Interactions of Copper(I) Phenanthroline Chelate with Polyadenylic-Polyuridylic Acid in Aqueous Dioxane

摘要

Acid-base transformations in the system copper(I) phenanthroline chelate [Cu(phen)_2]_(aq)~+-poly-adenylic-polyuridylic acid in aqueous dioxane were studied by spectrophotometry.Changes in band intensities and positions were revealed in the visible and near UV regions,dependent on the pH of the solution.Factor analysis was used to show that the absorption variance on titration of copper(I) bisphenanthroline chelate is determined by mutual transformations of three spectral forms of complexes.Concentration profiles were calculated for compounds prevailing in the solution.In the presence of polyadenylic-polyuridylic acid,an additional spectral form appears as a result of a short-wave shift of the d-pi~* MLCT transition in the copper(I) chelate complex.Analysis of the calculated concentration profiles established that the new complex is formed at pH 5.2-5.6 from the bisphenanthroline chelate and the double-helix rod-like form of the polymer.