Temperature dependence of radiationless processes. Isoquinoline in solution

Huber, J. Robert; Mahaney, May; Morris, J.

doi:10.1016/0301-0104(76)87028-0

Cited by 27 publications

(9 citation statements)

References 19 publications

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“…These decay times clearly indicate and fairly support our earlier assumption that shorter lifetime corresponds to the neutrals, whereas cations have longer lifetimes. It can be mentioned here that a somewhat shorter decay time of 0.25 ns for neutrals was reported by Huber at al., 10 which may be due to uncertainty in the decay time because of their instrumental resolution.…”

Section: Resultsmentioning

confidence: 99%

“…The electronic states and luminescence properties of isoquinoline (IQ) and its derivatives have been the subject of considerable interest and study. − Being isoelectronic with naphthalene, these molecules provide useful comparisons for checking the electronic and vibrational state assignments, ionization potentials, and other properties of the parent hydrocarbon.…”

Section: Introductionmentioning

confidence: 99%

“…The effect of temperature on the radiationless process in IQ in solution (ethanol) was studied by Huber et al and found that the lifetime increases from 0.25 to 9.0 ns at 77 K . Felker and Zewail studied IQ and its methanol/water complex in supersonic jet and found that coupling of n –π* and π–π* states is important in the deactivation process …”

Section: Introductionmentioning

confidence: 99%

“…The effect of temperature on the radiationless process in IQ in solution (ethanol) was studied by Huber et al 10 and found that the lifetime increases from 0.25 to 9.0 ns at 77 K. 10 supersonic jet and found that coupling of n−π* and π−π* states is important in the deactivation process. 11 Moomaw and Anton 12,13 reported the effect of hydrogen bonding solvent on the spectral properties of IQ and proposed the mechanism of proton transfer reaction in the excited state.…”

Section: Introductionmentioning

confidence: 99%

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Steady State and Time-Resolved Fluorescence Study of Isoquinoline: Reinvestigation of Excited State Proton Transfer

Joshi

Gahlaut

et al. 2012

J. Phys. Chem. A

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In the present work we report some hitherto unnoticed features in the steady state and time-resolved measurements of isoquinoline in water and trifluoroethanol (TFE). Absorption spectra reveal that in water, neutrals as well cationic species are present. Emission spectrum shows structured features at shorter wavelengths accompanied with a broad band around 375 nm, which correspond to neutrals and cations respectively. However, time-resolved data indicate that protonation does not take place in the excited state in water. On the contrary, in stronger hydrogen bonding solvent TFE, distribution of decay components is observed and at longer wavelengths a small rise time is present. This is ascribed to neutral and cation-like species present in the ground as well as in the excited state. The difference in the results is explained in terms of different excited state potential energy surfaces for water and TFE; particularly, the presence of a rather small barrier for protonation in case of TFE.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Steady State and Time-Resolved Fluorescence Study of Isoquinoline: Reinvestigation of Excited State Proton Transfer

Joshi

Gahlaut

et al. 2012

J. Phys. Chem. A

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“…An inspection of the literature data indicates that isoquinoline-3-amine derivatives exhibit fluorescent properties and may constitute potential fluorophores [13,14,15]. Moreover, for many years the electronic states and optical properties of isoquinoline and its derivatives have been an object of particular interest and study [16,17,18,19,20,21,22,23,24,25]. Recently, notable progress has been made in the synthesis and development of novel organic fluorophores with diverse applications and uses in in vivo imaging.…”

Section: Introductionmentioning

confidence: 99%

Synthesis and Fluorescent Properties of Novel Isoquinoline Derivatives

et al. 2019

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Isoquinoline derivatives have attracted great interest for their wide biological and fluorescent properties. In the current study, we focused on the synthesis of a series of novel isoquinoline derivatives substituted at position 3 of the heteroaromatic ring. Compounds were obtained in a Goldberg–Ullmann-type coupling reaction with appropriate amides in the presence of copper(I) iodide, N,N-dimethylethylenediamine (DMEDA), and potassium carbonate. The structures of novel isoquinolines were confirmed by IR, NMR, and elemental analysis, as well as X-ray crystallography. In the course of our research work, the visible fluorescence of this class of compounds was observed. The above findings prompted us to investigate the optical properties of the selected compounds.

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Triplet State Interrogation in Supersonic Beams by Surface Electron Ejection

Sneh

Cheshnovsky

1990

Israel Journal of Chemistry

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Recently, we have developed an experimental method for the detection of triplet states generated by laser excitation in supersonic beams. It is based on electron ejection from low work‐function surfaces by metastable triplet states. We have detected both directly laser‐excited triplets and triplets generated via intersystem crossing from laser‐excited singlet states. Here, we review the applications of this method and discuss its mechanism. By comparing the laser‐induced fluorescence (LIF) spectrum and Surface Electron Ejection by Laser‐Excited Metastables (SEELEM), we have measured relative triplet formation quantum yields for several aromatic compounds. By utilizing a detector mounted on a translational stage, we could vary the distance between the pulsed laser excitation and the detector and measure the decay rates of triplets in molecular beams. The major advantage of the method is in extending the measurement of triplet lifetimes to the ∼ 1‐ms range. The combination of LIF, SEELEM, and fluorescence quantum yields enabled us to discriminate between intersystem crossing and internal conversion in isoquinoline. SEELEM is now being utilized in studying the spectroscopy and the dynamics of directly laser‐excited triplet states. Although the oscillator strength of the lowest triplet state of pyrazine is about 10−8, we have measured the spectrum and the decay rates of its various vibronic levels. Our results support the notion that surface Penning ionization is the mechanism of SEELEM. The detector is insensitive to vibrational energy (thus enabling the distinction between intersystem crossing and internal conversion). The detection sensitivity of triplets rises with the excess electronic energy and with the lowering of the surface work‐function.

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Temperature dependence of radiationless processes. Isoquinoline in solution

Cited by 27 publications

References 19 publications

Steady State and Time-Resolved Fluorescence Study of Isoquinoline: Reinvestigation of Excited State Proton Transfer

Steady State and Time-Resolved Fluorescence Study of Isoquinoline: Reinvestigation of Excited State Proton Transfer

Synthesis and Fluorescent Properties of Novel Isoquinoline Derivatives

Triplet State Interrogation in Supersonic Beams by Surface Electron Ejection

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