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Miao Z, Scott FJ, van Tol J, Bowers CR, Veige AS, Mentink-Vigier F. Soliton Based Dynamic Nuclear Polarization: An Overhauser Effect in Cyclic Polyacetylene at High Field and Room Temperature. J Phys Chem Lett 2024:3369-3375. [PMID: 38498927 DOI: 10.1021/acs.jpclett.3c03591] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/20/2024]
Abstract
Polyacetylene, a versatile material with an electrical conductivity that can span 7 orders of magnitude, is the prototypical conductive polymer. In this letter, we report the observation of a significant Overhauser effect at the high magnetic field of 14.1 T that operates at 100 K and room temperature in both linear and cyclic polyacetylene. Significant NMR signal enhancements ranging from 24 to 45 are obtained. The increased sensitivity enabled the characterization of the polymer chain defects at natural abundance. The absence of end methyl group carbon-13 signals provides proof of the closed-loop molecular structure of cyclic polyacetylene. The remarkable efficiency of the soliton based Overhauser effect DNP mechanism at high temperature and high field holds promise for applications and extension to other conductive polymer systems.
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Affiliation(s)
- Z Miao
- Center for Catalysis, Department of Chemistry, University of Florida, Gainesville, Florida 32611, United States
| | - F J Scott
- National High Magnetic Field Laboratory, Florida State University, 1800 E. Paul Dirac Drive, Tallahassee, Florida 32310, United States
| | - J van Tol
- National High Magnetic Field Laboratory, Florida State University, 1800 E. Paul Dirac Drive, Tallahassee, Florida 32310, United States
| | - C R Bowers
- Center for Catalysis, Department of Chemistry, University of Florida, Gainesville, Florida 32611, United States
- National High Magnetic Field Laboratory, Florida State University, 1800 E. Paul Dirac Drive, Tallahassee, Florida 32310, United States
| | - A S Veige
- Center for Catalysis, Department of Chemistry, University of Florida, Gainesville, Florida 32611, United States
| | - F Mentink-Vigier
- National High Magnetic Field Laboratory, Florida State University, 1800 E. Paul Dirac Drive, Tallahassee, Florida 32310, United States
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Ghassemi N, Poulhazan A, Deligey F, Mentink-Vigier F, Marcotte I, Wang T. Solid-State NMR Investigations of Extracellular Matrixes and Cell Walls of Algae, Bacteria, Fungi, and Plants. Chem Rev 2021; 122:10036-10086. [PMID: 34878762 DOI: 10.1021/acs.chemrev.1c00669] [Citation(s) in RCA: 55] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Extracellular matrixes (ECMs), such as the cell walls and biofilms, are important for supporting cell integrity and function and regulating intercellular communication. These biomaterials are also of significant interest to the production of biofuels and the development of antimicrobial treatment. Solid-state nuclear magnetic resonance (ssNMR) and magic-angle spinning-dynamic nuclear polarization (MAS-DNP) are uniquely powerful for understanding the conformational structure, dynamical characteristics, and supramolecular assemblies of carbohydrates and other biomolecules in ECMs. This review highlights the recent high-resolution investigations of intact ECMs and native cells in many organisms spanning across plants, bacteria, fungi, and algae. We spotlight the structural principles identified in ECMs, discuss the current technical limitation and underexplored biochemical topics, and point out the promising opportunities enabled by the recent advances of the rapidly evolving ssNMR technology.
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Affiliation(s)
- Nader Ghassemi
- Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803, United States
| | - Alexandre Poulhazan
- Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803, United States.,Department of Chemistry, Université du Québec à Montréal, Montreal H2X 2J6, Canada
| | - Fabien Deligey
- Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803, United States
| | | | - Isabelle Marcotte
- Department of Chemistry, Université du Québec à Montréal, Montreal H2X 2J6, Canada
| | - Tuo Wang
- Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803, United States
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3
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Belh SJ, Ghosh G, Greer A. Surface-Radical Mobility Test by Self-Sorted Recombination: Symmetrical Product upon Recombination (SPR). J Phys Chem B 2021; 125:4212-4220. [PMID: 33856798 DOI: 10.1021/acs.jpcb.1c01099] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We describe here a study of the mobility of the alkoxy radical on a surface by detection of its recombination product. A novel method called symmetrical product recombination (SRP) uses an unsymmetrical peroxide that upon sensitized homolysis recombines to a symmetrical product [R'OOR → R'O•↑ + •OR → ROOR]. This allows for self-sorting of the radical to enhance the recombination path to a symmetrical product, which has been used to deduce surface migratory aptitude. SPR also provides a new opportunity for mechanistic studies of interfacial radicals, including monitoring competition between radical recombination versus surface hydrogen abstraction. This is an approach that might work for other surface-borne radicals on natural and artificial particles.
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Affiliation(s)
- Sarah J Belh
- Department of Chemistry, Brooklyn College, 2900 Bedford Avenue, Brooklyn, New York 11210, United States.,Ph.D. Program in Chemistry, The Graduate Center of the City University of New York, 365 Fifth Avenue, New York, New York 10016, United States
| | - Goutam Ghosh
- Department of Chemistry, Brooklyn College, 2900 Bedford Avenue, Brooklyn, New York 11210, United States.,Ph.D. Program in Chemistry, The Graduate Center of the City University of New York, 365 Fifth Avenue, New York, New York 10016, United States
| | - Alexander Greer
- Department of Chemistry, Brooklyn College, 2900 Bedford Avenue, Brooklyn, New York 11210, United States.,Ph.D. Program in Chemistry, The Graduate Center of the City University of New York, 365 Fifth Avenue, New York, New York 10016, United States
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4
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Durantini AM, Greer A. Interparticle Delivery and Detection of Volatile Singlet Oxygen at Air/Solid Interfaces. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:3559-3567. [PMID: 33660980 DOI: 10.1021/acs.est.0c07922] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
An interparticle system has been devised, allowing airborne singlet oxygen to transfer between particle surfaces. Singlet oxygen is photogenerated on a sensitizer particle, where it then travels through air to a second particle bearing an oxidizable compound-a particulate-based approach with some similarities to reactive oxygen quenching in the atmosphere. In atmospheric photochemistry, singlet oxygen is generated by natural particulate matter, but its formation and quenching between particles has until now not been determined. Determining how singlet oxygen reacts on a second surface is useful and was developed by a three-phase system (particle-air-particle) interparticulate photoreaction with tunable quenching properties. We identify singlet oxygen quenching directly by near-IR phosphorescence in the airborne state and at the air/particle interface for total quenching rate constants (kT) of adsorbed anthracene trapping agents. The air/solid interface kT of singlet oxygen by anthracene-coated particles was (2.8 ± 0.8) × 107 g mol-1 s-1 for 9,10-dimethylanthracene and (2.1 ± 0.9) × 107 g mol-1 s-1 for 9,10-anthracene dipropionate dianion, and the lifetime of airborne singlet oxygen was measured to be 550 μs. These real-time interactions and particle-induced quenching steps open up new opportunities for singlet oxygen research of atmospheric and particulate processes.
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Affiliation(s)
- Andrés M Durantini
- Department of Chemistry, Brooklyn College, Brooklyn, New York 11210, United States
- Ph.D. Program in Chemistry, The Graduate Center of the City University of New York, New York, New York 10016, United States
| | - Alexander Greer
- Department of Chemistry, Brooklyn College, Brooklyn, New York 11210, United States
- Ph.D. Program in Chemistry, The Graduate Center of the City University of New York, New York, New York 10016, United States
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Goodlett DW, Sindt AJ, Hossain MS, Merugu R, Smith MD, Garashchuk S, Gudmundsdottir AD, Shimizu LS. From Incident Light to Persistent and Regenerable Radicals of Urea-Assembled Benzophenone Frameworks: A Structural Investigation. J Phys Chem A 2021; 125:1336-1344. [PMID: 33534579 DOI: 10.1021/acs.jpca.0c08953] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Herein we probe the effects of crystalline structure and geometry on benzophenone photophysics, self-quenching, and the regenerable formation of persistent triplet radical pairs at room temperature. Radical pairs are not observed in solution but appear via an emergent pathway within the solid-state assembly. Single crystal X-ray diffraction (SC-XRD) of two sets of constitutional isomers, benzophenone bis-urea macrocycles, and methylene urea-tethered dibenzophenones are compared. Upon irradiation with 365 nm light-emitting diodes (LEDs), each forms photogenerated radicals as monitored by electron paramagnetic resonance (EPR). Once generated, the radicals exhibit half-lives from 2 to 60 days before returning to starting material without degradation. Re-exposure to light regenerates the radicals with similar efficiency. Subtle differences in the structure of the crystalline frameworks modulates the maximum concentration of photogenerated radicals, phosphorescence quantum efficiency (φ), and n-type self-quenching as observed using laser flash photolysis (LFP). These studies along with the electronic structure analysis based on the time-dependent density functional theory (TD-DFT) suggest the microenvironment surrounding benzophenone largely dictates the favorability of self-quenching or radical formation and affords insights into structure/function correlations. Advances in understanding how structure determines the excited state pathway solid-state materials undertake will aid in the design of new radical initiators, components of OLEDs, and NMR polarizing agents.
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Affiliation(s)
- Dustin W Goodlett
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208, United States
| | - Ammon J Sindt
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208, United States
| | - Muhammad Saddam Hossain
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208, United States
| | - Rajkumar Merugu
- Department of Chemistry, University of Cincinnati, Cincinnati, Ohio 45221, United States
| | - Mark D Smith
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208, United States
| | - Sophya Garashchuk
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208, United States
| | - Anna D Gudmundsdottir
- Department of Chemistry, University of Cincinnati, Cincinnati, Ohio 45221, United States
| | - Linda S Shimizu
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208, United States
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Ghosh G, Greer A. A fluorinated phosphite traps alkoxy radicals photogenerated at the air/solid interface of a nanoparticle. J PHYS ORG CHEM 2020. [DOI: 10.1002/poc.4115] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Goutam Ghosh
- Department of Chemistry Brooklyn College Brooklyn New York USA
- Ph.D. Program in Chemistry The Graduate Center of the City University of New York New York New York USA
| | - Alexander Greer
- Department of Chemistry Brooklyn College Brooklyn New York USA
- Ph.D. Program in Chemistry The Graduate Center of the City University of New York New York New York USA
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7
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DeHaven BA, Liberatore HK, Greer A, Richardson SD, Shimizu LS. Probing the Formation of Reactive Oxygen Species by a Porous Self-Assembled Benzophenone Bis-Urea Host. ACS OMEGA 2019; 4:8290-8298. [PMID: 31459915 PMCID: PMC6648088 DOI: 10.1021/acsomega.9b00831] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Accepted: 04/25/2019] [Indexed: 06/10/2023]
Abstract
Herein, we examine the photochemical formation of reactive oxygen species (ROS) by a porous benzophenone-containing bis-urea host (1) to investigate the mechanism of photooxidations that occur within the confines of its nanochannels. UV irradiation of the self-assembled host in the presence of molecular oxygen generates both singlet oxygen and superoxide when suspended in solution. The efficiency of ROS generation by the host is lower than that of benzophenone (BP), which could be beneficial for reactions carried out catalytically, as ROS species react quickly and often unselectively. Superoxide formation was detected through reaction with 5,5-dimethyl-1-pyrroline N-oxide in the presence of methanol. However, it is not detected in CHCl3, as it reacts rapidly with the solvent to generate methaneperoxy and chloride anions, similar to BP. The lifetime of airborne singlet oxygen (τΔairborne) was examined at the air-solid outer surface of the host and host·quencher complexes and suggests that quenching is a surface phenomenon. The efficiency of the host and BP as catalysts was compared for the photooxidation of 1-methyl-1-cyclohexene in solution. Both the host and BP mediate the photooxidation in CHCl3, benzene, and benzene-d 6, producing primarily epoxide-derived products with low selectivity likely by both type I and type II photooxidation processes. Interestingly, in CHCl3, two chlorohydrins were also formed, reflecting the formation of chloride in this solvent. In contrast, UV irradiation of the host·guest crystals in an oxygen atmosphere produced no epoxide and appeared to favor mainly the type II processes. Photolysis afforded high conversion to only three products: an enone, a tertiary allylic alcohol, and a diol, which demonstrates the accessibility of the encapsulated reactants to oxygen and the influence of confinement on the reaction pathway.
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Affiliation(s)
- Baillie A. DeHaven
- Department of Chemistry
and Biochemistry, University of South Carolina, Columbia, South Carolina 29208, United States
| | - Hannah K. Liberatore
- Department of Chemistry
and Biochemistry, University of South Carolina, Columbia, South Carolina 29208, United States
| | - Alexander Greer
- Department of Chemistry, Brooklyn College, Brooklyn, New York 11210, United States
- Ph.D. Program in Chemistry, Graduate Center
of City University of New York, New York, New York 10016, United States
| | - Susan D. Richardson
- Department of Chemistry
and Biochemistry, University of South Carolina, Columbia, South Carolina 29208, United States
| | - Linda S. Shimizu
- Department of Chemistry
and Biochemistry, University of South Carolina, Columbia, South Carolina 29208, United States
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DeHaven BA, Goodlett DW, Sindt AJ, Noll N, De Vetta M, Smith MD, Martin CR, González L, Shimizu LS. Enhancing the Stability of Photogenerated Benzophenone Triplet Radical Pairs through Supramolecular Assembly. J Am Chem Soc 2018; 140:13064-13070. [PMID: 30212205 DOI: 10.1021/jacs.8b08501] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Supramolecular assembly of urea-tethered benzophenone molecules results in the formation of remarkably persistent triplet radical pairs upon UV irradiation at room temperature, whereas no radicals were observed in solution. The factors that lead to emergent organic radicals are correlated with the microenvironment around the benzophenone carbonyl, types of proximal hydrogens, and the rigid supramolecular network. The absorption spectra of the linear analogues were rationalized using time-dependent density functional theory calculations on the crystal structure and in dimethyl sulfoxide, employing an implicit solvation model to describe structural and electronic solvent effects. Inspection of the natural transition orbitals for the more important excitation bands of the absorption spectra indicates that crystallization of the benzophenone-containing molecules should present a stark contrast in photophysical properties versus that in solution, which was indeed reflected by their quantum efficiencies upon solid-state assembly. Persistent organic radicals have prospective applications ranging from organic light-emitting diode technology to NMR polarizing agents.
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Affiliation(s)
- Baillie A DeHaven
- Department of Chemistry and Biochemistry , University of South Carolina , Columbia , South Carolina 29208 , United States
| | - Dustin W Goodlett
- Department of Chemistry and Biochemistry , University of South Carolina , Columbia , South Carolina 29208 , United States
| | - Ammon J Sindt
- Department of Chemistry and Biochemistry , University of South Carolina , Columbia , South Carolina 29208 , United States
| | - Niklas Noll
- Department of Chemistry and Biochemistry , University of South Carolina , Columbia , South Carolina 29208 , United States
| | - Martina De Vetta
- Institute of Theoretical Chemistry, Faculty of Chemistry , University of Vienna , Währinger Strasse 17 , 1090 Vienna , Austria
| | - Mark D Smith
- Department of Chemistry and Biochemistry , University of South Carolina , Columbia , South Carolina 29208 , United States
| | - Corey R Martin
- Department of Chemistry and Biochemistry , University of South Carolina , Columbia , South Carolina 29208 , United States
| | - Leticia González
- Institute of Theoretical Chemistry, Faculty of Chemistry , University of Vienna , Währinger Strasse 17 , 1090 Vienna , Austria
| | - Linda S Shimizu
- Department of Chemistry and Biochemistry , University of South Carolina , Columbia , South Carolina 29208 , United States
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