title: Cyclic tetranuclear half-sandwich ruthenium(II) complexes with 4,7-phenanthroline and hydroxo bridges: crystal structure, solution behaviour and binding to nucleosides.
abstract: The reaction between [(eta(6)-p-cymene)Ru(H2O)3]X2 and 4,7-phenanthroline (phen) leads to the formation of the rectangular tetranuclear complexes [(eta(6)-p-cymene)4Ru4(mu-4,7-phen-N4,N7)(2)(mu-OH)4]X4 (X=NO3, 1a; SO3CF3, 1b) which have been structurally characterised by X-ray crystallography. 1H NMR spectroscopic studies suggest the presence of a partially dissociated dinuclear species of type [(eta6-p-cymene)2Ru2(mu-4,7-phen-N4,N7)(solv)4]4+ in equilibrium with the tetranuclear cyclic species found in the solid state. The temperature effect for this equilibrium was studied by variable temperature 1H NMR experiments in D2O and MeOD. The results reveal that the proportion of the tetranuclear species increases with the polarity of the solvent which favour stacking interactions between the phenanthroline moieties. In addition, the reactivity of the tetranuclear species towards the nucleosides guanosine (Guo), cytidine (Cyt), 2'-deoxythymidine (Thy) and 2'-deoxyadenosine (dAdo) has been monitored by (1)H NMR as a potential model for the interaction of the 1 species with the probable DNA target. The results reveal that the 1 systems are able to bind the nucleobases endocyclic nitrogen atoms of Guo Cyt, and dAdo.
authors.affiliation: Departmento de Química Inorgánica, Universidad de Granada, Av. Fuentenueva s/n, 18071 Granada, Spain.
authors.forename: Miguel A
authors.initials: MA
authors.lastname: Galindo
authors.forename: Miguel
authors.initials: M
authors.lastname: Quirós
authors.forename: M Angustias
authors.initials: MA
authors.lastname: Romero
authors.forename: Jorge A R
authors.initials: JA
authors.lastname: Navarro
mesh_terms: D000970:Antineoplastic Agents / Q000737:chemistry*; D000081007:Cymenes; D039821:Monoterpenes / Q000737:chemistry; D019906:Nuclear Magnetic Resonance, Biomolecular; D009705:Nucleosides / Q000737:chemistry*; D009942:Organometallic Compounds / Q000737:chemistry*; D010618:Phenanthrolines / Q000737:chemistry*; D012428:Ruthenium / Q000737:chemistry*
chemical_list: D000970:Antineoplastic Agents; D000081007:Cymenes; D039821:Monoterpenes; D009705:Nucleosides; D009942:Organometallic Compounds; D010618:Phenanthrolines; C007210:4-cymene; C053487:4,7-phenanthroline; D012428:Ruthenium