1,10-phenanthroline-2,9-dicarboxylate (hereafter PDA) has a synergistic combination of donor groups, two N atoms and two O atoms, in which the charged carboxylate groups fulfill the function of lowering the charge on the metal ions.1 In this work, we prepared and characterized copper(II) complex with PDA2- ligand, generated from the in situ one-step oxidation of neocuproine (2,9-dimethyl-1,10-phenanthroline). In continuing, reactions of 1,10-phenanthroline-2,9-dicarboxylic acid (H2PDA) with CoCl2.6H2O, FeCl3.6H2O, and Fe(NO3)3.9H2O were performed under solvothermal conditions. The stucture of compounds were characterized using infrared spectroscopy and elemental analysis (CHN). H2PDA is an excellent dicarboxylate ligand that is a member of an unrecognized class of ligands, which include 1,10-phenenthroline (Phen) itself, which show levels of pre-organization higher than that of macrocycles. And shows promise of being useful in a wide variety of biomedical applications such as Gd(ш) contrast agents in MRI technique.2 Multidentate macrocyclic or rigid ligands might even enforce a particular structure on a metal complex formed. PDA displays strong size-based selectivity, owing to the formation of three rigid five-membered chelate rings upon complex formation.3 Additionally a CSD search revealed that just 51 complexes of H2PDA reported up to now. None of the above mentioned reports include Phen and PDA simultaneously.

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