Palladium(II) complexes with cytidine-guanosine pair in DMSO

Solutions containing nucleosides: cytidine and guanosine, and Pd(II) ion in dimethylsulphoxide have been investigated using 1H NMR method. It has been found that the glycylglycinate-palladium(II) complex reacts with cytidine through its N(3) nitrogen atom as the fourth donor for Pd(II) ion, and with guanosine which binds with Pd(II) through N(7) of purine ring. The primary binding site of cytidine-guanosine pair for the glycylglycinate-Pd(II) complex was N(7) of guanosine. However, in the reaction of PdCl2 with the cytidine-guanosine pair, equivalent binding sites were N(1) of guanosine and N(3) of cytidine giving CydN(3)-Pd-N(1)Guo ternary complex.