Non-Isotype Crystals of 2,6-Diaminopurinium(1+) Salts with Bis(pyridine-2,6-dicarboxylate)metal(II) anions (M = Co or Cu)

Adeninium(1+) ions generate isostructural series of compounds (H(2)ade)(2)[M-II(pdc)(2)]center dot 3H(2)O (M = Mn, Co, Ni, Cu or Zn). Hade(+) exists as nearly coplanar pairs of tautomers A:B = H-2(N1,N9)ade(+): H-2(N3,N7)ade(+). These base pairs are H-bonded in a ladder (A:B)(n). In the crystal of (H(2)dap)(2)[Cu-II(pdc)(2)]center dot 4H(2)O the 2,6-diaminopurinium(1+) ions only exist as the tautomer H-2(N3,N7)dap(+), but forming two non-equivalent homo-pairs, {H(2)dap(1)(+)}(2) and {H(2)dap(2)(+)}(2), both using NI as acceptor but an N6-H or N2-H bond as H-donor. These homo-pairs alternate in the laddered chains. The crystal of (H(2)dap)(2) [Co(II)pdc)(2)]center dot 6H(2)O has also the tautomer H-2(N3,N7)dap(+) forming two non-equivalent homo-pairs, but with or without the mediation of water: {H(2)dap(1)(+)}(2) and {H(2)dap(2)(+)center dot H2O}(2), respectively.