Comprehensive Experimental and DFT‐Based Theoretical Analysis of a Novel Cobalt(II) Complex : Structural Characterization and Optical Properties

This work aims to investigate a novel structure based on 1-methylpiperazine cation [Co(NCS)4(OH2)2]·(C5H14N2)·H2O. The novel complex, 1-methylpiperazine-1,4-diium diaquatetrakis (thiocyanato)-cobalt hydrate, was investigated using DRX, differential thermogravimetry analysis, FTIR, UV–vis, impedance complex analysis, and density functional theory (DFT). Based on the reported results of these characterization tools, the desired complex phases were confirmed. In the title compound, the aromatic ring in the cationic entity adopts a slightly distorted chair conformation, which ensures coordination stability. FTIR analysis were occurred, which supported the presence of surface ligand groups of thiocyanates, and UV–vis spectroscopy of the electronic transition. Explorations of impedance spectroscopy on [Co(NCS)4(OH2)2]·(C5H14N2)·H2O reveal a fascinating electrical behavior which reveals that the Co complex component can be used as an electronic chip and under certain conditions. The electronic structure and optical properties of the complex were explored using the DFT, confirming it as a direct bandgap semiconductor with a predicted bandgap of 2.89 eV. Optical anisotropic features of the complex, aligning with its monoclinic structure, were identified via analysis of the dielectric function across the [100], [010], and [001] crystallographic directions. The thermal analysis was used to confirm the crystal thermal stability.