Synthesis, Characterization, and BSA-Binding Studies of Novel Sulfonated Zinc-Triazine Complexes

Abstract

Four Zn(II) complexes containing a pyridyl triazine core (<i>L</i>1 = 3-(2-pyridyl)-5,6-di(2-furyl)-1,2,4-triazine-5',5″-disulfonic acid disodium salt and <i>L</i>2 = 3-(2-pyridyl)-5,6-diphenyl-1,2,4-triazine-4',4″-disulfonic acid sodium salt) were synthesized, and their chemical formulas were finalized as [Zn(L1)Cl₂]·5H₂O·ZnCl₂ (<b>1</b>), [Zn(L1)₂Cl₂]·4H₂O·2CH₃OH (<b>2</b>), [Zn(L2)Cl₂]·3H₂O·CH₃OH (<b>3</b>), and [Zn(L2)₂Cl₂] (<b>4</b>). The synthesized complexes are water soluble, making them good candidates for biological applications. All four complexes have been characterized by elemental analysis and ¹H NMR, IR, and UV-Vis spectroscopy. The IR stretching frequency of N=N and C=N bonds of complexes <b>1</b>-<b>4</b> have shifted to lower frequencies in comparison with free ligands, and a bathochromic shift was observed in UV-Vis spectra of all four complexes. The binding studies of ligands and complexes <b>1</b>-<b>4</b> with bovine serum albumin (BSA) resulted binding constants (<i>K</i>_b) of 3.09 × 10⁴ M^-1, 12.30 × 10⁴ M^-1, and 16.84 × 10⁴ M^-1 for ferene, complex <b>1</b>, and complex <b>2</b>, respectively, indicating potent serum distribution via albumins.