Synthesis, characterization and antimicrobial activity of novel platinum(IV) and palladium(II) complexes with meso-1,2-diphenyl-ethylenediamine-N,N′-di-3-propanoic acid – Crystal structure of H2-1,2-dpheddp·2HCl·H2O

In the reaction of meso-1,2-diphenyl-ethylenediamine (1,2-dphen) with neutralized 3-chlor-propanoic acid, the new linear tetradentate edda-like ligand (edda = ethylenediamine-N,N′-diacetic ion) meso-1,2-diphenyl-ethylenediamine-N,N′-di-3-propanoic acid dihydrochloride monohydrate (H2-1,2-dpheddp·2HCl·H2O) was prepared. The corresponding platinum(IV) complex, s-cis-dichlorido-(meso-1,2-diphenyl-ethylenediamine-N,N′-di-3-propanoate)-platinum(IV) ([PtCl2(1,2-dpheddp)]) was synthesized by heating potassium-hexachloridoplatinate(IV) and H2-1,2-dpheddp·2HCl·H2O on steam bath for 12 h with neutralization by means of lithium-hydroxide. The palladium(II) complex, cis-dichlorido-(meso-1,2-diphenyl-ethylenediamine-N,N′-di-3-propanoate)-palladium(II) ([PdCl2(1,2-dpheddp)]) was obtained in the similar way using potassium-tetrachloridopalladate(II), H2-1,2-dpheddp·2HCl·H2O and lithium-hydroxide. The compounds were characterized by elemental analysis and infrared spectroscopy. The spectroscopically predicted structure of the synthesized tetradentate ligand was confirmed by X-ray analysis of the H2-1,2-dpheddp·2HCl·H2O.Antimicrobial activity of the ligand and corresponding palladium(II) and platinum(IV) complexes is investigated against 25 species of microorganisms. Testing is preformed by microdilution method and minimum inhibitory concentrations (MIC) and minimum microbicidal concentration (MMC) have been determined. The difference between antimicrobial activity of the ligand and corresponding platinum(IV) and palladium(II) complex is noticed and, in general, palladium(II) complex was the most active.

► Ligand H2-1,2-dpheddp·2HCl·H2O, palladium(II) and platinum(IV) complexes were prepared. ► Structure of ligand was confirmed by X-ray analysis. ► Antimicrobial activity was tested against 25 species of microorganisms. ► Complexes demonstrated more potent inhibitory effects on growth of bacteria than fungi. ► In general, Pd(II) complex shows higher antimicrobial activity.