Symmetrical diazo compounds comprising 4-pyridinium groups and a cationic or non-cationic linker, compositions comprising them, method for coloring, and device

摘要

Disclosed herein are symmetrical cationic diazo compounds chosen from compounds of formula (I), their resonance forms, their acid addition salts, and their solvates: Also disclosed herein are dyeing compositions comprising such compounds as a direct dye in a medium appropriate for the dyeing of keratin fibers, a method of coloring keratin fibers comprising contacting the keratin fibers with such compositions, and a device comprising a plurality of compartments.