Electronic Properties and π-π* Absorption Spectrum of 2-Pyridone

Fujimoto, Akira; Inuzuka, Kōzō; Shiba, Ryuichi

doi:10.1246/bcsj.54.2802

Cited by 31 publications

(22 citation statements)

References 13 publications

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“…Assignment for most of the bands could fit into this scheme except the 4e band that was not observed. The absorption spectrum of 1MPY in solution 20 shows a vibrational band associated with the first -* state located at 334 nm, that is, 118 cm −1 away from the observed O 0 0 band at 29 822 cm −1 . In 2-methyl pyridine, although the methyl group activity was not seen in the mass resolved excitation spectrum, the low frequency band observed at 120.6 cm −1 was assigned as a vibronic band.…”

Section: -Methyl-2"1h…pyridone "1mpy…mentioning

confidence: 87%

Spectroscopic studies on methyl torsional behavior in 1-methyl-2(1H)-pyridone, 1-methyl-2(1H)-pyridinimine, and 3-methyl-2(1H)-pyridone. I. Excited state

Sinha

Pradhan

Wategaonkar

et al. 2007

The Journal of Chemical Physics

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The laser induced fluorescence excitation and dispersed fluorescence spectra of three nitrogen heterocyclic molecules 1-methyl-2͑1H͒pyridone ͑1MPY͒, 1-methyl-2͑1H͒pyridinimine ͑1MPI͒, and 3-methyl-2͑1H͒pyridone ͑3MPY͒ have been studied under supersonic jet cooled condition. The methyl torsional and some low frequency vibrational transitions in the fluorescence excitation spectrum were assigned for 1MPY. These new assignments modify the potential parameters to the methyl torsion reported earlier. Some striking similarities exist between the torsional and vibrational transitions in the fluorescence excitation spectra of 1MPY and 1MPI. Apart from pure torsional transitions, a progression of vibration-torsion combination bands was observed for both these molecules. The excitation spectrum of 3MPY resembles the spectrum of its parent molecule, 2-pyridone. The barrier height of the methyl torsion in the excited state of 3MPY is highest amongst all these molecules, whereas the barrier in 1MPI is higher than that of 1MPY. To get an insight into the methyl torsional barrier for these molecules, results of the ab initio calculations were compared with the experimental results. It was found that the conformation of the methyl group undergoes a 60°rotation in the excited state in all these molecules with respect to their ground state conformation. This phase shift of the excited state potential is attributed to the * -* hyperconjugation between the out-of-plane hydrogen of the methyl group and the molecular frame. It has been inferred that the change in lowest unoccupied molecular orbital energy plays the dominant role in the excited state barrier formation.

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Section: -Methyl-2"1h…pyridone "1mpy…mentioning

confidence: 87%

Spectroscopic studies on methyl torsional behavior in 1-methyl-2(1H)-pyridone, 1-methyl-2(1H)-pyridinimine, and 3-methyl-2(1H)-pyridone. I. Excited state

Sinha

Pradhan

Wategaonkar

et al. 2007

The Journal of Chemical Physics

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“…[1][2][3][4][5][6][7][15][16][17][18][19][20][21] In liquid phases, both forms coexist in nonpolar solvents, while 2PY substantially dominates in a pure crystalline or in polar solvents. 1,3,11,12,19 Such a difference of the relative abundance in solvents can be associated with the relative stabilization energy and a drastic decrease of the barrier height by the solvation. As these results suggests, the tautomeric equilibrium depends inherently on the environment surrounding the molecule.…”

Section: Introductionmentioning

confidence: 99%

Vibrational spectroscopy of 2-pyridone and its clusters in supersonic jets: Structures of the clusters as revealed by characteristic shifts of the NH and C=O bands

Matsuda¹,

Ebata²,

Mikami³

1999

The Journal of Chemical Physics

153

159

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Articles you may be interested inPhotofragment emission yield spectroscopy of acetylene in the D̃ 1 Π u , Ẽ 1 A, and F̃ 1 Σ u + states by vacuum ultraviolet and infrared vacuum ultraviolet double-resonance laser excitations Structures of hydrogen-bonded clusters of benzyl alcohol with water investigated by infrared-ultraviolet double resonance spectroscopy in supersonic jet J. Chem. Phys. 111, 8438 (1999); 10.1063/1.480184 Structures and the vibrational relaxations of size-selected benzonitrile-( H 2 O ) n=1-3 and -( CH 3 OH ) n=1-3 clusters studied by fluorescence detected Raman and infrared spectroscopies J. Chem. Phys. 110, 9504 (1999); 10.1063/1.478915Characterizations of the hydrogen-bond structures of 2-naphthol-( H 2 O ) n (n=0-3 and 5) clusters by infraredultraviolet double-resonance spectroscopy Vibrational spectroscopy of the key functional vibrations of 2-pyridone and its hydrogen-bonded clusters with water, methanol, dioxane, dimethylether, as well as its dimer, has been carried out by using infrared-ultraviolet ͑IR-UV͒ and stimulated Raman-UV double resonance methods combined with fluorescence detection. The characteristic spectral changes upon the cluster formation have been observed for the NH and CvO stretching vibrations of the bare molecule and also for the OH stretching vibrations of the solvent molecules. The cluster structures were investigated by comparing the observed spectra with the simulated ones of the energy-optimized structures obtained by ab-initio molecular orbital calculations. It was found that the ''ring-type'' hydrogen-bonded structure is appropriate for the cluster with water or methanol, while the ''linear-type'' hydrogen-bonded structure is appropriate for the cluster with dioxane or dimethylether. The symmetric form of 2-pyridone dimer was confirmed by the observed spectra, as well as the ab-initio calculation. A clear correlation between the observed frequency shifts of the NH stretching vibrations and the calculated NH¯O hydrogen-bond angles was obtained indicating that the hydrogen-bond angle distortion reduces the local hydrogen-bond strength. Also it was found the blue shifts of the origin bands of the S 1 ←S 0 electronic transition strongly depends on the type of the cluster structures.

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“…For example, UV-vis spectroscopy has been used extensively. 4,10,11 Electronic spectra, although relatively easy to acquire, are often broad and featureless, which complicates the analysis when multiple tautomers co-exist. X-ray crystallography cannot determine accurate proton positions, hence limiting its use for directly identifying weakly populated tautomers.…”

mentioning

confidence: 99%

Identification of Lactam–Lactim Tautomers of Aromatic Heterocycles in Aqueous Solution Using 2D IR Spectroscopy

Peng

Tokmakoff

2012

J. Phys. Chem. Lett.

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The tautomerism of aromatic heterocycles is of great interest because it directly affects their chemical properties and biological function. The tautomerism of 2-pyridone, 6-chloro-2-pyridone, and 4-pyrimidinone have been examined in D2O using FTIR, two-dimensional IR (2D IR) spectroscopy and density functional theory (DFT) calculations. Using the 2D IR cross-peak patterns, the lactim tautomer of 6-chloro-2-pyridone was separated from the lactam tautomer, and its population was observed to increase with temperature. The equilibrium constant of [lac-tam]/[lactim] was determined to be 2.1 at room temperature for 6-chloro-2-pyridone. Similarly, the N1H and N3H lactam tautomers of 4-pyrimidinone were identified with 2D IR. To assign the vibrational modes of different tautomers, DFT calculations of these chemical species were performed with explicit water molecules, and the hydration effects on the vibrational frequencies and intensities were established.

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Electronic Properties and π-π* Absorption Spectrum of 2-Pyridone

Cited by 31 publications

References 13 publications

Spectroscopic studies on methyl torsional behavior in 1-methyl-2(1H)-pyridone, 1-methyl-2(1H)-pyridinimine, and 3-methyl-2(1H)-pyridone. I. Excited state

Spectroscopic studies on methyl torsional behavior in 1-methyl-2(1H)-pyridone, 1-methyl-2(1H)-pyridinimine, and 3-methyl-2(1H)-pyridone. I. Excited state

Vibrational spectroscopy of 2-pyridone and its clusters in supersonic jets: Structures of the clusters as revealed by characteristic shifts of the NH and C=O bands

Identification of Lactam–Lactim Tautomers of Aromatic Heterocycles in Aqueous Solution Using 2D IR Spectroscopy

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