Two novel proton transfer compounds LH2, (tataH2)(pydc), and L'H2, (tataH)2(pydc), (pydcH2 = 2,6-pyridinedicarboxylic acid and tata = melamine, 2,4,6-triamino-1,3,5-triazine), were synthesized and characterized by IR, 1Hand 13C NMRspectroscopy and solid state CPMAS 13C NMR. The (tataH2)2[Pb(pydc)2]2x2tata x4H2O complex (1) was prepared using L'H2and lead(II) nitrate, and characterized by IR andNMRspectroscopy and single crystal X-ray analysis. The PbII complex is a binuclear anionic complex [Pb(pydc)2] 2 4 , in which two metal fragments are linked via a central ten-membered PbN(13)C(18)C(22)O(24)Pb(A)N(13A)C(18A)C(22A)O(24A) ring. Extensive hydrogen bonding between carboxylate groups, (tataH2)2+ and water molecules throughout the PbII complex together with ion pairing play important roles in stabilizing the corresponding lattice. The protonation constants of the reactants, the equilibrium constants for the reaction of pydc with tata and the stoichiometry and stability of the PbII complex with L'H2 in aqueous solution were investigated by potentiometric pH titrations. The stoichiometry of one of themost abundant complexed species in solution was found to be the same as that of the crystalline lead complex.
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