Downloads: 3
Research Paper | Chemistry | Volume 15 Issue 8, August 2026 | Pages: 64 - 70 | India
A Comparative DFT Study on the Impact of Heteroatom (O, N, and S) Variation on Aromatic Character
Abstract: Aromaticity cannot be measured or quantified directly by a single experiment. However, theoretical methods are used to assess aromaticity based on different magnetic, electronic, energetic, and structural indices. The aim of this study is to analyze, how the substitution of carbon with heteroatoms like O, N, and S effect the aromaticity of the cyclic conjugated systems. In the present DFT study, 28 considered systems are fully optimized using B3LYP/6-31G(d) basis set. NICS and HOMA indices were used to measure and quantify aromaticity, based on magnetic and structural criteria of the molecules. NICS and HOMA correlate well and provide reliable results. In our calculations, benzene shows the highest aromatic character. Five membered rings with heteroatom exhibit aromaticity while four membered cyclic system shows the anti-aromatic character. Furthermore, fused systems show high aromatic character and enhanced stability due to the delocalization of ?-electrons. In three-ring fused system the middle ring shows anti-aromatic or slight aromatic character and outer ring exhibit higher aromatic character. This study provides better insights of aromaticity at undergraduate level to build the concept, enhance the quality of education, and deep understanding of this hypothetical concept.
Keywords: Aromaticity, Anti-aromaticity, HOMA, NICS, Resonance, Theoretical Study
How to Cite?: Sanjeev Kumar Mishra, Kulsum Husain, Jyoti Tyagi, "A Comparative DFT Study on the Impact of Heteroatom (O, N, and S) Variation on Aromatic Character", Volume 15 Issue 8, August 2026, International Journal of Science and Research (IJSR), Pages: 64-70, https://www.ijsr.net/getabstract.php?paperid=SR26730144104, DOI: https://dx.doi.org/10.21275/SR26730144104