Title
Probing the structural and electronic effects to stabilize nonplanar forms of thioamide derivatives: A computational study.
Abstract
Density functional calculations have been performed to examine the stability of nonplanar conformations of thioamide derivatives. Electrostatic, orbital, and ring strain effects were invoked to stabilize the nonplanar conformations of thioamide systems 2-7. Electrostatic interactions helped to achieve the twisted forms of thioamide derivatives; however, pyramidal forms predicted to be the global minimum. Negative hyperconjugative type interactions enhanced the stability of the twisted form 4b when compared with the planar form 4a. The influence of ring strain effect to achieve the twisted form of thioamide was observed with azirine ring. The predictions made with B3LYP/cc-pVDZ+ level of theory was found to be in good agreement with more accurate CBS-QB3 method. The solvent calculations performed with polarized continuum solvation model suggest that the relative stabilities of the nonplanar forms of thioamide derivatives are in general similar to the gas phase results. The importance of hydrogen bonding interactions between the solvent molecules and thioamide derivatives was observed toward the enhanced stability of twisted forms using a combination of explicit solvent molecules and continuum model. The natural bond orbital analysis confirmed the participation of n(N) -> pi*(C=S) delocalizations in the planar forms and corroborated the earlier reports on larger delocalizations in thioamide systems. Furthermore, the influence of electrostatic and ring strain effects on the amide, natural amides, and selenoamide has also been studied. (C) 2011 Wiley Periodicals, Inc. J Comput Chem 32: 2170-2176, 2011
Year
DOI
Venue
2011
10.1002/jcc.21800
JOURNAL OF COMPUTATIONAL CHEMISTRY
Keywords
Field
DocType
thioamide,DFT,twisted conformation,electrostatic effect,negative hyperconjugation
Natural bond orbital,Electronic effect,Computational chemistry,Chemistry,Molecular dynamics,Negative hyperconjugation,Ring strain,Implicit solvation,Hydrogen bond,Thioamide
Journal
Volume
Issue
ISSN
32.0
10
0192-8651
Citations 
PageRank 
References 
1
0.40
1
Authors
2
Name
Order
Citations
PageRank
Manoj K. Kesharwani110.40
Bishwajit Ganguly232.09