title: Why Is the Spontaneous Deprotonation of [Cu(uracil)2](2+) Complexes Accompanied by Enolization of the System?
abstract: 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.
authors.affiliation: Departamento de Química, Módulo 13, Universidad Autónoma de Madrid, Campus de Excelencia UAM-CSIC, Cantoblanco, 28049 Madrid (Spain).
authors.forename: Oriana
authors.initials: O
authors.lastname: Brea
authors.affiliation: Departamento de Química, Módulo 13, Universidad Autónoma de Madrid, Campus de Excelencia UAM-CSIC, Cantoblanco, 28049 Madrid (Spain). manuel.yanez@uam.es.
authors.forename: Manuel
authors.initials: M
authors.lastname: Yáñez
authors.affiliation: Departamento de Química, Módulo 13, Universidad Autónoma de Madrid, Campus de Excelencia UAM-CSIC, Cantoblanco, 28049 Madrid (Spain).
authors.forename: Otilia
authors.initials: O
authors.lastname: Mó
authors.affiliation: Departamento de Química, Módulo 13, Universidad Autónoma de Madrid, Campus de Excelencia UAM-CSIC, Cantoblanco, 28049 Madrid (Spain). mokhtar.lamsabhi@uam.es.
authors.forename: Al Mokhtar
authors.initials: AM
authors.lastname: Lamsabhi
keywords: copper; nucleobases; proton transfer; reaction mechanisms; tautomerism