title: Structural models for the interaction of Cd(II) with DNA: trans-[Cd(9-RGH-N7)2(H2O)4]2+.
abstract: Reactions of Cd(NO(3))(2) with the model nucleobases 9-alkylguanine in water at neutral pH, give the compounds trans-[Cd(9-RGH-N7)(2)(H(2)O)(4)](NO(3))(2)(R=Me, Et), with the 9-alkylguanine ligands bound to the metal cation at the N(7) position. The X-ray structures of both compounds are reported. The six-coordinate Cd(II) complexes consist of a highly regular octahedral geometry in which the two 9-alkylguanine ligands are in a trans position to each other and approximately collinear with the metal cation. In addition, the networks of both compounds show interesting features. Thus, intramolecular H-bonds between O(6) and a coordinated water molecule are present, and self-association of guanines via H-bonding of N(3)-H...N(2) take place, leading to a 1D supramolecular polymeric ribbon. Density functional theory calculations have been applied to both compounds in order to study the stability of N(7) metalated guanine-guanine associations by comparing experimental and theoretical results. The potential relevance with regard to possible Cd(II)-DNA cross-links is briefly discussed.
authors.affiliation: Departamento de Tecnología Industrial, Universidad Alfonso X El Sabio, 28691 Villanueva de la Cañada, Madrid, Spain.
authors.forename: Pilar Amo
authors.initials: PA
authors.lastname: Ochoa
authors.forename: M Isabel
authors.initials: MI
authors.lastname: Rodríguez-Tapiador
authors.forename: Simone S
authors.initials: SS
authors.lastname: Alexandre
authors.forename: César
authors.initials: C
authors.lastname: Pastor
authors.forename: Félix
authors.initials: F
authors.lastname: Zamora
mesh_terms: D019187:Cadmium Compounds / Q000737:chemistry*; D003198:Computer Simulation; D018360:Crystallography, X-Ray; D004247:DNA / Q000737:chemistry*; D006860:Hydrogen Bonding; D008024:Ligands; D008958:Models, Molecular; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000737:chemistry*; D013329:Structure-Activity Relationship
chemical_list: D019187:Cadmium Compounds; D008024:Ligands; D009942:Organometallic Compounds; D004247:DNA