The photophysics and photochemistry of .alpha.,.omega.-diphenylpolyene singlet states

Allen, Mary Tedd; Whitten, David G.

doi:10.1021/cr00098a003

Cited by 183 publications

(152 citation statements)

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“…Orbital A g is assigned to a highly symmetric state, a "covalent" character, while the B u state presents more "ionic" characteristics. 10 showed that the main absorptivity parameter of DPH is the solvent polarizability (a S ) rather than the polarity, which is related to the refractive index. The higher the solvent refractive index, the greater the red-shifted absorption band.…”

Section: 5mentioning

confidence: 99%

Section: 5mentioning

confidence: 99%

“…The resulting decrease of the S 1 -S 2 coupling promotes a decrease of F F . 10,15,16 This effect is more evident in polar solvents, such as ethanol and acetonitrile, than in non-polar solvents.1 The present work investigated an unusual fluorescence behavior of DPH associated with the presence of water in organic solvents (ethanol and DMSO) attributed to DPH excited states quenching by water molecules. …”

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confidence: 93%

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Unusual 1,6-diphenyl-1,3,5-hexatriene (DPH) spectrophotometric behavior in water/ethanol and water/DMSO mixtures

Gracetto

Batistela

Santos

et al. 2010

J. Braz. Chem. Soc.

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O espectro de absorção de DPH, em concentração fixa, não varia com o teor de água em solvente orgânico. Tem-se a banda de monômeros igual àquela em etanol puro. A absorção não muda até o limite de 54 e 46% de água em etanol e DMSO, respectivamente, para [DPH] = 5,0 × 10 -6 mol L -1 a 30 °C. Entretanto, em misturas com água muito abaixo desses conteúdos críticos, observou-se um decaimento intenso de fluorescência enquanto a absorção manteve-se constante. Propõe-se que moléculas de água atuam como supressores dos estados excitados e a constante de supressão de Stern-Volmer através de intensidade relativas, resultou em 7,4 × 10 -2 (água/etanol) e 2,6 × 10 -2 L mol -1 (água/DMSO). Os tempos de vida do DPH na ausência e presença do supressor forneceram constantes de 7,1 × 10 -2 L mol -1 em água/etanol, indicando supressão dinâmica. Em investigações de ambientes com esta sonda, este processo deve ser considerado tendo em vista o risco de erros de interpretação.The absorption spectra of DPH at fixed concentration do not change with water content in organic solvents. It exhibits monomer bands, such as those obtained in ethanol. The absorption did not change for solutions up to 54 and 46% of water in ethanol and DMSO, respectively, for [DPH] = 5.0 × 10 -6 mol L -1 at 30 °C. However, at the same experimental conditions, a gradual sharp decay of the DPH fluorescence is observed. It is proposed that water molecules below these water concentration limits act as quenchers of the excited states of DPH. Stern-Volmer quenching constants by intensities measurements are 7.4 × 10 -2 (water/ethanol) and 2.6 × 10 -2 L mol -1 (water/DMSO). DPH lifetime measurements in the absence and presence of water resulted in 7.1 × 10 -2 L mol -1 in water/ethanol, which pointed out that the process is a dynamic quenching by water molecules. For experiments using DPH as probe, this process can affect data, leading to misunderstanding interpretation.Keywords: diphenylhexatriene, DPH, DPH fluorescence, dynamic quenching, lifetime 3,, which is used as a fluorescence probe, has a rod-like structure that absorbs and emits light with a high quantum efficiency, although it is not a large conjugative p-electron system. Introduction 1,2The spectrophotometric properties of DPH are very sensitive to the experimental conditions, which allows using this compound and its derivatives as environmental probes in colloidal systems to determine the critical micellar concentration of surfactants 3 and in biological cell membranes. 4,5 The measurement of the fluorescence anisotropy of DPH is extensively used for membranes, particularly in studies of microviscosities, 6 due to the non-polar characteristic, the low water solubility, and the suitable geometric design, which maintains the molecule aligned parallel to the phospholipids chains of the membranes. 7 Although the DPH molecule remains inserted in the membrane layer, it stays in contact with water molecules. 2,5The majority of DPH spectrophotometric studies on electronic transitions are performed in organic solven...

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Section: 5mentioning

confidence: 99%

Section: 5mentioning

confidence: 99%

mentioning

confidence: 93%

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Unusual 1,6-diphenyl-1,3,5-hexatriene (DPH) spectrophotometric behavior in water/ethanol and water/DMSO mixtures

Gracetto

Batistela

Santos

et al. 2010

J. Braz. Chem. Soc.

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“…The optically bright 1 1 B u state is dominated by the single excitation from the highest occupied molecular orbital (HOMO) to the lowest unoccupied molecular orbital (LUMO). While this state is the S 1 state in the shortest member of this series, 1,2-diphenylethene (stilbene), 2 1 A g is known to constitute the S 1 state in longer polyenes. [1] It has pronounced multiconfiguration character with the doubly excited (HOMO!LUMO) 2 configuration and the singly excited (HOMOÀ1!LUMO) and (HOMO!LUMO + 1) configurations as leading terms.…”

Section: Introductionmentioning

confidence: 99%

“…While this state is the S 1 state in the shortest member of this series, 1,2-diphenylethene (stilbene), 2 1 A g is known to constitute the S 1 state in longer polyenes. [1] It has pronounced multiconfiguration character with the doubly excited (HOMO!LUMO) 2 configuration and the singly excited (HOMOÀ1!LUMO) and (HOMO!LUMO + 1) configurations as leading terms. [2] The state reversal appears to happen between 1,4-diphenyl-1,3-butadiene (DPB) and DPH in vacuum and in hydrocarbon solutions.…”

Section: Introductionmentioning

confidence: 99%

On the Photophysics of 1,6‐Diphenyl‐1,3,5‐Hexatriene Isomers and Rotamers

et al. 2011

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Herein, the low-lying electronic states of various isomers and rotamers of 1,6-diphenyl-1,3,5-hexatriene (DPH) are studied by a combination of density functional theory and multireference configuration interaction. Starting from the all-trans nuclear arrangement, trans-cis isomerization pathways in the electronic ground state and in the first excited triplet state were determined. Further, spin-orbit coupling calculations were carried out at selected points where singlet-triplet energy gaps are small. The calculations reveal that the primarily excited, optically bright 1(1)B(u) state undergoes a curve crossing with the optically dark multiconfigurational 2(1)A(g) state upon geometry relaxation in the excited state. The strong vibronic coupling of the two singlets in the neighborhood of the conical intersection provides a conclusive explanation for the experimentally observed fast equilibration of the states and the appearance of delayed fluorescence. With regard to the trans-cis isomerization of the central CC bond, the perpendicular conformation is found to represent a maximum on the energy profile not only of the electronic ground state, but also of the low-lying excited states. The lack of a strong driving force along the torsional coordinate explains the low tendency of DPH for isomerization. Finally, the results of our spin-orbit coupling calculations suggest that the intramolecular formation of DPH molecules in the T(1)(1(3)B(u)) state proceeds from the 1(1)B(u) state and involves intermediately the T(2)(1(3)A(g)) state.

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Structure of theT1-state wave function of linear polyenes

Takahashi

Watanabe

Kikuchi

1998

Int. J. Quant. Chem.

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Configuration interaction singles CIS calculations of the planar T state 1 of hexatriene, octatetraene, decapentaene, and dodecahexaene showed that the Ž . Ž . HOMO y i ª LUMO q i type single excitations contribute significantly. This is attributed to the similarity of the HOMO, LUMO, and HOMO y i, LUMO q i overlap densities which stem from nodal properties of the molecular orbitals. CASSCF calculations for hexatriene and octatetraene also showed remarkable contributions of the Ž . Ž . HOMO y i ª LUMO q i type singly excited configurations.

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The photophysics and photochemistry of .alpha.,.omega.-diphenylpolyene singlet states

Cited by 183 publications

References 36 publications

Unusual 1,6-diphenyl-1,3,5-hexatriene (DPH) spectrophotometric behavior in water/ethanol and water/DMSO mixtures

Unusual 1,6-diphenyl-1,3,5-hexatriene (DPH) spectrophotometric behavior in water/ethanol and water/DMSO mixtures

On the Photophysics of 1,6‐Diphenyl‐1,3,5‐Hexatriene Isomers and Rotamers

Structure of theT1-state wave function of linear polyenes

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