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Why Is the Spontaneous Deprotonation of [Cu(uracil) 2 ] 2+ Complexes Accompanied by Enolization of the System?
Author(s) -
Brea Oriana,
Yáñez Manuel,
Mó Otilia,
Lamsabhi Al Mokhtar
Publication year - 2015
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.201500262
Subject(s) - deprotonation , chemistry , keto–enol tautomerism , tautomer , uracil , moiety , photochemistry , computational chemistry , stereochemistry , ion , organic chemistry , dna , biochemistry
The reaction‐force formalism is applied to carry out a detailed analysis of the mechanisms behind the enolization processes undergone by the complexes formed on interaction of uracil dimers with Cu 2+ ions after spontaneous deprotonation of the resulting complexes. These enolization processes apparently involve a single proton transfer (PT) from an NH group to a carbonyl group of the same uracil moiety, which should involve a rather high activation barrier that prevents the process occurring. However, the reaction‐force, chemical‐potential, and electronic‐flux profiles unambiguously indicate that the actual mechanism involves three low‐barrier elementary steps, and this explains why enolization of the [Cu(uracil−H)(uracil)] + complexes is a highly facile, assisted PT process. All of the observed PT processes show a typical profile for both the chemical potential and the electronic flux associated with the bond‐breaking and the bond‐formation processes.