3H-Indolium,2-[7-[1,3-dihydro-1-(2-hydroxyethyl)-3,3-dimethyl-2H-indol-2-ylidene]-4-(diphenylamino)-1,3,5-heptatrienyl]-1-(2-hydroxyethyl)-3,3-dimethyl-,perchlorate (salt) [ 95736-59-7 ]