title: A calorimetric study of the Ni(II)-5' AMP system. A base-stacking stabilization.
abstract: The thermodynamic parameters of the interaction between Ni(II) (M) and 5'-AMP in aqueous solution were determined calorimetrically (I = 0.1 tetramethylammonium bromide, 25 degrees C) at physiological pH. The experimental conditions were carefully selected to avoid the polynuclear complex formation. From the Ni(5'AMP)-complex-formation constant (logK1 = 2.55), the Ni(5'AMP)2(2-)-complex-formation constant and the Ni(5'AMP) (ML) and Ni(5'AMP)2(2-) (ML2) complex-formation enthalpies were determined (logK2 = 2.34, delta H1 = -10.0 kJ/mol and delta H2 = 21.6 kJ/mol). These results confirm the formation of the ML2 complex in solution and agree very well with the hypothesis of the 'stacking' between the purine rings, promoted for metal ions.
authors.affiliation: Department of Chemistry, Universitat de les Illes Balears, Palma de Mallorca, Spain.
authors.forename: L A
authors.initials: LA
authors.lastname: Herrero
authors.forename: A M
authors.initials: AM
authors.lastname: Calafat
authors.forename: A
authors.initials: A
authors.lastname: Terrón
mesh_terms: D000249:Adenosine Monophosphate / Q000737:chemistry*; D002151:Calorimetry; D002413:Cations, Divalent; D008433:Mathematics; D009532:Nickel / Q000737:chemistry*; D012984:Software; D013816:Thermodynamics
chemical_list: D002413:Cations, Divalent; D000249:Adenosine Monophosphate; D009532:Nickel