کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
5417753 | 1506951 | 2008 | 6 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
CN bond rotation and E-Z isomerism in some N-benzyl-N-methylcarbamoyl chlorides: A DFT study
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
شیمی
شیمی تئوریک و عملی
پیش نمایش صفحه اول مقاله
![عکس صفحه اول مقاله: CN bond rotation and E-Z isomerism in some N-benzyl-N-methylcarbamoyl chlorides: A DFT study CN bond rotation and E-Z isomerism in some N-benzyl-N-methylcarbamoyl chlorides: A DFT study](/preview/png/5417753.png)
چکیده انگلیسی
The current report presents the first theoretical study of the restricted CN bond rotation in carbamoyl chlorides. Several N-benzyl-N-methylcarbamoyl chlorides were investigated, with varying pattern of substitution in the aromatic ring. Optimizations and frequency calculations were conducted employing DFT at the B3LYP/6-31+G(d) level of theory. Each of the studied structures exhibits a pair of rotamers (s-Z and s-E), generated upon rotation around the C(O)N bond. The s-E isomer is the global minimum in every case, but the preference for it is usually less than 1Â kcal/mol. Two possible transition state structures were identified for the rotamer interconversion: TSsyn and TSanti, in close analogy to other related compounds, such as amides and carbamates. In contrast to the two latter types, however, the preferred transition state in the case of carbamoyl chlorides is TSsyn, which we attribute to a stabilizing gauche effect. The optimized minima structures of the studied carbamoyl chlorides were subjected to GIAO B3LYP/6-311+G(2d,p) calculations, and the resultant isotropic shifts were found to be in excellent agreement with available experimental values. This has allowed us to provide unambiguous NMR signal assignments for the s-E and s-Z isomers of the studied compounds.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Molecular Structure: THEOCHEM - Volume 850, Issues 1â3, 15 February 2008, Pages 105-110
Journal: Journal of Molecular Structure: THEOCHEM - Volume 850, Issues 1â3, 15 February 2008, Pages 105-110
نویسندگان
Michael Horwath, Vladimir Benin,