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Journal of the Korean Chemical Society (JKCS)

ISSN 1017-2548(Print)
ISSN 2234-8530(Online)
Volume 32, Number 3
JKCSEZ 32(3)
June 20, 1988 

 
Title
MO Studies on the Conformational Stabilities and the Rotational Barriers about C-N Bond in Amides

Amide류에서 형태안정화와 C-N결합의 회전장벽에 관한 분자궤도론적 연구
Author
Wang Ki Kim, Chang Kook Sohn, Ikchoon Lee

김왕기, 송창국, 이익춘
Keywords
Abstract
N-methyl formamide, N,N-dimethyl formamide, N-methyl acetamide, 및 N,N-dimethyl acetamide의 여러 형태에 대한 상대에너지를 MNDO법으로 구하여 C-N결합 및 메틸기 회전에 대한 회전장벽에 미치는 1-전자 및 입체 반발에너지의 영향을 논의하였다. 그 결과 formamide의 형태안정화는 주로 1-전자 에너지항에 의하여 결정되고, acetamide의 형태안정화는 주로 입체인자항에 의하여 결정됨을 알았다. C-N 결합에 대한 회전장벽을 구한 결과 N-methyl formamide와 N-methyl acetamide에서 입체 장애 효과는 바닥상태에서 보다 전이상태에서 크게 작용하지만 N,N-dimethyl formamide와 N,N-dimethyl acetamide에서 입체장애 효과는 전이상태에서 보다 바닥상태에서 더 크게 작용함을 알았다.

The MNDO calculations were performed on the various rotamers of N-methyl formamide, N,N-dimethyl formamide, N-methyl acetamide, and N,N-dimethylacetamide in order to investigate the contribution of the one-electron and the steric effect on their rotational barriers about the C-N bond. Results show that while the conformational stabilities of formamides depend mainly on the one-electron factor, those of acetamides depend mainly on the steric factor. According to results obtained by calculations on the rotational barriers about C-N bond, for N-monosubstituted amides the steric effect is larger in the rotational ground state than in the transition state and for N,N-disubstituted amides the steric effect is larger in the rotational transition state.

Page
163 - 170
Full Text
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