Synthesis, structural, spectroscopic and electric/dielectric studies of a nanocrystalline Ni(ii) complex based on...

A Ni²⁺ nanocomplex based on a heterocyclic ligand containing a pyrazole moiety was developed in this work, and its electric conductivity and dielectric characteristics were studied. The Ni²⁺ nanocomplex with the general formula [Ni(PyT)₂(H₂O)₂]Cl₂·½H₂O, where PyT = [(1,3-diphenyl-1H-pyrazol-4-yl)methylene]thiocarbonohydrazide, was characterized using various techniques, including elemental and thermal analyses, as well as conductivity, magnetism, TEM, and spectroscopic (FT-IR, UV-Vis and XRD) studies. The results showed that PyT was bonded to the Ni(ii) centers via a neutral bidentate ligand, resulting in an octahedral-shaped, thermally stable mononuclear complex. The frequency response of the dielectric properties and ac conductivity was studied in the range from 200 Hz to 6 kHz. Both dielectric constant and dielectric loss decreased with increasing frequency. In addition, the effect of temperature was investigated in the range of 294.1-363.4 K. The ac conductivity increased with increasing temperature in the range of 294.1-333.5 K. The ac conduction is described as correlated barrier hopping between non-intimate valence alternation pairs. Furthermore, the PyT and Ni(PyT) nanocomplex structures were optimized using theoretical calculations and DFT computations.