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Lohmeyer L, Werr M, Kaifer E, Himmel H. Interplay and Competition Between Two Different Types of Redox-Active Ligands in Cobalt Complexes: How to Allocate the Electrons? Chemistry 2022; 28:e202201789. [PMID: 35894809 PMCID: PMC9804828 DOI: 10.1002/chem.202201789] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Indexed: 01/09/2023]
Abstract
The field of molecular transition metal complexes with redox-active ligands is dominated by compounds with one or two units of the same redox-active ligand; complexes in which different redox-active ligands are bound to the same metal are uncommon. This work reports the first molecular coordination compounds in which redox-active bisguanidine or urea azine (biguanidine) ligands as well as oxolene ligands are bound to the same cobalt atom. The combination of two different redox-active ligands leads to mono- as well as unprecedented dinuclear cobalt complexes, being multiple (four or six) center redox systems with intriguing electronic structures, all exhibiting radical ligands. By changing the redox potential of the ligands through derivatisation, the electronic structure of the complexes could be altered in a rational way.
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Affiliation(s)
- Lukas Lohmeyer
- Anorganisch-Chemisches InstitutRuprecht-Karls-Universität HeidelbergIm Neuenheimer Feld 27069120HeidelbergGermany
| | - Marco Werr
- Anorganisch-Chemisches InstitutRuprecht-Karls-Universität HeidelbergIm Neuenheimer Feld 27069120HeidelbergGermany
| | - Elisabeth Kaifer
- Anorganisch-Chemisches InstitutRuprecht-Karls-Universität HeidelbergIm Neuenheimer Feld 27069120HeidelbergGermany
| | - Hans‐Jörg Himmel
- Anorganisch-Chemisches InstitutRuprecht-Karls-Universität HeidelbergIm Neuenheimer Feld 27069120HeidelbergGermany
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2
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Scherer TM, Hartenbach I, Lissner F, Schwederski B, Hübner R, Fiedler J, Záliš S, Sarkar B, Kaim W. Analysis of Multiple Redox Sites in Complexes [M(C
5
Me
5
)(Q)(NO)]
n
, M=Ru or Os, Q=
o
‐Quinones. Z Anorg Allg Chem 2021. [DOI: 10.1002/zaac.202000420] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Thomas M. Scherer
- Institut für Anorganische Chemie Universität Stuttgart Pfaffenwaldring 55 D-70550 Stuttgart Germany
| | - Ingo Hartenbach
- Institut für Anorganische Chemie Universität Stuttgart Pfaffenwaldring 55 D-70550 Stuttgart Germany
| | - Falk Lissner
- Institut für Anorganische Chemie Universität Stuttgart Pfaffenwaldring 55 D-70550 Stuttgart Germany
| | - Brigitte Schwederski
- Institut für Anorganische Chemie Universität Stuttgart Pfaffenwaldring 55 D-70550 Stuttgart Germany
| | - Ralph Hübner
- Institut für Anorganische Chemie Universität Stuttgart Pfaffenwaldring 55 D-70550 Stuttgart Germany
| | - Jan Fiedler
- The Czech Academy of Sciences J. Heyrovský Institute of Physical Chemistry Dolejškova 3 18223 Prague Czech Republic
| | - Stanislav Záliš
- The Czech Academy of Sciences J. Heyrovský Institute of Physical Chemistry Dolejškova 3 18223 Prague Czech Republic
| | - Biprajit Sarkar
- Institut für Anorganische Chemie Universität Stuttgart Pfaffenwaldring 55 D-70550 Stuttgart Germany
| | - Wolfgang Kaim
- Institut für Anorganische Chemie Universität Stuttgart Pfaffenwaldring 55 D-70550 Stuttgart Germany
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3
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Bauer S, Záliš S, Fiedler J, Ringenberg MR, Kaim W. Oxidation State Assignments in the Organoplatinum One‐Electron Redox Series [(N
^
N)PtMes
2
]
n
,
n
= +,0, –,2‐. Eur J Inorg Chem 2020. [DOI: 10.1002/ejic.202000257] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Affiliation(s)
- Sonja Bauer
- Institut für Anorganische Chemie Universität Stuttgart Pfaffenwaldring 55 70550 Stuttgart Germany
| | - Stanislav Záliš
- J. Heyrovský Institute of Physical Chemistry The Czech Academy of Sciences Dolejškova 3 18223 Prague Czech Republic
| | - Jan Fiedler
- J. Heyrovský Institute of Physical Chemistry The Czech Academy of Sciences Dolejškova 3 18223 Prague Czech Republic
| | - Mark R. Ringenberg
- Institut für Anorganische Chemie Universität Stuttgart Pfaffenwaldring 55 70550 Stuttgart Germany
| | - Wolfgang Kaim
- Institut für Anorganische Chemie Universität Stuttgart Pfaffenwaldring 55 70550 Stuttgart Germany
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4
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Bagh B, Broere DLJ, Siegler MA, van der Vlugt JI. Redox-Active-Ligand-Mediated Formation of an Acyclic Trinuclear Ruthenium Complex with Bridging Nitrido Ligands. Angew Chem Int Ed Engl 2016. [DOI: 10.1002/ange.201603659] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Bidraha Bagh
- Homogeneous, Bioinspired and Supramolecular Catalysis, Van't Hoff Institute for Molecular Sciences; University of Amsterdam; Science Park 904 1098 XH Amsterdam The Netherlands
| | - Daniël L. J. Broere
- Homogeneous, Bioinspired and Supramolecular Catalysis, Van't Hoff Institute for Molecular Sciences; University of Amsterdam; Science Park 904 1098 XH Amsterdam The Netherlands
| | - Maxime A. Siegler
- Small Molecule X-ray Crystallography Facility, Department of Chemistry; John Hopkins University; Baltimore MD 21218 USA
| | - Jarl Ivar van der Vlugt
- Homogeneous, Bioinspired and Supramolecular Catalysis, Van't Hoff Institute for Molecular Sciences; University of Amsterdam; Science Park 904 1098 XH Amsterdam The Netherlands
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Bagh B, Broere DLJ, Siegler MA, van der Vlugt JI. Redox-Active-Ligand-Mediated Formation of an Acyclic Trinuclear Ruthenium Complex with Bridging Nitrido Ligands. Angew Chem Int Ed Engl 2016; 55:8381-5. [PMID: 27321547 DOI: 10.1002/anie.201603659] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2016] [Indexed: 01/24/2023]
Abstract
Coordination of a redox-active pyridine aminophenol ligand to Ru(II) followed by aerobic oxidation generates two diamagnetic Ru(III) species [1 a (cis) and 1 b (trans)] with ligand-centered radicals. The reaction of 1 a/1 b with excess NaN3 under inert atmosphere resulted in the formation of a rare bis(nitrido)-bridged trinuclear ruthenium complex with two nonlinear asymmetrical Ru-N-Ru fragments. The spontaneous reduction of the ligand centered radical in the parent 1 a/1 b supports the oxidation of a nitride (N(3-) ) to half an equivalent of N2 . The trinuclear omplex is reactive toward TEMPO-H, tin hydrides, thiols, and dihydrogen.
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Affiliation(s)
- Bidraha Bagh
- Homogeneous, Bioinspired and Supramolecular Catalysis, Van't Hoff Institute for Molecular Sciences, University of Amsterdam, Science Park 904, 1098, XH, Amsterdam, The Netherlands
| | - Daniël L J Broere
- Homogeneous, Bioinspired and Supramolecular Catalysis, Van't Hoff Institute for Molecular Sciences, University of Amsterdam, Science Park 904, 1098, XH, Amsterdam, The Netherlands
| | - Maxime A Siegler
- Small Molecule X-ray Crystallography Facility, Department of Chemistry, John Hopkins University, Baltimore, MD, 21218, USA
| | - Jarl Ivar van der Vlugt
- Homogeneous, Bioinspired and Supramolecular Catalysis, Van't Hoff Institute for Molecular Sciences, University of Amsterdam, Science Park 904, 1098, XH, Amsterdam, The Netherlands.
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6
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Kaim W. Complete and Partial Electron Transfer Involving Coordinated NOx. ADVANCES IN INORGANIC CHEMISTRY 2015. [DOI: 10.1016/bs.adioch.2014.10.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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7
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Bittner MM, Kraus D, Lindeman SV, Popescu CV, Fiedler AT. Synthetic, spectroscopic, and DFT studies of iron complexes with iminobenzo(semi)quinone ligands: implications for o-aminophenol dioxygenases. Chemistry 2013; 19:9686-98. [PMID: 23744733 PMCID: PMC3965334 DOI: 10.1002/chem.201300520] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2013] [Revised: 04/17/2013] [Indexed: 11/10/2022]
Abstract
The oxidative C-C bond cleavage of o-aminophenols by nonheme Fe dioxygenases is a critical step in both human metabolism (the kynurenine pathway) and the microbial degradation of nitroaromatic pollutants. The catalytic cycle of o-aminophenol dioxygenases (APDOs) has been proposed to involve formation of an Fe(II)/O2/iminobenzosemiquinone complex, although the presence of a substrate radical has been called into question by studies of related ring-cleaving dioxygenases. Recently, we reported the first synthesis of an iron(II) complex coordinated to an iminobenzosemiquinone (ISQ) ligand, namely, [Fe((Ph2)Tp)((tBu)ISQ)] (2a; where (Ph2)Tp=hydrotris(3,5-diphenylpyrazol-1-yl)borate and (tBu)ISQ is the radical anion derived from 2-amino-4,6-di-tert-butylphenol). In the current manuscript, density functional theory (DFT) calculations and a wide variety of spectroscopic methods (electronic absorption, Mössbauer, magnetic circular dichroism, and resonance Raman) were employed to obtain detailed electronic-structure descriptions of 2a and its one-electron oxidized derivative [3a](+). In addition, we describe the synthesis and characterization of a parallel series of complexes featuring the neutral supporting ligand tris(4,5-diphenyl-1-methylimidazol-2-yl)phosphine ((Ph2)TIP). The isomer shifts of about 0.97 mm s(-1) obtained through Mössbauer experiments confirm that 2a (and its (Ph2)TIP-based analogue [2b](+)) contain Fe(II) centers, and the presence of an ISQ radical was verified by analysis of the absorption spectra in light of time-dependent DFT calculations. The collective spectroscopic data indicate that one-electron oxidation of the Fe(II)-ISQ complexes yields complexes ([3a](+) and [3b](2+)) with electronic configurations between the Fe(III)-ISQ and Fe(II)-IBQ limits (IBQ=iminobenzoquinone), highlighting the ability of o-amidophenolates to access multiple oxidation states. The implications of these results for the mechanism of APDOs and other ring-cleaving dioxygenases are discussed.
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Affiliation(s)
- Michael M. Bittner
- Department of Chemistry, Marquette University, Milwaukee, Wisconsin 53201, United States
| | - David Kraus
- Department of Chemistry, Ursinus College, Collegeville, Pennsylvania 19426, United States
| | - Sergey V. Lindeman
- Department of Chemistry, Marquette University, Milwaukee, Wisconsin 53201, United States
| | - Codrina V. Popescu
- Department of Chemistry, Ursinus College, Collegeville, Pennsylvania 19426, United States
| | - Adam T. Fiedler
- Department of Chemistry, Marquette University, Milwaukee, Wisconsin 53201, United States
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Das D, Agarwala H, Chowdhury AD, Patra T, Mobin SM, Sarkar B, Kaim W, Lahiri GK. Four-Center Oxidation State Combinations and Near-Infrared Absorption in [Ru(pap)(Q)2]n(Q=3,5-Di-tert-butyl-N-aryl-1,2-benzoquinonemonoimine, pap=2-Phenylazopyridine). Chemistry 2013; 19:7384-94. [DOI: 10.1002/chem.201204620] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2012] [Indexed: 12/26/2022]
Affiliation(s)
- Dipanwita Das
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai-400076, India
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9
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Das A, Scherer TM, Mobin SM, Kaim W, Lahiri GK. 9-Oxidophenalenone: a noninnocent β-diketonate ligand? Inorg Chem 2012; 51:4390-7. [PMID: 22435485 DOI: 10.1021/ic300207d] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The redox systems [Ru(L)(bpy)(2)](k), [Ru(L)(2)(bpy)](m), and [Ru(L)(3)](n) containing the potentially redox-active ligand 9-oxidophenalenone = L(-) were investigated by spectroelectrochemistry (UV-vis-near-IR and electron paramagnetic resonance) in conjunction with density functional theory (DFT) calculations. Compounds [Ru(L(-))(bpy)(2)]ClO(4) ([1]ClO(4)) and [Ru(L(-))(2)(bpy)]ClO(4) ([2]ClO(4)) were structurally characterized. In addition to establishing electron-transfer processes involving the Ru(II)/Ru(III)/Ru(IV) and bpy(0)/bpy(•-) couples, evidence for the noninnocent behavior of L(-) was obtained from [Ru(IV)(L(•))(L(-))(bpy)](3+), which exhibits strong near-IR absorption due to ligand-to-ligand charge transfer. In contrast, the lability of the electrogenerated anion [Ru(L)(2)(bpy)](-) is attributed to a resonance situation [Ru(II)(L(•2-))(L(-))(bpy)](-)/[Ru(II)(L(-))(2) (bpy(•-))](-), as suggested by DFT calculations.
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Affiliation(s)
- Amit Das
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
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Walther M, Puchta R. Ligand exchange processes on solvated beryllium cations VII – water exchange on cationic [Be(H2O)3(Ln)]2+n (Ln: 4-O-Py−, Py, 4-(Py)-Py+, 3,5-(Py)2-Py2+, 3,4,5-(Py)3-Py3+). RSC Adv 2012. [DOI: 10.1039/c2ra20665j] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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11
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Das D, Sarkar B, Kumbhakar D, Mondal TK, Mobin SM, Fiedler J, Urbanos FA, Jiménez-Aparicio R, Kaim W, Lahiri GK. Bis(acetylacetonato)ruthenium Complexes of Noninnocent 1,2-Dioxolene Ligands: Qualitatively Different Bonding in Relation to Monoimino and Diimino Analogues. Chemistry 2011; 17:11030-40. [DOI: 10.1002/chem.201101009] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2011] [Indexed: 11/11/2022]
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12
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Tejel C, Asensio L, del Río MP, de Bruin B, López JA, Ciriano MA. Developing Synthetic Approaches with Non-Innocent Metalloligands: Easy Access to IrI/Pd0 and IrI/Pd0/IrI Cores. Angew Chem Int Ed Engl 2011. [DOI: 10.1002/ange.201104045] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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13
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Tejel C, Asensio L, del Río MP, de Bruin B, López JA, Ciriano MA. Developing Synthetic Approaches with Non-Innocent Metalloligands: Easy Access to IrI/Pd0 and IrI/Pd0/IrI Cores. Angew Chem Int Ed Engl 2011; 50:8839-43. [DOI: 10.1002/anie.201104045] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2011] [Indexed: 11/10/2022]
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Abstract
The potential of redox-active ligands to behave "noninnocently" in transition-metal coordination compounds is reflected with respect to various aspects and situations. These include the question of establishing "correct" oxidation states, the identification and characterization of differently charged radical ligands, the listing of structural and other consequences of ligand redox reactions, and the distinction between barrierless delocalized "resonance" cases M(n)/L(n) ↔ M(n+1)L(n-1) versus separated valence tautomer equilibrium situations M(n)/L(n) ⇌ M(n+1)L(n-1). Further ambivalence arises for dinuclear systems with radical bridge M(n)(μ-L(•))M(n) versus mixed-valent alternatives M(n+1)(μ-L(-))M(n), for noninnocent ligand-bridged coordination compounds of higher nuclearity such as (μ(3)-L)M(3), (μ(4)-L)M(4), (μ-L)(4)M(4), or coordination polymers. Conversely, the presence of more than one noninnocently behaving ligand at a single transition-metal site in situations such as L(n)-M-L(n-1) or L(•)-M-L(•) may give rise to corresponding ligand-to-ligand interaction phenomena (charge transfer, electron hopping, and spin-spin coupling) and to redox-induced electron transfer with counterintuitive oxidation-state changes. The relationships of noninnocent ligand behavior with excited-state descriptions and perspectives regarding material properties and single-electron or multielectron reactivity are also illustrated briefly.
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Affiliation(s)
- Wolfgang Kaim
- Institut für Anorganische Chemie, Universität Stuttgart, Pfaffenwaldring 55, D-70550 Stuttgart, Germany.
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Kundu T, Sarkar B, Mondal TK, Mobin SM, Urbanos FA, Fiedler J, Jiménez-Aparicio R, Kaim W, Lahiri GK. Redox-rich spin-spin-coupled semiquinoneruthenium dimers with intense near-IR absorption. Inorg Chem 2011; 50:4753-63. [PMID: 21517015 DOI: 10.1021/ic102280q] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Using the [RuCl(μ-tppz)ClRu](2+) [tppz = 2,3,5,6-tetrakis(2-pyridyl)pyrazine] platform for bridging two o-quinone/catecholate two-step redox systems (unsubstituted, Q(n), or 3,5- di-tert-butyl-substituted, DTBQ(n)), we have obtained the stable complexes [(Q(•-))Ru(II)Cl(μ-tppz)ClRu(II)(Q(•-))] (1) and the structurally characterized [(DTBQ(•-))Ru(II)Cl(μ-tppz)ClRu(II)(DTBQ(•-))] (2). The compounds exhibit mostly quinone-ligand-based redox activity within a narrow potential range, high-intensity near-IR absorptions (λ(max) ≈ 920 nm; ε > 50,000 M(-1) cm(-1)), and variable intra- and intermolecular spin-spin interactions. Density functional theory calculations, electron paramagnetic resonance (EPR), and spectroelectrochemical results (UV-vis-near-IR region) for three one-electron-reduction and two one-electron-oxidation processes were used to probe the electronic structures of the systems in the various accessible valence states. EPR spectroscopy of the singly charged doublet species showed semiquinone-type response for 1(+), 2(+), and 2(-), while 1 exhibits more metal based spin, a consequence of the easier reduction of Q as compared to DTBQ. Comparison with the analogous redox series involving a more basic N-phenyliminoquinone ligand reveals significant differences related to the shifted redox potentials, different space requirements, and different interactions between the metals and the quinone-type ligands. As a result, the tppz bridge is reduced here only after full reduction of the terminal quinone ligands to their catecholate states.
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Affiliation(s)
- Tanaya Kundu
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
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