Cation-dependent structural diversity of zinc(II), calcium(II) mono- and binuclear complexes of aryl-imidazo-1,10-phenanthroline derivatives
Abstract
The syntheses of azacrown-containing aryl-imidazophenanthroline by reaction of 1,10-phenanthroline-5,6-dion with 4-(1.4.7.10-tetraoxa-13-azacyclopentadecan-13-yl)benzaldehyde producing the ligand 2 in high yield is described. Examination of their Zn(II), Ca(II) and mixed complexes by UV/Vis and NMR spectroscopy suggests electronic communication between the two metal centers of ligand 2. Stability constants, determined by spectrophotometric titration, indicate that the Zn(II) possesses higher affinity toward phenanthroline residue than Ca(II) and does not bind with azacrown-ether residue. This selectivity allows to prepare a mixed Zn(II)/Ca(II) complex. (C) 2016 Elsevier B.V. All rights reserved.