1
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Hilgers F, Hogenkamp F, Klaus O, Kruse L, Loeschcke A, Bier C, Binder D, Jaeger KE, Pietruszka J, Drepper T. Light-mediated control of gene expression in the anoxygenic phototrophic bacterium Rhodobacter capsulatus using photocaged inducers. Front Bioeng Biotechnol 2022; 10:902059. [PMID: 36246361 PMCID: PMC9561348 DOI: 10.3389/fbioe.2022.902059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Accepted: 09/07/2022] [Indexed: 11/13/2022] Open
Abstract
Photocaged inducer molecules, especially photocaged isopropyl-β-d-1-thiogalactopyranoside (cIPTG), are well-established optochemical tools for light-regulated gene expression and have been intensively applied in Escherichia coli and other bacteria including Corynebacterium glutamicum, Pseudomonas putida or Bacillus subtilis. In this study, we aimed to implement a light-mediated on-switch for target gene expression in the facultative anoxygenic phototroph Rhodobacter capsulatus by using different cIPTG variants under both phototrophic and non-phototrophic cultivation conditions. We could demonstrate that especially 6-nitropiperonyl-(NP)-cIPTG can be applied for light-mediated induction of target gene expression in this facultative phototrophic bacterium. Furthermore, we successfully applied the optochemical approach to induce the intrinsic carotenoid biosynthesis to showcase engineering of a cellular function. Photocaged IPTG thus represents a light-responsive tool, which offers various promising properties suitable for future applications in biology and biotechnology including automated multi-factorial control of cellular functions as well as optimization of production processes.
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Affiliation(s)
- Fabienne Hilgers
- Institute of Molecular Enzyme Technology, Heinrich Heine University Düsseldorf at Forschungszentrum Jülich, Jülich, Germany
| | - Fabian Hogenkamp
- Institute of Bioorganic Chemistry, Heinrich Heine University Düsseldorf at Forschungszentrum Jülich, Jülich, Germany
| | - Oliver Klaus
- Institute of Molecular Enzyme Technology, Heinrich Heine University Düsseldorf at Forschungszentrum Jülich, Jülich, Germany
| | - Luzie Kruse
- Institute of Molecular Enzyme Technology, Heinrich Heine University Düsseldorf at Forschungszentrum Jülich, Jülich, Germany
| | - Anita Loeschcke
- Institute of Molecular Enzyme Technology, Heinrich Heine University Düsseldorf at Forschungszentrum Jülich, Jülich, Germany
| | - Claus Bier
- Institute of Bioorganic Chemistry, Heinrich Heine University Düsseldorf at Forschungszentrum Jülich, Jülich, Germany
| | - Dennis Binder
- Institute of Molecular Enzyme Technology, Heinrich Heine University Düsseldorf at Forschungszentrum Jülich, Jülich, Germany
| | - Karl-Erich Jaeger
- Institute of Molecular Enzyme Technology, Heinrich Heine University Düsseldorf at Forschungszentrum Jülich, Jülich, Germany
- Institute of Bio- and Geosciences: Biotechnology (IBG-1), Forschungszentrum Jülich, Jülich, Germany
| | - Jörg Pietruszka
- Institute of Bioorganic Chemistry, Heinrich Heine University Düsseldorf at Forschungszentrum Jülich, Jülich, Germany
- Institute of Bio- and Geosciences: Biotechnology (IBG-1), Forschungszentrum Jülich, Jülich, Germany
- *Correspondence: Jörg Pietruszka, ; Thomas Drepper,
| | - Thomas Drepper
- Institute of Molecular Enzyme Technology, Heinrich Heine University Düsseldorf at Forschungszentrum Jülich, Jülich, Germany
- *Correspondence: Jörg Pietruszka, ; Thomas Drepper,
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2
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Nitu C, Crespi S. Computational study on the reduction and solvolysis of triplet chlorobenzenes. J PHYS ORG CHEM 2022. [DOI: 10.1002/poc.4437] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Cristina Nitu
- Department of Chemistry, Ångström Laboratory Uppsala University Uppsala Sweden
- Stratingh Institute for Chemistry, Faculty of Mathematics and Natural Sciences, University of Groningen, AG Groningen The Netherlands
| | - Stefano Crespi
- Department of Chemistry, Ångström Laboratory Uppsala University Uppsala Sweden
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3
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Qin C, Abrell L, Troya D, Hunt E, Taylor S, Dontsova K. Outdoor dissolution and photodegradation of insensitive munitions formulations IMX-101 and IMX-104: Photolytic transformation pathway and mechanism study. CHEMOSPHERE 2021; 280:130672. [PMID: 33964749 DOI: 10.1016/j.chemosphere.2021.130672] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Revised: 04/16/2021] [Accepted: 04/22/2021] [Indexed: 06/12/2023]
Abstract
New munition compounds have been developed to replace traditional explosives to prevent unintended detonations. However, insensitive munitions (IM) can leave large proportion of unexploded charge in the field, where it is subjected to photodegradation and dissolution in precipitation. The photolytic reactions occurring on the surfaces of IMX-101 and IMX-104 formulations and the subsequent fate of photolytic products in the environment were thoroughly investigated. The constituents of IMX-101 and IMX-104 formulations dissolve sequentially under rainfall in the order of aqueous solubility: 3-nitro-1,2,4-triazol-5-one (NTO) > nitroguanidine (NQ) > 2,4-dinitroanisole (DNAN) > 1,3,5-hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX). A linear relationship between DNAN dissolution and rainwater volume was observed (r2: 0.86-0.99). It was estimated that it would take 16-228 years to completely dissolve these formulation particles under natural environmental conditions in Oracle, AZ. We used LC/MS/MS and GC/MS to examine the dissolution samples from IMX-101 and 104 particles exposed to rainfall and sunlight and found six DNAN photo-transformation products including 2-methoxy-5-nitrophenol, 4-methoxy-3-nitrophenol, 4-methoxy-3-nitroaniline, 2-methoxy-5-nitroaniline, 2,4-dinitrophenol, and methoxy-dinitrophenol, which are in good agreement with computational modeling results of bond strengths. The main DNAN photodegradation pathways are therefore proposed. Predicted eco-toxicity values suggested that the parent compound DNAN, methoxy-nitrophenols, methoxy-nitroanilines and the other two products (2,4-dinitrophenol and methoxy-dinitrophenol) would be harmful to fish and daphnid. Our study provides improved insight about the rain dissolution and photochemical behavior of IM formulations under natural conditions, which helps to form target-oriented strategies to mitigate explosive contamination in military training sites.
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Affiliation(s)
- Chao Qin
- College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, 210095, China; Biosphere 2, University of Arizona, Oracle, AZ, 85721-0158, United States.
| | - Leif Abrell
- Department of Environmental Science, University of Arizona, Tucson, AZ, 85721-0038, United States
| | - Diego Troya
- Department of Chemistry, Virginia Tech, Blacksburg, VA, 24061, United States
| | - Edward Hunt
- Biosphere 2, University of Arizona, Oracle, AZ, 85721-0158, United States
| | - Susan Taylor
- U.S. Army Engineer Research and Development Center, Hanover, NH, 03755-1290, United States
| | - Katerina Dontsova
- Biosphere 2, University of Arizona, Oracle, AZ, 85721-0158, United States; Department of Environmental Science, University of Arizona, Tucson, AZ, 85721-0038, United States.
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4
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Buck AT, Beck CL, Winter AH. Inverted Substrate Preferences for Photochemical Heterolysis Arise from Conical Intersection Control. J Am Chem Soc 2014; 136:8933-40. [DOI: 10.1021/ja501777r] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Alexander T. Buck
- Department of Chemistry, Iowa State University, 2101d Hach Hall, Ames, Iowa 50011, United States
| | - Christie L. Beck
- Department of Chemistry, Iowa State University, 2101d Hach Hall, Ames, Iowa 50011, United States
| | - Arthur H. Winter
- Department of Chemistry, Iowa State University, 2101d Hach Hall, Ames, Iowa 50011, United States
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5
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Wubbels GG, Tamura R, Gannon EJ. Temperature-Dependent Regioselectivity of Nucleophilic Aromatic Photosubstitution. Evidence That Activation Energy Controls Reactivity. J Org Chem 2013; 78:4834-9. [DOI: 10.1021/jo400367c] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Gene G. Wubbels
- Department
of Chemistry, University of Nebraska at Kearney, Kearney, Nebraska 68849, United
States
| | - Ryo Tamura
- Department
of Chemistry, University of Nebraska at Kearney, Kearney, Nebraska 68849, United
States
| | - Emmett J. Gannon
- Department
of Chemistry, University of Nebraska at Kearney, Kearney, Nebraska 68849, United
States
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6
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Rao B, Wang W, Cai Q, Anderson T, Gu B. Photochemical transformation of the insensitive munitions compound 2,4-dinitroanisole. THE SCIENCE OF THE TOTAL ENVIRONMENT 2013; 443:692-699. [PMID: 23228715 DOI: 10.1016/j.scitotenv.2012.11.033] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2012] [Revised: 11/03/2012] [Accepted: 11/06/2012] [Indexed: 06/01/2023]
Abstract
The insensitive munitions compound 2,4-dinitroanisole (DNAN) is increasingly being used as a replacement for traditional, sensitive munitions compounds (e.g., trinitrotoluene [TNT]), but the environmental fate and photo-transformation of DNAN in natural water systems are currently unknown. In this study, we investigated the photo-transformation rates of DNAN with both ultraviolet (UV) and sunlight irradiation under different environmentally relevant conditions. Sunlight photo-transformation of DNAN in water was found to follow predominantly pseudo-first-order decay kinetics with an average half-life (t(1/2)) of approximately 0.70 d and activation energy (E(a)) of 53 kJ mol(-1). Photo-transformation rates of DNAN were dependent on the wavelength of the light source: irradiation with UV-B light (280-315 nm) resulted in a greater quantum yield of transformation (φ(UV-B)=3.7×10(-4)) than rates obtained with UV-A light (φ(UV-A)=2.9×10(-4) at 316-400 nm) and sunlight (φ(sun)=1.1×10(-4)). Photo-oxidation was the dominant mechanism for DNAN photo-transformation, based on the formation of nitrite (NO(2)(-)) and nitrate (NO(3)(-)) as major N species and 2,4-dinitrophenol as the minor species. Environmental factors (e.g., temperature, pH, and the presence or absence of naturally dissolved organic matter) displayed modest to little effects on the rate of DNAN photo-transformation. These observations indicate that sunlight-induced photo-transformation of DNAN may represent a significant abiotic degradation pathway in surface water, which may have important implications in evaluating the potential impacts and risks of DNAN in the environment.
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Affiliation(s)
- Balaji Rao
- Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA.
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7
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Wubbels GG, Danial H, Policarpio D. Temperature dependence of regioselectivity in nucleophilic photosubstitution of 4-nitroanisole. The activation energy criterion for regioselectivity. J Org Chem 2010; 75:7726-33. [PMID: 20954696 DOI: 10.1021/jo1015882] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Photosubstitution of the nitro group vs the methoxy group of triplet 4-nitroanisole by hydroxide ion in water leads to product yields of about 80% 4-methoxyphenol and 20% 4-nitrophenol. The ratio depends slightly on temperature from 3 to 73 °C. The slight temperature variation in the yield ratio is reproduced almost perfectly with a simple Arrhenius model for a mechanism involving bonding of hydroxide ion with the triplet state of 4-nitroanisole. The competing transition states have activation energies of 2.2 and 2.6 kcal/mol, respectively. Correct prediction of regioselectivity can be done for this case by quantum chemical calculation of the competing triplet transition-state energies, or those of the corresponding triplet σ-complexes. Other models for aromatic photosubstitution regioselectivity in mechanisms of the S(N)2Ar* type, such as those based on calculated electron densities, HOMO/LUMO coefficients, or energy gap sizes, are discussed and shown to be inferior to the relative activation energies model. The photoreaction in alcohol solvents, claimed by others to generate the same products as in water and to have an exceedingly large variation of the product ratio with temperature, may reflect chemical changes other than those reported.
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Affiliation(s)
- Gene G Wubbels
- Department of Chemistry, University of Nebraska at Kearney, Kearney, Nebraska 68847, United States
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8
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van Dorp JWJ, Lodder G. Substituent Effects on the Photogeneration and Selectivity of Triaryl Vinyl Cations. J Org Chem 2008; 73:5416-28. [DOI: 10.1021/jo800687z] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Jan Willem J. van Dorp
- Leiden Institute of Chemistry, Gorlaeus Laboratories, Leiden University, P.O. Box 9502, 2300 RA Leiden, The Netherlands
| | - Gerrit Lodder
- Leiden Institute of Chemistry, Gorlaeus Laboratories, Leiden University, P.O. Box 9502, 2300 RA Leiden, The Netherlands
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9
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Wubbels GG, Brown TR, Babcock TA, Johnson KM. The Element Effect and Nucleophilicity in Nucleophilic Aromatic Photosubstitution (SN2Ar*). Local Atom Effects as Mechanistic Probes of Very Fast Reactions. J Org Chem 2008; 73:1925-34. [DOI: 10.1021/jo702468d] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Gene G. Wubbels
- Department of Chemistry, University of Nebraska at Kearney, Kearney, Nebraska 68849
| | - Toby R. Brown
- Department of Chemistry, University of Nebraska at Kearney, Kearney, Nebraska 68849
| | - Travis A. Babcock
- Department of Chemistry, University of Nebraska at Kearney, Kearney, Nebraska 68849
| | - Kandra M. Johnson
- Department of Chemistry, University of Nebraska at Kearney, Kearney, Nebraska 68849
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Pintér B, De Proft F, Veszprémi T, Geerlings P. Theoretical Study of the Orientation Rules in Photonucleophilic Aromatic Substitutions. J Org Chem 2008; 73:1243-52. [DOI: 10.1021/jo701392m] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- B. Pintér
- Inorganic and Analytical Chemistry Department, Budapest University of Technology and Economics (BUTE), Szent Gellért tér 4, 1521 Budapest, Hungary, and Eenheid Algemene Chemie (ALGC), Faculteit Wetenschappen, Vrije Universiteit Brussel (VUB), Pleinlaan 2, 1050 Brussels, Belgium
| | - F. De Proft
- Inorganic and Analytical Chemistry Department, Budapest University of Technology and Economics (BUTE), Szent Gellért tér 4, 1521 Budapest, Hungary, and Eenheid Algemene Chemie (ALGC), Faculteit Wetenschappen, Vrije Universiteit Brussel (VUB), Pleinlaan 2, 1050 Brussels, Belgium
| | - T. Veszprémi
- Inorganic and Analytical Chemistry Department, Budapest University of Technology and Economics (BUTE), Szent Gellért tér 4, 1521 Budapest, Hungary, and Eenheid Algemene Chemie (ALGC), Faculteit Wetenschappen, Vrije Universiteit Brussel (VUB), Pleinlaan 2, 1050 Brussels, Belgium
| | - P. Geerlings
- Inorganic and Analytical Chemistry Department, Budapest University of Technology and Economics (BUTE), Szent Gellért tér 4, 1521 Budapest, Hungary, and Eenheid Algemene Chemie (ALGC), Faculteit Wetenschappen, Vrije Universiteit Brussel (VUB), Pleinlaan 2, 1050 Brussels, Belgium
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11
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Wubbels GG, Johnson KM, Babcock TA. The element effect in nucleophilic aromatic photosubstitution (SN2Ar*). Org Lett 2007; 9:2803-6. [PMID: 17602637 DOI: 10.1021/ol070910m] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Photoreactions of 4-nitroanisole and the 2-halo-4-nitroanisoles (halogen = F, Cl, Br, I) with NaCN have been investigated. 4-Nitroanisole gave a novel, stable nitronate ion adduct (74%) with cyanide. For the five compounds, we report product distributions, Stern-Volmer kinetic plots, triplet lifetimes, and triplet yields, which afford rate constants for attack by the cyanide ion. Cyanide attack on the fluoride is diffusion controlled; the relative rates for attack at F, Cl, Br, and I are 27:2:2:1, respectively.
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Affiliation(s)
- Gene G Wubbels
- Department of Chemistry, University of Nebraska at Kearney, Kearney, Nebraska 68849, USA.
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12
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Wubbels GG, Johnson KM. New nitronate sigma complexes and the mechanism of nucleophilic aromatic photosubstitution para to a nitro group. Org Lett 2006; 8:1451-4. [PMID: 16562914 DOI: 10.1021/ol0602497] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
[reaction: see text] Photolysis of 4-nitroanisole with aliphatic amines gives mainly N-substituted 4-nitroanilines. Reactions of this type have been widely attributed to a geminate radical mechanism. We questioned this interpretation and have searched for and found by NMR spectroscopy a new class of stable nitronate adducts generated under the reaction conditions. The adducts imply that photosubstitution by amines para to the nitro group occurs by meta sigma complex formation followed by an unprecedented sigmatropic rearrangement.
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Affiliation(s)
- Gene G Wubbels
- Department of Chemistry, University of Nebraska at Kearney, Kearney, Nebraska 68849, USA.
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13
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Weiss EA, Wasielewski MR, Ratner MA. Molecules as Wires: Molecule-Assisted Movement of Charge and Energy. MOLECULAR WIRES AND ELECTRONICS 2005; 257:103-33. [DOI: 10.1007/b136068] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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14
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Manickam MCD, Pitchumani K, Srinivasan C. Regioselective photoamination of 4-nitroveratrole upon cyclodextrin complexation. J CHEM SCI 2003. [DOI: 10.1007/bf02704218] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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15
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Klán P, Růzicka R, Heger D, Literák J, Kulhánek P, Loupy A. Temperature-sensitive photochemical aromatic substitution on 4-nitroanisole. Photochem Photobiol Sci 2002; 1:1012-6. [PMID: 12661600 DOI: 10.1039/b209010d] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A temperature-sensitive photochemical nucleophilic aromatic substitution on 4-nitroanisole by a hydroxide ion in homogeneous solutions, in a two-phase system under phase-transfer catalysis conditions, and in the microwave field is reported. It was found that reaction regioselectivity dramatically changes with temperature in the region of -20 to 196 degrees C. The quantum yield of the 4-methoxyphenol formation was found to be temperature independent, in contrast to that of the 4-nitrophenol formation, suggesting that there is a temperature dependent process occurring after the partitioning between replacement of the nitro group and the methoxy group has taken place. The reaction was also investigated by using quantum chemical calculations. A technique for microwave-assisted photochemical synthesis is proposed as an efficient and practical tool for organic synthesis.
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Affiliation(s)
- Petr Klán
- Department of Organic Chemistry, Faculty of Science, Masaryk University, Kotlarska 2, 611 37 Brno, Czech Republic.
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Selectivity in photohydroxylation of 4-nitroveratrole and nitroanisoles catalysed by cyclodextrins. J Photochem Photobiol A Chem 2002. [DOI: 10.1016/s1010-6030(02)00016-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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17
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Fan FRF, Yang J, Cai L, Price DW, Dirk SM, Kosynkin DV, Yao Y, Rawlett AM, Tour JM, Bard AJ. Charge transport through self-assembled monolayers of compounds of interest in molecular electronics. J Am Chem Soc 2002; 124:5550-60. [PMID: 11996598 DOI: 10.1021/ja017706t] [Citation(s) in RCA: 296] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The electrical properties of self-assembled monolayers (SAMs) on metal surfaces have been explored for a series of molecules to address the relation between the behavior of a molecule and its structure. We probed interfacial electron transfer processes, particularly those involving unoccupied states, of SAMs of thiolates or arylates on Au by using shear force-based scanning probe microscopy (SPM) combined with current-voltage (i-V) and current-distance (i-d) measurements. The i-V curves of hexadecanethiol in the low bias regime were symmetric around 0 V and the current increased exponentially with V at high bias voltage. Different than hexadecanethiol, reversible peak-shaped i-V characteristics were obtained for most of the nitro-based oligo(phenylene ethynylene) SAMs studied here, indicating that part of the conduction mechanism of these junctions involved resonance tunneling. These reversible peaked i-V curves, often described as a negative differential resistance (NDR) effect of the junction, can be used to define a threshold tip bias, V(TH), for resonant conduction. We also found that for all of the SAMs studied here, the current decreased with increasing distance, d, between tip and substrate. The attenuation factor beta of hexadecanethiol was high, ranging from 1.3 to 1.4 A(-1), and was nearly independent of the tip bias. The beta-values for nitro-based molecules were low and depended strongly on the tip bias, ranging from 0.15 A(-1) for tetranitro oligo(phenylene ethynylene) thiol, VII, to 0.50 A(-1) for dinitro oligo(phenylene) thiol, VI, at a -3.0 V tip bias. Both the V(TH) and beta values of these nitro-based SAMs were also strongly dependent on the structures of the molecules, e.g. the number of electroactive substituent groups on the central benzene, the molecular wire backbone, the anchoring linkage, and the headgroup. We also observed charge storage on nitro-based molecules. For a SAM of the dintro compound, V, approximately 25% of charge collected in the negative scan is stored in the molecules and can be collected at positive voltages. A possible mechanism involving lateral electron hopping is proposed to explain this phenomenon.
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Affiliation(s)
- Fu-Ren F Fan
- Department of Chemistry and Biochemistry and Center for Nano-and Molecular Science and Technology, The University of Texas at Austin, 78712, USA
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18
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Mir M, Marquet J, Massot O. Photosubstitution-photoreduction mechanistic duality in the SET photoreactions of nitrophenyl ethers with amines. The role of the steps that follow the ET. Tetrahedron 1999. [DOI: 10.1016/s0040-4020(99)00735-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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19
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20
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Cervera M, Marquet J. Effects of superoxide anion generated from aromatic radical anions produced in nucleophilic aromatic photosubstitution reactions. CAN J CHEM 1998. [DOI: 10.1139/v98-044] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Superoxide anion is generated from aromatic radical anions produced in nucleophilic aromatic photosubstitutions when the reactions are carried out in non-deoxygenated solutions of polar aprotic solvents. Superoxide anion thus generated displaces cyanide anion from acetonitrile and benzyl cyanide, ethoxide anion from ethyl acetate, and methanesulfenate anion from dimethyl sulfoxide. Hence, non-deoxygenated polar aprotic solvents should be avoided in nucleophilic aromatic photosubstitution reactions.Key words: superoxide, fluoride, nucleophilic aromatic photosubstitution.
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21
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Konstantinov A, Kingsmill CA, Ferguson G, Bunce NJ. Successive Photosubstitution of Hexachlorobenzene with Cyanide Ion. J Am Chem Soc 1998. [DOI: 10.1021/ja980403n] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Alexandre Konstantinov
- Contribution from the Department of Chemistry and Biochemistry and Laboratory Services Division, University of Guelph, Guelph, Ontario, Canada N1G 2W1
| | - Carol A. Kingsmill
- Contribution from the Department of Chemistry and Biochemistry and Laboratory Services Division, University of Guelph, Guelph, Ontario, Canada N1G 2W1
| | - George Ferguson
- Contribution from the Department of Chemistry and Biochemistry and Laboratory Services Division, University of Guelph, Guelph, Ontario, Canada N1G 2W1
| | - Nigel J. Bunce
- Contribution from the Department of Chemistry and Biochemistry and Laboratory Services Division, University of Guelph, Guelph, Ontario, Canada N1G 2W1
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22
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Evans CH, Árnadóttir G, Scaiano JC. Reactivity of the 3-Nitroanisole Triplet: Methanol Inhibition of Photohydroxylation. J Org Chem 1997. [DOI: 10.1021/jo971188g] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Christopher H. Evans
- Science Institute, University of Iceland, Dunhaga 3, IS-107 Reykjavik, Iceland, and Department of Chemistry, University of Ottawa, 10 Marie Curie, Ottawa, Canada K1N-6N5
| | - Gudrún Árnadóttir
- Science Institute, University of Iceland, Dunhaga 3, IS-107 Reykjavik, Iceland, and Department of Chemistry, University of Ottawa, 10 Marie Curie, Ottawa, Canada K1N-6N5
| | - J. C. Scaiano
- Science Institute, University of Iceland, Dunhaga 3, IS-107 Reykjavik, Iceland, and Department of Chemistry, University of Ottawa, 10 Marie Curie, Ottawa, Canada K1N-6N5
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The search for biochemical photoprobes. IV1. The photoreactions of 2,6-difluoro-4-nitroanisole with nucleophiles. Tetrahedron 1995. [DOI: 10.1016/0040-4020(95)00343-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Mutai K, Kobayashi K, Yokoyama K. Photoinduced intramolecular substitution-III photocyclization of ω-anilinoalkyl m-nitrophenyl ethers. Tetrahedron 1984. [DOI: 10.1016/s0040-4020(01)91127-5] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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