Rotational Isomerization of Dithienylethenes:  A Study on the Mechanism Determining Quantum Yield of Cyclization Reaction

Goldberg, Alexander; Murakami, Akinori; Kanda, Katsuya; Kobayashi, Takao; Nakamura, Shinichiro; Uchida, Kôji; Sekiya, Hiroshi; Fukaminato, Tuyoshi; Kawai, Tsuyoshi; Kobatake, Seiya; Irie, Masahiro

doi:10.1021/jp0213553

Cited by 44 publications

(33 citation statements)

References 16 publications

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“…Due to the high computational cost of the excited state optimization, the PES of the firstexcited state and second-excited state are calculated as vertical excitations for the ground state geometries. Calculations of the first-excited state PES of diarylethenes were reported in the literature with CASSCF, 17,27 TDDFT, 20 and by changing the occupation of the frontier orbitals by promoting an electron from HOMO to LUMO. 47 Despite the conceptional differences in the level of theory and degree of approximation, the calculated excited-state PESs are qualitatively similar.…”

Section: Resultsmentioning

confidence: 99%

Electrochemical and Photochemical Cyclization and Cycloreversion of Diarylethenes and Diarylethene-Capped Sexithiophene Wires

et al. 2011

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A combined theoretical and experimental study was performed on diarylethenes and diarylethene-capped sexithiophenes aiming at an improved understanding of the electrochemical and photochemical ring-opening and ring-closing mechanisms. Theoretical calculations, based on DFT and TDDFT, suggested that the spatial distribution and the occupancy of the frontier orbitals determine and control the diarylethenes’ ring-opening and ring-closing upon photoirradiation and electrochemical oxidation. Optimized geometries, potential energy surfaces, and activation energies between the open-ring and closed-ring forms were calculated for diarylethenes in the neutral ground state, excited states, and mono- and dicationic states. Analysis of the frontier orbitals was employed to understand the cyclization and cycloreversion of diarylethenes and to predict and explain the switching properties of diarylethene-capped sexithiophene molecular wires. The TDDFT data were verified with experimentally measured UV/vis spectra. The DFT calculations estimated open-shell ground states of diarylethene-capped sexithiophene dications, which were verified with EPR spectroscopy, and the broadening of the peaks in the EPR spectra were explained with the calculated singlet−triplet splitting. The good agreement of experiment and theory allows for the understanding of switching behavior of diarylethenes in solutions, in metal break junctions, in monolayers on metal surfaces, and as a part of complex organic molecular wires.

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Section: Resultsmentioning

confidence: 99%

Electrochemical and Photochemical Cyclization and Cycloreversion of Diarylethenes and Diarylethene-Capped Sexithiophene Wires

et al. 2011

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“…We have first optimized the geometries of each isolated molecule of Figure with the Gaussian 2009 package, using a standard DFT/B3LYP/6–31G(d,p) approach, which is known to correctly reproduce the geometries of diarylethene molecules . To ensure that every electronic structure calculation is done at the same level of theory, we have then calculated the electronic levels of the isolated molecule with the ATK 2008.10 package used for transmission spectra simulations.…”

Section: Methodsmentioning

confidence: 99%

Fermi Level Pinning and Orbital Polarization Effects in Molecular Junctions: The Role of Metal Induced Gap States

Dyck

Geskin

Cornil

2014

Adv Funct Materials

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Understanding the alignment of molecular orbitals and corresponding transmission peaks with respect to the Fermi level of the electrodes is a major challenge in the fi eld of molecular electronics. In order to design functional devices, it is of utmost importance to assess whether controlled changes in the electronic structure of isolated compounds are preserved once they are inserted in the molecular junctions. Here, light is shed on this central issue by performing density functional theory calculations on junctions including diarylethene-based molecules. It is demonstrated that the chemical potential equalization principle allows to rationalize the existence or not of a Fermi level pinning (i.e., same alignment in spite of a varying ionization potential in the isolated compounds), pointing to the essential role played by metal induced gap states (MIGS). It is further evidenced that the degree of level pinning is intimately linked to the degree of orbital polarization when a bias is applied between the two electrodes.

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“…High ring-closure quantum yields are also shown by diarylethenes having p-donor substituents on the thiophene rings, 21,28,39 and for some of these compounds a prevalence of the antiparallel conformer has been detected. 28 It has also been suggested that polar solvents favor antiparallel conformers, 6 but inconsistent results have been obtained about the effect of the solvent on the ring-closure quantum yield. 33,40, 41 The ring-closure quantum yield of 1a is practically constant when irradiation is performed in the lowest-energy absorption band (313 or 334 nm, U = 0.7), but a higher (U = 0.9) upon excitation in the second band (254 nm); no explanation can be advanced for this difference.…”

Section: Photochemical Behaviourmentioning

confidence: 99%

“…NMR 5, 6 and absorption spectroscopy 6 studies have shown that five-membered heterocyclic diarylethenes exhibit in solution at According to the Woodward-Hoffmann rule, 7 the cyclization reaction occurs photochemically in a conrotatory mode, while the corresponding thermal reaction would require a disrotatory mode; 8 therefore, the conrotatory antarafacial photocyclization reaction can only proceed from the antiparallel open-ring conformer. Since the interconversion between the conformers occurs in a time scale larger than the excited-state lifetime, 5 only the light absorbed by the antiparallel form can induce photocyclization.…”

Section: Introductionmentioning

confidence: 99%

Photochemical investigation of a photochromic diarylethene compound that can be used as a wide range actinometer

Santos

Ballardini

Belser

et al. 2009

Photochem Photobiol Sci

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The photochromic diarylethene derivative 1,2-bis(5-(4-ethynylphenyl)-2-methylthiophen-3-yl)perfluorocyclopentene (1) was submitted to photochemical, thermal stability and fatigue resistance studies in acetonitrile, also to evaluate its possible application as a new actinometer. This photochromic system covers a wide spectral absorption range, with intense bands in the UV and visible regions for the open-ring and closed-ring isomers, respectively. Very high ring-closure quantum yield values were obtained, in contrast with the low ring-opening quantum yields, which are nevertheless high enough to exploit 1 as an actinometer. The procedure required to determine the photon flux of an irradiation source with this fatigue resistant compound is indeed very simple.

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Rotational Isomerization of Dithienylethenes: A Study on the Mechanism Determining Quantum Yield of Cyclization Reaction

Cited by 44 publications

References 16 publications

Electrochemical and Photochemical Cyclization and Cycloreversion of Diarylethenes and Diarylethene-Capped Sexithiophene Wires

Electrochemical and Photochemical Cyclization and Cycloreversion of Diarylethenes and Diarylethene-Capped Sexithiophene Wires

Fermi Level Pinning and Orbital Polarization Effects in Molecular Junctions: The Role of Metal Induced Gap States

Photochemical investigation of a photochromic diarylethene compound that can be used as a wide range actinometer

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