<i>In</i><i>situ</i> synthesis, characterization, bovine serum albumin (BSA) binding studies of Fe<sup>II</sup>/Co<sup>II</sup>/Ni<sup>II</sup> complexes derived from a new double bis-triazole macrocyclic ligand

<p>The design and synthesis of macrocyclic ligands has become a hot research field of coordination chemistry for their novel structures and intriguing properties. Starting from bis (5-amion-1H-1,2,4-triazole) ligand (<i>L</i><sup>1</sup>), three macrocyclic complexes with a novel double bis-triazole macrocyclic ligand (<i>L</i><sup>2</sup>), [MCl<sub>2</sub>L<sup>2</sup>] (M = Fe, Co, Ni), were designed and synthesized by <i>in situ</i> reaction. In the process of reaction, metal ions played a key role for contributing to the formation of novel macrocyclic structures. The molecular structures of complexes were characterized by single-crystal X-ray diffraction, and the detailed description of synthesis is presented in this paper. The fluorescence quenching spectra and UV–vis spectra were used to study the interaction of complexes with bovine serum albumin (BSA). The results showed that the fluorescence quenching of BSA by these complexes was the presence of static quenching.</p>