Reactions of uridine with copper(II) acetate dimer

Abstract

Two groups of cis diols may be categorized according to their reaction with the dimer Cu 2(CH 3COO −) 4 in dimethylsulfoxide. Cis diols of the ribose class destroy the dimer, as is revealed by a shift of the visible absorption to larger wavelengths with a loss of intensity and by an increase in magnetic moment. Addition of a uridine class cis diol also results in a loss of intensity but without a shift in the characteristic dimer 715 nm absorption maximum and by little change in magnetic moment. A quantitative analysis is presented of the changes in the visible absorption intensity upon uridine addition. The dimer to monomer equilibrium of copper acetate is taken into account. One molecule of uridine as a twice deprotonated cis diolate (R) reacts with one mol of copper acetate dimer (CuA 2) with expulsion of two acetates (A) as acetic acid to give Cu 2A 2R. A second product is also formed. Only upon inclusion of a product tetranuclear complex composed of Cu 4A 4R 2 is there achieved a satisfactory quantitative description of the interactions over a 30 fold range of total Cu(II) concentration.