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Kohl SJ, Sigmund LM, Schmitt M, Greb L. Nitrogen monoxide and calix[4]pyrrolato aluminate: structural constraint enabled NO dimerization. Chem Sci 2024; 15:10803-10809. [PMID: 39027292 PMCID: PMC11253113 DOI: 10.1039/d4sc02378a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2024] [Accepted: 06/15/2024] [Indexed: 07/20/2024] Open
Abstract
The dimerization of nitrogen monoxide (NO) is highly relevant in homo- and heterogeneous biochemical and environmental redox processes, but a broader understanding is challenged by the endergonic nature of this equilibrium. The present work describes NO-dimerization leveraged by structurally constrained aluminum and metal-ligand cooperativity at the anionic calix[4]pyrrolato aluminate(III). Quantum chemical calculations reveal the driving force for N-N bond formation, while reactivity tests shed light on subsequent redox chemistry and NO decomposition at metal surfaces. Inhibiting the dimerization pathway by saturating NO's unpaired electron with a phenyl group (nitrosobenzene) allows trapping the 1,2-adduct as a key intermediate. Elevated temperatures result in an unprecedented and high-yielding rearrangement of the calix[4]pyrrolato ligand scaffold. Kinetic and theoretical studies provide a comprehensive picture of the rearrangement mechanism and delineate systematics for ring modification of the prominent calix[4]pyrrole macrocycle.
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Affiliation(s)
- Senta J Kohl
- Anorganisch-Chemisches Institut Ruprecht-Karls-Universität Heidelberg Im Neuenheimer Feld 270 69120 Heidelberg Germany
| | - Lukas M Sigmund
- Anorganisch-Chemisches Institut Ruprecht-Karls-Universität Heidelberg Im Neuenheimer Feld 270 69120 Heidelberg Germany
| | - Manuel Schmitt
- Anorganisch-Chemisches Institut Ruprecht-Karls-Universität Heidelberg Im Neuenheimer Feld 270 69120 Heidelberg Germany
| | - Lutz Greb
- Anorganisch-Chemisches Institut Ruprecht-Karls-Universität Heidelberg Im Neuenheimer Feld 270 69120 Heidelberg Germany
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2
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Park D, Lee SJ, Park JW. Aptamer-Based Smart Targeting and Spatial Trigger-Response Drug-Delivery Systems for Anticancer Therapy. Biomedicines 2024; 12:187. [PMID: 38255292 PMCID: PMC10813750 DOI: 10.3390/biomedicines12010187] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2023] [Revised: 01/05/2024] [Accepted: 01/11/2024] [Indexed: 01/24/2024] Open
Abstract
In recent years, the field of drug delivery has witnessed remarkable progress, driven by the quest for more effective and precise therapeutic interventions. Among the myriad strategies employed, the integration of aptamers as targeting moieties and stimuli-responsive systems has emerged as a promising avenue, particularly in the context of anticancer therapy. This review explores cutting-edge advancements in targeted drug-delivery systems, focusing on the integration of aptamers and stimuli-responsive platforms for enhanced spatial anticancer therapy. In the aptamer-based drug-delivery systems, we delve into the versatile applications of aptamers, examining their conjugation with gold, silica, and carbon materials. The synergistic interplay between aptamers and these materials is discussed, emphasizing their potential in achieving precise and targeted drug delivery. Additionally, we explore stimuli-responsive drug-delivery systems with an emphasis on spatial anticancer therapy. Tumor microenvironment-responsive nanoparticles are elucidated, and their capacity to exploit the dynamic conditions within cancerous tissues for controlled drug release is detailed. External stimuli-responsive strategies, including ultrasound-mediated, photo-responsive, and magnetic-guided drug-delivery systems, are examined for their role in achieving synergistic anticancer effects. This review integrates diverse approaches in the quest for precision medicine, showcasing the potential of aptamers and stimuli-responsive systems to revolutionize drug-delivery strategies for enhanced anticancer therapy.
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Affiliation(s)
- Dongsik Park
- Drug Manufacturing Center, Daegu-Gyeongbuk Medical Innovation Foundation (K-MEDI Hub), Daegu 41061, Republic of Korea
| | - Su Jin Lee
- Drug Manufacturing Center, Daegu-Gyeongbuk Medical Innovation Foundation (K-MEDI Hub), Daegu 41061, Republic of Korea
| | - Jee-Woong Park
- Medical Device Development Center, Daegu-Gyeongbuk Medical Innovation Foundation (K-MEDI Hub), Daegu 41061, Republic of Korea
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3
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Park J, Kim J, Jeong GY, Kim Y, Lee E. Uncovering Nitrosyl Reactivity at N-Heterocyclic Carbene Center. Angew Chem Int Ed Engl 2023:e202314978. [PMID: 37917039 DOI: 10.1002/anie.202314978] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2023] [Revised: 10/31/2023] [Accepted: 11/02/2023] [Indexed: 11/03/2023]
Abstract
N-heterocyclic carbenes (NHCs) have garnered much attention due to their unique properties, such as strong σ-donating and π-accepting abilities, as well as their transition-metal-like reactivity toward small molecules. In 2015, we discovered that NHCs can react with nitric oxide (NO) gas to form radical adducts that resemble transition metal nitrosyl complexes. To elucidate the analogy between NHC and transition metal NO adducts, here we have undertaken a systematic investigation of the electron- and proton-transfer chemistry of [NHC-NO]⋅ (N-heterocyclic carbene nitric oxide radical) compounds. We have accessed a suite of compounds, comprised of [NHC-NO]+ , [NHC-NO]- , [NHC-NOH]0 , and [NHC-NHOH]+ species. In particular, [NHC-NO]- was isolated as potassium and lithium ion adducts. Most interestingly, a monomeric potassium [NHC-NO]- compound was isolated with the assistance of 18-crown-6, which is the first instance of a monomeric alkali N-oxyl compound to the best of our knowledge. Our results demonstrate that [NHC-NO]⋅ exhibits redox behavior broadly similar to metal nitrosyl complexes, which opens up more possibilities for utilizing NHCs to build on the known reactivity of metal complexes.
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Affiliation(s)
- Junbeom Park
- Department of Chemistry, Pohang University of Science and Technology, Pohang, 37673, Republic of Korea
| | - Jaelim Kim
- Department of Chemistry, Pohang University of Science and Technology, Pohang, 37673, Republic of Korea
| | - Gu Yoon Jeong
- Department of Chemistry, Pohang University of Science and Technology, Pohang, 37673, Republic of Korea
| | - Youngsuk Kim
- Department of Chemistry, Pusan National University, Busan, 46241, Republic of Korea
| | - Eunsung Lee
- Department of Chemistry, Pohang University of Science and Technology, Pohang, 37673, Republic of Korea
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4
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Song H, Lee E. Revisiting the Reaction of IPr with Tritylium: An Alternative Mechanistic Pathway. Chemistry 2023; 29:e202203364. [PMID: 36445754 DOI: 10.1002/chem.202203364] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2022] [Revised: 11/29/2022] [Accepted: 11/29/2022] [Indexed: 11/30/2022]
Abstract
Despite a recent proposal on the mechanism of a single-electron transfer (SET) process between tritylium and 2,6-bis(diisopropylphenyl)imidazol-2-ylidene (IPr) based on evidence of transient IPr radical cation intermediate ([IPr]⋅+ ) formation, such oxidation is still contentious because of the high oxidation potential of N-heterocyclic carbenes. Our experimental analysis indicates that the appearance of deep purple color, previously considered to be from transient [IPr]⋅+ , originates from a zwitterionic intermediate (3 a), not a radical cation. Here, we propose an alternative mechanism for the reaction involving tritylium and IPr. This mechanism is noteworthy for explaining how [NHC-H]+ can be generated without the formation of transient [NHC]⋅+ , which has been frequently proposed as an intermediate for the reaction between NHC and oxidants. These results also show that a transient strong single-electron donor (3 a) could be generated by the alternative mechanism for oxidants using NHCs, which is a more feasible explanation for the reactivity of NHCs with oxidants.
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Affiliation(s)
- Hayoung Song
- Department of Chemistry, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea
| | - Eunsung Lee
- Department of Chemistry, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea.,Division of Advanced Materials Science, Pohang University of Science and Technology, Pohang, 37673, Republic of Korea
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5
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Merschel A, Rottschäfer D, Neumann B, Stammler HG, Ringenberg M, van Gastel M, Demirer TI, Andrada DM, Ghadwal RS. Crystalline Anions Based on Classical N-Heterocyclic Carbenes. Angew Chem Int Ed Engl 2023; 62:e202215244. [PMID: 36398890 PMCID: PMC10107637 DOI: 10.1002/anie.202215244] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Revised: 11/18/2022] [Accepted: 11/18/2022] [Indexed: 11/19/2022]
Abstract
Herein, the first stable anions K[SIPrBp ] (4 a-K) and K[IPrBp ] (4 b-K) (SIPrBp =BpC{N(Dipp)CH2 }2 , IPrBp =BpC{N(Dipp)CH}2 ; Bp=4-PhC6 H4 ; Dipp=2,6-iPr2 C6 H3 ) derived from classical N-heterocyclic carbenes (NHCs) (i.e. SIPr and IPr) have been isolated as violet crystalline solids. 4 a-K and 4 b-K are prepared by KC8 reduction of the neutral radicals [SIPrBp ] (3 a) and [IPrBp ] (3 b), respectively. The radicals 3 a and 3 b as well as [Me-IPrBp ] 3 c (Me-IPrBp =BpC{N(Dipp)CMe}2 ) are accessible as crystalline solids on treatment of the respective 1,3-imidazoli(ni)um bromides (SIPrBp )Br (2 a), (IPrBp )Br (2 b), and (Me-IPrBp )Br (2 c) with KC8 . The cyclic voltammograms of 2 a-2 c exhibit two one-electron reversible redox processes in -0.5 to -2.5 V region that correspond to the radicals 3 a-3 c and the anions (4 a-4 c)- . Computational calculations suggest a closed-shell singlet ground state for (4 a-4 c)- with the singlet-triplet energy gap of 17-24 kcal mol-1 .
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Affiliation(s)
- Arne Merschel
- Anorganische Molekülchemie und Katalyse, Lehrstuhl für Anorganische Chemie und Strukturchemie, Centrum für Molekulare Materialien, Fakultät für Chemie, Universität Bielefeld, Universitätsstr. 25, 33615, Bielefeld, Germany
| | - Dennis Rottschäfer
- Anorganische Molekülchemie und Katalyse, Lehrstuhl für Anorganische Chemie und Strukturchemie, Centrum für Molekulare Materialien, Fakultät für Chemie, Universität Bielefeld, Universitätsstr. 25, 33615, Bielefeld, Germany.,Current address: Department of Chemistry, Philipps-University Marburg, Hans-Meerwein-Str. 4, Marburg, Germany
| | - Beate Neumann
- Anorganische Molekülchemie und Katalyse, Lehrstuhl für Anorganische Chemie und Strukturchemie, Centrum für Molekulare Materialien, Fakultät für Chemie, Universität Bielefeld, Universitätsstr. 25, 33615, Bielefeld, Germany
| | - Hans-Georg Stammler
- Anorganische Molekülchemie und Katalyse, Lehrstuhl für Anorganische Chemie und Strukturchemie, Centrum für Molekulare Materialien, Fakultät für Chemie, Universität Bielefeld, Universitätsstr. 25, 33615, Bielefeld, Germany
| | - Mark Ringenberg
- Institut für Anorganische Chemie, Universität Stuttgart, Pfaffenwaldring 55, 70569, Stuttgart, Germany
| | - Maurice van Gastel
- Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470, Mülheim a. d. Ruhr, Germany
| | - T Ilgin Demirer
- Allgemeine und Anorganische Chemie, Universität des Saarlandes, 66123, Saarbrücken, Germany
| | - Diego M Andrada
- Allgemeine und Anorganische Chemie, Universität des Saarlandes, 66123, Saarbrücken, Germany
| | - Rajendra S Ghadwal
- Anorganische Molekülchemie und Katalyse, Lehrstuhl für Anorganische Chemie und Strukturchemie, Centrum für Molekulare Materialien, Fakultät für Chemie, Universität Bielefeld, Universitätsstr. 25, 33615, Bielefeld, Germany
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6
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Dolai R, Kumar R, Elvers BJ, Pal PK, Joseph B, Sikari R, Nayak MK, Maiti A, Singh T, Chrysochos N, Jayaraman A, Krummenacher I, Mondal J, Priyakumar UD, Braunschweig H, Yildiz CB, Schulzke C, Jana A. Carbodicarbenes and Striking Redox Transitions of their Conjugate Acids: Influence of NHC versus CAAC as Donor Substituents. Chemistry 2023; 29:e202202888. [PMID: 36129127 PMCID: PMC10100033 DOI: 10.1002/chem.202202888] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Indexed: 01/11/2023]
Abstract
Herein, a new type of carbodicarbene (CDC) comprising two different classes of carbenes is reported; NHC and CAAC as donor substituents and compare the molecular structure and coordination to Au(I)Cl to those of NHC-only and CAAC-only analogues. The conjugate acids of these three CDCs exhibit notable redox properties. Their reactions with [NO][SbF6 ] were investigated. The reduction of the conjugate acid of CAAC-only based CDC with KC8 results in the formation of hydrogen abstracted/eliminated products, which proceed through a neutral radical intermediate, detected by EPR spectroscopy. In contrast, the reduction of conjugate acids of NHC-only and NHC/CAAC based CDCs led to intermolecular reductive (reversible) carbon-carbon sigma bond formation. The resulting relatively elongated carbon-carbon sigma bonds were found to be readily oxidized. They were, thus, demonstrated to be potent reducing agents, underlining their potential utility as organic electron donors and n-dopants in organic semiconductor molecules.
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Affiliation(s)
- Ramapada Dolai
- Tata Institute of Fundamental Research Hyderabad Gopanpally, Hyderabad, 500046, Telangana, India
| | - Rahul Kumar
- Tata Institute of Fundamental Research Hyderabad Gopanpally, Hyderabad, 500046, Telangana, India
| | - Benedict J Elvers
- Institut für Biochemie, Universität Greifswald, Felix-Hausdorff-Strasse 4, 17489, Greifswald, Germany
| | - Pradeep Kumar Pal
- International Institute of Information Technology Gachibowli, Hyderabad, 500032, India
| | - Benson Joseph
- Tata Institute of Fundamental Research Hyderabad Gopanpally, Hyderabad, 500046, Telangana, India
| | - Rina Sikari
- Tata Institute of Fundamental Research Hyderabad Gopanpally, Hyderabad, 500046, Telangana, India
| | - Mithilesh Kumar Nayak
- Tata Institute of Fundamental Research Hyderabad Gopanpally, Hyderabad, 500046, Telangana, India
| | - Avijit Maiti
- Tata Institute of Fundamental Research Hyderabad Gopanpally, Hyderabad, 500046, Telangana, India
| | - Tejender Singh
- Tata Institute of Fundamental Research Hyderabad Gopanpally, Hyderabad, 500046, Telangana, India
| | - Nicolas Chrysochos
- Tata Institute of Fundamental Research Hyderabad Gopanpally, Hyderabad, 500046, Telangana, India
| | - Arumugam Jayaraman
- Institute of Inorganic Chemistry and Institute for Sustainable Chemistry & Catalysis with Boron (ICB), Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Ivo Krummenacher
- Institute of Inorganic Chemistry and Institute for Sustainable Chemistry & Catalysis with Boron (ICB), Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Jagannath Mondal
- Tata Institute of Fundamental Research Hyderabad Gopanpally, Hyderabad, 500046, Telangana, India
| | - U Deva Priyakumar
- International Institute of Information Technology Gachibowli, Hyderabad, 500032, India
| | - Holger Braunschweig
- Institute of Inorganic Chemistry and Institute for Sustainable Chemistry & Catalysis with Boron (ICB), Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Cem B Yildiz
- Department of Aromatic and Medicinal Plants, Aksaray University, Aksaray, 68100, Turkey
| | - Carola Schulzke
- Institut für Biochemie, Universität Greifswald, Felix-Hausdorff-Strasse 4, 17489, Greifswald, Germany
| | - Anukul Jana
- Tata Institute of Fundamental Research Hyderabad Gopanpally, Hyderabad, 500046, Telangana, India
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7
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Dodd NA, Cao Y, Bacsa J, Towles EC, Gray TG, Sadighi JP. Three-Electron Nickel(I)/Nickel(0) Half-Bond. Inorg Chem 2022; 61:16317-16324. [PMID: 36179078 DOI: 10.1021/acs.inorgchem.2c02291] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
An (N-heterocyclic carbene)nickel(I) cation precursor reacts with the corresponding nickel(0) complex to form a dinickel(I,0) monocation. The Ni···Ni distance in this cation is 0.93 Å shorter than in the analogous dinickel(0) complex. Although the solid-state structure shows equivalent Ni centers, density functional theory calculations indicate significant electronic localization. Reactions with CO and NO form mononuclear carbonyl and nitrosyl complexes. Oxidative addition of an aryl bromide results in C-arylation of the carbene ligands.
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Affiliation(s)
- Neil A Dodd
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332-0400, United States
| | - Yu Cao
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332-0400, United States
| | - John Bacsa
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332-0400, United States.,X-ray Crystallography Center, Department of Chemistry, Emory University, 1515 Dickey Drive, Atlanta, Georgia 30322, United States
| | - Eric C Towles
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332-0400, United States
| | - Thomas G Gray
- Department of Chemistry, Case Western Reserve University, Cleveland, Ohio 44106, United States
| | - Joseph P Sadighi
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332-0400, United States
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8
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Breitwieser K, Bahmann H, Weiss R, Munz D. Gauging Radical Stabilization with Carbenes. Angew Chem Int Ed Engl 2022; 61:e202206390. [PMID: 35796423 PMCID: PMC9545232 DOI: 10.1002/anie.202206390] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2022] [Indexed: 11/29/2022]
Abstract
Carbenes, including N‐heterocyclic carbene (NHC) ligands, are used extensively to stabilize open‐shell transition metal complexes and organic radicals. Yet, it remains unknown, which carbene stabilizes a radical well and, thus, how to design radical‐stabilizing C‐donor ligands. With the large variety of C‐donor ligands experimentally investigated and their electronic properties established, we report herein their radical‐stabilizing effect. We show that radical stabilization can be understood by a captodative frontier orbital description involving π‐donation to‐ and π‐donation from the carbenes. This picture sheds a new perspective on NHC chemistry, where π‐donor effects usually are assumed to be negligible. Further, it allows for the intuitive prediction of the thermodynamic stability of covalent radicals of main group‐ and transition metal carbene complexes, and the quantification of redox non‐innocence.
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Affiliation(s)
- Kevin Breitwieser
- Coordination Chemistry Saarland University Campus C4.1 66123 Saarbrücken Germany
| | - Hilke Bahmann
- Physical and Theoretical Chemistry Saarland University Campus B2.2 66123 Saarbrücken Germany
| | - Robert Weiss
- Organische Chemie Friedrich-Alexander-Universität (FAU) Erlangen-Nürnberg Henkestr. 42 91054 Erlangen Germany
| | - Dominik Munz
- Coordination Chemistry Saarland University Campus C4.1 66123 Saarbrücken Germany
- Inorganic and General Chemistry Friedrich-Alexander-Universität (FAU) Erlangen-Nürnberg Egerlandstr. 1 91058 Erlangen Germany
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9
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Kim T, Nah Y, Kim J, Lee S, Kim WJ. Nitric-Oxide-Modulatory Materials for Biomedical Applications. Acc Chem Res 2022; 55:2384-2396. [PMID: 35786846 DOI: 10.1021/acs.accounts.2c00159] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Nitric oxide (NO) is an endogenous signaling molecule that participates in various physiological and biological pathways associated with vasodilation, immune response, and cell apoptosis. Interestingly, NO has versatile and distinct functions in vivo depending on its concentration and the duration of exposure; it aids cellular proliferation at nanomolar concentrations but causes cellular death at micromolar concentrations. Therefore, achieving the precise and on-demand modulation of microenvironmental NO concentrations has become a major research target in biomedical fields. To this end, many studies have investigated feasible means for developing functional moieties that can either exogenously donate or selectively scavenge NO. However, these advances are limited by poor stability and a lack of target specificity, which represent two significant obstacles regarding the spatiotemporal adjustment of NO in vivo. Our group has addressed this issue by contributing to the development of next-generation NO-modulatory materials over the past decade. Over this period, we utilized various polymeric, inorganic, and hybrid systems to enhance the bioavailability of traditional NO donors or scavengers in an attempt to maximize their clinical usage while also minimizing their unwanted side effects. In this Account, strategies regarding the rational design of NO-modulatory materials are first summarized and discussed, depending on their specific purposes. These strategies include chemical approaches for encapsulating traditional NO donors inside specific vehicles; this prevents spontaneous NO release and allows said donors to be exposed on-demand, under a certain stimulus. The current status of these approaches and the recent contributions of other groups are also comprehensively discussed here to ensure an objective understanding of the topic. Moreover, in this paper, we discuss strategies for the selective depletion of NO from local inflammatory sites, where the overproduction of NO is problematic. Finally, the major challenges for current NO-modulatory systems are discussed, and requirements are outlined that need to be tackled to achieve their future therapeutic development. Starting from this current, relatively early stage of development, we propose that, through continuous efforts to surmount existing challenges, it will be possible in the future to achieve clinical translations regarding NO-modulatory systems. This Account provides insightful guidelines regarding the rational design of NO-modulatory systems for various biomedical applications. Moreover, it can facilitate the achievement of previously unattainable goals while revolutionizing future therapeutics.
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Affiliation(s)
- Taejeong Kim
- Department of Chemistry, POSTECH-CATHOLIC Biomedical Engineering Institute, Pohang University of Science and Technology (POSTECH), 77 Cheongam-ro, Nam-gu, Pohang 37673, Republic of Korea
| | - Yunyoung Nah
- Department of Chemistry, POSTECH-CATHOLIC Biomedical Engineering Institute, Pohang University of Science and Technology (POSTECH), 77 Cheongam-ro, Nam-gu, Pohang 37673, Republic of Korea
| | - Jeonghyun Kim
- Department of Chemistry, POSTECH-CATHOLIC Biomedical Engineering Institute, Pohang University of Science and Technology (POSTECH), 77 Cheongam-ro, Nam-gu, Pohang 37673, Republic of Korea
| | - Sangmin Lee
- Department of Chemistry, POSTECH-CATHOLIC Biomedical Engineering Institute, Pohang University of Science and Technology (POSTECH), 77 Cheongam-ro, Nam-gu, Pohang 37673, Republic of Korea
| | - Won Jong Kim
- Department of Chemistry, POSTECH-CATHOLIC Biomedical Engineering Institute, Pohang University of Science and Technology (POSTECH), 77 Cheongam-ro, Nam-gu, Pohang 37673, Republic of Korea.,School of Interdisciplinary Bioscience and Bioengineering, Pohang University of Science and Technology (POSTECH), Jigok-ro 64, Nam-gu, Pohang 37666, Republic of Korea.,OmniaMed Co., Ltd, Pohang 37666, Republic of Korea
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10
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Song H, Pietrasiak E, Lee E. Persistent Radicals Derived from N-Heterocyclic Carbenes for Material Applications. Acc Chem Res 2022; 55:2213-2223. [PMID: 35849761 DOI: 10.1021/acs.accounts.2c00222] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Persistent radicals are potential building blocks of novel materials in many fields. Recently, highly stable persistent radicals are considered to be within reach, thanks to several radical stabilization strategies such as spin delocalization and steric protection. N-Heterocyclic carbene (NHC)-derived substituents can be attached to a radical center for these purposes, as illustrated by numerous NHC-stabilized radicals reported in the last two decades.This Account describes our recent work on developing NHC-derived persistent radicals, as well as their prospective applications. Considering that NHCs not only stabilize radicals but also reversibly interact with gas molecules, in 2015 our group reported NHC-nitric oxide (NHC-NO) radicals produced by reversibly trapping nitric oxide (NO) radical gas in NHCs. The resultant compounds were loaded into biocompatible poly(ethylene glycol)-block-poly(caprolactone) (PEG-b-PCL) micelles and injected into tumor-bearing mice. Then, NO release was triggered by high-intensity focused ultrasound irradiation of the tumor tissue. Furthermore, the NHC-NO radicals could also serve as a platform to generate other organic radicals such as oxime ether or iminyl radicals. Apart from medicine-related applications, radicals stabilized by NHCs can be used as energy storage materials. In this context, the triazenyl radical containing two NHC units reported by our laboratory could be a cathode active material in batteries, as an organic alternative to LiCoO2. The subsequently prepared unsymmetrical triazenyl radical derivatives were applied as anolytes in nonaqueous all-organic redox flow batteries. In addition, a ferrocene-based redox flow battery anolyte was obtained by introducing NHC-derived substituents that effectively stabilize the ferrocenate derivatives previously reported only at low temperatures. The batteries containing NHC-supported radicals exhibited high energy efficiency and insignificant radical decomposition over multiple cycles. Finally, toward developing air-persistent organic radicals for flexible devices and MRI contrasting agents, we also highlight our recent air- and physiologically stable organic radicals derived from NHCs. Coordination of tris(pentafluorophenyl)borane to the NHC-NO radical produced a new radical cation that is stable in an organic solvent under air for several months. The readily accessible 1,2-dicarbonyl radical cations generated by the reaction of NHCs with oxalyl chloride are remarkably persistent even in an aqueous solution for several months. They are also highly stable even under physiological conditions, making them particularly attractive potential candidates for organic MRI contrast agents. We hope that this Account will serve as a guide for the future development of stable NHC-derived organic radicals and draw the attention of the synthetic community to their potential applications in material science.
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Affiliation(s)
- Hayoung Song
- Department of Chemistry, Pohang University of Science and Technology. Pohang, 37673, Republic of Korea
| | - Ewa Pietrasiak
- Department of Chemistry, Pohang University of Science and Technology. Pohang, 37673, Republic of Korea
| | - Eunsung Lee
- Department of Chemistry, Pohang University of Science and Technology. Pohang, 37673, Republic of Korea
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11
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Breitwieser K, Bahmann H, Weiss R, Munz D. Gauging Radical Stabilization with Carbenes. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202206390] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Kevin Breitwieser
- Saarland University: Universitat des Saarlandes Coordination Chemistry GERMANY
| | - Hilke Bahmann
- Saarland University: Universitat des Saarlandes Theoretical Chemistry GERMANY
| | - Robert Weiss
- FAU Erlangen Nuremberg: Friedrich-Alexander-Universitat Erlangen-Nurnberg Organic Chemistry GERMANY
| | - Dominik Munz
- Universitat des Saarlandes Inorganic Chemistry: Coordination Chemistry Campus C 4.1 66123 Saarbrücken GERMANY
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12
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Maiti A, Elvers BJ, Bera S, Lindl F, Krummenacher I, Ghosh P, Braunschweig H, Yildiz CB, Schulzke C, Jana A. Disclosing Cyclic(Alkyl)(Amino)Carbenes as One‐Electron Reductants: Synthesis of Acyclic(Amino)(Aryl)Carbene‐Based Kekulé Diradicaloids. Chemistry 2022; 28:e202104567. [PMID: 35262232 PMCID: PMC9321839 DOI: 10.1002/chem.202104567] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Indexed: 11/10/2022]
Affiliation(s)
- Avijit Maiti
- Tata Institute of Fundamental Research Hyderabad Gopanpally Hyderabad 500046, Telangana India
| | - Benedict J. Elvers
- Institut für Biochemie Universität Greifswald Felix-Hausdorff-Straße 4 17489 Greifswald Germany
| | - Sachinath Bera
- Department of Chemistry Ramakrishna Mission Residential College Narendrapur Kolkata 700103 India
- Shahid Matangini Hazra Govt General Degree College for Women Tamluk Purba Medinipur 721649 India
| | - Felix Lindl
- Institute of Inorganic Chemistry and Institute for Sustainable Chemistry & Catalysis with Boron (ICB) Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
| | - Ivo Krummenacher
- Institute of Inorganic Chemistry and Institute for Sustainable Chemistry & Catalysis with Boron (ICB) Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
| | - Prasanta Ghosh
- Department of Chemistry Ramakrishna Mission Residential College Narendrapur Kolkata 700103 India
| | - Holger Braunschweig
- Institute of Inorganic Chemistry and Institute for Sustainable Chemistry & Catalysis with Boron (ICB) Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
| | - Cem B. Yildiz
- Department of Aromatic and Medicinal Plants Aksaray University Aksaray 68100 Turkey
| | - Carola Schulzke
- Institut für Biochemie Universität Greifswald Felix-Hausdorff-Straße 4 17489 Greifswald Germany
| | - Anukul Jana
- Tata Institute of Fundamental Research Hyderabad Gopanpally Hyderabad 500046, Telangana India
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13
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Gong W, Xia C, He Q. Therapeutic gas delivery strategies. WILEY INTERDISCIPLINARY REVIEWS-NANOMEDICINE AND NANOBIOTECHNOLOGY 2021; 14:e1744. [PMID: 34355863 DOI: 10.1002/wnan.1744] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Revised: 07/12/2021] [Accepted: 07/14/2021] [Indexed: 12/14/2022]
Abstract
Gas molecules with pharmaceutical effects offer emerging solutions to diseases. In addition to traditional medical gases including O2 and NO, more gases such as H2 , H2 S, SO2 , and CO have recently been discovered to play important roles in various diseases. Though some issues need to be addressed before clinical application, the increasing attention to gas therapy clearly indicates the potentials of these gases for disease treatment. The most important and difficult part of developing gas therapy systems is to transport gas molecules of high diffusibility and penetrability to interesting targets. Given the particular importance of gas molecule delivery for gas therapy, distinguished strategies have been explored to improve gas delivery efficiency and controllable gas release. Here, we summarize the strategies of therapeutic gas delivery for gas therapy, including direct gas molecule delivery by chemical and physical absorption, inorganic/organic/hybrid gas prodrugs, and natural/artificial/hybrid catalyst delivery for gas generation. The advantages and shortcomings of these gas delivery strategies are analyzed. On this basis, intelligent gas delivery strategies and catalysts use in future gas therapy are discussed. This article is categorized under: Therapeutic Approaches and Drug Discovery > Emerging Technologies Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease.
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Affiliation(s)
- Wanjun Gong
- Department of Pharmacy, Shenzhen Hospital, Southern Medical University, Shenzhen, China.,Guangdong Provincial Key Laboratory of Biomedical Measurements and Ultrasound Imaging, National-Regional Key Technology Engineering Laboratory for Medical Ultrasound, Marshall Laboratory of Biomedical Engineering, School of Biomedical Engineering, Health Science Center, Shenzhen University, Shenzhen, China
| | - Chao Xia
- Guangdong Provincial Key Laboratory of Biomedical Measurements and Ultrasound Imaging, National-Regional Key Technology Engineering Laboratory for Medical Ultrasound, Marshall Laboratory of Biomedical Engineering, School of Biomedical Engineering, Health Science Center, Shenzhen University, Shenzhen, China
| | - Qianjun He
- Guangdong Provincial Key Laboratory of Biomedical Measurements and Ultrasound Imaging, National-Regional Key Technology Engineering Laboratory for Medical Ultrasound, Marshall Laboratory of Biomedical Engineering, School of Biomedical Engineering, Health Science Center, Shenzhen University, Shenzhen, China.,Center of Hydrogen Science, Shanghai Jiao Tong University, Shanghai, China
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14
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Kim Y, Byeon JE, Jeong GY, Kim SS, Song H, Lee E. Highly Stable 1,2-Dicarbonyl Radical Cations Derived from N-Heterocyclic Carbenes. J Am Chem Soc 2021; 143:8527-8532. [PMID: 33974426 DOI: 10.1021/jacs.1c00707] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Stable organic radicals have been of great academic interest not only in the context of fundamental understanding of reactive intermediates but also because of their numerous applications as functional materials. Apart from the early examples of triphenylmethyl and TEMPO derivatives, reports on air- and water-stable organic radicals are scarce, and their development remains a challenge. Herein, we present the design and synthesis of a novel organic radical based on a 1,2-dicarbonyl scaffold supported by N-heterocyclic carbenes (NHCs). The presented radical cations exhibit remarkable stability toward various harsh conditions, such as the presence of reactive chemicals (reductants, oxidants, strong acids, and bases) or high temperatures, by far exceeding the stability of triphenylmethyl and TEMPO radicals. In addition, physiological conditions including aqueous buffer and blood serum are tolerated. The steric and electronic stabilization provided by the two NHC moieties enabled the successful design of the highly stable radical.
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Affiliation(s)
- Youngsuk Kim
- Department of Chemistry, Pohang University of Science and Technology (POSTECH), Pohang 37673, Republic of Korea
| | - Jung Eun Byeon
- Department of Chemistry, Pohang University of Science and Technology (POSTECH), Pohang 37673, Republic of Korea
| | - Gu Yoon Jeong
- Department of Chemistry, Pohang University of Science and Technology (POSTECH), Pohang 37673, Republic of Korea
| | - Seoung Su Kim
- Department of Chemistry, Pohang University of Science and Technology (POSTECH), Pohang 37673, Republic of Korea
| | - Hayoung Song
- Department of Chemistry, Pohang University of Science and Technology (POSTECH), Pohang 37673, Republic of Korea
| | - Eunsung Lee
- Department of Chemistry, Pohang University of Science and Technology (POSTECH), Pohang 37673, Republic of Korea
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15
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Kim S, Lee HE, Suh JM, Lim MH, Kim M. Sequential Connection of Mutually Exclusive Catalytic Reactions by a Method Controlling the Presence of an MOF Catalyst: One-Pot Oxidation of Alcohols to Carboxylic Acids. Inorg Chem 2020; 59:17573-17582. [PMID: 33216548 DOI: 10.1021/acs.inorgchem.0c02809] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A functionalized metal-organic framework (MOF) catalyst applied to the sequential one-pot oxidation of alcohols to carboxylic acids controls the presence of a heterogeneous catalyst. The conversion of alcohols to aldehydes was acquired through aerobic oxidation using a well-known amino-oxy radical-functionalized MOF. In the same flask, a simple filtration of the radical MOF with mild heating of the solution completely altered the reaction media, providing radical scavenger-free conditions suitable for the autoxidation of the aldehydes formed in the first step to carboxylic acids. The mutually exclusive radical-catalyzed aerobic oxidation (the first step with MOF) and radical-inhibited autoxidation (the second step without MOF) are sequentially achieved in a one-pot manner. Overall, we demonstrate a powerful and efficient method for the sequential oxidation of alcohols to carboxylic acids by employing a readily functionalizable heterogeneous MOF. In addition, our MOF in-and-out method can be utilized in an environmentally friendly way for the oxidation of alcohols to carboxylic acids of industrial and economic value with broad functional group tolerance, including 2,5-furandicarboxylic acid and 1,4-benzenedicarboxylic acid, with good yield and reusability. Furthermore, MOF-TEMPO, as an antioxidative stabilizer, prevents the undesired oxidation of aldehydes, and the perfect "recoverability" of such a reactive MOF requires a re-evaluation of the advantages of MOFs from heterogeneity in catalytic and related applications.
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Affiliation(s)
- Seongwoo Kim
- Department of Chemistry, Chungbuk National University, Cheongju 28644, Korea
| | - Ha-Eun Lee
- Department of Chemistry, Chungbuk National University, Cheongju 28644, Korea
| | - Jong-Min Suh
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Korea
| | - Mi Hee Lim
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Korea
| | - Min Kim
- Department of Chemistry, Chungbuk National University, Cheongju 28644, Korea
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16
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Lu B, Song C, Qian W, Wu Z, Császár AG, Zeng X. Heterocumulenic carbene nitric oxide radical OCCNO˙. Chem Commun (Camb) 2019; 55:13510-13513. [PMID: 31584053 DOI: 10.1039/c9cc07056g] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The elusive heterocumulenic radical OCCNO˙ and its isotopologues OC13CNO˙ and OCC15NO˙ have been prepared by reacting photolytically generated unsaturated carbene OCC/OC13C with ˙NO/15˙NO in cryogenic N2-, Ar-, and Ne-matrices. Upon UV-light (365 nm) irradiation, the C-C bond in OCCNO˙ breaks and yields a long-sought ground-state radical CNO˙ (X2Π), which has also been identified with matrix-isolation infrared spectroscopy.
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Affiliation(s)
- Bo Lu
- College of Chemistry, Chemical Engineering and Materials Science, Soochow University, 215123 Suzhou, China.
| | - Chao Song
- College of Chemistry, Chemical Engineering and Materials Science, Soochow University, 215123 Suzhou, China.
| | - Weiyu Qian
- College of Chemistry, Chemical Engineering and Materials Science, Soochow University, 215123 Suzhou, China.
| | - Zhuang Wu
- College of Chemistry, Chemical Engineering and Materials Science, Soochow University, 215123 Suzhou, China.
| | - Attila G Császár
- MTA-ELTE Complex Chemical Systems Research Group, Laboratory of Molecular Structure and Dynamics, Institute of Chemistry, ELTE Eötvös Loránd University, Pázmány Péter sétány 1/A, H-1117 Budapest, Hungary
| | - Xiaoqing Zeng
- College of Chemistry, Chemical Engineering and Materials Science, Soochow University, 215123 Suzhou, China. and Department of Chemistry, Fudan University, 200433 Shanghai, China.
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17
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Keilwerth M, Hohenberger J, Heinemann FW, Sutter J, Scheurer A, Fang H, Bill E, Neese F, Ye S, Meyer K. A Series of Iron Nitrosyl Complexes {Fe-NO} 6-9 and a Fleeting {Fe-NO} 10 Intermediate en Route to a Metalacyclic Iron Nitrosoalkane. J Am Chem Soc 2019; 141:17217-17235. [PMID: 31566964 DOI: 10.1021/jacs.9b08053] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Iron-nitrosyls have fascinated chemists for a long time due to the noninnocent nature of the NO ligand that can exist in up to five different oxidation and spin states. Coordination to an open-shell iron center leads to complex electronic structures, which is the reason Enemark-Feltham introduced the {Fe-NO}n notation. In this work, we succeeded in characterizing a series of {Fe-NO}6-9 complexes, including a reactive {Fe-NO}10 intermediate. All complexes were synthesized with the tris-N-heterocyclic carbene ligand tris[2-(3-mesitylimidazol-2-ylidene)ethyl]amine (TIMENMes), which is known to support iron in high and low oxidation states. Reaction of NOBF4 with [(TIMENMes)Fe]2+ resulted in formation of the {Fe-NO}6 compound [(TIMENMes)Fe(NO)(CH3CN)](BF4)3 (1). Stepwise chemical reduction with Zn, Mg, and Na/Hg leads to the isostructural series of high-spin iron nitrosyl complexes {Fe-NO}7,8,9 (2-4). Reduction of {Fe-NO}9 with Cs electride finally yields the highly reduced {Fe-NO}10 intermediate, key to formation of [Cs(crypt-222)][(TIMENMes)Fe(NO)], (5) featuring a metalacyclic [Fe-(NO-NHC)3-] nitrosoalkane unit. All complexes were characterized by single-crystal XRD analyses, temperature and field-dependent SQUID magnetization methods, as well as 57Fe Mössbauer, IR, UV/vis, multinuclear NMR, and dual-mode EPR spectroscopy. Spectroscopy-based DFT analyses provide insight into the electronic structures of all compounds and allowed assignments of oxidation states to iron and NO ligands. An alternative synthesis to the {Fe-NO}8 complex was found via oxygenation of the nitride complex [(TIMENMes)Fe(N)](BF4). Surprisingly, the resulting {Fe-NO}8 species is electronically and structural similar to the [(TIMENMes)Fe(N)]+ precursor. Based on the structural and electronic similarities between this nitrosyl/nitride complex couple, we adopted the strategy, developed by Wieghardt et al., of extending the Enemark-Feltham nomenclature to nitrido complexes, rendering [(TIMENMes)Fe(N)]+ as a {Fe-N}8 species.
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Affiliation(s)
- Martin Keilwerth
- Department of Chemistry and Pharmacy, Inorganic Chemistry , Friedrich-Alexander-University Erlangen-Nürnberg (FAU) , Egerlandstrasse 1 , D-91058 Erlangen , Germany
| | - Johannes Hohenberger
- Department of Chemistry and Pharmacy, Inorganic Chemistry , Friedrich-Alexander-University Erlangen-Nürnberg (FAU) , Egerlandstrasse 1 , D-91058 Erlangen , Germany
| | - Frank W Heinemann
- Department of Chemistry and Pharmacy, Inorganic Chemistry , Friedrich-Alexander-University Erlangen-Nürnberg (FAU) , Egerlandstrasse 1 , D-91058 Erlangen , Germany
| | - Jörg Sutter
- Department of Chemistry and Pharmacy, Inorganic Chemistry , Friedrich-Alexander-University Erlangen-Nürnberg (FAU) , Egerlandstrasse 1 , D-91058 Erlangen , Germany
| | - Andreas Scheurer
- Department of Chemistry and Pharmacy, Inorganic Chemistry , Friedrich-Alexander-University Erlangen-Nürnberg (FAU) , Egerlandstrasse 1 , D-91058 Erlangen , Germany
| | - Huayi Fang
- Max-Planck-Institut für Chemische Energiekonversion , Stiftstraße 34-36 , D-45470 Mülheim an der Ruhr, Germany
| | - Eckhard Bill
- Max-Planck-Institut für Chemische Energiekonversion , Stiftstraße 34-36 , D-45470 Mülheim an der Ruhr, Germany
| | - Frank Neese
- Max-Planck-Institut für Kohlenforschung , Kaiser-Wilhelmplatz 1 , D-45470 Mülheim an der Ruhr , Germany
| | - Shengfa Ye
- Max-Planck-Institut für Kohlenforschung , Kaiser-Wilhelmplatz 1 , D-45470 Mülheim an der Ruhr , Germany
| | - Karsten Meyer
- Department of Chemistry and Pharmacy, Inorganic Chemistry , Friedrich-Alexander-University Erlangen-Nürnberg (FAU) , Egerlandstrasse 1 , D-91058 Erlangen , Germany
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18
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Benaissa I, Pallova L, Morantin ME, Lafitte T, Huynh M, Barthes C, Vendier L, Lugan N, Bastin S, César V. N-Heterocyclic Carbenes as Key Intermediates in the Synthesis of Fused, Mesoionic, Tricyclic Heterocycles. Chemistry 2019; 25:13030-13036. [PMID: 31385630 DOI: 10.1002/chem.201903242] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Indexed: 01/16/2023]
Abstract
Coupling between 5-bromoimidazo[1,5-a]pyridinium salts and malonate or arylacetate esters leads to a facile and straightforward access to the new mesoionic, fused, tricyclic system of imidazo[2,1,5-cd]indolizinium-3-olate. Mechanistic studies show that the reaction pathway consists of nucleophilic aromatic substitution on the cationic, bicyclic heterocycle by an enolate-type moiety and in the nucleophilic attack of a transient free N-heterocyclic carbene (NHC) species on the ester group; the relative order of these two steps depends on the nature of the starting ester. This work highlights the valuable implementation of free NHC species as key intermediates in synthetic chemistry, beyond their classical use as stabilizing ligands or organocatalysts.
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Affiliation(s)
- Idir Benaissa
- LCC-CNRS, Université de Toulouse, CNRS, Toulouse, 31077, France
| | - Lenka Pallova
- LCC-CNRS, Université de Toulouse, CNRS, Toulouse, 31077, France
| | | | - Thomas Lafitte
- LCC-CNRS, Université de Toulouse, CNRS, Toulouse, 31077, France
| | - Mathieu Huynh
- LCC-CNRS, Université de Toulouse, CNRS, Toulouse, 31077, France
| | - Cécile Barthes
- LCC-CNRS, Université de Toulouse, CNRS, Toulouse, 31077, France
| | - Laure Vendier
- LCC-CNRS, Université de Toulouse, CNRS, Toulouse, 31077, France
| | - Noël Lugan
- LCC-CNRS, Université de Toulouse, CNRS, Toulouse, 31077, France
| | | | - Vincent César
- LCC-CNRS, Université de Toulouse, CNRS, Toulouse, 31077, France
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19
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Kim Y, Bielawski CW, Lee E. Oxygen atom transfer: a mild and efficient method for generating iminyl radicals. Chem Commun (Camb) 2019; 55:7061-7064. [PMID: 31143894 DOI: 10.1039/c9cc03521d] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Treating iminoxyl species with oxygen acceptors such as PPh3 resulted in oxygen atom transfer and afforded the corresponding iminyl radicals. DFT and other calculations revealed that association between the oxygen atom acceptors and the iminoxyl species results in the formation of key intermediates during the reaction. Subsequent dissociation is accompanied with homolytic cleavage of the N-O bond and generates iminyl radicals with spin densities that are localized on exocyclic nitrogen atoms.
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Affiliation(s)
- Youngsuk Kim
- Department of Chemistry, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea. and Center for Self-assembly and Complexity (CSC), Institute for Basic Science (IBS), Pohang, 37673, Republic of Korea
| | - Christopher W Bielawski
- Center for Multidimensional Carbon Materials (CMCM), Institute for Basic Science (IBS), Ulsan, 44919, Republic of Korea and Department of Chemistry, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea and Department of Energy Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea
| | - Eunsung Lee
- Department of Chemistry, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea. and Center for Self-assembly and Complexity (CSC), Institute for Basic Science (IBS), Pohang, 37673, Republic of Korea and Division of Advanced Materials Science, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea
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20
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Kang Y, Kim J, Park J, Lee YM, Saravanakumar G, Park KM, Choi W, Kim K, Lee E, Kim C, Kim WJ. Tumor vasodilation by N-Heterocyclic carbene-based nitric oxide delivery triggered by high-intensity focused ultrasound and enhanced drug homing to tumor sites for anti-cancer therapy. Biomaterials 2019; 217:119297. [PMID: 31255980 DOI: 10.1016/j.biomaterials.2019.119297] [Citation(s) in RCA: 56] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Revised: 06/17/2019] [Accepted: 06/20/2019] [Indexed: 11/16/2022]
Abstract
Nitric oxide (NO) is widely known as an effective vasodilator at low concentrations. Drug delivery systems combined with NO can dilate blood vessels surrounding tumor tissues, and the drug accumulation in tumors is accelerated by the enhanced permeability and retention effect, leading to an improvement in the anti-tumor effect. N-heterocyclic carbene-based NO donors (e.g., 1,3-bis-(2,4,6-trimethylphenyl)imidazolylidene nitric oxide (IMesNO) have been developed for stable NO storing in air and water, and NO release by thermolysis. Herein, we demonstrated on-demand NO release by high-intensity focused ultrasound (HIFU) as a stimulus, which generated high heat and exerted an ablation effect when treated in vivo. We demonstrated IMesNO to be a HIFU-responsive NO donor and its potential application in vivo using IMesNO-loaded micelles. Moreover, IMesNO-loaded micelles mixed with drug-loaded micelles (IMesNO/DOX@MCs) showed acceleration of drug accumulation in tumor sites and enhanced tumor growth inhibition. Thus, our findings suggest a potential clinical bioapplication of NO-releasing drug-loaded micelles owing to the therapeutic function of NO and HIFU treatment for anti-cancer therapy.
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Affiliation(s)
- Youngnam Kang
- School of Interdisciplinary Bioscience and Bioengineering, POSTECH (Pohang University of Science and Technology), Pohang 37673, Republic of Korea
| | - Jeesu Kim
- Department of Creative IT Engineering and Electrical Engineering, POSTECH (Pohang University of Science and Technology), Pohang 37673, Republic of Korea
| | - Junbeom Park
- Center for Self-Assembly and Complexity (CSC), Institute for Basic Science (IBS), Pohang 37673, Republic of Korea; Department of Chemistry, POSTECH (Pohang University of Science and Technology), Pohang 37673, Republic of Korea
| | - Yeong Mi Lee
- Department of Chemistry, POSTECH (Pohang University of Science and Technology), Pohang 37673, Republic of Korea
| | - Gurusamy Saravanakumar
- Department of Chemistry, POSTECH (Pohang University of Science and Technology), Pohang 37673, Republic of Korea
| | - Kyeng Min Park
- Center for Self-Assembly and Complexity (CSC), Institute for Basic Science (IBS), Pohang 37673, Republic of Korea
| | - Wonseok Choi
- Department of Creative IT Engineering and Electrical Engineering, POSTECH (Pohang University of Science and Technology), Pohang 37673, Republic of Korea
| | - Kimoon Kim
- Center for Self-Assembly and Complexity (CSC), Institute for Basic Science (IBS), Pohang 37673, Republic of Korea; Department of Chemistry, POSTECH (Pohang University of Science and Technology), Pohang 37673, Republic of Korea.
| | - Eunsung Lee
- Center for Self-Assembly and Complexity (CSC), Institute for Basic Science (IBS), Pohang 37673, Republic of Korea; Department of Chemistry, POSTECH (Pohang University of Science and Technology), Pohang 37673, Republic of Korea.
| | - Chulhong Kim
- Department of Creative IT Engineering and Electrical Engineering, POSTECH (Pohang University of Science and Technology), Pohang 37673, Republic of Korea.
| | - Won Jong Kim
- School of Interdisciplinary Bioscience and Bioengineering, POSTECH (Pohang University of Science and Technology), Pohang 37673, Republic of Korea; Department of Chemistry, POSTECH (Pohang University of Science and Technology), Pohang 37673, Republic of Korea.
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21
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Doddi A, Peters M, Tamm M. N-Heterocyclic Carbene Adducts of Main Group Elements and Their Use as Ligands in Transition Metal Chemistry. Chem Rev 2019; 119:6994-7112. [PMID: 30983327 DOI: 10.1021/acs.chemrev.8b00791] [Citation(s) in RCA: 290] [Impact Index Per Article: 58.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
N-Heterocyclic carbenes (NHC) are nowadays ubiquitous and indispensable in many research fields, and it is not possible to imagine modern transition metal and main group element chemistry without the plethora of available NHCs with tailor-made electronic and steric properties. While their suitability to act as strong ligands toward transition metals has led to numerous applications of NHC complexes in homogeneous catalysis, their strong σ-donating and adaptable π-accepting abilities have also contributed to an impressive vitalization of main group chemistry with the isolation and characterization of NHC adducts of almost any element. Formally, NHC coordination to Lewis acids affords a transfer of nucleophilicity from the carbene carbon atom to the attached exocyclic moiety, and low-valent and low-coordinate adducts of the p-block elements with available lone pairs and/or polarized carbon-element π-bonds are able to act themselves as Lewis basic donor ligands toward transition metals. Accordingly, the availability of a large number of novel NHC adducts has not only produced new varieties of already existing ligand classes but has also allowed establishment of numerous complexes with unusual and often unprecedented element-metal bonds. This review aims at summarizing this development comprehensively and covers the usage of N-heterocyclic carbene adducts of the p-block elements as ligands in transition metal chemistry.
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Affiliation(s)
- Adinarayana Doddi
- Technische Universität Braunschweig, Institut für Anorganische und Analytische Chemie, Hagenring 30, 38106 Braunschweig, Germany
| | - Marius Peters
- Technische Universität Braunschweig, Institut für Anorganische und Analytische Chemie, Hagenring 30, 38106 Braunschweig, Germany
| | - Matthias Tamm
- Technische Universität Braunschweig, Institut für Anorganische und Analytische Chemie, Hagenring 30, 38106 Braunschweig, Germany
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22
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Kim H, Kim H, Kim K, Lee E. Structural Control of Metal–Organic Framework Bearing N-Heterocyclic Imidazolium Cation and Generation of Highly Stable Porous Structure. Inorg Chem 2019; 58:6619-6627. [DOI: 10.1021/acs.inorgchem.8b03173] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Hyunseok Kim
- Department of Chemistry, Pohang University of Science and Technology, Pohang, 790-784, Republic of Korea
| | - Hyunyong Kim
- Center for Self-assembly and Complexity, Institute for Basic Science (IBS), Pohang, 790-784, Republic of Korea
- Department of Chemistry, Pohang University of Science and Technology, Pohang, 790-784, Republic of Korea
| | - Kimoon Kim
- Center for Self-assembly and Complexity, Institute for Basic Science (IBS), Pohang, 790-784, Republic of Korea
- Department of Chemistry, Pohang University of Science and Technology, Pohang, 790-784, Republic of Korea
- Division of Advanced Materials Science, Pohang University of Science and Technology, Pohang, 790-784, Republic of Korea
| | - Eunsung Lee
- Center for Self-assembly and Complexity, Institute for Basic Science (IBS), Pohang, 790-784, Republic of Korea
- Department of Chemistry, Pohang University of Science and Technology, Pohang, 790-784, Republic of Korea
- Division of Advanced Materials Science, Pohang University of Science and Technology, Pohang, 790-784, Republic of Korea
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23
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Alkorta I, Elguero J. Interaction ofN-Heterocyclic Carbenes and Simple Carbenes with Small Molecules (One to Three Atoms) Excluding Metals: Formation of Covalent C-X Bonds. J Heterocycl Chem 2018. [DOI: 10.1002/jhet.3331] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Affiliation(s)
- Ibon Alkorta
- Instituto de Química Médica; CSIC; Juan de la Cierva, 3 Madrid E-28006 Spain
| | - José Elguero
- Instituto de Química Médica; CSIC; Juan de la Cierva, 3 Madrid E-28006 Spain
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24
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Kim Y, Lee E. Stable Organic Radicals Derived from N‐Heterocyclic Carbenes. Chemistry 2018; 24:19110-19121. [PMID: 30058298 DOI: 10.1002/chem.201801560] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2018] [Revised: 06/23/2018] [Indexed: 11/11/2022]
Affiliation(s)
- Youngsuk Kim
- Center for Self-assembly and ComplexityInstitute for Basic Science (IBS) Pohang 37673 Republic of Korea
- Department of ChemistryPohang University of Science and Technology Pohang 37673 Republic of Korea
| | - Eunsung Lee
- Center for Self-assembly and ComplexityInstitute for Basic Science (IBS) Pohang 37673 Republic of Korea
- Department of ChemistryPohang University of Science and Technology Pohang 37673 Republic of Korea
- Division of Advanced Materials SciencePohang University of Science and Technology Pohang 37673 Republic of Korea
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25
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Grineva AA, Valyaev DA, César V, Filippov OA, Khrustalev VN, Nefedov SE, Lugan N. Oxidative Coupling of Anionic Abnormal N‐Heterocyclic Carbenes: Efficient Access to Janus‐Type 4,4′‐Bis(2
H
‐imidazol‐2‐ylidene)s. Angew Chem Int Ed Engl 2018. [DOI: 10.1002/ange.201801530] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
- Alina A. Grineva
- LCC-CNRSUniversité de Toulouse, CNRS France
- Kurnakov Institute of General and Inorganic ChemistryRussian Academy of Sciences 31 Leninsky Pr. Moscow 119991 Russia
| | | | | | - Oleg A. Filippov
- A. N. Nesmeyanov Institute of Organoelement Compounds (INEOS)Russian Academy of Sciences 28 Vavilov str., GSP-1, B-334 Moscow 119991 Russia
| | - Victor N. Khrustalev
- Peoples Friendship University of Russia (RUDN University) 6 Miklukho Maklaya str. Moscow 117198 Russia
- National Research Center “Kurchatov Institute” 1, Akademika Kurchatova pl. Moscow 123182 Russia
| | - Sergei E. Nefedov
- Kurnakov Institute of General and Inorganic ChemistryRussian Academy of Sciences 31 Leninsky Pr. Moscow 119991 Russia
| | - Noël Lugan
- LCC-CNRSUniversité de Toulouse, CNRS France
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26
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Grineva AA, Valyaev DA, César V, Filippov OA, Khrustalev VN, Nefedov SE, Lugan N. Oxidative Coupling of Anionic Abnormal N-Heterocyclic Carbenes: Efficient Access to Janus-Type 4,4'-Bis(2H-imidazol-2-ylidene)s. Angew Chem Int Ed Engl 2018. [PMID: 29528185 DOI: 10.1002/anie.201801530] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The oxidative coupling of anionic imidazol-4-ylidenes protected at the C2 position with [MnCp(CO)2 ] or BH3 led to the corresponding 4,4'-bis(2H-imidazol-2-ylidene) complexes or adducts, in which the two carbene moieties are connected through a single C-C bond. Subsequent acidic treatment of the later species led to the corresponding 4,4'-bis(imidazolium) salts in good yields. The overall procedure offers practical access to a novel class of Janus-type bis(NHC)s. Strikingly, the coplanarity of the two NHC rings within the mesityl derivative 4,4'-bis(IMes), favored by steric hindrance along with stabilizing intramolecular C-H⋅⋅⋅π aryl interactions, allows the alignment of the π-systems and, as a direct consequence, significant electron communication through the bis(carbene) scaffold.
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Affiliation(s)
- Alina A Grineva
- LCC-CNRS, Université de Toulouse, CNRS, France.,Kurnakov Institute of General and Inorganic Chemistry, Russian Academy of Sciences, 31 Leninsky Pr., Moscow, 119991, Russia
| | | | | | - Oleg A Filippov
- A. N. Nesmeyanov Institute of Organoelement Compounds (INEOS), Russian Academy of Sciences, 28 Vavilov str., GSP-1, B-334, Moscow, 119991, Russia
| | - Victor N Khrustalev
- Peoples Friendship University of Russia (RUDN University), 6 Miklukho Maklaya str., Moscow, 117198, Russia.,National Research Center "Kurchatov Institute", 1, Akademika Kurchatova pl., Moscow, 123182, Russia
| | - Sergei E Nefedov
- Kurnakov Institute of General and Inorganic Chemistry, Russian Academy of Sciences, 31 Leninsky Pr., Moscow, 119991, Russia
| | - Noël Lugan
- LCC-CNRS, Université de Toulouse, CNRS, France
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27
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Ruamps M, Bastin S, Rechignat L, Sournia-Saquet A, Valyaev DA, Mouesca JM, Lugan N, Maurel V, César V. Unveiling the redox-active character of imidazolin-2-thiones derived from amino-substituted N-heterocyclic carbenes. Chem Commun (Camb) 2018; 54:7653-7656. [DOI: 10.1039/c8cc03934h] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Spectroscopic, structural and computational studies on the amino-substituted imidazolin-2-thiones reveal the imidazolyl ring to be redox active.
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Affiliation(s)
- Mirko Ruamps
- LCC-CNRS, Université de Toulouse
- INPT
- UPS
- 31077 Toulouse cedex 4
- France
| | - Stéphanie Bastin
- LCC-CNRS, Université de Toulouse
- INPT
- UPS
- 31077 Toulouse cedex 4
- France
| | - Lionel Rechignat
- LCC-CNRS, Université de Toulouse
- INPT
- UPS
- 31077 Toulouse cedex 4
- France
| | | | | | | | - Noël Lugan
- LCC-CNRS, Université de Toulouse
- INPT
- UPS
- 31077 Toulouse cedex 4
- France
| | | | - Vincent César
- LCC-CNRS, Université de Toulouse
- INPT
- UPS
- 31077 Toulouse cedex 4
- France
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28
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Kim Y, Lee E. An air-stable N-heterocyclic carbene iminoxyl borate radical zwitterion. Chem Commun (Camb) 2018; 54:6824-6827. [DOI: 10.1039/c8cc01399c] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The presented N-heterocyclic carbene iminoxyl borate radical zwitterion shows remarkable stability toward air, moisture, and silica gel.
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Affiliation(s)
- Youngsuk Kim
- Center for Self–assembly and Complexity
- Institute for Basic Science (IBS)
- Pohang
- Republic of Korea
- Department of Chemistry
| | - Eunsung Lee
- Center for Self–assembly and Complexity
- Institute for Basic Science (IBS)
- Pohang
- Republic of Korea
- Department of Chemistry
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29
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Kim Y, Kim K, Lee E. Oxime Ether Radical Cations Stabilized by N-Heterocyclic Carbenes. Angew Chem Int Ed Engl 2017; 57:262-265. [DOI: 10.1002/anie.201710530] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2017] [Indexed: 02/03/2023]
Affiliation(s)
- Youngsuk Kim
- Center for Self-assembly and Complexity; Institute for Basic Science (IBS); Pohang 37673 Republic of Korea
- Department of Chemistry; Pohang University of Science and Technology; Pohang 37673 Republic of Korea
| | - Kimoon Kim
- Center for Self-assembly and Complexity; Institute for Basic Science (IBS); Pohang 37673 Republic of Korea
- Department of Chemistry; Pohang University of Science and Technology; Pohang 37673 Republic of Korea
- Division of Advanced Materials Science; Pohang University of Science and Technology; Pohang 37673 Republic of Korea
| | - Eunsung Lee
- Center for Self-assembly and Complexity; Institute for Basic Science (IBS); Pohang 37673 Republic of Korea
- Department of Chemistry; Pohang University of Science and Technology; Pohang 37673 Republic of Korea
- Division of Advanced Materials Science; Pohang University of Science and Technology; Pohang 37673 Republic of Korea
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30
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Kim Y, Kim K, Lee E. Oxime Ether Radical Cations Stabilized by N-Heterocyclic Carbenes. Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201710530] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Youngsuk Kim
- Center for Self-assembly and Complexity; Institute for Basic Science (IBS); Pohang 37673 Republic of Korea
- Department of Chemistry; Pohang University of Science and Technology; Pohang 37673 Republic of Korea
| | - Kimoon Kim
- Center for Self-assembly and Complexity; Institute for Basic Science (IBS); Pohang 37673 Republic of Korea
- Department of Chemistry; Pohang University of Science and Technology; Pohang 37673 Republic of Korea
- Division of Advanced Materials Science; Pohang University of Science and Technology; Pohang 37673 Republic of Korea
| | - Eunsung Lee
- Center for Self-assembly and Complexity; Institute for Basic Science (IBS); Pohang 37673 Republic of Korea
- Department of Chemistry; Pohang University of Science and Technology; Pohang 37673 Republic of Korea
- Division of Advanced Materials Science; Pohang University of Science and Technology; Pohang 37673 Republic of Korea
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31
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Song H, Kim Y, Park J, Ko YH, Kim K, Lee E. An N-Heterocyclic-Carbene-Tetracyanoethylene Zwitterion: Experimental and Theoretical Study on Its Formation and Reactivity. European J Org Chem 2017. [DOI: 10.1002/ejoc.201601648] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Hayoung Song
- Center for Self-assembly and Complexity; Institute for Basic Science (IBS); 37673 Pohang Republic of Korea
- Department of Chemistry; Pohang University of Science and Technology (POSTECH); 37673 Pohang Republic of Korea
| | - Youngsuk Kim
- Center for Self-assembly and Complexity; Institute for Basic Science (IBS); 37673 Pohang Republic of Korea
- Department of Chemistry; Pohang University of Science and Technology (POSTECH); 37673 Pohang Republic of Korea
| | - Junbeom Park
- Center for Self-assembly and Complexity; Institute for Basic Science (IBS); 37673 Pohang Republic of Korea
- Department of Chemistry; Pohang University of Science and Technology (POSTECH); 37673 Pohang Republic of Korea
| | - Young Ho Ko
- Center for Self-assembly and Complexity; Institute for Basic Science (IBS); 37673 Pohang Republic of Korea
| | - Kimoon Kim
- Center for Self-assembly and Complexity; Institute for Basic Science (IBS); 37673 Pohang Republic of Korea
- Department of Chemistry; Pohang University of Science and Technology (POSTECH); 37673 Pohang Republic of Korea
- Division of Advanced Materials Science; Pohang University of Science and Technology (POSTECH); 37673 Pohang Republic of Korea
| | - Eunsung Lee
- Center for Self-assembly and Complexity; Institute for Basic Science (IBS); 37673 Pohang Republic of Korea
- Department of Chemistry; Pohang University of Science and Technology (POSTECH); 37673 Pohang Republic of Korea
- Division of Advanced Materials Science; Pohang University of Science and Technology (POSTECH); 37673 Pohang Republic of Korea
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32
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Lee HJ, Kwon H, Sim J, Song D, Kim Y, Kim J, Kim K, Lee E. Synthetic control of coincidental formation of an N-heterocyclic carbene–copper(i) complex and imidazolium cations within metal–organic frameworks. CrystEngComm 2017. [DOI: 10.1039/c7ce00078b] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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33
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Longobardi LE, Liu L, Grimme S, Stephan DW. Stable Borocyclic Radicals via Frustrated Lewis Pair Hydrogenations. J Am Chem Soc 2016; 138:2500-3. [DOI: 10.1021/jacs.5b12823] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Lauren E. Longobardi
- Department of Chemistry, University of Toronto, 80 St. George
Street, Toronto, Ontario M5S 3H6, Canada
- Mulliken Center for Theoretical
Chemistry, Institut für Physikalische und Theoretische Chemie, Universität Bonn, Beringstrasse 4, D-53115 Bonn, Germany
| | - Lei Liu
- Department of Chemistry, University of Toronto, 80 St. George
Street, Toronto, Ontario M5S 3H6, Canada
- Mulliken Center for Theoretical
Chemistry, Institut für Physikalische und Theoretische Chemie, Universität Bonn, Beringstrasse 4, D-53115 Bonn, Germany
| | - Stefan Grimme
- Department of Chemistry, University of Toronto, 80 St. George
Street, Toronto, Ontario M5S 3H6, Canada
- Mulliken Center for Theoretical
Chemistry, Institut für Physikalische und Theoretische Chemie, Universität Bonn, Beringstrasse 4, D-53115 Bonn, Germany
| | - Douglas W. Stephan
- Department of Chemistry, University of Toronto, 80 St. George
Street, Toronto, Ontario M5S 3H6, Canada
- Mulliken Center for Theoretical
Chemistry, Institut für Physikalische und Theoretische Chemie, Universität Bonn, Beringstrasse 4, D-53115 Bonn, Germany
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34
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Kim Y, Lee E. Activation of C–F bonds in fluoroarenes by N-heterocyclic carbenes as an effective route to synthesize abnormal NHC complexes. Chem Commun (Camb) 2016; 52:10922-5. [DOI: 10.1039/c6cc04896j] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
An unexpected consecutive C–F activation of fluoroarenes by NHCs is presented, offering a versatile strategy to access aNHC metal complexes.
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Affiliation(s)
- Youngsuk Kim
- Center for Self-assembly and Complexity
- Institute for Basic Science (IBS)
- Pohang
- Republic of Korea
- Department of Chemistry
| | - Eunsung Lee
- Center for Self-assembly and Complexity
- Institute for Basic Science (IBS)
- Pohang
- Republic of Korea
- Department of Chemistry
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35
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Chandra Mondal K, Roy S, Roesky HW. Silicon based radicals, radical ions, diradicals and diradicaloids. Chem Soc Rev 2016; 45:1080-111. [DOI: 10.1039/c5cs00739a] [Citation(s) in RCA: 150] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Diradical (cAAC˙)2SiCl2 is isolated in two polymorphic forms. The crystals of one of the polymorphs are stable in open air for over a week.
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Affiliation(s)
| | - Sudipta Roy
- Institut für Anorganische Chemie
- Georg-August-Universität
- 37077 Göttingen
- Germany
| | - Herbert W. Roesky
- Institut für Anorganische Chemie
- Georg-August-Universität
- 37077 Göttingen
- Germany
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