Local Aromaticity in Natural Nucleobases and Their Size-Expanded Benzo-Fused Derivatives

• DOI: 10.1021/jp063790t
• Publication Date: 2006-10-17T16:02:44Z
• Authors: Oscar Huertas; Jordi Poater; Miguel Fuentes-Ca...; Modesto Orozco; Miquel Solà; F. Javier Luque
• Keywords: Nucleobase

The influence of the insertion/addition a benzene ring to natural nucleic acid bases on local aromaticity so-called size-expanded (xN, with N being adenine, guanine, cytosine, and thymine) is examined. To this end, six- five-membered rings in both their benzoderivatives determined using HOMA, NICS, aromatic fluctuation index (FLU), para-delocalization (PDI) descriptors. In general, there good correspondence between different indices, so that moieties more negative NICS values also have larger HOMA PDI measures lower FLU indices. results point out notable differences character bases, which generally are hardly affected upon hydrogen bonding. highest occupied molecular orbital−lowest unoccupied orbital (HOMO−LUMO) gap for nucleobases show an inverse correlation fused ring, HOMO−LUMO is, destabilization experienced by bases. This finding suggests introduction suitable chemical modifications might be useful modulate while enabling design modified DNA duplexes able act as wires.