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Mekhail MA, Pota K, Kharel S, Freire DM, Green KN. Pyridine modifications regulate the electronics and reactivity of Fe-pyridinophane complexes. Dalton Trans 2023; 52:892-901. [PMID: 36537287 PMCID: PMC10903111 DOI: 10.1039/d2dt03485a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
12-Membered pyridinophanes are the focus of many studies as biological mimics, chelators, and catalytic precursors. Therefore, the desire to tune the reactivity of pyridinophanes to better control the applications of derivative metal complexes has inspired many structure-activity relationship studies. However, the separation of structural versus electronic changes imparted by ligand modification has made these structure-activity relationship studies of transition metal catalysts challenging to define. In this work we show that 4-substitution of the pyridine ring in 12-membered tetra-aza pyridinophanes successfully provides a regulatory handle on the electronic properties of the metal center and, therefore, the catalytic C-C coupling activity of the respective iron complexes. The C-C coupling reaction catalyzed by Fe(L1-L6) provides a range of yields (32-58%) that directly correlate with iron redox potentials (ΔE1/2 = 152 mV) and metal binding constants (Δlog β = 3.45), while the geometry of the complexes was virtually indistinguishable. These are the first results to definitively show the redox potential and metal binding as independent properties from the coordination chemistry in one ligand series. Adjustments to these chemical properties were then shown to provide a regulatory handle for the C-C coupling reactivity tuned via pyridine substitution in pyridinophanes.
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Affiliation(s)
- Magy A Mekhail
- Department of Chemistry and Biochemistry, Texas Christian University, Fort Worth, Texas 76129, USA.
| | - Kristof Pota
- Department of Chemistry and Biochemistry, Texas Christian University, Fort Worth, Texas 76129, USA.
| | - Sugam Kharel
- Department of Chemistry and Biochemistry, Texas Christian University, Fort Worth, Texas 76129, USA.
| | - David M Freire
- Department of Chemistry and Biochemistry, Texas Christian University, Fort Worth, Texas 76129, USA.
| | - Kayla N Green
- Department of Chemistry and Biochemistry, Texas Christian University, Fort Worth, Texas 76129, USA.
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2
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Panza N, Tseberlidis G, Caselli A, Vicente R. Recent progresses in the chemistry of 12-membered pyridine-containing tetraazamacrocycles: From synthesis to catalysis. Dalton Trans 2022; 51:10635-10657. [DOI: 10.1039/d2dt00597b] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
This article provides an overview (non-comprehensive) on recent developments regarding pyridine-containing 12-membered tetraazamacrocycles with pyclen or Py2N2 backbones and their metal complexes from 2017 to the present. Firstly, the synthesis...
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3
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Brewer SM, Schwartz TM, Mekhail MA, Turan LS, Prior TJ, Hubin TJ, Janesko BG, Green KN. Mechanistic Insights into Iron-Catalyzed C–H Bond Activation and C–C Coupling. Organometallics 2021; 40:2467-2477. [DOI: 10.1021/acs.organomet.1c00211] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
- Samantha M. Brewer
- Department of Chemistry and Biochemistry, Texas Christian University, 2950 S. Bowie, Fort Worth, Texas 76129, United States
| | - Timothy M. Schwartz
- Department of Chemistry and Biochemistry, Texas Christian University, 2950 S. Bowie, Fort Worth, Texas 76129, United States
| | - Magy A. Mekhail
- Department of Chemistry and Biochemistry, Texas Christian University, 2950 S. Bowie, Fort Worth, Texas 76129, United States
| | - Lara S. Turan
- Department of Chemistry and Biochemistry, Texas Christian University, 2950 S. Bowie, Fort Worth, Texas 76129, United States
| | - Timothy J. Prior
- Department of Chemistry and Biochemistry, University of Hull, Hull HU6 7RX, U.K
| | - Timothy J. Hubin
- Department of Chemistry and Physics, Southwestern Oklahoma State University, 100 Campus Drive, Weatherford, Oklahoma 73096, United States
| | - Benjamin G. Janesko
- Department of Chemistry and Biochemistry, Texas Christian University, 2950 S. Bowie, Fort Worth, Texas 76129, United States
| | - Kayla N. Green
- Department of Chemistry and Biochemistry, Texas Christian University, 2950 S. Bowie, Fort Worth, Texas 76129, United States
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4
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Hunjan MK, Panday S, Gupta A, Bhaumik J, Das P, Laha JK. Recent Advances in Functionalization of Pyrroles and their Translational Potential. CHEM REC 2021; 21:715-780. [PMID: 33650751 DOI: 10.1002/tcr.202100010] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Revised: 02/08/2021] [Accepted: 02/10/2021] [Indexed: 12/25/2022]
Abstract
Among the known aromatic nitrogen heterocycles, pyrrole represents a privileged aromatic heterocycle ranging its occurrence in the key component of "pigments of life" to biologically active natural products to active pharmaceuticals. Pyrrole being an electron-rich heteroaromatic compound, its predominant functionalization is legendary to aromatic electrophilic substitution reactions. Although a few excellent reviews on the functionalization of pyrroles including the reports by Baltazzi in 1963, Casiraghi and Rassu in 1995, and Banwell in 2006 are available, they are fragmentary and over fifteen years old, and do not cover the modern aspects of catalysis. A review covering a comprehensive package of direct functionalization on pyrroles via catalytic and non-catalytic methods including their translational potential is described. Subsequent to statutory yet concise introduction, the classical functionalization on pyrroles using Lewis acids largely following an ionic mechanism is discussed. The subsequent discussion follows the various metal-catalyzed C-H functionalization on pyrroles, which are otherwise difficult to implement by Lewis acids. A major emphasize is given on the radical based pyrrole functionalization under metal-free oxidative conditions, which is otherwise poorly highlighted in the literature. Towards the end, the current development of pyrrole functionalization under photocatalyzed and electrochemical conditions is appended. Only a selected examples of substrates and important mechanisms are discussed for different methods highlighting their scopes and limitations. The aromatic nucleophillic substitution on pyrroles (being an electron-rich heterocycle) happened to be the subject of recent investigations, which has also been covered accentuating their underlying conceptual development. Despite great achievements over the past several years in these areas, many challenges and problems are yet to be solved, which are all discussed in summary and outlook.
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Affiliation(s)
- Mandeep Kaur Hunjan
- Department of Pharmaceutial Technology (Process Chemistry), National Institute of Pharmaceutical Education & Research (NIPER) S.A.S. Nagar, Mohali, 160062, India
| | - Surabhi Panday
- Department of Pharmaceutial Technology (Process Chemistry), National Institute of Pharmaceutical Education & Research (NIPER) S.A.S. Nagar, Mohali, 160062, India
| | - Anjali Gupta
- Department of Pharmaceutial Technology (Process Chemistry), National Institute of Pharmaceutical Education & Research (NIPER) S.A.S. Nagar, Mohali, 160062, India
| | - Jayeeta Bhaumik
- Center of Innovative and Applied Bioprocessing (CIAB), Department of Biotechnology (DBT), Government of India, Sector 81 (Knowledge City), S.A.S., Nagar, 140306, Punjab, India
| | - Parthasarathi Das
- Department of Chemistry, Indian Institute of Technology (Indian School of Mines) Dhanbad, Dhanbad, 826004, India
| | - Joydev K Laha
- Department of Pharmaceutial Technology (Process Chemistry), National Institute of Pharmaceutical Education & Research (NIPER) S.A.S. Nagar, Mohali, 160062, India
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Panza N, Biase A, Rizzato S, Gallo E, Tseberlidis G, Caselli A. Catalytic Selective Oxidation of Primary and Secondary Alcohols Using Nonheme [Iron(III)(Pyridine‐Containing Ligand)] Complexes. European J Org Chem 2020. [DOI: 10.1002/ejoc.202001201] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Nicola Panza
- Department of Chemistry Università degli Studi di Milano and CNR‐SCITEC via Golgi 19 – 20133 Milano Italy
| | - Armando Biase
- Department of Chemistry Università degli Studi di Milano and CNR‐SCITEC via Golgi 19 – 20133 Milano Italy
| | - Silvia Rizzato
- Department of Chemistry Università degli Studi di Milano and CNR‐SCITEC via Golgi 19 – 20133 Milano Italy
| | - Emma Gallo
- Department of Chemistry Università degli Studi di Milano and CNR‐SCITEC via Golgi 19 – 20133 Milano Italy
| | - Giorgio Tseberlidis
- Department of Chemistry Università degli Studi di Milano and CNR‐SCITEC via Golgi 19 – 20133 Milano Italy
- Department of Materials Science and Solar Energy Research Center (MIB‐SOLAR) University of Milano‐Bicocca Via Cozzi 55 20125 Milano Italy
| | - Alessandro Caselli
- Department of Chemistry Università degli Studi di Milano and CNR‐SCITEC via Golgi 19 – 20133 Milano Italy
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Freire DM, Beeri D, Pota K, Johnston HM, Palacios P, Pierce BS, Sherman BD, Green KN. Hydrogen Peroxide Disproportionation with Manganese Macrocyclic Complexes of Cyclen and Pyclen. Inorg Chem Front 2020; 7:1573-1582. [PMID: 32457818 DOI: 10.1039/c9qi01509d] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The catalase family of enzymes, which include a variety with a binuclear manganese active site, mitigate the risk from reactive oxygen species by facilitating the disproportionation of hydrogen peroxide into molecular oxygen and water. In this work, hydrogen peroxide disproportionation using complexes formed between manganese and cyclen or pyclen were investigated due to the spectroscopic similarities with the native MnCAT enzyme. Potentiometric titrations were used to construct speciation diagrams that identify the manganese complex compositions at different pH values. Each complex behaves as a functional mimic of catalase enzymes. UV-visible spectroscopic investigations of the H2O2 decomposition reaction yielded information about the structure of the initial catalyst and intermediates that include monomeric and dimeric species. The results indicate that rigidity imparted by the pyridine ring of pyclen is a key factor in increased TON and TOF values measured compared to cyclen.
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Affiliation(s)
- David M Freire
- Department of Chemistry and Biochemistry, Texas Christian University, 2950 W.Bowie, Fort Worth, TX 76129, United States
| | - Debora Beeri
- Department of Chemistry and Biochemistry, Texas Christian University, 2950 W.Bowie, Fort Worth, TX 76129, United States
| | - Kristof Pota
- Department of Chemistry and Biochemistry, Texas Christian University, 2950 W.Bowie, Fort Worth, TX 76129, United States
| | - Hannah M Johnston
- Department of Chemistry and Biochemistry, Texas Christian University, 2950 W.Bowie, Fort Worth, TX 76129, United States
| | - Philip Palacios
- Department of Chemistry and Biochemistry, The University of Texas at Arlington, 700 Planetarium Place, Arlington, TX 76019
| | - Brad S Pierce
- Department of Chemistry and Biochemistry, University of Alabama, 250 Hackberry Lane, Box 870336 Tuscaloosa, AL 35487
| | - Benjamin D Sherman
- Department of Chemistry and Biochemistry, Texas Christian University, 2950 W.Bowie, Fort Worth, TX 76129, United States
| | - Kayla N Green
- Department of Chemistry and Biochemistry, Texas Christian University, 2950 W.Bowie, Fort Worth, TX 76129, United States
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7
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Thapa P, Palacios PM, Tran T, Pierce BS, Foss FW. 1,2-Disubstituted Benzimidazoles by the Iron Catalyzed Cross-Dehydrogenative Coupling of Isomeric o-Phenylenediamine Substrates. J Org Chem 2020; 85:1991-2009. [PMID: 31928002 DOI: 10.1021/acs.joc.9b02714] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Benzimidazoles are common in nature, medicines, and materials. Numerous strategies for preparing 2-arylbenzimidazoles exist. In this work, 1,2-disubstituted benzimidazoles were prepared from various mono- and disubstituted ortho-phenylenediamines (OPD) by iron-catalyzed oxidative coupling. Specifically, O2 and FeCl3·6H2O catalyzed the cross-dehydrogenative coupling and aromatization of diarylmethyl and dialkyl benzimidazole precursors. N,N'-Disubstituted-OPD substrates were significantly more reactive than their N,N-disubstituted isomers, which appears to be relative to their propensity for complexation and charge transfer with Fe3+. The reaction also converted N-monosubstituted OPD substrates to 2-substituted benzimidazoles; however, electron-poor substrates produce 1,2-disubstituted benzimidazoles by intermolecular imino-transfer. Kinetic, reagent, and spectroscopic (UV-vis and EPR) studies suggest a mechanism involving metal-substrate complexation, charge transfer, and aerobic turnover, involving high-valent Fe(IV) intermediates. Overall, comparative strategies for the relatively sustainable and efficient synthesis of 1,2-disubstituted benzimidazoles are demonstrated.
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Affiliation(s)
- Pawan Thapa
- Department of Chemistry and Biochemistry , The University of Texas Arlington , Arlington , Texas 76019-0065 , United States
| | - Philip M Palacios
- Department of Chemistry and Biochemistry , The University of Texas Arlington , Arlington , Texas 76019-0065 , United States
| | - Tam Tran
- Department of Chemistry and Biochemistry , The University of Texas Arlington , Arlington , Texas 76019-0065 , United States
| | - Brad S Pierce
- Department of Chemistry and Biochemistry , The University of Alabama , Tuscaloosa , Alabama 35487 , United States
| | - Frank W Foss
- Department of Chemistry and Biochemistry , The University of Texas Arlington , Arlington , Texas 76019-0065 , United States
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8
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Mekhail MA, Pota K, Schwartz TM, Green KN. Functionalized pyridine in pyclen-based iron( iii) complexes: evaluation of fundamental properties. RSC Adv 2020; 10:31165-31170. [PMID: 34094507 PMCID: PMC8174454 DOI: 10.1039/d0ra05756h] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Six iron(iii) pyridinophane complexes were evaluated to determine whether functionalizing the pyridine ring could introduce a handle by which electrochemical properties and thermodynamic stability can be tuned.
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Affiliation(s)
- Magy A. Mekhail
- Department of Chemistry and Biochemistry
- Texas Christian University
- Fort Worth
- USA
| | - Kristof Pota
- Department of Chemistry and Biochemistry
- Texas Christian University
- Fort Worth
- USA
| | - Timothy M. Schwartz
- Department of Chemistry and Biochemistry
- Texas Christian University
- Fort Worth
- USA
| | - Kayla N. Green
- Department of Chemistry and Biochemistry
- Texas Christian University
- Fort Worth
- USA
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9
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Green KN, Pota K, Tircsó G, Gogolák RA, Kinsinger O, Davda C, Blain K, Brewer SM, Gonzalez P, Johnston HM, Akkaraju G. Dialing in on pharmacological features for a therapeutic antioxidant small molecule. Dalton Trans 2019; 48:12430-12439. [PMID: 31342985 PMCID: PMC6863055 DOI: 10.1039/c9dt01800j] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The pyridinophane molecule L2 (3,6,9,15-tetraazabicyclo[9.3.1]penta-deca-1(15),11,13-trien-13-ol) has shown promise as a therapuetic for neurodegenerative diseases involving oxidative stress and metal ion misregulation. Protonation and metal binding stability constants with Mg2+, Ca2+, Cu2+, and Zn2+ ions were determined to further explore the therapeutic and pharmacological potential of this water soluble small molecule. These studies show that incorporation of an -OH group in position 4 of the pyridine ring decreases the pI values compared to cyclen and L1 (3,6,9,15-tetraazabicyclo[9.3.1]penta-deca-1(15),11,13-triene). Furthermore, this approach tunes the basicity of the tetra-aza macrocyclic ligand through the enhanced resonance stabilization of the -OH in position 4 and rigidity of the pyridine ring such that L2 has increased basicity compared to previously reported tetra-aza macrocycles. A metal binding preference for Cu2+, a redox cycling agent known to produce oxidative stress, indicates that this would be the in vivo metal target of L2. However, the binding constant of L2 with Cu2+ is moderated compared to cyclen due to the rigidity of the ligand and shows how ligand design can be used to tune metal selectivity. An IC50 = 298.0 μM in HT-22 neuronal cells was observed. Low metabolic liability was determined in both Phase I and II in vitro models. Throughout these studies other metal binding systems were used for comparison and as appropriate controls. The reactivity reported to date and pharmacological features described herein warrant further studies in vivo and the pursuit of L2 congeners using the knowledge that pyridine substitution in a pyridinophane can be used to tune the structure of the ligand and retain the positive therapeutic outcomes.
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Affiliation(s)
- Kayla N Green
- Department of Chemistry and Biochemistry, Texas Christian University, 2950 S. Bowie, Fort Worth, TX 76129, USA.
| | - Kristof Pota
- Department of Chemistry and Biochemistry, Texas Christian University, 2950 S. Bowie, Fort Worth, TX 76129, USA.
| | - Gyula Tircsó
- Department of Physical Chemistry, Faculty of Science and Technology, University of Debrecen, Egyetem tér 1, Debrecen, H-4010, Hungary
| | - Réka Anna Gogolák
- Department of Physical Chemistry, Faculty of Science and Technology, University of Debrecen, Egyetem tér 1, Debrecen, H-4010, Hungary
| | - Olivia Kinsinger
- Department of Biology, Texas Christian University, 2950 S. Bowie, Fort Worth, TX 76129, USA
| | - Collin Davda
- Department of Chemistry and Biochemistry, Texas Christian University, 2950 S. Bowie, Fort Worth, TX 76129, USA.
| | - Kimberly Blain
- Department of Chemistry and Biochemistry, Texas Christian University, 2950 S. Bowie, Fort Worth, TX 76129, USA. and Department of Biology, Texas Christian University, 2950 S. Bowie, Fort Worth, TX 76129, USA
| | - Samantha M Brewer
- Department of Chemistry and Biochemistry, Texas Christian University, 2950 S. Bowie, Fort Worth, TX 76129, USA.
| | - Paulina Gonzalez
- Department of Chemistry and Biochemistry, Texas Christian University, 2950 S. Bowie, Fort Worth, TX 76129, USA.
| | - Hannah M Johnston
- Department of Chemistry and Biochemistry, Texas Christian University, 2950 S. Bowie, Fort Worth, TX 76129, USA.
| | - Giridhar Akkaraju
- Department of Biology, Texas Christian University, 2950 S. Bowie, Fort Worth, TX 76129, USA
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10
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Tseberlidis G, Demonti L, Pirovano V, Scavini M, Cappelli S, Rizzato S, Vicente R, Caselli A. Controlling Selectivity in Alkene Oxidation: Anion Driven Epoxidation or Dihydroxylation Catalysed by [Iron(III)(Pyridine‐Containing Ligand)] Complexes. ChemCatChem 2019. [DOI: 10.1002/cctc.201901045] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Giorgio Tseberlidis
- Department of Chemistry and ISTM-CNR-MilanoUniversità degli Studi di Milano Via Golgi 19 Milano 20133 Italy
| | - Luca Demonti
- Department of Chemistry and ISTM-CNR-MilanoUniversità degli Studi di Milano Via Golgi 19 Milano 20133 Italy
| | - Valentina Pirovano
- Department of Pharmaceutical Sciences General and Organic Chemistry Section “A. Marchesini”University of Milan Via Venezian 21 Milano 20133 Italy
| | - Marco Scavini
- Department of Chemistry and ISTM-CNR-MilanoUniversità degli Studi di Milano Via Golgi 19 Milano 20133 Italy
| | - Serena Cappelli
- Department of Chemistry and ISTM-CNR-MilanoUniversità degli Studi di Milano Via Golgi 19 Milano 20133 Italy
| | - Silvia Rizzato
- Department of Chemistry and ISTM-CNR-MilanoUniversità degli Studi di Milano Via Golgi 19 Milano 20133 Italy
| | - Rubén Vicente
- Departamento de Química Orgánica e Inorgánica and Instituto Universitario de Química Organometálica “Enrique Moles”Universidad de Oviedo c/ Julián Clavería 8 Oviedo 33007 Spain
| | - Alessandro Caselli
- Department of Chemistry and ISTM-CNR-MilanoUniversità degli Studi di Milano Via Golgi 19 Milano 20133 Italy
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11
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Brewer SM, Wilson KR, Jones DG, Reinheimer EW, Archibald SJ, Prior TJ, Ayala MA, Foster AL, Hubin TJ, Green KN. Increase of Direct C-C Coupling Reaction Yield by Identifying Structural and Electronic Properties of High-Spin Iron Tetra-azamacrocyclic Complexes. Inorg Chem 2018; 57:8890-8902. [PMID: 30024738 PMCID: PMC7067264 DOI: 10.1021/acs.inorgchem.8b00777] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Macrocyclic ligands have been explored extensively as scaffolds for transition metal catalysts for oxygen and hydrogen atom transfer reactions. C-C reactions facilitated using earth abundant metals bound to macrocyclic ligands have not been well-understood but could be a green alternative to replacing the current expensive and toxic precious metal systems most commonly used for these processes. Therefore, the yields from direct Suzuki-Miyaura C-C coupling of phenylboronic acid and pyrrole to produce 2-phenylpyrrole facilitated by eight high-spin iron complexes ([Fe3+L1(Cl)2]+, [Fe3+L4(Cl)2]+, [Fe2+L5(Cl)]+, [Fe2+L6(Cl)2], [Fe3+L7(Cl)2]+, [Fe3+L8(Cl)2]+, [Fe2+L9(Cl)]+, and [Fe2+L10(Cl)]+) were compared to identify the effect of structural and electronic properties on catalytic efficiency. Specifically, catalyst complexes were compared to evaluate the effect of five properties on catalyst reaction yields: (1) the coordination requirements of the catalyst, (2) redox half-potential of each complex, (3) topological constraint/rigidity, (4) N atom modification(s) increasing oxidative stability of the complex, and (5) geometric parameters. The need for two labile cis-coordination sites was confirmed based on a 42% decrease in catalytic reaction yield observed when complexes containing pentadentate ligands were used in place of complexes with tetradentate ligands. A strong correlation between iron(III/II) redox potential and catalytic reaction yields was also observed, with [Fe2+L6(Cl)2] providing the highest yield (81%, -405 mV). A Lorentzian fitting of redox potential versus yields predicts that these catalysts can undergo more fine-tuning to further increase yields. Interestingly, the remaining properties explored did not show a direct, strong relationship to catalytic reaction yields. Altogether, these results show that modifications to the ligand scaffold using fundamental concepts of inorganic coordination chemistry can be used to control the catalytic activity of macrocyclic iron complexes by controlling redox chemistry of the iron center. Furthermore, the data provide direction for the design of improved catalysts for this reaction and strategies to understand the impact of a ligand scaffold on catalytic activity of other reactions.
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Affiliation(s)
- Samantha M. Brewer
- Department of Chemistry and Biochemistry, Texas Christian University, 2950 S. Bowie, Fort Worth, TX 76129, United States
| | - Kevin R. Wilson
- Department of Chemistry and Physics, Southwestern Oklahoma State University, 100 Campus Drive, Weatherford, OK 73096, United States
| | - Donald G. Jones
- Department of Chemistry and Physics, Southwestern Oklahoma State University, 100 Campus Drive, Weatherford, OK 73096, United States
| | - Eric W. Reinheimer
- Rigaku Oxford Diffraction, 9009 New Trails Drive The Woodlands, TX, United States
| | - Stephen J. Archibald
- Department of Chemistry and Positron Emission Tomography Research Centre, University of Hull, Cottingham Road, Hull HU6 7RX, UK
| | - Timothy J. Prior
- Department of Chemistry and Positron Emission Tomography Research Centre, University of Hull, Cottingham Road, Hull HU6 7RX, UK
| | - Megan A. Ayala
- Department of Chemistry and Physics, Southwestern Oklahoma State University, 100 Campus Drive, Weatherford, OK 73096, United States
| | - Alexandria L. Foster
- Department of Chemistry and Physics, Southwestern Oklahoma State University, 100 Campus Drive, Weatherford, OK 73096, United States
| | - Timothy J. Hubin
- Department of Chemistry and Physics, Southwestern Oklahoma State University, 100 Campus Drive, Weatherford, OK 73096, United States
| | - Kayla N. Green
- Department of Chemistry and Biochemistry, Texas Christian University, 2950 S. Bowie, Fort Worth, TX 76129, United States
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