Substituent and solvent effects on the rotational barriers in selenoamides: A theoretical study

Kaur, Damanjit ; Sharma, Punita ; Bharatam, Prasad V. ; Dogra, Neeru (2006) Substituent and solvent effects on the rotational barriers in selenoamides: A theoretical study Journal of Molecular Structure: THEOCHEM, 759 (1-3). pp. 41-49. ISSN 0166-1280

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Official URL: http://doi.org/10.1016/j.theochem.2005.10.001

Related URL: http://dx.doi.org/10.1016/j.theochem.2005.10.001

Abstract

Theoretical calculations at HF, MP2 and B3LYP levels using 6-31+G* basis set have been performed on nine substituted selenoamides and their thio- and oxo-analogs (H2NC(=X)Y, X=Se, S, O and Y=F, Cl, Br, NO2, CN, NH2, CH3, CF3, SH). The variations of barrier heights for rotation around C–N bond in nine substituted selenoamides are studied in comparative context with series of substituted thioamides and amides. The change in bond length, atomic charges for the equilibrium conformations, orbital interactions and rotational barriers indicate that pπ–pπ type electron delocalization is affected by π donor nature of substituents at carbonyl carbon rather than electron withdrawing nature. In addition steric effects, hyperconjugation, anomeric effect and change in hybridization during rotation also play important role. Solvent effects predict increase of rotational barrier with increase in polarity of the solvent, consistent with the experimental results on amides that suggest retardation of C–N rotation with increasing polarity of the solvent.

Item Type:Article
Source:Copyright of this article belongs to Elsevier B.V.
Keywords:Amides; Rotational Barriers; NBO Analysis; NPA; Solvent Effect.
ID Code:116641
Deposited On:12 Apr 2021 11:07
Last Modified:12 Apr 2021 11:07

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