New mixed-ligand complexes of Cu(II), Pd(II) and Pt(IV) with homophthalic acid (hpH2) and nitrogen-containing heterocyclic bases have been prepared and characterized by elemental analyses, conductometric, magnetic, infrared, and electronic spectral studies. The complexes have the compositions [M(hp).L] and [Pt(hp)2-L] (M = Cu(II) or Pd(II); L = 2-aminopyridine (2-Apy), 3-aminopyridine (3-Apy), 2,2'-bipyridine (Bipy), 1,10-phenanthroline (Phen) or 2,2'-biquinoline (Biq); hp = dianion of homophthalic acid), respectively. A proposed square-planar structure for the Cu(II) and Pd(II) complexes and octahedral structure for the Pt(IV) complexes are supported by magnetic and spectral data.
