The reactivity of N-(2-aminophenyl)-d-glycero-d-gulo-heptonamide (adgha), with the group 12 cations, Zn(II), Cd(II), and Hg(II), was studied in DMSO-d(6) solution. The studied system showed a selective coordination to Hg(II), and the products formed were characterized by (1)H and (13)C NMR in DMSO-d(6) solution and fast atom bombardment (FAB(+)) mass spectra. The expected coordination compounds, [Hg(adgha)](NO(3))(2) and [Hg(adgha)(2)](NO(3))(2), were observed as unstable intermediates that decompose to bis-[2-(d-glycero-d-gulo-hexahydroxyhexyl)-benzimidazole-κN]mercury(II) dinitrate, [Hg(ghbz)(2)](NO(3))(2). The chemical transformation of the complexes was followed by NMR experiments, and the nature of the species formed is sustained by a theoretical study done using DFT methodology. From this study, we propose the structure of the complexes formed in solution, the relative stability of the species formed, and the possible role of the solvent in the observed transformations.