LIGAND-EXCHANGE REACTION BETWEEN TRIS(1,10-PHENANTHROLINE)METAL(II)J AND TRIS(4,7-DIPHENYL-1,10-PHENANTHROLINE)METAL(II) IONS

摘要

The ligand exchange reaction between (M(phen)_3)~(2+) and (M(DIP)_3)~(2+) (where M is the same and M Fe~(II) or Ni~(II), phen = 1,10-phenanthroline, DIP=4,7-diphenyl-1,10-phenanthroline) has been investigated by reversed phase ion-paired chromatography (RP-IPC). The effect of pH and solvent on the ligand-exchange reaction is studied by monitoring the variation in chromatograms with time after mixing. The results have shown that the ligand exchange reaction between (M(phen)_3)~(2+) and (M(DIP)_3)~(2+) takes place in the pH range of 3 - 8 and the rate of reaction for nickel(II) complexes is about two times slower than that for iron(II) complexes. Experiments on the effect of various solvents on the ligand-exchange reaction have revealed that the rate of reaction is enhanced by the solvent in the following order: (CH_3)_2CO> CHCl_3 >= CH_2Cl_2 > CH_3CN> CH_3OH. Elemental analysis and UV-visible spectroscopy confirmed that the products obtained from the ligand-exchange reaction are mixed-ligand complexes containing phen and DIP ligands, i.e., (M(phen)_2(DIP))~(2+) and (M(phen)(DIP)_2)~(2+).