Synthesis, spectroscopic investigations, antimicrobial and DNA binding studies of a new charge transfer complex of o-phenylenediamine with 3,5-dinitrosalicylic acid

A charge transfer complex of o-phenylenediamine (OPD) as donor with 3,5-dinitrosalicylic acid (DNSH) as acceptor, was synthesized and characterized by FTIR, 1H NMR, 13C NMR, mass spectroscopy, elemental analysis and X-ray crystallography. The structural investigations exhibit that the cation and anion are joined together by strong N+H⋯O− type hydrogen bonds and stoichiometry of CT complex was found to be 1:1. The CT (charge transfer) complex shows remarkable interaction with Calf thymus DNA, and the CT complex was also screened for its microbial activity such as antimicrobial and antifungal activities. A molecular frame work through H-bonding interactions via n → π* transitions between neighboring moieties is found which is responsible for high melting point of resulting CT complex. This has been attributed to the formation of 1:1 CT complex.

Graphical abstractA new CT complex of o-phenylenediamine and 3,5-dinitrosalicylic acid has been synthesized and characterized by X-ray crystallography. DNA binding interaction studies have also been performed using fluorescence spectroscopy.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► The H-bonded new charge transfer complex has been reported. ► The complex is characterized by various spectral techniques. ► Single-crystal X-ray studies confirmed the H-bonded network. ► DNA-binding studies of CT complex have been performed. ► The CT complex is also screened for antifungal and antibacterial activity.