Copper(II) complexes with substituted iminodiacetic acid and N-heterocyclic ligand:: Crystal structures of [Cu(Heida)(Bipy)]•2H2O, [Cu(Heida)(Im)2]•H2O, and [Cu(Bida)(Im)2]•0.5Im

The crystal structures of the mixed-ligand compounds [Cu(Heida)(Bipy)] . 2H(2)O (I), [Cu(Heida)(Im)(2)] . H2O (II), and [Cu(Bida)(Im)(2)] . 0.5Im (III) (RI = 0.0386, 0.0280, and 0.0195 from the 3181, 2627, and 3796 reflections with I > 2 sigma (I) for I-III, respectively) were determined. The Cu atoms form mononuclear complexes in I-III. The hexacoordinated complexes I and ii have similar structures but differ by several geometric parameters. Three O atoms and the N atom of the Heida(2-) ligand, as well as two N atoms of the Bipy molecule in I and of two Tm molecules in II, are involved in Cu coordination. The Cu-O-COO and Cu-O-OH axial bonds are elongated asymmetrically (2.284 and 2.546 ) in I and Angstrom almost equally (2.415 and 2.445 Angstrom) in II. The crystals of III are built of pentacoordinated complexes and disordered imidazole molecules. Compared to I and II, the copper environment in III lacks the O atom of the hydroxyethyl group. The Cu-O-COO axial bond length is 2.288 Angstrom. The systems of II-bonds form frameworks in I and II and doubled chains of complexes in III.