Molecular recognition modes between adenine or adeniniun(1 +) ion and binary MII(pdc) chelates (MCoZn; pdc = pyridine-2,6-dicarboxylate(2-) ion)

MII(pdc) chelates (Co-Zn) recognize H(N9)adenine via the M-N7 bond and the N6-H···O interligand interaction irrespective of the coordination geometry, the different hydrates of the ternary complexes and the neutral or cationic adenine coligand. μ2-Hade mode (figure) involves Cu-N3 and Cu-N7 bonds and the N9-H···O and N6-H···O interactions, respectively.