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Metal‐stabilized rare tautomers: N4 metalated cytosine (M = Li + , Na + , K + , Rb + and Cs + ), theoretical views
Author(s) -
Monajjemi Majid,
Ghiasi Reza,
Sadjadi M. A. Seyed
Publication year - 2003
Publication title -
applied organometallic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.53
H-Index - 71
eISSN - 1099-0739
pISSN - 0268-2605
DOI - 10.1002/aoc.469
Subject(s) - chemistry , nucleobase , tautomer , protonation , metalation , molecular orbital , ring (chemistry) , ab initio quantum chemistry methods , crystallography , stereochemistry , computational chemistry , molecule , dna , ion , organic chemistry , biochemistry
Ab initio calculations indicate that metalation of the exocyclic amino group of cytosine by the elements of Group IA (Li, Na, K, Rb and Cs) induces protonation of a nucleobase ring nitrogen atom, and hence causes a proton shift from an exocyclic to an endocyclic nitrogen atom. Thus, this metal‐assisted process leads to the generation of rare nucleobase tautomers. The calculations suggest that this kind of metalation increases the protonation energies of the aromatic ring of the nucleobase. The present study reports the quantum chemistry analysis of the metal‐assisted tautomerization. The calculations clearly demonstrate that metalation of the exocyclic amino group of the nucleobase significantly increases the protonation energy of the aromatic rings of the nucleobase. Also, absolute anisotropy shift, molecular orbital and natural bond orbital calculations are compatible with these results. Copyright © 2003 John Wiley & Sons, Ltd.