34127 Trieste, Italy
| | - Debasis Das
- Department
of Chemistry, University of Calcutta, 92,
A. P. C. Road, Kolkata
700 009, India
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36
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Hassan HHAM, Elhusseiny AF, Sweyllam AM, Linhardt RJ. New sulfonated aramide nanoparticles and their copper complexes with anomalous dielectric behavior. J Appl Polym Sci 2012. [DOI: 10.1002/app.36791] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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37
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Oseback SN, Shim SW, Kumar M, Greer SM, Gardner SR, Lemar KM, DeGregory PR, Papish ET, Tierney DL, Zeller M, Yap GPA. Crowded bis ligand complexes of TtzPh,Me with first row transition metals rearrange due to ligand field effects: structural and electronic characterization (TtzPh,Me = tris(3-phenyl-5-methyl-1,2,4-triazolyl)borate). Dalton Trans 2012; 41:2774-87. [DOI: 10.1039/c2dt12029a] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Affiliation(s)
- Shannon N Oseback
- Departments of Chemistry, Drexel University, Philadelphia, PA 19104, USA
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38
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Hassan HH, Elhusseiny AF, Sweyllam AM. Polyamides nanoparticles containing flexible linkages and their copper complexes with novel dielectric properties: Structure–property relationship. J Mol Struct 2011. [DOI: 10.1016/j.molstruc.2011.06.023] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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39
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Verma P, Weir J, Mirica L, Stack TDP. Tale of a twist: magnetic and optical switching in copper(II) semiquinone complexes. Inorg Chem 2011; 50:9816-25. [PMID: 21696132 DOI: 10.1021/ic200958g] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
An intermediate (C) that is observed in both phenol hydroxylation and catechol oxidation with the side-on peroxide species [Cu(2)O(2)(DBED)(2)](2+) (DBED = N(1),N(2)-di-tert-butylethane-1,2-diamine) is identified as a copper(II) semiquinone species ([1](+)) through independent synthesis and characterization. The reaction of the redox-active 3,5-di-tert-butylquinone ligand with [(DBED)Cu(I)(MeCN)](+) yields a copper(II) semiquinone [1](+) complex with a singlet ground state and an intense purple chromophore (ε(580) ~ 3500 M(-1) cm(-1)). All other copper(II) semiquinone complexes characterized to date are paramagnetic and weakly colored (ε(800) ~ 500 M(-1) cm(-1)). Antiferromagnetic coupling between the Cu(II) center and the semiquinone radical in [1](+) is characterized by paramagnetic (1)H NMR and SQUID magnetometry. Comparative X-ray crystal structures along with density functional theory calculations correlate the geometric structures of copper(II) semiquinone complexes with their magnetic and optical properties. The unique observable properties of [1](+) originate from an increase in the overlap of the Cu 3d and semiquinone π orbitals resulting from a large rhombic distortion in the structure with a twist of 51°, attributable to the large isotropic demands of the tert-butyl substituents of the DBED ligand. Independent characterization of [1](+) allows the spectroscopic yields of intermediate C to be quantified in this intriguing hydroxylation reaction.
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Affiliation(s)
- Pratik Verma
- Department of Chemistry, Stanford University, Stanford, California 94305, USA
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40
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Al Radadi NS, Al Ashqar SMA, Mostafa MM. Synthesis and Characterization of Some New Binary and Ternary CuII Complexes. ACTA ACUST UNITED AC 2011. [DOI: 10.1080/15533174.2010.538287] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- Najlaa S. Al Radadi
- a Scientific Department, College of Education (Girl’s) , Taibah University , Al-Madinah Al-Munawwarah, Saudi Arabia
| | - Sawsan M. A. Al Ashqar
- b Chemistry Department, Faculty of Applied Sciences (Girl’s) , Umm Al-Qura University , Makkah, Saudi Arabia
| | - Mohsen M. Mostafa
- c Chemistry Department, Faculty of Science , Mansoura University , Mansoura, Egypt
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41
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42
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Hassan HHAM, Elhusseiny AF, Sweyllam AM. Synthesis and Properties of Narrow-sized Spherical Aramides Nanoparticles Containing Pyridine and their Copper (II) Complexes. JOURNAL OF MACROMOLECULAR SCIENCE PART A-PURE AND APPLIED CHEMISTRY 2010. [DOI: 10.1080/10601325.2011.528312] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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43
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Graf M, Wolmershäuser G, Kelm H, Demeschko S, Meyer F, Krüger HJ. Temperature-Induced Spin-Transition in a Low-Spin Cobalt(II) Semiquinonate Complex. Angew Chem Int Ed Engl 2010. [DOI: 10.1002/ange.200903789] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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44
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Kirk ML, Shultz DA, Schmidt RD, Habel-Rodriguez D, Lee H, Lee J. Ferromagnetic nanoscale electron correlation promoted by organic spin-dependent delocalization. J Am Chem Soc 2009; 131:18304-13. [PMID: 19928960 PMCID: PMC3505726 DOI: 10.1021/ja904648r] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
We describe the electronic structure and the origin of ferromagnetic exchange coupling in two new metal complexes, NN-SQ-Co(III)(py)(2)Cat-NN (1) and NN-Ph-SQ-Co(III)(py)(2)Cat-Ph-NN (2) (NN = nitronylnitroxide radical, Ph = 1,4-phenylene, SQ = S = (1)/(2) semiquinone radical, Cat = S = 0 catecholate, and py = pyridine). Near-IR electronic absorption spectroscopy for 1 and 2 reveals a low-energy optical band that has been assigned as a Psi(u) --> Psi(g) transition involving bonding and antibonding linear combinations of delocalized dioxolene (SQ/Cat) valence frontier molecular orbitals. The ferromagnetic exchange interaction in 1 is so strong that only the high-spin quartet state (S(T) = (3)/(2)) is thermally populated at temperatures up to 300 K. The temperature-dependent magnetic susceptibility data for 2 reveals that an excited state spin doublet (S(T) = (1)/(2)) is populated at higher temperatures, indicating that the phenylene spacer modulates the magnitude of the magnetic exchange. The valence delocalization within the dioxolene dyad of 2 results in ferromagnetic alignment of two localized NN radicals separated by over 22 A. The ferromagnetic exchange in 1 and 2 results from a spin-dependent delocalization (double exchange type) process and the origin of this strong electron correlation has been understood in terms of a valence bond configuration interaction (VBCI) model. We show that ferromagnetic coupling promoted by organic mixed-valency provides keen insight into the ability of single molecules to communicate spin information over nanoscale distances. Furthermore, the strong interaction between the itinerant dioxolene electron and localized NN electron spins impacts our ability to understand the exchange interaction between delocalized electrons and pinned magnetic impurities in technologically important dilute magnetic semiconductor materials. The long correlation length (22 A) of the itinerant electron that mediates this coupling indicates that high-spin pi-delocalized organic molecules could find applications as nanoscale spin-polarized electron injectors and molecular wires.
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Affiliation(s)
- Martin L. Kirk
- Department of Chemistry and Chemical Biology, The University of New Mexico, MSC03 2060, 1 University of New Mexico, Albuquerque, NM 87131-0001
| | - David A. Shultz
- Department of Chemistry, North Carolina State University, Raleigh, NC 27695-8204
| | - Robert D. Schmidt
- Department of Chemistry, North Carolina State University, Raleigh, NC 27695-8204
| | - Diana Habel-Rodriguez
- Department of Chemistry and Chemical Biology, The University of New Mexico, MSC03 2060, 1 University of New Mexico, Albuquerque, NM 87131-0001
| | - Hyoyoung Lee
- NCRI Center for Smart Molecular Memory, Department of Chemistry, Sungkyunkwan University, Suwon 440-746, Republic of Korea
| | - Junghyun Lee
- NCRI Center for Smart Molecular Memory, Department of Chemistry, Sungkyunkwan University, Suwon 440-746, Republic of Korea
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45
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Graf M, Wolmershäuser G, Kelm H, Demeschko S, Meyer F, Krüger HJ. Temperature-Induced Spin-Transition in a Low-Spin Cobalt(II) Semiquinonate Complex. Angew Chem Int Ed Engl 2009; 49:950-3. [DOI: 10.1002/anie.200903789] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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46
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Zhao N, Van Stipdonk MJ, Bauer C, Campana C, Eichhorn DM. Sandwich Compounds of Cyanotrispyrazolylborates: Complexation-Induced Ligand Isomerization. Inorg Chem 2007; 46:8662-7. [PMID: 17845029 DOI: 10.1021/ic700628b] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Reaction of the new cyanoscorpionate ligand, hydrotris(4-cyano-3-phenyl)pyrazolylborate (Tp(Ph),(4CN)) with Co(II), Mn(II), and Fe(II) unexpectedly results in the isolation only of crystals containing sandwich complexes in which the ligands have been isomerized to produce the heterocyanoscorpionate hydrobis(4-cyano-3-phenylpyrazolyl)(4-cyano-5-phenylpyrazolyl)borate (Tp(Ph),(4CN*)). The three complexes have been characterized crystallographically and are isostructural, with each ligand acting in a tridentate manner toward the metal. The isomerization of the ligand appears to be more facile than that of the analogous non-cyano ligand, Tp(Ph), with which crystals of the unisomerized sandwich compound have been isolated for Mn(II) and Fe(II).
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Affiliation(s)
- Ningfeng Zhao
- Department of Chemistry, Wichita State University, Wichita, Kansas 67260, USA
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Shashidhar, Shivakumar K, Reddy PV, Halli MB. Synthesis and spectroscopic characterization of metal complexes with naphthofuran-2-carbohydrazide Schiff 's base. J COORD CHEM 2007. [DOI: 10.1080/00958970601112051] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- Shashidhar
- a Materials Research Centre, Indian Institute of Science , Bangalore 560 012
| | - K. Shivakumar
- b Department of Chemistry , Gulbarga University , Gulbarga, Karnataka-India 585 106
| | - P. Vithal Reddy
- c Department of Chemistry , B.V.B. Degree College , Bidar 585 403
| | - M. B. Halli
- b Department of Chemistry , Gulbarga University , Gulbarga, Karnataka-India 585 106
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El-Metwally NM, Gabr IM, Shallaby AM, El-Asmy AA. Synthesis and spectroscopic characterization of new mono- and binuclear complexes of some NH(1) thiosemicarbazides. J COORD CHEM 2007. [DOI: 10.1080/00958970500155771] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Affiliation(s)
- Nashwa M. El-Metwally
- a Department of Chemistry , Faculty of Science, Mansoura University , Mansoura, Egypt
| | - I. M. Gabr
- a Department of Chemistry , Faculty of Science, Mansoura University , Mansoura, Egypt
| | - A. M. Shallaby
- a Department of Chemistry , Faculty of Science, Mansoura University , Mansoura, Egypt
| | - A. A. El-Asmy
- a Department of Chemistry , Faculty of Science, Mansoura University , Mansoura, Egypt
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El-Metwaly NM. Spectral and biological investigation of 5-hydroxyl-3-oxopyrazoline 1-carbothiohydrazide and its transition metal complexes. TRANSIT METAL CHEM 2006. [DOI: 10.1007/s11243-006-0135-9] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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50
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Loginova N, Koval’chuk T, Zheldakova R, Chernyavskaya A, Osipovich N, Glushonok G, Polozov G, Povalishev V, Sorokin V, Shadyro O. Synthesis, characterization and antifungal activity of copper (II) complexes of sterically hindered o-diphenol derivatives. Polyhedron 2006. [DOI: 10.1016/j.poly.2006.07.015] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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