| abstract |
The present invention relates to compounds of formula (I) n n ArCH.sub.2 R.sup.1 (I) n n or a monomethyl or a monoethyl ether thereof (the compound of formula (I) including these ethers may contain no more than 30 carbon atoms in total); ethers, esters thereof; acid additon salts thereof; wherein Ar is a perylene or substituted perylene ring system; R 1 contains not more than eight carbon carbon atoms and is a group ##STR1## wherein m is 0 or 1; n R 5 is hydrogen; n R 6 and R 7 are the same or different and each is hydrogen or C 1-3 alkyl optionally substituted by hydroxy; n R 8 and R 9 are the same or different and each is hydrogen or C 1-3 alkyl; ##STR2## is a five- or six-membered saturated carbocyclic ring; R 10 is hydrogen, methyl or hydroxymethyl; n R 11 , R 12 and R 13 are the same or different and each is hydrogen or methyl; R 14 is hydrogen, methyl, hydroxy, or hydroxymethyl. |