In this study, a novel NO-type Schiff base ligand (LH) was synthesized via the condensation reaction of 4-(2,5-di(thiophen-2-yl)-1H-pyrrol-1-yl)aniline and 2-hydroxy-1-naphthaldehyde, followed by the preparation of its corresponding Ni(II) complex. The structures of the ligand and its metal complex were comprehensively characterized by elemental analysis, 1 H NMR, FT-IR, UV–Vis spectroscopy, cyclic voltammetry (CV), thermal analysis (TGA/DTA), scanning electron microscopy (SEM), and magnetic measurements. Spectroscopic and magnetic results indicate that the Ni(II) complex adopts a four-coordinated distorted geometry with an ML₂ stoichiometry. Electrochemical investigations reveal that the redox behavior is governed by the conjugated SNS backbone and the imine functionality, confirming the donor–acceptor nature of the system. SEM analysis demonstrates a heterogeneous and porous morphology, which is favorable for ion diffusion and charge transport. Furthermore, metal coordination leads to a decrease in the electrochemical band gap, confirming enhanced charge delocalization and improved electronic properties. These results establish a clear correlation between coordination-induced electronic modulation and electrochemical behavior. In addition, the incorporation of heteroatoms (N, O, and S) within the ligand framework highlights the relevance of main group elements in tuning coordination and electronic properties. Overall, this study provides valuable insights into SNS-based Schiff base systems and demonstrates their potential for electrochemical and optoelectronic applications.
Lacinel et al. (Thu,) studied this question.