Mixed-ligand Co(II) and Pd(II) schiff base–phenanthroline complexes: structural, thermal, DNA binding, and catalytic studies

OpenAlex İngilizce

In this study, a Schiff base ligand (Sadpa) was synthesized and subsequently employed for the preparation of mixed-ligand Co(II) and Pd(II) complexes containing 1,10-phenanthroline. The resulting complexes were comprehensively characterized using complementary physicochemical techniques. In addition, DFT calculations were performed to elucidate the electronic structure, chemical reactivity, and electrostatic properties of both complexes. DNA binding interactions were investigated using both UV–Vis spectrophotometric and electrochemical methods, confirming effective interactions of both complexes with DNA. Spectrophotometric measurements yielded binding constants of 9.40 × 105 M−1 for the SadpaPhen–Co complex and 6.45 × 106 M−1 for the SadpaPhen–Pd complex. Consistent with these findings, electrochemical studies afforded binding constants of 1.0 × 105 M−1 and 1.2 × 106 M−1 for the SadpaPhen–Co and SadpaPhen–Pd complexes, respectively. The significantly stronger DNA-binding affinity of the Pd(II) complex is in good agreement with the DFT results, which indicate enhanced electronic flexibility and greater chemical reactivity compared with its Co(II) analog. Furthermore, the complexes were evaluated as catalysts for the microwave-assisted transfer hydrogenation of D-glucose to D-sorbitol. Among the investigated compounds, the Pd(II)–Sadpa–phenanthroline complex exhibited outstanding catalytic performance, achieving 98.62% glucose conversion with 99.23% selectivity toward sorbitol and negligible mannitol formation.