Green Synthesis of New Tetra Schiff Bases and Bis-Azo Bis-Schiff Bases Derived from 2,6-Diaminopyridine as Promising Photosensitizers

Abstract

Nine new tetra Schiff bases (M 2-M 9) were prepared in moderate yields via the condensation of different aromatic amines and bis-Schiff base (M 1) in microwave synthesizer. Also five new azo-Schiff bases (M 16-M 20) were prepared by the condensation of (M 1) with the azo-salicylaldehyde (M 11-M 15) using the same method. The green synthesis by microwave irradiation was chosen as route due to its novelty, cleanliness, efficiency, time and solvent saving properties compared with the conventional methods which lack these advantages; such as time consume and wasting environment polluting organic solvents to achieve the same efficiency in synthesis. The prepared compounds which are believed by us to be competent as photosensitizers in photochemical systems were identified by IR and NMR spectroscopy besides elemental analysis.

Synthesis, Characterization and Biological Evaluation of Some Azo and Azo-Schiff Compounds

“…These compounds are very stable which makes them suitable to be used in pharmacological and biological researches. Having more than one functional group makes them versatile molecules to be used in different reaction types and a good candidate for stable active photosensitizers [15].…”

Design, Microwave Assisted Synthesis of Some Schiff Bases Derivatives of Congo Red and Conventional Preparation of Their Structurally Reversed Analogous Compounds

“…Synthesis of bis-Schiff bases of Congo red (Glacial acetic acid method) The same procedure was applied replacing DMF by (6 -8) drops of glacial acetic acid. The obtained results are given below: The azo dyes were prepared according to a method similar to that described previously [24]. The obtained results are given below: synthesis was worked out in giving the desired Schiff base derivatives of Congo red in medium to high temperature heating in two separate trials.…”

“…These compounds are already synthesized within a two-step process: In the first step a coupling reaction of a diazonium ion with various substituted aromatic aldehydes is held to form the so called azo-aldehydes. In the second one the carbonyl group of this compound is condensed with alkyl or aryl amines using various chemical ways, such as refluxing [19] [20] [21] [22], fusion [23], irradiating in microwave reactors and others [24]. During the past forty years, numerous mono, bis, tris and tetra azo-Schiff bases were synthesized using traditional as well as green chemistry techniques.…”

“…Subsequently a variety of researches have been published focusing on the biological activity of this sort of organic compounds [22] [25] [26] and considerable progress has been recorded considering their uses as ligands to form advantageous complexes [27] [30]; but a little work is recorded relating to their photophysical properties [23]. In this manuscript we are proceeding our initial studies [24] to synthesize new compounds of this type of organic molecule derived from the biological and photoactive acid-base indicator Congo red and some synthesized analogous compounds as a part of comprehensive strategy to design and prepare what we hope to be energy rich sensitizers in photochemical conversion systems or push pull compounds which may be applied in dye sensitized solar cells.…”

Synthesis of Azo Schiff Base Ligands and Their Ni(II), Cu(II) and Zn(II) Metal Complexes as Highly‐Active Antibacterial Agents

“…Azo schiff bases possessing imine group (C=N) had been used for industrial purposes, such as pigments, intermediates in organic synthesis, polymer stabilizers and for liquid‐liquid extraction . As the azo compounds belongs to new class of chemical compounds, concern towards it increasing in scientific research because of their remarkable applications in many fields . Recent study reported that the incorporation of schiff bases into azo compound enhances the photostability of the synthesized azo schiff base compound as compared with the azo precursor, also there was an shifting in the absorption to the longer wavelength due to azo linkage in the schiff base, this property enables them to be potential photosensitizers in photochemical systems for solar energy conversion method .…”