The mixed ligand complex [Pd(bpy)(Z,-asp)*3.5H2O (bpy = 2,2'- bipyridine, L-asp= L-aspaitic acid) (1) has been synthesized and characterized by IR spectra, elemental analysis and electroconductivity. The molecular structure and the packing of 1 have been determined by single crystal X-ray structure analysis. The results show that the Pd( II ) in 1 has a square planar coordination geometry and the molecules of 1 are assembled via hydrogen bond and intermolecular aromatic ring stacking. The crystal of 1 belongs to tetragonal, space group P4(l)2(l)2, a - h - 1.5979(3) nm, c = 1.3749(5) ran, Z = %, V- 3.5105(15) ran3. The stability of the mixed ligand complex was determined by the pH potentiometric titration technique in water at 37 °C and 0.10 ionic strength (NaCl). The results show that the complex is quite stable, The higher scale values of relative stability AlgX and lgZ demonstrate that the complex possesses enhanced stability. The reasons that lead to these results were discussed in terms of 7r-electron back donation and electroneutralization.

Key words: BIPYRIDINE P, ASPARTIC ACID, PALLADIUM COMPOUNDS, ELEMENTAL ANALYSIS, IR, XRD, CRYSTAL STRUCTURE