Crystal structure characterization as well as theoretical study of spectroscopic properties of novel Schiff bases containing pyrazole group

Synthesis, characterization, and DNA binding study of ruthenium(II/III) complexes containing ONS donor Schiff base

A chelating ligand of thioether with ONS donor Schiff base HL [(E)-2-(((2-(benzylthio)phenyl)imino)methyl)napthalen-1-ol] and its metal complexes (RuL₁ and RuL₂) have been synthesized. They have been characterized by UV-Vis, FTIR, ¹H NMR, ¹³C NMR, mass spectrometry methods. The formulas of the synthesized compounds have been confirmed by elemental analysis and magnetic susceptibility measurements. The binding ability studies of the ligand (HL) and its Ru complexes (RuL₁ and RuL₂), with calf-thymus DNA have been explored by the absorption titration method. The binding interaction study reveals that the ligand (HL) and the complex RuL₁ interact with CT-DNA through an intercalative mode of binding whereas the complex RuL₂ does not show any interaction with CT-DNA due to steric effect.

Synthesis of quinoline derivatives containing pyrazole group and investigation of their crystal structure and spectroscopic properties in relation to acidity and alkalinity of mediums

Two series of quinoline derivatives containing pyrazole group were synthesized and characterized by means of (1)H NMR, FT-IR, MS, elemental analysis and X-ray single crystal diffraction, and their UV-vis absorption behavior and fluorescence properties were also measured. Moreover, the effects of acetic acid and triethylamine on the spectroscopic properties of synthesized products were examined with compounds 3a and 5a as examples. It has been found that all synthesized quinoline derivatives show maximum absorption peak at 303 nm and emission peaks around 445 nm. Besides, both acetic acid and triethylamine can change the acidity of the medium, thereby influencing the UV-vis absorption spectra and fluorescence spectra of synthesized products. Moreover, theoretical investigations indicate that the integration of H(+) and N atom of quinoline ring favors the formation of a new product in the presence of acetic acid, and the product obtained in this case shows a new UV-vis absorption peak at 400 nm.