Structural, spectroscopic, magnetic behavior and DFT investigations of l-tyrosinato nickel(ii) coordination polymer

Abstract

New 1D-coordination polymer {[Ni(L-Tyr)₂(μ-4,4′-bpy)]·4H₂O}_n (1) (L-Tyr = L-tyrosine, 4,4′-bpy = 4,4′-bipyridine) is composed of L-tyrosinate anions chelated nickel(II) centres via N amino and O carboxylate atoms, whereas the apices of the elongated octahedral coordination sphere are occupied by the N atoms of 4,4′-bipyridine. Its molecular structure was determined by single-crystal X-ray diffraction and characterized using vibrational (FT-IR), Raman spectroscopy (FT-Raman), electronic (NIR-Vis-UV) and high field electron paramagnetic resonance (HF-EPR) spectroscopy and thermal (TG-DTA, DSC) and magnetic methods. The tetragonality distortion parameter (T) equals 0.945. The g_x, g_y and g_z parameters (HF-EPR spectra) are slightly temperature dependent and the set g_x = 2.178(5), g_y = 2.156(4), g_z = 2.19(1), D = −5.76(2) cm⁻¹, E = −0.41(1) cm⁻¹ was found at 5 K. The analysis of the temperature and field dependent magnetization shows the weakness of magnetic interactions in 1.