Dicopper(II)-EDTA Chelate as a Bicephalic Receptor Model for a Synthetic Adenine Nucleoside

This research was funded by Agencia Estatal de Investigacion, Ministerio de Ciencia, Innovacion y Universidades (MICIU) from Spain, and was co-funded by FEDER-EU (project nos. PGC2018-102047-B-I00 and CTQ2017-85821-R), Junta de Andalucia (research group FQM-283), and University of Granada (project ref. PPJIA2019-03).
The contributions of the undergraduate student Patricia Quirantes-Gualda and the technical and human support from SGIker (UPV/EHU) are gratefully acknowledged.
In the extensive field of metal ions, their interactions with nucleic acids, and their constituents, the main aim of this work is to develop a metal chelate suitable to recognize two molecules of an adenine nucleoside. For this purpose, the dinuclear chelate Cu-2 (mu-EDTA) (ethylenediaminetetraacetate(4-) ion (EDTA)) is chosen as a bicephalic receptor model for N9-(2-hydroxyethyl)adenine (9heade). A one-pot synthesis is reported to obtain the compound [Cu-2(mu(2)-EDTA)(9heade)(2)(H2O)(4)]center dot 3H(2)O, which has been characterized by single-crystal X-ray diffraction and various spectral, thermal, and magnetic methods. The complex unit is a centro-symmetric molecule, where each Cu (II) center is chelated by a half-EDTA, and is further surrounded by an N7-dentate 9heade nucleoside and two non-equivalent trans-O-aqua molecules. The metal chelate-nucleoside molecular recognition is referred to as an efficient cooperation between the Cu-N7(9heade) coordination bond and a (9heade)N6-H center dot center dot center dot O(carboxyl, EDTA) interligand interaction. Theoretical calculations are also made to account for the relevance of this interaction. The extreme weakness with which each water molecule binds to the metal center disturbs the thermal stability and the infrared (FT-IR) and electron spin resonance (ESR) spectra of the compound.
Agencia Estatal de Investigacion, Ministerio de Ciencia, Innovacion y Universidades (MICIU) from Spain
European Commission PGC2018-102047-B-I00 CTQ2017-85821-R
Junta de Andalucia
University of Granada PPJIA2019-03