Chemists from RUDN University recently initiated an in-depth analysis on nature of chlorine and nitrogen intermolecular bonds in molecules of azo dyes in a bid to define photochromic properties of azo molecules. The results and analysis is published in the Dyes and Pigments Journal, which reveal significance of halogen and hydrogen intermolecular bonds in stabilizing structure of dyes. The insights and conclusions provided in the research can be used for various categories of azo dyes and in their applications, according to RUDN chemists.
After analyzing the structure of azo dyes, chemists from RUDN University discovered characteristics and positions of intermolecular and intramolecular bonds of nitrogen bonds present on the photochromic base of azo dyes. The bonds existing on the photochromic base of azo dyes had similar characteristic properties and structure to intermolecular bonds inside the molecules. These bonds are developed between molecules. Regardless of their low energy levels, they significantly impacted the spatial space of large molecules, for instance DNA.
Bonds between one atom of chlorine and two nitrogen atoms within the dye molecule were analyzed by the chemists. The analysis revealed that there was high flexibility between chlorine and nitrogen bonds with their position dependent upon the structure of other substituents that are essentially molecule parts attached to the nucleus. The research also revealed that inter-orbital interactive processes and hydrogen bonds fixed the azo dye molecules’ positions in the structure of the crystal.
First stage of research began with six dye samples with varying structures with Nitrobenzaldehyde being used as the first substance for carrying out synthesis. The second stage began with analysis on structure of intramolecular and intermolecular bonds using chemical and physical analytical methods. Techniques used to carry out structure analysis were NMR spectroscopy, UV spectrometry, mass spectrometry and X-ray crystallography. Mass spectrometry and NMR spectroscopy techniques revealed the hydrogen bond characteristics present between molecules of various compounds that are categorized as azo dyes. Study further revealed that structural changes in compounds in difference solvents are caused with changing polarity of environment.
RUDN chemists, with their research, stressed on the significant prominence of non-covalent interactions of intramolecular and intermolecular bonds in development of new azo dyes. These results can be leveraged in development of promising dyes, functional material with vital chemical and physical properties and catalysts, according to RUDN University.
This study can enable scientists to alter structure and position of substitutes and change the dye color and nature of dye’s reaction with solvents and the base. This can be pivotal in development of medicinal drugs, acceleration of reactions and controlling assembly processes of supra-molecules.