Nir dyes, methods of preparing them and their use

Abstract

The compounds of the formula I ##STR1## in which Y and Y.sub.1 are each, independently of one another, O, S, NH or N-alkyl, N-cycloalkyl, N-phenyl or N-benzyl, or Y and Y.sub.1 are together N-alkylene-N, R and R.sub.1 are each, independently of one another, H, alkyl, cycloalkyl, aralkyl or aryl, R.sub.2 and R.sub.3 are each, independently of one another, H, or R.sub.2 forms, together with R.sub.6 and the N and C atoms linking them, a 5- or 6-membered ring and R.sub.3 is H, or R.sub.3 forms, together with R.sub.7 and the N and C atoms linking them, a 5- or 6-membered ring and R.sub.2 is H, R.sub.4 and R.sub.5 are each, independently of one another, H, R.sub.4 forms, together with R.sub.8 and the N and C atoms linking them, a 5- or 6-membered ring and R.sub.5 is H, or R.sub.5 forms, together with R.sub.9 and the N and C atoms linking them, a 5- or 6-membered ring and R.sub.4 is H, R.sub.6, R.sub.7, R.sub.8 and R.sub.9 are each, independently of one another, H, alkyl, cycloalkyl, aralkyl or aryl, or R.sub.6 and R.sub.8 and/or R.sub.7 and R.sub.9 form, together with the N atom linking them, a piperidine radical, a morpholine radical or an unsubstituted piperazine radical or a piperazine radical substituted on the N atom by C.sub.1 -C.sub.4 alkyl, hydroxyl-C.sub.1 -C.sub.4 alkyl or amino-C.sub.1 -C.sub.4 alkyl, Z is H or aryl and An.sup..crclbar. is an anion of a monobasic acid, the alkyl or cycloalkyl being unsubstituted or substituted by halogen, hydroxyl, C.sub.1 -C.sub.4 alkoxy, cyano or phenyl, and the aryl or aralkyl being unsubstituted or substituted by halogen, hydroxyl, NH-alkyl, N(alkyl).sub.2, C.sub.1 -C.sub.6 alkyl, C.sub.1 -C.sub.4 alkoxy, carboxyl, alkoxycarbonyl, carbonamido, mono- or dialkylcarbonamido, nitro or CN, are suitable as light-absorbing substances in optical recording media.