1
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Carbonel H, Mikulski TD, Nugraha K, Johnston J, Wang Y, Brown SN. Optically active bis(aminophenols) and their metal complexes. Dalton Trans 2023; 52:13290-13303. [PMID: 37668189 DOI: 10.1039/d3dt02436a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/06/2023]
Abstract
Optically active C2-symmetric bis(aminophenols) based on (R)-2,2'-diaminobinaphthyl (BiniqH4) and (R,R)-2,3-butanediyldianthranilate (BdanH4) have been prepared by condensation of the diamines with 3,5-di-tert-butylcatechol. Group 10 bis(iminosemiquinone) complexes (R)-(Biniq)M (M = Pd, Pt) and (C,R,R)-(Bdan)Pd have been prepared by oxidatively metalating the corresponding ligands. In (R)-(Biniq)M, the C2 axis passes through the approximate square plane of the bis(iminosemiquinone)metal core, while in (C,R,R)-(Bdan)Pd the C2 axis is perpendicular to this plane. In the latter compound, the (R,R)-butanediyl strap binds selectively over one enantioface of the metal complex in a conformation where the methyl groups are anti to one another. Osmium oxo complexes with the intrinsically chiral OsO(amidophenoxide)2 chromophore are obtained by metalation of OsO(OCH2CH2O)2 with (R,R)-BdanH4. Both the (A,R,R) and (C,R,R) diastereomers can be observed, with metalation in refluxing toluene selectively giving the latter isomer. The electronic structures of the complexes are illuminated by the circular dichroism spectra, in conjuction with the optical spectra and TDDFT calculations.
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Affiliation(s)
- Halen Carbonel
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556-5670, USA.
| | - Timothy D Mikulski
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556-5670, USA.
| | - Kahargyan Nugraha
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556-5670, USA.
| | - James Johnston
- Department of Chemical and Biomolecular Engineering, University of Notre Dame, Notre Dame, IN 46556, USA
| | - Yichun Wang
- Department of Chemical and Biomolecular Engineering, University of Notre Dame, Notre Dame, IN 46556, USA
| | - Seth N Brown
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556-5670, USA.
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2
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Vo NT, Herrero C, Guillot R, Inceoglu T, Leibl W, Clémancey M, Dubourdeaux P, Blondin G, Aukauloo A, Sircoglou M. Intercepting a transient non-hemic pyridine N-oxide Fe(III) species involved in OAT reactions. Chem Commun (Camb) 2021; 57:12836-12839. [PMID: 34787138 DOI: 10.1039/d1cc04521k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In the context of bioinspired OAT catalysis, we developed a tetradentate dipyrrinpyridine ligand, a hybrid of hemic and non-hemic models. The catalytic activity of the iron(III) derivative was investigated in the presence of iodosylbenzene. Unexpectedly, MS, EPR, Mössbauer, UV-visible and FTIR spectroscopic signatures supported by DFT calculations provide convincing evidence for the involvement of a relevant FeIII-O-NPy active intermediate.
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Affiliation(s)
- Nhat Tam Vo
- Université Paris-Saclay, CNRS, Institut de chimie moléculaire et des matériaux d'Orsay, 91405, Orsay, France.
| | - Christian Herrero
- Université Paris-Saclay, CNRS, Institut de chimie moléculaire et des matériaux d'Orsay, 91405, Orsay, France.
| | - Régis Guillot
- Université Paris-Saclay, CNRS, Institut de chimie moléculaire et des matériaux d'Orsay, 91405, Orsay, France.
| | - Tanya Inceoglu
- Université Paris-Saclay, CNRS, Institut de chimie moléculaire et des matériaux d'Orsay, 91405, Orsay, France.
| | - Winfried Leibl
- Institute for integrative Biology of the Cell (I2BC), CEA, CNRS Université Paris-Saclay, 1, UMR 9198, 9119, Gif-sur-Yvette, France
| | - Martin Clémancey
- Laboratoire de Chimie et Biologie des Métaux, Univ. Grenoble Alpes, CNRS, CEA, IRIG, 17 rue des Martyrs, Grenoble F-38000, France
| | - Patrick Dubourdeaux
- Laboratoire de Chimie et Biologie des Métaux, Univ. Grenoble Alpes, CNRS, CEA, IRIG, 17 rue des Martyrs, Grenoble F-38000, France
| | - Geneviève Blondin
- Laboratoire de Chimie et Biologie des Métaux, Univ. Grenoble Alpes, CNRS, CEA, IRIG, 17 rue des Martyrs, Grenoble F-38000, France
| | - Ally Aukauloo
- Université Paris-Saclay, CNRS, Institut de chimie moléculaire et des matériaux d'Orsay, 91405, Orsay, France. .,Institute for integrative Biology of the Cell (I2BC), CEA, CNRS Université Paris-Saclay, 1, UMR 9198, 9119, Gif-sur-Yvette, France
| | - Marie Sircoglou
- Université Paris-Saclay, CNRS, Institut de chimie moléculaire et des matériaux d'Orsay, 91405, Orsay, France.
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3
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Ranis LG, Gianino J, Hoffman JM, Brown SN. Nonclassical oxygen atom transfer reactions of an eight-coordinate dioxomolybdenum( vi) complex. Inorg Chem Front 2021. [DOI: 10.1039/d1qi00308a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Eight-coordinate MoO2(DOPOQ)2 can donate two oxygen atoms to substrates such as phosphines in a four-electron nonclassical oxygen atom transfer reaction.
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Affiliation(s)
- Leila G. Ranis
- Department of Chemistry and Biochemistry
- University of Notre Dame
- Notre Dame
- USA
| | - Jacqueline Gianino
- Department of Chemistry and Biochemistry
- University of Notre Dame
- Notre Dame
- USA
| | - Justin M. Hoffman
- Department of Chemistry and Biochemistry
- University of Notre Dame
- Notre Dame
- USA
| | - Seth N. Brown
- Department of Chemistry and Biochemistry
- University of Notre Dame
- Notre Dame
- USA
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4
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Mashima K. Redox-Active α-Diimine Complexes of Early Transition Metals: From Bonding to Catalysis. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 2020. [DOI: 10.1246/bcsj.20200056] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Affiliation(s)
- Kazushi Mashima
- Department of Chemistry, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan
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5
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Do TH, Brown SN. Mono- and bimetallic pentacoordinate silicon complexes of a chelating bis(catecholimine) ligand. Dalton Trans 2019; 48:11565-11574. [PMID: 31297499 DOI: 10.1039/c9dt02475a] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Schiff base condensation of 4,5-diamino-9,9-dimethylxanthene with 4,6-di-tert-butylcatechol-3-carboxaldehyde affords the bis(catecholimine) ligand XbicH4, which can bind metals in both a square bis(catecholate) upper pocket and a pentagonal N2O3 lower pocket. Metalation with PhSiCl3 results in [(XbicH2)SiPh][HCl2], where the silicon adopts a five-coordinate, square pyramidal geometry in the upper pocket and the lower pocket binds to two protons on the imine nitrogens. Deprotonation of the imines with LiOtBu, NaN[SiMe3]2, or AgOAc results in binding of the univalent metal ion in the lower pocket, where it adopts an unusual pentagonal monopyramidal geometry in the solid state. The complexes show irreversible electrochemistry, with oxidations taking place at relatively high potentials.
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Affiliation(s)
- Thomas H Do
- Department of Chemistry and Biochemistry, University of Notre Dame, 251 Nieuwland Science Hall, Notre Dame, IN 46556-5670, USA.
| | - Seth N Brown
- Department of Chemistry and Biochemistry, University of Notre Dame, 251 Nieuwland Science Hall, Notre Dame, IN 46556-5670, USA.
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6
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Abstract
Strong π bonding in molybdenum(vi) tris(amidophenoxides) drives a preference for the fac geometry and quenches the metal's Lewis acidity.
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Affiliation(s)
- Alexander N. Erickson
- Department of Chemistry and Biochemistry
- 251 Nieuwland Science Hall
- University of Notre Dame
- Notre Dame
- USA
| | - Seth N. Brown
- Department of Chemistry and Biochemistry
- 251 Nieuwland Science Hall
- University of Notre Dame
- Notre Dame
- USA
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7
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Hoffman JM, Oliver AG, Brown SN. The Metal or the Ligand? The Preferred Locus for Redox Changes in Oxygen Atom Transfer Reactions of Rhenium Amidodiphenoxides. J Am Chem Soc 2017; 139:4521-4531. [DOI: 10.1021/jacs.7b00985] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Justin M. Hoffman
- Department of Chemistry and Biochemistry, University of Notre Dame, 251 Nieuwland Science Hall, Notre Dame, Indiana 46556-5670, United States
| | - Allen G. Oliver
- Department of Chemistry and Biochemistry, University of Notre Dame, 251 Nieuwland Science Hall, Notre Dame, Indiana 46556-5670, United States
| | - Seth N. Brown
- Department of Chemistry and Biochemistry, University of Notre Dame, 251 Nieuwland Science Hall, Notre Dame, Indiana 46556-5670, United States
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8
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Clarke RM, Hazin K, Thompson JR, Savard D, Prosser KE, Storr T. Electronic Structure Description of a Doubly Oxidized Bimetallic Cobalt Complex with Proradical Ligands. Inorg Chem 2015; 55:762-74. [DOI: 10.1021/acs.inorgchem.5b02231] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
- Ryan M. Clarke
- Department
of Chemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
| | - Khatera Hazin
- Department
of Chemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
| | - John R. Thompson
- Department
of Chemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
| | - Didier Savard
- Department
of Chemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
| | - Kathleen E. Prosser
- Department
of Chemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
| | - Tim Storr
- Department
of Chemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
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9
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Broere DLJ, Plessius R, van der Vlugt JI. New avenues for ligand-mediated processes--expanding metal reactivity by the use of redox-active catechol, o-aminophenol and o-phenylenediamine ligands. Chem Soc Rev 2015; 44:6886-915. [PMID: 26148803 DOI: 10.1039/c5cs00161g] [Citation(s) in RCA: 329] [Impact Index Per Article: 36.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Redox-active ligands have evolved from being considered spectroscopic curiosities - creating ambiguity about formal oxidation states in metal complexes - to versatile and useful tools to expand on the reactivity of (transition) metals or to even go beyond what is generally perceived possible. This review focusses on metal complexes containing either catechol, o-aminophenol or o-phenylenediamine type ligands. These ligands have opened up a new area of chemistry for metals across the periodic table. The portfolio of ligand-based reactivity invoked by these redox-active entities will be discussed. This ranges from facilitating oxidative additions upon d(0) metals or cross coupling reactions with cobalt(iii) without metal oxidation state changes - by functioning as an electron reservoir - to intramolecular ligand-to-substrate single-electron transfer to create a reactive substrate-centered radical on a Pd(ii) platform. Although the current state-of-art research primarily consists of stoichiometric and exploratory reactions, several notable reports of catalysis facilitated by the redox-activity of the ligand will also be discussed. In conclusion, redox-active ligands containing catechol, o-aminophenol or o-phenylenediamine moieties show great potential to be exploited as reversible electron reservoirs, donating or accepting electrons to activate substrates and metal centers and to enable new reactivity with both early and late transition as well as main group metals.
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Affiliation(s)
- Daniël L J Broere
- University of Amsterdam, van't Hoff Institute for Molecular Sciences, Homogeneous, Bio-Inspired and Supramolecular Catalysis Group, Science Park 904, Amsterdam, the Netherlands
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10
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Jurss JW, Khnayzer RS, Panetier JA, El Roz KA, Nichols EM, Head-Gordon M, Long JR, Castellano FN, Chang CJ. Bioinspired design of redox-active ligands for multielectron catalysis: effects of positioning pyrazine reservoirs on cobalt for electro- and photocatalytic generation of hydrogen from water. Chem Sci 2015; 6:4954-4972. [PMID: 29142725 PMCID: PMC5664355 DOI: 10.1039/c5sc01414j] [Citation(s) in RCA: 81] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2015] [Accepted: 06/09/2015] [Indexed: 01/18/2023] Open
Abstract
Mononuclear metalloenzymes in nature can function in cooperation with precisely positioned redox-active organic cofactors in order to carry out multielectron catalysis. Inspired by the finely tuned redox management of these bioinorganic systems, we present the design, synthesis, and experimental and theoretical characterization of a homologous series of cobalt complexes bearing redox-active pyrazines. These donor moieties are locked into key positions within a pentadentate ligand scaffold in order to evaluate the effects of positioning redox non-innocent ligands on hydrogen evolution catalysis. Both metal- and ligand-centered redox features are observed in organic as well as aqueous solutions over a range of pH values, and comparison with analogs bearing redox-inactive zinc(ii) allows for assignments of ligand-based redox events. Varying the geometric placement of redox non-innocent pyrazine donors on isostructural pentadentate ligand platforms results in marked effects on observed cobalt-catalyzed proton reduction activity. Electrocatalytic hydrogen evolution from weak acids in acetonitrile solution, under diffusion-limited conditions, reveals that the pyrazine donor of axial isomer 1-Co behaves as an unproductive electron sink, resulting in high overpotentials for proton reduction, whereas the equatorial pyrazine isomer complex 2-Co is significantly more active for hydrogen generation at lower voltages. Addition of a second equatorial pyrazine in complex 3-Co further minimizes overpotentials required for catalysis. The equatorial derivative 2-Co is also superior to its axial 1-Co congener for electrocatalytic and visible-light photocatalytic hydrogen generation in biologically relevant, neutral pH aqueous media. Density functional theory calculations (B3LYP-D2) indicate that the first reduction of catalyst isomers 1-Co, 2-Co, and 3-Co is largely metal-centered while the second reduction occurs at pyrazine. Taken together, the data establish that proper positioning of non-innocent pyrazine ligands on a single cobalt center is indeed critical for promoting efficient hydrogen catalysis in aqueous media, akin to optimally positioned redox-active cofactors in metalloenzymes. In a broader sense, these findings highlight the significance of electronic structure considerations in the design of effective electron-hole reservoirs for multielectron transformations.
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Affiliation(s)
- Jonah W Jurss
- Department of Chemistry , University of California , Berkeley , California 94720 , USA . ; ;
- Department of Chemistry and Biochemistry , University of Mississippi , University , MS 38677 , USA
- Chemical Sciences Division , Lawrence Berkeley National Laboratory , Berkeley , California 94720 , USA
| | - Rony S Khnayzer
- Department of Chemistry , North Carolina State University , Raleigh , NC 27695-8204 , USA .
- Department of Natural Sciences , Lebanese American University , Beirut 1102-2801 , Chouran , Lebanon
| | - Julien A Panetier
- Department of Chemistry , University of California , Berkeley , California 94720 , USA . ; ;
- Materials Sciences Division , Lawrence Berkeley National Laboratory , Berkeley , California 94720 , USA
| | - Karim A El Roz
- Department of Chemistry , North Carolina State University , Raleigh , NC 27695-8204 , USA .
| | - Eva M Nichols
- Department of Chemistry , University of California , Berkeley , California 94720 , USA . ; ;
- Chemical Sciences Division , Lawrence Berkeley National Laboratory , Berkeley , California 94720 , USA
| | - Martin Head-Gordon
- Department of Chemistry , University of California , Berkeley , California 94720 , USA . ; ;
- Chemical Sciences Division , Lawrence Berkeley National Laboratory , Berkeley , California 94720 , USA
| | - Jeffrey R Long
- Department of Chemistry , University of California , Berkeley , California 94720 , USA . ; ;
- Materials Sciences Division , Lawrence Berkeley National Laboratory , Berkeley , California 94720 , USA
| | - Felix N Castellano
- Department of Chemistry , North Carolina State University , Raleigh , NC 27695-8204 , USA .
| | - Christopher J Chang
- Department of Chemistry , University of California , Berkeley , California 94720 , USA . ; ;
- Department of Molecular and Cell Biology , University of California , Berkeley , California 94720 , USA
- Chemical Sciences Division , Lawrence Berkeley National Laboratory , Berkeley , California 94720 , USA
- Howard Hughes Medical Institute , University of California , Berkeley , California 94720 , USA
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11
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Lindley BM, Wolczanski PT, Cundari TR, Lobkovsky EB. First-Row Transition Metal and Lithium Pyridine-ene-amide Complexes Exhibiting N- and C-Isomers and Ligand-Based Activation of Benzylic C–H Bonds. Organometallics 2015. [DOI: 10.1021/acs.organomet.5b00385] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Brian M. Lindley
- Department of Chemistry & Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853, United States
| | - Peter T. Wolczanski
- Department of Chemistry & Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853, United States
| | - Thomas R. Cundari
- Department of Chemistry, Center for Advanced
Scientific Computing and Modeling (CASCaM), University of North Texas, Box 305070, Denton, Texas 76203-5070, United States
| | - Emil B. Lobkovsky
- Department of Chemistry & Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853, United States
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12
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Matsumoto T, Yano H, Wakizaka M, Kobayashi A, Kato M, Chang HC. Syntheses and Structures of Molybdenum-Oxo Complexes Prepared by the Reactions of [MoII2(OAc)4] with tert-Butyl- or Bromo-Substituted Catechols. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 2015. [DOI: 10.1246/bcsj.20140208] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- Takeshi Matsumoto
- Department of Applied Chemistry, Faculty of Science and Engineering, Chuo University
| | - Hirokazu Yano
- Department of Chemistry, Faculty of Science, Hokkaido University
| | | | | | - Masako Kato
- Department of Chemistry, Faculty of Science, Hokkaido University
| | - Ho-Chol Chang
- Department of Applied Chemistry, Faculty of Science and Engineering, Chuo University
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13
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Marshall-Roth T, Brown SN. Redox activity and π bonding in a tripodal seven-coordinate molybdenum(vi) tris(amidophenolate). Dalton Trans 2015; 44:677-85. [DOI: 10.1039/c4dt02936d] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A tripodal seven-coordinate tris(amidophenolato)molybdenum(vi) complex shows strong ligand-to-metal π donation (40 kcal mol−1 per π bond) and undergoes facile ligand-centered oxidation.
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Affiliation(s)
| | - Seth N. Brown
- Department of Chemistry and Biochemistry
- University of Notre Dame
- Notre Dame
- USA
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14
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Hulley EB, Williams VA, Morris WD, Wolczanski PT, Hernández-Burgos K, Lobkovsky EB, Cundari TR. Disparate reactivity from isomeric {Me 2 C(CH 2 N CHpy) 2 } and {Me 2 C(CH NCH 2 py) 2 } chelates in iron complexation. Polyhedron 2014. [DOI: 10.1016/j.poly.2014.07.039] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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15
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Williams VA, Wolczanski PT, Sutter J, Meyer K, Lobkovsky EB, Cundari TR. Iron complexes derived from {nacnac-(CH2py)2}- and {nacnac-(CH2py)(CHpy)}n ligands: stabilization of iron(II) via redox noninnocence. Inorg Chem 2014; 53:4459-74. [PMID: 24762120 DOI: 10.1021/ic5001123] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Nacnac-based tetradentate chelates, {nacnac-(CH2py)2}(-) ({nn(PM)2}(-)) and {nacnac-(CH2py)(CHpy)}(n) ({nn(PM)(PI)}(n)) have been investigated in iron complexes. Treatment of Fe{N(TMS)2}2(THF) with {nn(PM)2}H afforded {nn(PM)2}FeN(TMS)2 [1-N(TMS)2], which led to {nn(PM)2}FeCl (1-Cl) from HCl and to {nn(PM)2}FeN3 (1-N3) upon salt metathesis. Dehydroamination of 1-N(TMS)2 was induced by L (L = PMe3, CO) to afford {nn(PM)(PI)}Fe(PMe3)2 [2-(PMe3)2] and {nn(PM)(PI)}FeCO (3-CO). Substitution of 2-(PMe3)2 led to {nn(PM)(PI)}Fe(PMe3)CO [2-(PMe3)CO], and exposure to a vacuum provided {nn(PM)(PI)}Fe(PMe3) (3-PMe3). Metathesis routes to {nn(PM)(PI)}FeL2 (2-L2; L = PMe3, PMe2Ph) and {nn(PM)(PI)}FeL (3-L; L = PMePh2, PPh3) from [{nn(PM)(PI)}(2-)]Li2 and FeBr2(THF)2 in the presence of L proved feasible, and 1e(-) and 2e(-) oxidation of 2-(PMe3)2 afforded 2(+)-(PMe3)2 and 2(2+)-(PMe3)2 salts. Mössbauer spectroscopy, structural studies, and calculational assessments revealed the dominance of iron(II) in both high-spin (1-X) and low-spin (2-L2 and 3-L) environments, and the redox noninnocence (RNI) of {nn(PM)(PI)}(n) [2-L2, 3-L, n = 2-; 2(+)-(PMe3)2, n = 1-; 2(2+)-(PMe3)2, n = 0]. A discussion regarding the utility of RNI in chemical reactivity is proffered.
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Affiliation(s)
- Valerie A Williams
- Baker Laboratory, Department of Chemistry & Chemical Biology, Cornell University , Ithaca, New York 14853, United States
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16
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Abstract
The dioxomolybdenum(vi) complex ((t)BuClipH2)MoO2 ((t)BuClipH4 = 4,4'-di-tert-butyl-N,N'-bis(3,5-di-tert-butyl-2-hydroxyphenyl)-2,2'-diaminobiphenyl) reacts with 3,5-di-tert-butylcatechol to form oxo-free ((t)BuClip)Mo(3,5-(t)Bu2Cat). The bis(amidophenoxide)-monocatecholate complex is monomeric and exhibits a cis-β geometry in the solid state. Variable-temperature NMR data are consistent with two fluxional processes, one that interconverts several geometric isomers at low temperature, and a second that interchanges the ends of the (t)BuClip ligand at ambient temperatures. The high-temperature fluxional process can be explained by a single Bailar trigonal twist coupled with atropisomerization of the chiral diaminobiaryl backbone. Addition of excess catechol to ((t)BuClipH2)MoO2 results in formation of a dimolybdenum mono-oxo complex ((t)BuClip)Mo(μ-3,5-(t)Bu2Cat)2Mo(O)(3,5-(t)Bu2Cat). This complex, which contains a seven-coordinate bis(amidophenoxide)molybdenum center and a six-coordinate oxomolybdenum center, represents a structural hybrid between dimeric oxomolybdenumbis(catecholate) and molybdenum tris(catecholate) complexes. Both mono- and dimolybdenum complexes are best formulated as containing Mo(vi), but there is structural evidence for significant π donation from the amidophenolates. ((t)BuClip)Mo(3,5-(t)Bu2Cat) binds pyridine to form a mixture of isomeric seven-coordinate adducts. The Lewis acidity of the mixed amidophenoxide-catecholate appears to be lower than its tris(catecholate) or oxobis(amidophenoxide) analogues, which manifests itself principally in relatively slow binding of pyridine to the six-coordinate complex (k = 8 × 10(4) L mol(-1) s(-1) at 0 °C) rather than in the rate of dissociation of pyridine from the seven-coordinate adduct.
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Affiliation(s)
- Sukesh Shekar
- Department of Chemistry and Biochemistry, 251 Nieuwland Science Hall, University of Notre Dame, Notre Dame, IN 46556-5670, USA.
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17
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Randolph AH, Seewald NJ, Rickert K, Brown ASN. Tris(3,5-di-tert-butylcatecholato)molybdenum(VI): Lewis Acidity and Nonclassical Oxygen Atom Transfer Reactions. Inorg Chem 2013; 52:12587-98. [DOI: 10.1021/ic401736f] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Amanda H. Randolph
- Department of Chemistry and Biochemistry, University of Notre Dame, 251 Nieuwland
Science Hall, Notre Dame, Indiana 46556-5670, United States
| | - Nicholas J. Seewald
- Department of Chemistry and Biochemistry, University of Notre Dame, 251 Nieuwland
Science Hall, Notre Dame, Indiana 46556-5670, United States
| | - Karl Rickert
- Department of Chemistry and Biochemistry, University of Notre Dame, 251 Nieuwland
Science Hall, Notre Dame, Indiana 46556-5670, United States
| | - and Seth N. Brown
- Department of Chemistry and Biochemistry, University of Notre Dame, 251 Nieuwland
Science Hall, Notre Dame, Indiana 46556-5670, United States
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18
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Munhá RF, Zarkesh RA, Heyduk AF. Tuning the Electronic and Steric Parameters of a Redox-Active Tris(amido) Ligand. Inorg Chem 2013; 52:11244-55. [DOI: 10.1021/ic401496w] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Affiliation(s)
- Rui F. Munhá
- Department
of Chemistry, University of California, Irvine, California 92697-2025, United States
| | - Ryan A. Zarkesh
- Department
of Chemistry, University of California, Irvine, California 92697-2025, United States
| | - Alan F. Heyduk
- Department
of Chemistry, University of California, Irvine, California 92697-2025, United States
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Wright DD, Brown SN. Nonclassical Oxygen Atom Transfer as a Synthetic Strategy: Preparation of an Oxorhenium(V) Complex of the Bis(3,5-di-tert-butyl-2-phenoxo)amide Ligand. Inorg Chem 2013; 52:7831-3. [DOI: 10.1021/ic4010592] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Daniel D. Wright
- Department
of Chemistry and Biochemistry, 251 Nieuwland Science Hall, University of Notre Dame, Notre Dame, Indiana 46556-5670,
United States
| | - Seth N. Brown
- Department
of Chemistry and Biochemistry, 251 Nieuwland Science Hall, University of Notre Dame, Notre Dame, Indiana 46556-5670,
United States
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20
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Nippe M, Khnayzer RS, Panetier JA, Zee DZ, Olaiya BS, Head-Gordon M, Chang CJ, Castellano FN, Long JR. Catalytic proton reduction with transition metal complexes of the redox-active ligand bpy2PYMe. Chem Sci 2013. [DOI: 10.1039/c3sc51660a] [Citation(s) in RCA: 151] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
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21
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Williams VA, Hulley EB, Wolczanski PT, Lancaster KM, Lobkovsky EB. Exploring the limits of redox non-innocence: pseudo square planar [{κ4-Me2C(CH2NCHpy)2}Ni]n (n = 2+, 1+, 0, −1, −2) favor Ni(ii). Chem Sci 2013. [DOI: 10.1039/c3sc50743b] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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22
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Munhá RF, Zarkesh RA, Heyduk AF. Group transfer reactions of d0 transition metal complexes: redox-active ligands provide a mechanism for expanded reactivity. Dalton Trans 2013; 42:3751-66. [DOI: 10.1039/c2dt32063k] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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23
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Basu P, Kail BW, Adams AK, Nemykin VN. Quantitation of the ligand effect in oxo-transfer reactions of dioxo-Mo(VI) trispyrazolyl borate complexes. Dalton Trans 2012; 42:3071-81. [PMID: 23212540 DOI: 10.1039/c2dt32349d] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The oxygen atom transfer reactivity (OAT) of dioxo-Mo(VI) complexes of hydrotrispyrazolyl borate (hydrotris(3,5-dimethylpyrazolyl)borate, Tp(Me2); hydrotris(3-isopropylpyrazol-1-yl)borate, Tp(iPr)) with tertiary phosphines (PMe(3), PMe(2)Ph, PEt(3), PEt(2)Ph, PBu(n)(3), PMePh(2), or PEtPh(2)) has been investigated. In acetonitrile, these reactions proceed via the formation of a phosphoryl intermediate complex that undergoes a solvolysis reaction. We report the synthesis and characterization of several phosphoryl complexes. The rates of formation of phosphoryl complexes and their solvation were determined by spectrophotometry. The rates of the reactions and the properties of the phosphoryl species were investigated using the Quantitative Analysis of Ligand Effect (QALE) methodology. The results show that, at least in this system, the first step of the reaction is controlled primarily by the steric factor, and in the second step, both electronic and steric factors are important. We also analyzed the effect of ligands on the reaction rate i.e., Tp(Me2)vs. Tp(iPr).
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Affiliation(s)
- Partha Basu
- Department of Chemistry and Biochemistry, Duquesne University, Pittsburgh, PA 15228, USA.
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