Structural studies of copper(ii) complexes with 2-(2-aminoethyl)pyridine derived Schiff bases and application as precursors of thin organic–inorganic layers

Abstract

Cu(ii) complexes with Schiff bases derived from 2-pyridin-2-ylethanamine were obtained and characterized by UV-Vis, fluorescence, and IR spectra. The X-ray crystal structures determined for [Cu(ii)(epy(di-t-Buba))Cl] × 0.042H2O and [Cu(ii)(epy(di-t-Buba))O2CCH3] revealed tetrahedral distortion of the Cu(ii) coordination sphere in the solid phase. For both molecules the Cu(ii) ions were found in tetragonal environments, as was confirmed by the values of EPR g-matrix diagonal components. The thermal properties of the complexes and the gas phase composition were studied by TG/IR techniques. Thin layers of the studied copper(ii) complexes were deposited on Si(111) by a spin coating method and characterized by scanning electron microscopy (SEM/EDS), atomic force microscopy (AFM) and fluorescence spectra. For copper(ii) layers the most intensive fluorescence band from intra-ligand transition was observed between 498 and 588 nm. The layers' fluorescence intensity was related to the rotation speed and deposition time.

A pair of novel helical Zn(II) enantiomers constructed from l- and d-threonine Schiff bases: Synthesis, crystal structures and properties

“…A small ν(C-O) red shift compared with the free ligands also confirms the naphthol O atom of ligands connected to central metal Zn(II) ions [33]. Moreover, the band of Zn-N stretching vibration was observed at 461 cm −1 for 1 and 2, Zn-O stretching vibration was noted at 567 cm −1 for 1, 568 cm −1 for 2 [33].…”

“…The -C_N [31] peaks of the both complexes are red-shifted compared with the corresponding ligands, indicating the zinc binding by the -C_N group [32]. A small ν(C-O) red shift compared with the free ligands also confirms the naphthol O atom of ligands connected to central metal Zn(II) ions [33]. Moreover, the band of Zn-N stretching vibration was observed at 461 cm −1 for 1 and 2, Zn-O stretching vibration was noted at 567 cm −1 for 1, 568 cm −1 for 2 [33].…”

Copper(II) Schiff base complexes and their mixed thin layers with ZnO nanoparticles

“…6,48 Similar way of coordination was already observed by us in the copper(II) complexes with Schiff bases derived from 2-(2-pyridyl)ethylamine. 23 The shift of the bands from stretching vibrations of the azomethine group in all the compounds and the presence of specific bands of the Cu-Cl or COO − asym / sym vibrations in the spectra of particular complexes indicated the correctness of the proposed coordination sphere.…”

“…Similar behavior was registered by us for layers of copper(II) complexes with Schiff bases derived from 2-(2-aminoethyl)pyridine. 23 Materials formed with [Cu(en(4Him) 2 )Cl 2 ] (2a)/Si were excited at 365 nm. In all cases, the emission from intraligand π → π* transitions at 462 nm was observed.…”

“…Previously, copper(II) and nickel(II) complexes with optically active Schiff bases derived from (1R, 2R)(-)cyclohexanediamine or 2-(2-aminoethyl)pyridine were deposited by us on silicon or glass using the spin coating method. [21][22][23] The obtained thin materials exhibited fluorescence, which depends on the spin coating parameters and the molecular structure of the complexes.…”