X-ray structure and magnetic and fluorescence characteristics of new Cu(ii) complexes with Schiff bases derived from 2-(2-aminoethyl)pyridine and 2-hydroxy-1-naphthaldehyde; morphology and fluorescence of their thin films

Abstract

Cu(II) complexes with tridentate Schiff bases derived from 2-(2-aminoethyl)pyridine and 2-hydroxy-1-naphthaldehyde and COO⁻, Cl⁻ and NO₃⁻ as ligands were obtained and characterized by crystal and molecular, spectroscopic (UV-Vis, fluorescence, IR, and EPR), magnetic and thermal methods. The X-ray crystal structure analysis revealed a distorted square planar geometry for [Cu(II)(PEMN)CH₃COO]CHCl₃, 1, and [Cu(II)(PEMN)Cl], 2, and a distorted square-pyramidal geometry for [Cu(II)(PEMN)NO₃], 3, corresponding to the values of EPR g-matrix diagonal components. The copper(II) complexes exhibited fluorescence in solution in the range of 370–410 nm. Thin layers of the studied copper(II) complexes were deposited on Si(111) by a spin coating method and studied by scanning electron microscopy (SEM/EDS), atomic force microscopy (AFM) and fluorescence spectroscopy. For copper(II) layers (2/Si), the most intense fluorescence band from an intraligand and a d–d transition between 490 and 550 nm was observed.