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Ab initio studies on the nonplanarity of a peptide unit: Calculations on model compounds
Author(s) -
Sawaryn A.,
Yadav J. S.
Publication year - 1982
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/qua.560220307
Subject(s) - cndo/2 , acetamide , chemistry , ab initio , planarity testing , computational chemistry , peptide , ab initio quantum chemistry methods , crystallography , molecule , organic chemistry , biochemistry
The nonplanarity of a peptide unit has been studied by the ab initio method (GAUSSIAN 76) considering both the pyramidal structure of nitrogen and the variation of the ω angle for the N ‐methyl‐acetamide and N ‐ethyl‐acetamide in their cis and trans conformations. Several semiempirical methods have also been used for the sake of completeness of this work. All methods except CNDO and PCILO support a nonpyramidal structure for the nitrogen. The distortions of the planarity of the peptide unit show for both cis and trans conformations of the model compounds a significant asymmetric shift of the minimum on the energy curve for the ω rotation.