The attachment of amino fragment to purine: inner-shell structures and spectra.

摘要: The impact of the amino fragment (–NH2) attachment on inner-shell structures and spectra unsubstituted purine ring adenine are studied. Density functional theory calculations, using LB94/TZ2P//B3LYP/TZVP model, reveal significant site-dependent electronic structural changes in inner shell species. A condensed Fukui function indicates that all N C sites, except for N(1) C(5), demonstrate electrophilic reactivity (f− > 0.5 |e|) purine. Once binds to C(6) position form adenine, these sites is greatly reduced. As expected, experiences substantial energy charge transfer, owing formation C—NH2 bond adenine. present study reveals N1s inherit purine, whereas C1s experience although have geometrically similar carbon frames. findings also indicate NH2 exhibits deeply rooted influences DNA/RNA bases. suggests some fragment-based methods may not be applicable spectral analyses shell.