Photophysical characterization of novel dipyrrine compounds based on pyrrolic hydrogen transfer

•Dipyrromethene compounds exhibited the red-shifted absorption degending on solvent and pH. The synthesized compounds were different in color in polar protic solvent, such that there was about 50 nm bathochromic shift in the absorption spectrum of the dyes in ethanol.•The use of phenyl substituted pyrrole derivatives causes an increase in the yield of dipyrromethene synthesis.•Electron donating methoxyphenyl groups at -α and -β positions of the dipyrrin skeleton were found to cause bathochromic shift in the absorption wavelengths of the compounds. In this work, we introduced novel dipyrromethene dyes which were synthesized in good yields from 2,4-diphenyl substituted pyrroles and aromatic aldehydes. The resulting structures were elucidated by NMR, FTIR and HRMS techniques. The absorption behaviors of the synthesized dipyrromethenes in various solvents and pH media were investigated by means of UV/Vis spectroscopy. It has been observed that the compounds with dipyrromethene skeleton respond very sensitively to pH changes in visible region. The compounds have two identical colors that vary according to the solvent and pH changings depending on pyrrolic proton. Their colors are dark green in the acidic region and vivid purple in the basic media. Presented study is important for the use of aryl substituted dipyrromethene compounds as dyes for colorimetric sensoric applications, as well as for the rational design of new dyes. [Display omitted]