کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
5416997 | 1506902 | 2010 | 9 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
In search of aromatic seven-membered rings
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
شیمی
شیمی تئوریک و عملی
پیش نمایش صفحه اول مقاله
چکیده انگلیسی
A theoretical search for aromatic seven-membered rings has been carried out using density functional theory calculations with the B3LYP functional. The rings considered include the C7H7+ cation and its hetero-derivatives by replacing C, CH or CC units by B, Al, Ga, Si, Ge, N, P, As and BN group, the B82â dianion, the CB7â anion, the neutral S3N4 ring and its derivatives by substituting one or two N atoms by CH group, the S4N3+ cation and the all-metallic cycles M73â and M7T with MÂ =Â Cu, Ag, Au and TÂ =Â Y, Sc. Most molecules studied have planar structure in their electronic ground state. Vibrational spectra of some derivatives are plotted. Nucleus independent chemical shift (NICS) indices show that the parent molecule C7H7+ has a higher degree of aromaticity than its derivatives. Substitution of N in S3N4 by CH marginally influences the aromaticity in such a way that S3N4, S3N3(CH) and S3N2(CH)2 are similarly aromatic. The B82â dianion and both D7h and C2v isomers of CB7â possess comparable aromatic character. As for the all-metal clusters Cu73â, Ag73â, Au73â, Cu7Sc, Cu7Y, Ag7Y and Au7Y, the binary clusters become more aromatic than the pure metal anions, and are thus characterized by Ï-aromaticity.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Molecular Structure: THEOCHEM - Volume 943, Issues 1â3, 15 March 2010, Pages 23-31
Journal: Journal of Molecular Structure: THEOCHEM - Volume 943, Issues 1â3, 15 March 2010, Pages 23-31
نویسندگان
Ling Lin, Peter Lievens, Minh Tho Nguyen,