Binding analysis of ytterbium(III) complex containing 1,10-phenanthroline with DNA and its antimicrobial activity.

To evaluate the biological preference of [Yb(phen)₂(OH₂)Cl₃](H₂O)₂ (phen is 1,10-phenanthroline) for DNA, interaction of Yb(III) complex with DNA in Tris-HCl buffer is studied by various biophysical and spectroscopic techniques which reveal that the complex binds to DNA. The results of fluorescence titration reveal that [Yb(phen)₂(OH₂)Cl₃](H₂O)₂ has strongly quenched in the presence of DNA. The binding site number n, apparent binding constant K b, and the Stern-Volmer quenching constant K SV are determined. ΔH⁰, ΔS⁰, and ΔG⁰ are obtained based on the quenching constants and thermodynamic theory (ΔH⁰ > 0, ΔS⁰ > 0, and ΔG⁰ < 0). The experimental results show that the Yb(III) complex binds to DNA by non-intercalative mode. Groove binding is the preferred mode of interaction for [Yb(phen)₂(OH₂)Cl₃](H₂O)₂ to DNA. The DNA cleavage results show that in the absence of any reducing agent, Yb(III) complex can cleave DNA. The antimicrobial screening tests are also recorded and give good results in the presence of Yb(III) complex.