The phosphorescent triplet states of aza-aromatics and their protonated cations in rigid solutions of ethanol and 1-butyl-3-methylimidazolium hexafluorophosphate

Matsuo, Ryuichiro; Uchiyama, Tetsuya; Mogi, Kentarou; Kaneko, Shunya; Kuwayama, Kenta; Kikuchi, Azusa; Yagi, Mikio

doi:10.1016/j.jphotochem.2008.12.011

Cited by 4 publications

(2 citation statements)

References 35 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The experimental setup for the EPR experiments is the same as that previously reported. , The EPR spectra were measured with a JEOL JES-FA200 spectrometer and a JEOL JES-FE1XG spectrometer with 100 kHz magnetic field modulation at microwave frequency close to 9.2 GHz. The external magnetic field was calibrated with an Echo Electronics EFM-2000AX proton NMR gauss meter.…”

Section: Methodsmentioning

confidence: 99%

Optical and Electron Paramagnetic Resonance Studies of the Excited States of 4-tert-Butyl-4′-Methoxydibenzoylmethane and 4-tert-Butyl-4′-Methoxydibenzoylpropane

2009

Self Cite

View full text Add to dashboard Cite

The excited states of 4-tert-butyl-4'-methoxydibenzoylmethane (BM-DBM) and 4-tert-butyl-4'-methoxydibenzoylpropane (BM-DBP), the model of the keto form of BM-DBM, have been studied through measurements of UV absorption, fluorescence, phosphorescence, and electron paramagnetic resonance spectra in ethanol at 77 K. The energy levels and lifetimes of the lowest excited triplet (T(1)) states of BM-DBP, dibenzoylpropane (DBP), the model of the keto form of dibenzoylmethane (DBM), and the keto and enol forms of BM-DBM and DBM were determined. The energy level of the T(1) state of the keto form is much higher than that of the enol form in BM-DBM. The effect of tautomerization on the T(1) lifetime is small in DBM but large in BM-DBM. The methoxy and tert-butyl groups play an important role in lengthening the T(1) lifetimes of BM-DBP and the keto form of BM-DBM. The nature of the T(1) states of the keto and enol forms of BM-DBM can be explained in terms of the mixing of the (3)npi* and (3)pipi* states. The observed energy levels and the lifetimes of the T(1) states of the UV absorbers provide a useful suggestion for designing more photostable UV absorbers.

show abstract

Section: Methodsmentioning

confidence: 99%

Optical and Electron Paramagnetic Resonance Studies of the Excited States of 4-tert-Butyl-4′-Methoxydibenzoylmethane and 4-tert-Butyl-4′-Methoxydibenzoylpropane

2009

Self Cite

View full text Add to dashboard Cite

show abstract

“…irradiation (355 nm) in frozen toluene at 77 K. This spectrum is composed of two triplet species: one is the excited triplet state of isolated tetracene, and another is that of an unidentified species. Table 1 shows the ZFS parameters and g value of the new species obtained from the mixed system, as well as the reported values for Ir(ppy) 3 , 12 2-phenylpyridine, 16 and tetracene. 17 The observed parameters of the new species are different from those of either tetracene or the ligand molecule of 2-phenylpyridine.…”

Section: ■ Introductionmentioning

confidence: 99%

Time-Resolved EPR Study on the Photoexcited Triplet State of the Electron–Donor–Acceptor Complex Formed in the System of fac-Tris[2-(4-octyl-phenyl) pyridine] Iridium(III) and Tetracene

Shuhei

Murai

2013

J. Phys. Chem. A

View full text Add to dashboard Cite

The physical properties of the phosphorescent organic light-emitting diode material fac-tris(phenylpyridine) iridium(III), Ir(ppy)3, have been reported with experimental and theoretical studies. Here, the photochemical properties of the excited triplet state of partially modified fac-tris[2-(4-octyl-phenyl) pyridine] iridium(III), Ir(C8ppy)3, were investigated using time-resolved electron paramagnetic resonance (tr-EPR) and optical methods by adding tetracene in the toluene solution. The tr-EPR observation at 77 K revealed the following two species: the excited triplet state of tetracene and another triplet species with zero field splitting parameters of |D| = 0.088 cm(-1) and |E| = 0.018 cm(-1) with characteristic spin polarization. The latter species was assigned to the electron-donor-acceptor (EDA) complex formed between Ir(C8ppy)3 and tetracene. The mechanism of formation and the properties of this EDA complex, including the information on the principal axes of (3)Ir(C8ppy)3*, are discussed.

show abstract

Luminescence and Electron Paramagnetic Resonance Studies of the Excited States of a UV Absorber, 2-Methylphenyl 2-Naphthoate

Kikuchi¹,

Yagi²

2009

Chemistry Letters

View full text Add to dashboard Cite

Fluorescence, phosphorescence, and electron paramagnetic resonance spectra have been observed for the excited states of a new UV absorber, 2-methylphenyl 2-naphthoate (2-MPN), in ethanol at 77 K. The observed phosphorescence spectrum, phosphorescence lifetime, and zero-field splitting parameters of the lowest excited triplet (T1) state of 2-MPN revealed that the T1 state of 2-MPN can be regarded as a locally excited triplet state within naphthalene.

show abstract

The phosphorescent triplet states of aza-aromatics and their protonated cations in rigid solutions of ethanol and 1-butyl-3-methylimidazolium hexafluorophosphate

Cited by 4 publications

References 35 publications

Optical and Electron Paramagnetic Resonance Studies of the Excited States of 4-tert-Butyl-4′-Methoxydibenzoylmethane and 4-tert-Butyl-4′-Methoxydibenzoylpropane

Optical and Electron Paramagnetic Resonance Studies of the Excited States of 4-tert-Butyl-4′-Methoxydibenzoylmethane and 4-tert-Butyl-4′-Methoxydibenzoylpropane

Time-Resolved EPR Study on the Photoexcited Triplet State of the Electron–Donor–Acceptor Complex Formed in the System of fac-Tris[2-(4-octyl-phenyl) pyridine] Iridium(III) and Tetracene

Luminescence and Electron Paramagnetic Resonance Studies of the Excited States of a UV Absorber, 2-Methylphenyl 2-Naphthoate

Contact Info

Product

Resources

About