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Spectroscopic proof for intermolecular or intramolecular hydrogen bonds in ketoenol tautomers of 1-phenyl-3-methyl-4-benzoyl-5-pyrazolone

✍ Scribed by Toyotoshi Ueda; Yoshifumi Akama

Publisher: Elsevier Science
Year: 1994
Tongue: English
Weight: 369 KB
Volume: 222
Category: Article
ISSN: 0009-2614
DOI: 10.1016/0009-2614(94)00392-0

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✦ Synopsis

The broad infrared bands of the polymorphic crystals of I-phenyl-3-methyl-4-benzoyl+pyrazolone (PMBP) were assigned unequivocally by examining the IR spectra of solutions and Raman spectra. The strong band at 2550 cm-' of a colourless crystal was attributed to an intermolecular hydrogen bond NH...O=C of the NH keto form, and the strong band at 3 100 cm-' of a yellow crystal, to an intramolecular hydrogen bond OH...O=C of the 0( 1 )H enol forms.

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Spectroscopic Studies of the Keto and En

Spectroscopic Studies of the Keto and Enol Tautomers of 1-Phenyl-3-Methyl-4-Benzoyl-5-Pyrazolone

✍ Yoshifumi Akama; Aijun Tong 📂 Article 📅 1996 🏛 Elsevier Science 🌐 English ⚖ 100 KB

Molecular structures of the two tautomers of a ␤-diketone 1-phenyl-3-methyl-4-benzoyl-5pyrazolone (PMBP) were studied by MS, UV, IR, and X-ray diffraction methods. The mass spectra show little difference for the two forms of PMBP, while there are notable differences in the IR spectra as KBr pellets