کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
5395307 | 1505661 | 2011 | 8 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Theoretical investigations on the structure and relative stabilities of the tautomeric forms of 6-amino-5-nitrosouracil and violuric acid derivatives (PM3-COSMO calculation)
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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: Theoretical investigations on the structure and relative stabilities of the tautomeric forms of 6-amino-5-nitrosouracil and violuric acid derivatives (PM3-COSMO calculation) Theoretical investigations on the structure and relative stabilities of the tautomeric forms of 6-amino-5-nitrosouracil and violuric acid derivatives (PM3-COSMO calculation)](/preview/png/5395307.png)
چکیده انگلیسی
In order to identify the structure of the most stable tautomers of 6-amino-5-nitrosouracil and violuric acid derivatives in different pH conditions, relative stabilities of potential tautomers (112) in aqueous phase have been calculated taking into account the entropy effects over the tautomeric equilibria. In each medium, the tautomer with lower energy must be the most representative form at the corresponding pH and the knowledge of the effect of the medium in the tautomerization energies allows to evaluate the possible effect of the medium over the molecular stability. Clearly, the results show that, in aqueous phase, the order of basicity of protonation sites in the 6-amino-5-nitrosouracil derivatives is N6Â >Â (N3Â >Â N1)Â >Â (O4, O5, O2), whereas for the violuric ones, the basicity order is (N3, N1)Â >Â O5Â >Â (O2, O4, O6). The 6-amino-5-nitrosouracil derivatives use to behave as an amino-nitroso-keto tautomer with a strong imino character, whereas, upon coordination, the violuric acids change from a keto-oxime tautomer (free acids) to a partially enolyzed keto-nitroso coordinated one, despite usually the authors refer to these forms as 5-oximato ligands.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Computational and Theoretical Chemistry - Volume 964, Issues 1â3, March 2011, Pages 83-90
Journal: Computational and Theoretical Chemistry - Volume 964, Issues 1â3, March 2011, Pages 83-90
نویسندگان
Nuria A. Illán-Cabeza, Antonio R. GarcÃa-GarcÃa, Miguel N. Moreno-Carretero,