Microwave assisted synthesis, photophysical and redox properties of (phenothiazinyl)vinyl-pyridinium dyes

• Microwaves assisted synthesis of N-alkyl-[(10-methyl-10H-phenothiazine-3-yl)vinyl) pyridinium iodide dyes.
• Strong UV–Vis absorptions in 440–470 nm region.
• Day light fluorescence in solid state (610–750 nm region).
• Oxidation potentials ranging between 806 and 889 mV (vs Ag/AgCl) as determined by cyclic voltammetry.
• Oxidative stress of red blood cells.

New cationic cyanine dyes, containing electron donor 10-alkyl-phenothiazine and electron acceptor pyridinium units connected through a vinylene bridge were conveniently synthesized by microwaves assisted condensation of phenothiazine carbaldehyde with methylpyridinium salts in dry media. Their photophysical properties revealing strong absorption bands in 440–470 nm region (ɛ ≈ 104–105) and large Stokes shifts of fluorescence emission (610–750 nm) in solid state were supported by computational data using TDDFT level of theory. The redox behavior of PVP was studied by means of electrochemical and biocatalytical oxidation processes.