3H-Indolium,5,6-dicyano-2-[2-[2-[[5,6-dicyano-1,3-dihydro-1-(2-methoxy-2-oxoethyl)-3,3-dipropyl-2H-indol-2-ylidene]ethylidene]-2H-1-benzopyran-4-yl]ethenyl]-1-(2-methoxy-2-oxoethyl)-3,3-dipropyl-, perchlorate