The synthesis and characterization of [cis-Ru(bpy)2(9mhyp-kappaN7)L]+/2+ and [cis-Ru(bpy)2(9egua-kappaN7)L]+/2+ (bpy = 2,2’-bipyridine, 9mhyp = 9-methylhypoxanthine, 9egua = 9-ethylpanine), where L = Cl- or H2O, is reported. Both ions are isolated as chlorides and hexafluorophosphates and show similar proton NMR patterns for the cis-configurated bpy ligands. The aqua complexes (L = H2O) have been isolated for both Ru(nucleobase-kappaN7) complexes as hexafluorophosphate salts. [cis-Ru(bpy)2(9egua-kappaN7)Cl]Cl crystallizes in the triclinic space group P1BAR with a = 11.895(4) angstrom, b = 12.407(2) angstrom, c = 13.329(5) angstrom, alpha = 91.5(2)degrees, beta = 90.8(3)degrees, gamma = 111.3(2)degrees, and Z - 1 for the formula C54H46Cl4N18O5Ru2. The structure was solved by direct methods and refined by Fourier and full-matrix least-squares techniques, resulting in R(w) = 0.0751 for 7346 independent significant reflections. The guanine moiety is positioned with the H(8) proton directed toward the coordinating chlorine and the keto group between the pyridyl groups of the bpy ligands. The distances from the oxygen atom of the keto group to the centroids of the bpy pyridyl rings are 3.95(3) and 3.60(3) angstrom, respectively. An additioned stabilizing interaction between the lone pairs located on the keto group and the pi systems of the pyridyl groups is deduced from comparison of the proton NMR data of the crystals and the same complex formed in solution. A statistical survey in the Cambridge Structural Database (CSD) has shown that the presented X-ray structure is the first example of such an interaction for a coordination compound. The 6-ketopurine orientation is important for studies on the covalent binding of [cis-Ru(diimine)2]2+ compounds to the N(7) site of guanine in B-DNA.