title: Molecular recognition patterns of 2-aminopurine versus adenine: a view through ternary copper(II) complexes.
abstract: In contrast to the comprehensive structural information about metal complexes with adenine, the corresponding to its isomer 2-aminopurine (H2AP) is extremely poor. With the aim to rationalize the metal binding pattern of H2AP, we report the molecular and/or crystal structure of four novel compounds with various iminodiacetate-like (IDA-like) copper(II) chelates: [Cu(IDA)(H2AP)(H2O)]·H2O (1), [Cu(MIDA)(H2AP)(H2O)]·3H2O (2), {[Cu(NBzIDA)(H2AP)]·1.5H2O}n (3) and [Cu(MEBIDA)(H2AP)(H2O)]·3.5 H2O (4), where IDA, MIDA, NBzIDA and MEBIDA are R=H, CH3, benzyl- and p-tolyl- in R-N-(CH2-COO-)2 ligands, respectively. Synthesis strategies include direct reactions of copper(II) chelates with H2AP (alone, for 1 and 3) and/or with the base pairs H2AP:thymine (1-4) or H2AP:cytosine (3). Moreover, these compounds have been also investigated by spectral and thermal methods. Regardless of the N-derivative of the IDA chelator, molecular recognition between H2AP and the referred Cu(II)-chelates only displays the formation of the Cu-N7(purine-like) bond what is clearly in contrast to what was previously reported for adenine. The metal binding pattern of 2-aminopurine is discussed on the basis of the electronic effects and steric hindrance of the 2-amino exocyclic group.
authors: Department of Inorganic Chemistry, Faculty of Pharmacy, Campus Cartuja, University of Granada, E-18071 Granada, Spain. adominguez@ugr.es
authors: Alicia
authors: A
authors: Domínguez-Martín
authors: Duane
authors: D
authors: Choquesillo-Lazarte
authors: Josefa María
authors: JM
authors: González-Pérez
authors: Alfonso
authors: A
authors: Castiñeiras
authors: Juan
authors: J
authors: Niclós-Gutiérrez
mesh_terms: D015075:2-Aminopurine / Q000737:chemistry*; D000225:Adenine / Q000737:chemistry*; D001665:Binding Sites; D002614:Chelating Agents / Q000737:chemistry*; D003300:Copper / Q000737:chemistry*; D003596:Cytosine / Q000737:chemistry; D007098:Imino Acids / Q000737:chemistry*; D007536:Isomerism; D008024:Ligands; D008958:Models, Molecular; D013941:Thymine / Q000737:chemistry
chemical_list: D002614:Chelating Agents; D007098:Imino Acids; D008024:Ligands; D015075:2-Aminopurine; D003300:Copper; D003596:Cytosine; D000225:Adenine; D013941:Thymine; C008109:iminodiacetic acid