Coordination chemistry of 1,4-bis[bis(2-pyridylmethyl)aminomethyl]benzene with copper(II)

The interaction of 1,4-bis[bis(2-pyridylmethyl)aminomethyl]benzene (p-XyDPA) with CuCl2·2H2O has resulted in the isolation of the dinuclear compound [Cu2(p-XyDPA)Cl4]·H2O (1). When the reaction was performed in presence of sodium perchlorate, sodium azide, sodium dicyanamide (Nadca) and disodium squarate (Na2C4O4) the compounds [Cu2(p-XyDPA)(ClO4)2Cl2] (2), [Cu2(p-XyDPA)(N3)4]·2H2O (3), [Cu2(p-XyDPA)(dca)4]·4H2O (4), and [Cu2(p-XyDPA)Cl2(H2O)2](C4O4)·5.4H2O (5) were obtained, respectively. The complexes were characterized by IR and UV–vis. spectroscopy. The visible spectra of the complexes revealed the square pyramidal geometry around the central Cu2+ ions. The molecular structures of the complexes 2, 3, 4 and 5 were determined by single crystal X-ray crystallography. This study revealed the dinuclear nature of the complexes and showed that the Cu(II) centers have distorted five-coordinate square pyramidal geometry with N3-donor atoms of the dipicolyl amine arms and the remaining coordination positions are occupied by the chloro and perchlorato ligands in 2, the monodentate azido ligands in 3 or the monodentate terminal nitrile dca in 4 and by the chloro and aqua ligands in 5 with the squarate dianion as counter ion.