STRUCTURE OF 2PYRONE AND 4PYRONE IN GAS PHASE

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STRUCTURE OF 2-PYRONE AND 4-PYRONE IN GAS PHASE

• ANEESHA.S
• DEPARTMENT OF CHEMISTRY
• S.N COLLEGE FOR WOMEN
• KOLLAM

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Computational chemistry is the application of
computer based models to the simulation of
chemical processes and the computation of
chemical properties. The development of various
software packages has facilitated the wide-spread
use of computational chemistry.
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• Computing the geometry of a molecule is one of
  the most basic functions of a computational
  chemistry program.
• The present investigation deals with the
  estimation of the molecular structure of pyrones
  in the gas phase using density functional theory.

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Pyrones are keto derivatives of pyrans. They
exist in two isomeric forms
2-pyrone 4-pyrone
Pyrone subunit is found in natural products like
flavones and chromones which show interesting
biological effects.
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• Methodology
• Software package used GAMESS (General Atomic
  and Molecular Electronic Structure System)
• Molecular geometry Specified using Z-matrix and
  viewed using Molden graphic program.
• Density functional theory Beckes 3-parameter
  exchange with Lee, Yang and Parrs correlation
  functional (B3LYP) is used.
• Basis set used is aug-cc-pVDZ.

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Results and discussion Optimized geometry of
pyrones in gas phase

2-pyrone
4-pyrone
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Table ICalculated and experimental bond length
of 2-pyrone in gas phase
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Table 2Calculated and experimental bond angles
of 2-pyrone in gas phase
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Table 3Calculated and experimental bond length
of 4-pyrone in gas phase
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Table 4Calculated and experimental bond angles
of 4-pyrone in gas phase
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Table 5Dipole moments of 2-pyrone and 4- pyrone
in gas phase
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Optimized geometry of 2-pyrone in the gas phase
showing the dipole moment vector
Optimized geometry of 4-pyrone in the gas phase
showing the dipole moment vector
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• The calculated bond lengths and bond angles of
  4-pyrone agree well with the experimental values.
  
• In 2-pyrone, two of the bond angles showed large
  deviation from the experimental values.
• The calculated dipole moments agree with the
  experimental values.

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Acknowledgement Dr.Reena Ravindran, Lecturer
(Senior Scale), Department of Chemistry, S.N
College for Women, Kollam. Prof.(Dr). K.R
Srivathsan, Director, IIITM-K , Tecknopark
Campus, Tvpm. Prof.(Dr). M.S Gopinathan, Emeritus
Professor, IIITM-K Dr.T.K Manojkumar, Assistant
Professor, IIITM-K