Effect of substituent position on optical properties of boron-dipyrromethane isomers

• New constitutional isoelectronic BODIPY isomers were synthesized and studied.
• The effect of conformational changes was evident from their optical profiles and change in 19F NMR spectra.
• Solution state behaviors were straightforward, compound 3 showed more fluorescence quantum yield followed by 2 and then 1.
• The most flexible isomer does not show π–π stacking interactions in the solid state.

Three isomeric meso-SiMe3C6H4 substituted BODIPYs have been synthesized and their optical properties studied. The constitutional isomers show similar absorption properties but vastly different emissive properties as a result of their different conformational flexibility. Fluorine-19 NMR study is used to unravel the conformational state of the BODIPY isomers at a molecular level.

Three isomeric meso-SiMe3Ph substituted BODIPYs were synthesized and studied. The constitutional isomers show similar absorption properties but vastly different in their emissive properties. The different emissive nature of the molecules was found to be resulting from their different conformational flexibility.19F NMR study was employed to understand the conformational state of the BODIPYs at molecular level.Figure optionsDownload as PowerPoint slide