4622-04-2Relevant articles and documents
Mechanistic Origin of Photoredox Catalysis Involving Iron(II) Polypyridyl Chromophores
Mccusker, James K.,Woodhouse, Matthew D.
, p. 16229 - 16233 (2020)
Photoredox catalysis employing ruthenium- and iridium-based chromophores have been the subject of considerable research. However, the natural abundance of these elements are among the lowest on the periodic table, a fact that has led to an interest in developing chromophores based on earth-abundant transition metals that can perform the same function. There have been reports of using FeII-based polypyridyl complexes as photocatalysts, but there is limited mechanistic information pertaining to the nature of their reactivity in the context of photoredox chemistry. Herein, we report the results of bimolecular quenching studies between [Fe(tren(py)3)]2+ (where tren(py)3 = tris(2-pyridyl-methylimino-ethyl)amine) and a series of benzoquinoid acceptors. The data provide direct evidence of electron transfer involving the lowest-energy ligand-field excited state of the Fe(II)-based photosensitizer, definitively establishing that Fe(II) polypyridyl complexes can engage in photoinduced redox reactions but by a mechanism that is fundamentally different than the MLCT-based chemistry endemic to their second- and third-row congeners.
A dicyanobenzoquinone based cathode material for rechargeable lithium and sodium ion batteries
Lyu, Hailong,Jafta, Charl J.,Popovs, Ilja,Meyer, Harry M.,Hachtel, Jordan A.,Huang, Jingsong,Sumpter, Bobby G.,Dai, Sheng,Sun, Xiao-Guang
, p. 17888 - 17895 (2019)
Organic quinone materials offer a sustainable approach for electric energy storage, however, their intrinsic electrical insulation and dissolution into the electrolyte during cycling have hampered their wide applications. To tackle these two issues, we have synthesized a novel organic cathode material by anchoring a quinone compound, 2,3-dicyano-p-benzoquinone (DCBQ) with a high redox potential of 3.37 V vs. Li/Li+, onto carbon nanotubes (CNTs) (CNTs-DCBQ) through a facile ''grafting to'' method. The elaborate combination of excellent electron conductivity and large surface area of CNTs and stable and reversible redox reaction of DCBQ enables CNTs-DCBQ to deliver high reversible capacities of 206.9 and 175.8 mA h g-1 at a current density of 10 mA g-1 and also remarkable capacities of 110.2 and 82.1 mA h g-1 at a higher current density of 200 mA g-1 with a capacity retention approaching 100% after 1000 cycles for lithium and sodium ion batteries, respectively.
Kinetics and thermochemistry of the [2π+2σ+2σ]-cycloaddition of quadricyclane with 2,3-dicyano-1,4-benzoquinone
Kornilov, Dmitry A.,Anikin, Oleg V.,Kolesnikova, Anastasia O.,Bermeshev, Maxim V.,Gubaidullin, Aidar T.,Kiselev, Vladimir D.
, p. 405 - 411 (2019)
Two-stage [2π+2σ+2σ]-cycloaddition of quadricyclane (2) with 2,3-dicyano-1,4-benzoquinone (1) with a huge difference in the activity of two reaction centers has been studied. In the first stage (kinetic control), the cycloaddition of 2 takes place on the activated С2=С3 bond of 1 to form the monoadduct 3, and in the second stage the cycloaddition of 2 on the С5=С6 bond of the monoadduct 3 occurs by 6 orders of magnitude lower with the formation of bisadduct 4. The structures of adducts 3 and 4 have been proved by NMR data and the X-Ray method, respectively. The kinetics of the first and second stages, the enthalpy of dissolution of 1 in the π-donor solvents, and the enthalpy of the reaction 1+2→3 have been measured.
Sharp difference in the rate of formation and stability of the Diels–Alder reaction adducts with 2,3-dicyano-1,4-benzoquinone and N-phenylimide-1,4-benzoquinone-2,3-dicarboxylic acid
Kiselev, Vladimir D.,Kolesnikova, Anastasia O.,Shulyatiev, Alexey A.,Dinikaev, Ildar F.,Kornilov, Dmitry A.
, p. 1306 - 1313 (2021/08/25)
This work reports new studies of the activity and Diels–Alder kinetics of a series of dienophiles: tetracyanoethylene (1), 2,3-dicyano-p-benzoquinone (10), and N-phenylimide-1,4-benzoquinone-2,3-dicarboxylic acid (11). Rate differences are interpreted in terms of the donor–acceptor properties of the reagents. The relative π-acceptor properties of the dienophiles are probed by measuring their interaction energies with a series π-donor solvents: benzene, toluene, o-xylene, and chlorobenzene. The normalized interaction energies of 1, 10, and 11 are found to be 100:64:28. Despite the increased energy of the donor–acceptor interaction, dienophile 10 is 255 times less active in the reaction with 9,10-dimethylanthracene than 11. It is suggested that this is due to the significantly lower energy of π-bond cleavage in bicyclic dienophile 11, compared with monocyclic 10.
Synthesis of six-membered functionalized carbocyclic compounds by one-pot reaction of hydroquinone derivatives and dienes
Cai, Guang-Rong,Guan, Zhi,He, Yan-Hong
experimental part, p. 3016 - 3025 (2011/09/16)
A general method for one-pot reaction of hydroquinone derivatives and dienes has been developed. The system of Pb3O4 in tetrahydrofuran- trifluoroacetic acid was found to play dual roles as oxidant for the generation of quinones in situ and as catalyst for the Diels-Alder cycloaddition, which makes the one-pot reaction efficient and easy to carry out. Using this method, a variety of six-membered functionalized carbocyclic compounds can be easily prepared in medium to excellent yields at room temperature. Copyright
Nitration of phenolic compounds and oxidation of hydroquinones using tetrabutylammonium chromate and dichromate under aprotic conditions
Pourali, Ali Reza,Goli, Arezou
scheme or table, p. 63 - 67 (2012/01/13)
In this work, we have reported a mild, efficient and selective method for the mononitration of phenolic compounds using sodium nitrite in the presence of tetrabutylammonium dichromate (TBAD) and oxidation of hydroquinones to quinones with TBAD in CH2Cl2. Using this method, high yields of nitrophenols and quinones were obtained under neutral aprotic conditions. Tetrabutylammonium chromate (TBAC) can also be used as oxidant at same conditions. Indian Academy of Sciences.
Photoinduced Electron Transfer in Pinacol Cleavage with Quinones via Highly Labile Cation Radicals. Direct Comparison of Charge-Transfer Excitation and Photosensitization
Perrier, Serge,Sankararaman, Seth,Kochi, Jay K.
, p. 825 - 837 (2007/10/02)
Benzopinacol and related diphenylethane-like donors (D) form electron donor-acceptor (EDA) complexes with chloranil and similar benzoquinones (A), in which the deliberate irradiation of the charge-transfer absorption band (hνCT) leads to oxidative cleavage (retropinacol) via electron transfer.Photosensitization by excitation of the ?-?* band of chloranil and diffusive quenching also effects the C-C bond cleavage of the same donors.The photoefficiencies of both photochemical processes are quantitatively compared with respect to the lifetimes of the pinacol cation radicals (D+ radical), as determined by the competition from back electron transfer and diffusion.These photoinduced processes are considered in the context of electron-transfer for an equivalent thermal reaction which occurs in the dark with high-potential quinones and electron-rich pinacols.
Kinetics of the Oxidation of Ascorbic Acid and Substituted 1,2- and 1,4-Dihydroxybenzenes by the Hexacyanoruthenate(III) Ion in Acidic Perchlorate Media
Hoddenbagh, J. Mark A.,Macartney, Donal H.
, p. 615 - 620 (2007/10/02)
The kinetics of oxidation of ascorbic acid and a series of substituted 1,2- and 1,4-dihydroxybenzene compounds (H2Q) by 3- have been investigated in acidic perchlorate media.The inverse dependences of the rate constants on acid concentrations for 2,3-dicyano-1,4-dihydroxybenzene, 4,5-dihydroxybenzene-1,3-disulphonate, and ascorbic acid have been attributed to concurrent rate-determining pathways involving the one-electron oxidations of H2Q or HQ(-) by 3- to the corresponding semiquinone or ascorbate radical intermediate.The cross-reaction rate constants have been correlated with the semiquinone or ascorbate reduction potentials in terms of the Marcus relationship to yield a 3--4- electron self-exchange rate constant of (1.0 +/- 0.8) . 105 dm3mol-1s-1.This is compared with those for other low-spin d5-d6 transition-metal complex couples and discussed in terms of the inner-sphere and solvent reorganization energies.
Energetic Comparison between Photoinduced Electron-Transfer Reactions from NADH Model Compounds to Organic and Inorganic Oxidants and Hydride-Transfer Reactions from NADH Model Compounds to p-Benzoquinone Derivatives
Fukuzumi, Shunichi,Koumitsu, Shintaro,Hironaka, Katsuhiko,Tanaka, Toshio
, p. 305 - 316 (2007/10/02)
Kinetics studies on photoinduced electron-transfer reactions from dihydropyridine compounds (PyH2) as being NADH model compounds to organic and inorganic oxidants and hydride-transfer reactions from PyH2 to p-benzoquinone derivatives (Q) in the absence and presence of Mg2+ ion are reported by determining over 150 rate constants.These results, combined with the values of Gibbs energy change of the photoinduced electron-transfer reactions as well as those of each step of the hydride-transfer reactions as being the e--H+-e- sequence, which are determined independently, revealed that the rate constants of the photoinduced electron-transfer reactions obey the Rehm-Weller-Gibbs energy relationship and that the activation barrier of the hydride-transfer reactions from PyH2 to Q is dependent solely on the Gibbs energy changes of the initial electron transfer from PyH2 to Q and the following proton transfer from PyH2.+ to Q.- and thus independent of the Gibbs energy change of the final electron transfer from PyH. to QH..The retarding effect of Mg2+ ion observed on the photoinduced electron transfer and hydride-transfer reactions of PyH2 is ascribed to the positive shifts of the redox potentials of the ground and excited states of PyH2 due to the complex formation with Mg2+ ion.
Charge-Transfer Complexes and Reactivity in Diels-Alder Cycloadditions
Sustmann, Reiner,Dern, Mechthild,Kasten, Ronald,Sicking, Willi
, p. 1315 - 1322 (2007/10/02)
The reactivity of 2,3-bis(methylene)norbornane (1) towards the highly reactive dienophiles 2,3-dicyano-p-benzoquinone (2), tetracyanoethylene (3), 2,3-dicyanomaleimide (4), and p-benzoquinone-2,3-dicarboxyclic anhydride (5) was analysed kinetically.CT complexes were observed for 1 with 2-5 and equilibrium constants for the formation of the CT complexes between 1 and 2-4 were determined kinetically.The relationship between relative rates, CT-excitation energies, HOMO-LUMO separations, and CT-complex equilibrium constants is discussed.The results do not require the CT complexes to be intermediates but strongly support the importance of CT interactions in the transition state of these cycloadditions.
