IR-LD Spectral Study and ab Initio Calculations of 1-Phenyl 3-Substituted Pyrazol-5-Ones

Authors: Ivanova B.¹; Chapkanov A.²; Arnaudov M.³; Petkov I.³

Source: Structural Chemistry, Volume 16, Number 1, February 2005 , pp. 47-53(7)

Publisher: Springer

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Abstract:

The stereo structural characterization of 1-phenyl-3-methyl (MPhP)- and 1-phenyl-3–phenyl (DPhP)-pyrazol-5-ones are achieved by means of a linear dichroic infrared spectral (IR-LD) spectroscopy of samples dissolved in nematic liquid crystal. The results, thus obtaining in both cases indicate a coplanar disposition of 1-phenyl substituent towards the pyrazole fragment, however, the benzene ring attached at 3-position in DFP is significantly deviated form the pyrazolone skeleton plane. Additionally the geometry parameters of both compounds are estimated by ab initio calculations using 6-31G** basis set on Hartee-Fock level of theory. The predicted stereo structure confirms the results achieved by the IR-LD spectral study that is in a good agreement with the X-ray data of the discussed pyrazol-5-ones derivatives.

Keywords: 1-phenyl-3-substituted-pyrazol-5-ones; oriented samples; IR-LD spectral study; Ab initio calculations; geometry optimization

Document Type: Research article

DOI: http://dx.doi.org/10.1007/s11224-005-1084-1

Affiliations: 1: Faculty of Chemistry, University of Sofia, 1164, Sofia, Bulgaria, Email: ahbi@chem.uni-sofia.bg 2: Department of Chemistry, South-West University “Neofit Rilski”, 66 Ivan Milanov Str., 2700, Blagoevgrad, Bulgaria, 3: Faculty of Chemistry, University of Sofia, 1164, Sofia, Bulgaria,

Publication date: 2005-02-01