کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
5224121 1383507 2010 5 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
The influence of aza-substitution on azole aromaticity
موضوعات مرتبط
مهندسی و علوم پایه شیمی شیمی آلی
پیش نمایش صفحه اول مقاله
The influence of aza-substitution on azole aromaticity
چکیده انگلیسی

A homogeneous set of values for the aromaticity indices ASE (Aromatic Stabilisation Energy), HOMA (Harmonic Oscillator Model of Aromaticity) and NICS(1) (Nucleus-Independent Chemical Shift) for azoles has been investigated using multiple linear regression analysis. Statistically-significant relationships were found between the aromaticity indices and the number of nitrogen atoms at positions 2/5 and 3/4 of the ring. Aza-derivatives of pyrrole, furan and thiophene all gave similar relationships. For all three indices aza-substitution at positions 2 and/or 5 increases aromaticity. However, aza-substitution at positions 3 and/or 4 decreases classical aromaticity (ASE and HOMA) but increases magnetic aromaticity (NICS(1)). These indices appear to be measuring different properties of the azoles. The influence of aza-substitution on these different aspects of aromaticity is tentatively rationalized in terms of either bond length equalization or uniformity of π electron distribution.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Tetrahedron - Volume 66, Issue 14, 3 April 2010, Pages 2695-2699
نویسندگان
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