Diiodinated Mono- and Dipyridylvinyl BODIPY Dyes: Photophysicochemical Properties, in vitro Antibacterial Studies, Molecular Docking and Theoretical Calculations.

In this study, novel mono- and dipyridylvinyl boron dipyrromethene dyes are prepared to compare their photodynamic antimicrobial chemotherapy (PACT) activities against Staphylococcus aureus to the corresponding core dyes. Pyridylvinyl substitution at the 3- or 3,5-positions of a meso-4-bromophenylBODIPY core dye via a Knoevenagel reaction with an aromatic 2-bromopyridinecarboxaldehyde shifts the major BODIPY spectral band to longer wavelength. The extended π-conjugation red shifts the main spectral band into the 602-618 nm region in CHCl 3 , THF, ethanol and DMSO after monopyridylvinyl substitution and to 685-704 nm after dipyridylvinyl substitution. An enhancement of the population of the T 1 state through the incorporation of iodine atoms at the 2,6-positions results in moderately high singlet oxygen quantum yields in DMSO. The π-extended dyes were found to have significantly lower PACT activities than the diiodinated core dye.