1
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White NJ, Vargas LA, Tunstall WW, Koku Hannadige Abeysooriya DN, Gichuhi WK. Cyanonaphthalene and cyanonaphthyl radicals: Vibrational structures via computed negative ion photoelectron spectra and thermochemistry of 1- and 2-cyanonaphthalene. J Chem Phys 2024; 161:034306. [PMID: 39017424 DOI: 10.1063/5.0220823] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2024] [Accepted: 06/27/2024] [Indexed: 07/18/2024] Open
Abstract
A double harmonic oscillator model is applied to compute the negative ion photoelectron spectra (NIPES) of the 1- and 2-cyanonaphthalene (CNN) radical anions. The computed Franck-Condon factors utilize optimized structures and harmonic vibrational frequencies obtained using density functional theory with the B3LYP 6-311++G (2d,2p) basis set while considering the mode-mixing Duschinsky effects. To test the accuracy of our model, the NIPES of α and β naphthyl radical anions were computed, and a strong agreement between the slow electron velocity-map ion imaging spectra and the predicted spectra was found. The adiabatic electron affinities (EAs) of the ground singlet states (S0) in 1-CNN and 2-CNN are 0.856 and 0.798 eV, respectively. The origin of the lowest-lying triplet (T1) states in 1-CNN and 2-CNN is found to be 3.226 and 3.266 eV, resulting in singlet-triplet energy splittings (ΔEST) of 2.370 and 2.468 eV, respectively. Both the NIPES for electron detachment to the S0 and T1 states exhibit well-resolved vibrational features, allowing for the assignment of several vibrational fundamental frequencies. Following deprotonation, several isomers are formed, with the most stable deprotonated radical anions in 1-CNN and 2-CNN, corresponding to the removal of the most acidic proton, with EAs of 2.062 and 2.16 eV. The rich spectroscopic and thermochemical data obtained in the current study make the CNN radical anions and their deprotonated species interesting systems for investigation in gas-phase, negative-ion experiments.
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Affiliation(s)
- Nolan J White
- Department of Chemistry, Tennessee Tech University, 1 William L. Jones Dr., Cookeville, Tennessee 38505, USA
| | - Lucia A Vargas
- Department of Chemistry, Tennessee Tech University, 1 William L. Jones Dr., Cookeville, Tennessee 38505, USA
- Department of Chemical Engineering, Tennessee Tech University, 1 William L. Jones Dr., Cookeville, Tennessee 38505, USA
| | - Wyatt W Tunstall
- Department of Chemistry, Tennessee Tech University, 1 William L. Jones Dr., Cookeville, Tennessee 38505, USA
- Department of Chemical Engineering, Tennessee Tech University, 1 William L. Jones Dr., Cookeville, Tennessee 38505, USA
| | - Dushmantha N Koku Hannadige Abeysooriya
- Department of Chemistry, Tennessee Tech University, 1 William L. Jones Dr., Cookeville, Tennessee 38505, USA
- School of Environmental Studies, Tennessee Tech University, 1 William L. Jones Dr., Cookeville, Tennessee 38505, USA
| | - Wilson K Gichuhi
- Department of Chemistry, Tennessee Tech University, 1 William L. Jones Dr., Cookeville, Tennessee 38505, USA
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2
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Li H, Wang C, Glaser F, Sinha N, Wenger OS. Metal-Organic Bichromophore Lowers the Upconversion Excitation Power Threshold and Promotes UV Photoreactions. J Am Chem Soc 2023; 145:11402-11414. [PMID: 37186558 DOI: 10.1021/jacs.3c02609] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Sensitized triplet-triplet annihilation upconversion is a promising strategy to use visible light for chemical reactions requiring the energy input of UV photons. This strategy avoids unsafe ultraviolet light sources and can mitigate photo-damage and provide access to reactions, for which filter effects hamper direct UV excitation. Here, we report a new approach to make blue-to-UV upconversion more amenable to photochemical applications. The tethering of a naphthalene unit to a cyclometalated iridium(III) complex yields a bichromophore with a high triplet energy (2.68 eV) and a naphthalene-based triplet reservoir featuring a lifetime of 72.1 μs, roughly a factor of 20 longer than the photoactive excited state of the parent iridium(III) complex. In combination with three different annihilators, consistently lower thresholds for the blue-to-UV upconversion to crossover from a quadratic into a linear excitation power dependence regime were observed with the bichromophore compared to the parent iridium(III) complex. The upconversion system composed of the bichromophore and the 2,5-diphenyloxazole annihilator is sufficiently robust under long-term blue irradiation to continuously provide a high-energy singlet-excited state that can drive chemical reactions normally requiring UV light. Both photoredox and energy transfer catalyses were feasible using this concept, including the reductive N-O bond cleavage of Weinreb amides, a C-C coupling reaction based on reductive aryl debromination, and two Paternò-Büchi [2 + 2] cycloaddition reactions. Our work seems relevant in the context of developing new strategies for driving energetically demanding photochemistry with low-energy input light.
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Affiliation(s)
- Han Li
- Department of Chemistry, University of Basel, St. Johanns-Ring 19, Basel 4056, Switzerland
| | - Cui Wang
- Department of Chemistry, University of Basel, St. Johanns-Ring 19, Basel 4056, Switzerland
| | - Felix Glaser
- Department of Chemistry, University of Basel, St. Johanns-Ring 19, Basel 4056, Switzerland
| | - Narayan Sinha
- Department of Chemistry, University of Basel, St. Johanns-Ring 19, Basel 4056, Switzerland
| | - Oliver S Wenger
- Department of Chemistry, University of Basel, St. Johanns-Ring 19, Basel 4056, Switzerland
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3
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Ashwood B, Ortiz-Rodríguez LA, Crespo-Hernández CE. Photochemical relaxation pathways of S 6-methylthioinosine and O 6-methylguanosine in solution. Faraday Discuss 2018; 207:351-374. [PMID: 29372193 DOI: 10.1039/c7fd00193b] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
S6-Methylthioinosine and O6-methylguanosine are byproducts resulting from the enzymatic reactions of sulfur-substituted prodrugs in cells and from the interaction of alkylating agents with cellular DNA, respectively. Their photochemistry has not been investigated, and it is currently unknown whether light absorption by these byproducts may pose any threat to the cell. In this contribution, their photoinduced processes upon absorption of UVB radiation are reported using broadband transient absorption spectroscopy. Plausible electronic relaxation mechanisms are proposed for both biological molecules, which are supported by steady-state absorption and emission measurements, and by singlet and triplet vertical excitation energies performed on a large subset of ground-state optimized conformational isomers in solution. The results are compared to the body of knowledge gathered in the scientific literature about the light-induced processes in the sulfur-substituted and canonical purine monomers. In particular, it is shown that S6-methylation decreases the rate to populate the lowest-energy triplet state and blueshifts the ground-state absorption spectrum compared to those for the sulfur-substituted prodrugs and for the 6-thioguanosine metabolite. Similarly, O6-methylation decreases the rate of internal conversion to the ground state observed in the guanine monomers by more than 10-fold in acetonitrile and 40-fold in aqueous solution, while it redshifts the ground-state absorption spectrum. Collectively, this investigation provides relevant new insights about the relationship between structural modifications of the purine chromophore and the electronic relaxation mechanisms in this important group of biological molecules.
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Affiliation(s)
- Brennan Ashwood
- Department of Chemistry, Center for Chemical Dynamics, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, Ohio 44106, USA.
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4
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Brister MM, Piñero-Santiago LE, Morel M, Arce R, Crespo-Hernández CE. Photochemical Relaxation Pathways in Dinitropyrene Isomer Pollutants. J Phys Chem A 2017; 121:8197-8206. [PMID: 28984454 DOI: 10.1021/acs.jpca.7b04769] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Dinitropyrenes are polycyclic aromatic pollutants prevalent in the environment. While their transformations by sunlight in the environment have been documented, the effect that the nitro-group substitution pattern has on the relaxation pathways has not been extensively studied. In this contribution, the steady-state and femtosecond-to-microsecond excited-state dynamics of 1,3-dinitropyrene and 1,8-dinitropyrene isomers are investigated upon visible light excitation at 425 nm and compared with those recently reported for the 1,6-dinitropyrene isomer. The experimental results are complemented with ground- and excited-state density functional calculations. It is shown that excitation at 425 nm results in the ultrafast branching of the excited-state population in the S1 state to populate the triplet state in ca. 90% yield and to form a nitropyrenoxy radical in less than 10% yield. In addition, the position of the NO2 group does not affect significantly the excited-state relaxation mechanism, while it does influence the absorption and fluorescence spectra, the fluorescence, triplet, singlet oxygen, and photodegradation yields, as well as the relative yield of radical formation. Radical formation is implicated in the photodegradation of these pollutants, while in the presence of hydrogen donors, direct reactions from the triplet state are also observed.
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Affiliation(s)
- Matthew M Brister
- Department of Chemistry, Case Western Reserve University , 10900 Euclid Avenue, Cleveland, Ohio 44106, United States
| | - Luis E Piñero-Santiago
- Department of Chemistry, University of Puerto Rico , Río Piedras Campus, San Juan, Puerto Rico 00931, United States
| | - María Morel
- Department of Chemistry, University of Puerto Rico , Río Piedras Campus, San Juan, Puerto Rico 00931, United States
| | - Rafael Arce
- Department of Chemistry, University of Puerto Rico , Río Piedras Campus, San Juan, Puerto Rico 00931, United States
| | - Carlos E Crespo-Hernández
- Department of Chemistry, Case Western Reserve University , 10900 Euclid Avenue, Cleveland, Ohio 44106, United States
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5
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Niklas JE, Farnum BH, Gorden JD, Gorden AEV. Structural Characterization and Redox Activity of a Uranyl Dimer and Transition-Metal Complexes of a Tetradentate BIAN Ligand. Organometallics 2017. [DOI: 10.1021/acs.organomet.7b00454] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Julie E. Niklas
- Department of Chemistry and Biochemistry, Auburn University, 179 Chemistry Building, Auburn, Alabama 36849, United States
| | - Byron H. Farnum
- Department of Chemistry and Biochemistry, Auburn University, 179 Chemistry Building, Auburn, Alabama 36849, United States
| | - John D. Gorden
- Department of Chemistry and Biochemistry, Auburn University, 179 Chemistry Building, Auburn, Alabama 36849, United States
| | - Anne E. V. Gorden
- Department of Chemistry and Biochemistry, Auburn University, 179 Chemistry Building, Auburn, Alabama 36849, United States
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7
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Dogruyol SK. Photo-DSC Investigation of Acetonaphthone Type Photoinitiators at Different Light Intensities. J PHOTOPOLYM SCI TEC 2017. [DOI: 10.2494/photopolymer.30.651] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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8
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Vogt RA, Reichardt C, Crespo-Hernández CE. Excited-State Dynamics in Nitro-Naphthalene Derivatives: Intersystem Crossing to the Triplet Manifold in Hundreds of Femtoseconds. J Phys Chem A 2013; 117:6580-8. [DOI: 10.1021/jp405656n] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- R. Aaron Vogt
- Department of Chemistry, Center
for Chemical Dynamics, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, Ohio 44106, United States
| | - Christian Reichardt
- Department of Chemistry, Center
for Chemical Dynamics, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, Ohio 44106, United States
| | - Carlos E. Crespo-Hernández
- Department of Chemistry, Center
for Chemical Dynamics, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, Ohio 44106, United States
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9
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Vogt RA, Gray TG, Crespo-Hernández CE. Subpicosecond Intersystem Crossing in Mono- and Di(organophosphine)gold(I) Naphthalene Derivatives in Solution. J Am Chem Soc 2012; 134:14808-17. [DOI: 10.1021/ja303592q] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Affiliation(s)
- R. Aaron Vogt
- Department
of Chemistry and Center for Chemical Dynamics, Case Western Reserve University, Cleveland, Ohio 44106,
United States
| | - Thomas G. Gray
- Department
of Chemistry and Center for Chemical Dynamics, Case Western Reserve University, Cleveland, Ohio 44106,
United States
| | - Carlos E. Crespo-Hernández
- Department
of Chemistry and Center for Chemical Dynamics, Case Western Reserve University, Cleveland, Ohio 44106,
United States
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10
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Sakamoto M, Majima T. Photochemistry for the Synthesis of Noble Metal Nanoparticles. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 2010. [DOI: 10.1246/bcsj.20100097] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
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11
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Fujitsuka M, Nakatani T, Sakamoto M, Sugimoto A, Majima T. Electron Transfer from Oligothiophenes in the Higher Triplet Excited States. J Phys Chem A 2010; 114:10789-94. [DOI: 10.1021/jp106056e] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Affiliation(s)
- Mamoru Fujitsuka
- Institute of Scientific and Industrial Research (SANKEN), Osaka University, Mihogaoka 8-1, Ibaraki, Osaka 567-0047, Japan
| | - Takeshi Nakatani
- Institute of Scientific and Industrial Research (SANKEN), Osaka University, Mihogaoka 8-1, Ibaraki, Osaka 567-0047, Japan
| | - Masanori Sakamoto
- Institute of Scientific and Industrial Research (SANKEN), Osaka University, Mihogaoka 8-1, Ibaraki, Osaka 567-0047, Japan
| | - Akira Sugimoto
- Institute of Scientific and Industrial Research (SANKEN), Osaka University, Mihogaoka 8-1, Ibaraki, Osaka 567-0047, Japan
| | - Tetsuro Majima
- Institute of Scientific and Industrial Research (SANKEN), Osaka University, Mihogaoka 8-1, Ibaraki, Osaka 567-0047, Japan
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12
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Bouit PA, Spänig F, Kuzmanich G, Krokos E, Oelsner C, Garcia-Garibay M, Delgado J, Martín N, Guldi D. Efficient Utilization of Higher-Lying Excited States to Trigger Charge-Transfer Events. Chemistry 2010; 16:9638-45. [DOI: 10.1002/chem.201001613] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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13
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Reichardt C, Vogt RA, Crespo-Hernández CE. On the origin of ultrafast nonradiative transitions in nitro-polycyclic aromatic hydrocarbons: Excited-state dynamics in 1-nitronaphthalene. J Chem Phys 2009; 131:224518. [DOI: 10.1063/1.3272536] [Citation(s) in RCA: 97] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
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14
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Horvat M, Görner H, Warzecha KD, Neudörfl J, Griesbeck AG, Mlinarić-Majerski K, Basarić N. Photoinitiated domino reactions: N-(adamantyl)phthalimides and N-(adamantylalkyl)phthalimides. J Org Chem 2009; 74:8219-31. [PMID: 19874065 DOI: 10.1021/jo901753z] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Phthalimides 1-6 undergo photochemical reactions upon direct irradiation as well as triplet sensitization and give rise to new products. Besides formation of the primary photoproducts, the first photochemical step initiates a subsequent thermal domino reaction or a domino sequence of a thermal and a photochemical reaction. The latter, involving two photochemical intramolecular gamma-H abstractions, was observed with phthalimides 1, 3, and 6 and delivered stereospecifically the hexacyclic benzazepine products 12, 19, and 27, respectively. The lowest triplet states of 1-6 were characterized in several solvents upon direct and acetone-sensitized excitation. The intermolecular electron transfer from triethylamine and DABCO was studied, and the radical anions were observed. Electrochemical measurements showed that intramolecular electron transfer from the adamantyl group of 1-6 to the lowest triplet state of the phthalimides is not feasible. The formation of products can be explained by intramolecular H-abstraction from the (alkyl)adamantane to the excited phthalimide, either from the excited singlet state or a hidden upper excited triplet state.
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Affiliation(s)
- Margareta Horvat
- Department of Organic Chemistry and Biochemistry, Ruder Bosković Institute, Bijenicka cesta 54, 10 000 Zagreb, Croatia
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15
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Collado-Fregoso E, Zugazagoitia JS, Plaza-Medina EF, Peon J. Excited-State Dynamics of Nitrated Push−Pull Molecules: The Importance of the Relative Energy of the Singlet and Triplet Manifolds. J Phys Chem A 2009; 113:13498-508. [PMID: 19839627 DOI: 10.1021/jp905379y] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Elisa Collado-Fregoso
- Instituto de Química, Universidad Nacional Autónoma de México, Circuito Exterior, Ciudad Universitaria, México, 04510, D.F., Mexico
| | - Jimena S. Zugazagoitia
- Instituto de Química, Universidad Nacional Autónoma de México, Circuito Exterior, Ciudad Universitaria, México, 04510, D.F., Mexico
| | - Eddy F. Plaza-Medina
- Instituto de Química, Universidad Nacional Autónoma de México, Circuito Exterior, Ciudad Universitaria, México, 04510, D.F., Mexico
| | - Jorge Peon
- Instituto de Química, Universidad Nacional Autónoma de México, Circuito Exterior, Ciudad Universitaria, México, 04510, D.F., Mexico
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16
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Zugazagoitia JS, Collado-Fregoso E, Plaza-Medina EF, Peon J. Relaxation in the Triplet Manifold of 1-Nitronaphthalene Observed by Transient Absorption Spectroscopy. J Phys Chem A 2009; 113:805-10. [DOI: 10.1021/jp8087397] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Jimena S. Zugazagoitia
- Universidad Nacional Autónoma de México, Instituto de Química, Ciudad Universitaria, 04510, México, D.F., México
| | - Elisa Collado-Fregoso
- Universidad Nacional Autónoma de México, Instituto de Química, Ciudad Universitaria, 04510, México, D.F., México
| | - Eddy F. Plaza-Medina
- Universidad Nacional Autónoma de México, Instituto de Química, Ciudad Universitaria, 04510, México, D.F., México
| | - Jorge Peon
- Universidad Nacional Autónoma de México, Instituto de Química, Ciudad Universitaria, 04510, México, D.F., México
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17
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Samori S, Fujitsuka M, Majima T. Properties of Excited Radical Cations of Substituted Oligothiophenes. J Phys Chem A 2008; 112:11312-8. [DOI: 10.1021/jp804369e] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Shingo Samori
- The Institute of Scientific and Industrial Research (SANKEN), Osaka University, Mihogaoka 8-1, Ibaraki, Osaka 567-0047, Japan
| | - Mamoru Fujitsuka
- The Institute of Scientific and Industrial Research (SANKEN), Osaka University, Mihogaoka 8-1, Ibaraki, Osaka 567-0047, Japan
| | - Tetsuro Majima
- The Institute of Scientific and Industrial Research (SANKEN), Osaka University, Mihogaoka 8-1, Ibaraki, Osaka 567-0047, Japan
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18
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Vasilieva NV, Irtegova IG, Vaganova TA, Shteingarts VD. Electrochemical, ESR and quantum chemical study of 1-substituted naphthalenes and their radical anions. J PHYS ORG CHEM 2008. [DOI: 10.1002/poc.1288] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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19
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Oseki Y, Fujitsuka M, Sakamoto M, Majima T. Intramolecular triplet energy transfer via higher triplet excited state during stepwise two-color two-laser irradiation. J Phys Chem A 2007; 111:9781-8. [PMID: 17824596 DOI: 10.1021/jp074062o] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
We studied the energy transfer processes in the molecular array consisting of pyrene (Py), biphenyl (Ph2), and bisphthalimidethiophene (ImT), (Py-Ph2)2-ImT, during two-color two-laser flash photolysis (2-LFP). The first laser irradiation predominantly generates ImT in the lowest triplet excited state (ImT(T1)) because of the efficient singlet energy transfer from Py in the lowest singlet excited state to ImT and, then, intersystem crossing of ImT. ImT(T1) was excited to the higher triplet excited state (Tn) with the second laser irradiation. Then, the triplet energy was rapidly transferred to Py via a two-step triplet energy transfer (TET) process through Ph2. The efficient generation of Py(T1) was suggested from the nanosecond-picosecond 2-LFP. The back-TET from Py(T1) to ImT was observed for several tens of microseconds after the second laser irradiation. The estimated intramolecular TET rate from Py(T1) to ImT was as slow as 3.1 x 104 s-1. Hence, long-lived Py(T1) was selectively and efficiently produced during the 2-LFP.
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Affiliation(s)
- Yosuke Oseki
- The Institute of Scientific and Industrial Research (SANKEN), Osaka University, Mihogaoka 8-1, Ibaraki, Osaka 567-0047, Japan
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20
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Cai X, Sakamoto M, Yamaji M, Fujitsuka M, Majima T. CO-Bond Cleavage of Esters with a Naphthyl Group in the Higher Triplet Excited State during Two-Color Two-Laser Flash Photolysis. Chemistry 2007; 13:3143-9. [PMID: 17212365 DOI: 10.1002/chem.200600822] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
A C-O-bond cleavage of esters having a naphthyl group, NpCO-OR and RCO-ONp (Np=alpha- and beta-naphthyl ((alpha)Np and (beta)Np, respectively), R=Ph and Me), was found during the two-color two-laser flash photolysis in acetonitrile. The C-O-bond cleavage occurred when NpCO-OR and RCO-ONp were excited to the singlet excited states (S1). On the other hand, no reaction occurred from the lowest triplet excited states (T1). When NpCO-OR(T1) and RCO-ONp(T1) were excited to the higher triplet excited states (Tn) using the second laser during the two-color two-laser flash photolysis, the C-O-bond cleavage occurred. The C-O-bond cleavage quantum yield (Phi) was estimated from the plots of the T1-state esters disappeared within a laser flash versus the second laser intensities. The C-O-bond cleavage in (beta)NpCO-OPh(Tn) occurred more efficiently than in (alpha)NpCO-OPh(Tn) and that in PhCO-O(beta)Np(Tn) occurred more efficiently than in PhCO-O(alpha)Np(Tn). The Phi value for ester with Ph and beta-Np groups was larger than that for ester with Ph and alpha-Np groups. The Phi value for MeCO-O(alpha)Np(Tn) was similar to those for PhCO-ONp(Tn), while that for MeCO-O(beta)Np(Tn) was much smaller than those for PhCO-ONp(Tn) and MeCO-O(alpha)Np(Tn). On the other hand, no C-O-bond cleavage was observed in NpCO-OMe(Tn). The Phi value depended on the characters of the groups (Np, Ph, and Me) on the ester. Whether R is Ph or Me with or without pi electron, respectively, is important for the C-O-bond cleavage. In other words, electronic delocalization of the T(n) state including Np and ester groups is necessary for the occurrence of the C-O-bond cleavage in NpCO-OR(Tn) and RCO-ONp(Tn).
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Affiliation(s)
- Xichen Cai
- The Institute of Scientific and Industrial Research (SANKEN), Osaka University, Mihogaoka 8-1, Ibaraki, Osaka 567-0047, Japan
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Griesbeck AG, Cho M. 9-Mesityl-10-methylacridinium: An Efficient Type II and Electron-Transfer Photooxygenation Catalyst. Org Lett 2007; 9:611-3. [PMID: 17256946 DOI: 10.1021/ol0628661] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The visible-light irradiation of 9-mesityl-10-methylacridinium perchlorate 1 in the presence of monoalkenes and molecular oxygen leads to typical products of singlet oxygen addition (type II photooxygenation). The molecular probes 1-methylcyclohexene and limonene, respectively, result in hydroperoxide mixtures with a characteristic product pattern. A switch in the oxidative mechanism (electron-transfer photooxygenation) is observed for naphthalene derivatives as electron-rich acceptor molecules, revealing that the 9-mesityl-10-methylacridinium cation serves as a dual sensitizer with the capacity of efficient singlet oxygen formation and electron-transfer reaction. [reaction: see text].
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Affiliation(s)
- Axel G Griesbeck
- Institute of Organic Chemistry, Greinstr. 4, D-50939 Köln, Germany.
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Tachikawa T, Tojo S, Fujitsuka M, Majima T. One-Electron Redox Processes during Polyoxometalate-Mediated Photocatalytic Reactions of TiO2 Studied by Two-Color Two-Laser Flash Photolysis. Chemistry 2006; 12:3124-31. [PMID: 16358350 DOI: 10.1002/chem.200501077] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The one-electron redox processes of several compounds during polyoxometalate (POM)-mediated photocatalytic reactions of TiO(2) were investigated using the two-color two-laser flash-photolysis technique. The efficiency of the one-electron oxidation of aromatic sulfides by the trapped hole (h(tr) (+)) or the surface-bound OH radical (OH(s) (.)) is found to be significantly enhanced due to electron transfer from the conduction band (CB) of TiO(2) to the POM. The efficiency of the electron transfer from the CB of TiO(2) to the POM decreases in the order H(2)W(12)O(40) (6-) < SiW(12)O(40) (4-) < PW(12)O(40) (3-), that is, it depends on the reduction potential (E(red)) of the POMs. Electron injection from PW(12)O(40) (4-) in the excited state (PW(12)O(40) (4-*)) to the CB of TiO(2) was clearly observed using the two-color two-laser flash-photolysis technique. Storage of electrons in the TiO(2)/PW(12)O(40) (3-)/methyl viologen (MV(2+)) ternary system was also achieved upon two-color two-laser irradiation.
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Affiliation(s)
- Takashi Tachikawa
- The Institute of Scientific and Industrial Research (SANKEN), Osaka University, Mihogaoka 8-1, Ibaraki, Osaka 567-0047, Japan
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Hara M, Samori S, Cai X, Fujitsuka M, Majima T. Importance of Properties of the Lowest and Higher Singlet Excited States on the Resonant Two-Photon Ionization of Stilbene and Substituted Stilbenes Using Two-Color Two-Lasers. J Phys Chem A 2005; 109:9831-5. [PMID: 16833297 DOI: 10.1021/jp0506437] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Radical cations of trans-stilbene and substituted trans-stilbenes (stilbenes and the radical cations denote Sand S(*+), respectively) were generated from the resonant two-photon ionization (TPI) in acetonitrile with irradiation of one-laser (266- or 355-nm laser) and with simultaneous irradiation of two-color two-lasers (266- and 532-nm or 355- and 532-nm lasers) with the pulse width of 5 ns each. The formation yields of S(*+), the TPI efficiency, depended on the properties of S in the lowest and higher singlet excited state (S(S(1)) and S(S(n))), generated from one-photon excitation with 266- or 355-nm laser and from two-photon excitation with simultaneous irradiation of 266- and 532-nm or 355- and 532-nm lasers, respectively. The TPI efficiency using two-color two-lasers increased compared with that using one-laser. It is confirmed that the TPI proceeds through two-step two-photon excitation with the S(0) --> S(1) --> S(n)() transition. In addition to the electronic character of S(S(0)) which depends on the substituent of S, oxidation potential, and molar absorption coefficient of the S(0) --> S(1) absorption as well-known important factors for the TPI efficiency, it is shown that properties of S(S(1)) and S(S(n)) such as lifetimes, electronic characters of S(S(1)) and S(S(n)), molar absorption coefficient of the S(1) --> S(n) absorption, and ionization rate from S(S(n)) are also important.
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Affiliation(s)
- Michihiro Hara
- The Institute of Scientific and Industrial Research (SANKEN), Osaka University, Mihogaoka 8-1, Ibaraki, Osaka 567-0047, Japan
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Samori S, Hara M, Ho TI, Tojo S, Kawai K, Endo M, Fujitsuka M, Majima T. Dihydrophenanthrene-Type Intermediates during Photoreaction of trans-4‘-Benzyl-5-styrylfuran. J Org Chem 2005; 70:2708-12. [PMID: 15787563 DOI: 10.1021/jo047977x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
[structure: see text] Photoreaction of trans-4'-benzyl-5-styrylfuran (trans-BSF) has been studied by the 355-nm laser flash photolysis (LFP) in CH2Cl2 using a Nd3+:YAG laser (30 ps, 5 mJ pulse(-1) or 5 ns, 30 mJ pulse(-1)). Transient fluorescence and absorption spectra assigned to the singlet excited trans-BSF were observed during the 30-ps LFP, whereas a transient absorption spectrum with two peaks at 400 and 510 nm, assigned to the trans-fused dihydrophenanthrene (DHP)-type intermediate (DP1), was observed during the 5-ns LFP. It is clearly suggested that a two-photon absorption process is involved in the formation of DP1. The first photoreaction is the photoisomerization of trans-BSF, which occurs to give cis-BSF. The second photoreaction process is photocyclization of cis-BSF, which occurs to give DP1 decaying with the half lifetime (tau1/2) of 2.8-4.0 micros to produce another DHP-type intermediate (DP2) with an absorption peak at 400 nm in the absence of O2, through [1,9]-hydrogen shift. DP2 decayed with tau1/2 > 500 micros to give the product through aromatization. In O2-saturated CH2Cl2, DP1 decayed with tau1/2 = 250 ns to give a radical intermediate (X) with two peaks at 410 and 510 nm, through hydrogen abstraction of DP1 by O2. X decayed with tau1/2 = 150 micros to give the product through successive hydrogen abstraction.
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Affiliation(s)
- Shingo Samori
- The Institute of Scientific and Industrial Research (SANKEN), Osaka University, Mihogaoka 8-1, Ibaraki, Osaka 567-0047, Japan
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Sakamoto M, Cai X, Hara M, Fujitsuka M, Majima T. Remarkable Reactivities of the Xanthone Ketyl Radical in the Excited State Compared with That in the Ground State. J Phys Chem A 2005; 109:2452-8. [PMID: 16833545 DOI: 10.1021/jp0448907] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The properties and reactivities of the xanthone (Xn) ketyl radical (XnH*) in the doublet excited state (XnH*(D1)) were examined by using two-color two-laser flash photolysis. The absorption and fluorescence of XnH*(D1) were observed for the first time. Several factors governing the deactivation processes of XnH*(D1) such as interaction and reaction with solvent molecules were discussed. The remarkable change of reactivity of XnH*(D1) compared with that in the ground state (XnH*(D0)) was indicated from the experimental results. The rapid halogen abstraction of XnH*(D1) from some halogen donors such as carbon tetrachloride (CCl4) was found to occur. The halogen abstraction occurred more efficiently in the polar solvents than in the nonpolar solvents. It is suggested that the polar solvents promote the spin distribution of XnH*(D1) of the phenyl ring favorable to the halogen abstraction.
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Affiliation(s)
- Masanori Sakamoto
- The Institute of Scientific and Industrial Research (SANKEN), Osaka University, Mihogaoka 8-1, Ibaraki, Osaka 567-0047, Japan
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Sakamoto M, Cai X, Hara M, Tojo S, Fujitsuka M, Majima T. Competitive Marcus-Type Electron Transfer and Energy Transfer from the Higher Triplet Excited State. J Phys Chem A 2004. [DOI: 10.1021/jp046892x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- Masanori Sakamoto
- The Institute of Scientific and Industrial Research (SANKEN), Osaka University, Mihogaoka 8-1, Ibaraki, Osaka 567-0047, Japan
| | - Xichen Cai
- The Institute of Scientific and Industrial Research (SANKEN), Osaka University, Mihogaoka 8-1, Ibaraki, Osaka 567-0047, Japan
| | - Michihiro Hara
- The Institute of Scientific and Industrial Research (SANKEN), Osaka University, Mihogaoka 8-1, Ibaraki, Osaka 567-0047, Japan
| | - Sachiko Tojo
- The Institute of Scientific and Industrial Research (SANKEN), Osaka University, Mihogaoka 8-1, Ibaraki, Osaka 567-0047, Japan
| | - Mamoru Fujitsuka
- The Institute of Scientific and Industrial Research (SANKEN), Osaka University, Mihogaoka 8-1, Ibaraki, Osaka 567-0047, Japan
| | - Tetsuro Majima
- The Institute of Scientific and Industrial Research (SANKEN), Osaka University, Mihogaoka 8-1, Ibaraki, Osaka 567-0047, Japan
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Oseki Y, Fujitsuka M, Hara M, Cai X, Sugimoto A, Majima T. Higher Triplet Excited States of Oligo(p-phenylenevinylene)s. J Phys Chem B 2004. [DOI: 10.1021/jp047275b] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Yosuke Oseki
- The Institute of Scientific and Industrial Research (SANKEN), Osaka University, Mihogaoka 8-1, Ibaraki, Osaka 567- 0047, Japan
| | - Mamoru Fujitsuka
- The Institute of Scientific and Industrial Research (SANKEN), Osaka University, Mihogaoka 8-1, Ibaraki, Osaka 567- 0047, Japan
| | - Michihiro Hara
- The Institute of Scientific and Industrial Research (SANKEN), Osaka University, Mihogaoka 8-1, Ibaraki, Osaka 567- 0047, Japan
| | - Xichen Cai
- The Institute of Scientific and Industrial Research (SANKEN), Osaka University, Mihogaoka 8-1, Ibaraki, Osaka 567- 0047, Japan
| | - Akira Sugimoto
- The Institute of Scientific and Industrial Research (SANKEN), Osaka University, Mihogaoka 8-1, Ibaraki, Osaka 567- 0047, Japan
| | - Tetsuro Majima
- The Institute of Scientific and Industrial Research (SANKEN), Osaka University, Mihogaoka 8-1, Ibaraki, Osaka 567- 0047, Japan
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