Three new complexes of zinc(II) with three different proton transfer compounds, obtained from pyridine- 2,6-dicarboxylic acid (dipicolinic acid) and different Lewis bases, were synthesized and characterized using IR, 1HNMR and 13C NMR spectroscopy and single crystal X-ray diffraction. The chemical formulae and space groups of the complexes are (pipzH2)[Zn(pydc)2] 4H2O, P21/n (1), (EDGnH2)[Zn(pydc)2] 3H2O, P21/c (2) and (pdaH2)[Zn (pydc)2] 4H2O, P1 (3) where pydc, pipz, EDGn and pda are standing for dipicolinic acid, piperazine, ethylenediguanidine and 1,3-propanediamine respectively. Cell parameters of the complexes are a = 7.9493(4) A ° , b = 13.4386(7) A ° , c = 21.0557(11) A ° , b = 90.415(5) for 1; a = 9.785(3) A ° , b = 25.671(4) A ° , c = 9.3402(16) A ° , b = 90.790(17) for 2 and a = 8.411(5) A ° , b = 11.650(7) A ° , c = 12.793(8) A ° , a = 115.534(9), b = 92.791(10), c = 97.778(10) for 3. The three crystal structures illustrate that the metal ion is sixcoordinated by two pydc’s. In all three compounds a large number of O–H_O, N–H_Oand C–H_Ohydrogen bonds
