Substituted phthalocyanines

Abstract

Substituted phthalocyanines of a formula (I) ##STR1## wherein M is a metal atom or a metal halide or oxide, or M is 2H, one H being bonded to each of the bonding N atoms (29 and 31 positions) shown, R.sub.1 to R.sub.8 are the same or different and are independently selected from C.sub.1 to C.sub.20 alkyl, C.sub.1 -C.sub.20 alkenyl, --X--COO--X.sup.1, --X--O--Y, .alpha., and --X--COZ where X is independently selected from a chemical bond, (--CH.sub.2).sub.n where n=0-20 or (CH.sub.2).sub.n --CH.dbd.CH (--CH.sub.2).sub.b where a and b are independently selected from 0-20 and a+b is in the range 0-20, X.sup.1 is independently selected from C.sub.1 -C.sub.20 alkyl or C.sub.2 -C.sub.20 alkenyl, Y is independently selected from C.sub.1 -C.sub.20 alkyl, C.sub.2 -C.sub.20 alkenyl or H and Z is selected from OH or NR.sup.1 R.sup.11 where R.sup.1 and R.sup.11 are independently selected from H, C.sub.1 -C.sub.20 alkyl and C.sub.2 -C.sub.20 alkenyl, provided that where Y is alkyl and X is a chemical bond at least one of the groups R.sub.1 -R.sub.8 is selected from --X--COO--X.sup.1 and --X--COZ, and further provided that is R.sub.1 -R.sub.8 all contain more than 6 carbon atoms and are all selected from alkyl or --X--O--Y where X is --(CH.sub.2)--.sub.n and Y is alkyl then R.sub.1 -R.sub.8 are not all in the 2, 3, 9, 10, 16, 17, 23 and 24 positions indicated in formula I. These phthalocyanines may exhibit discotic liquid crystal phases, absorb infra-red radiation and make good Langmuir-Blodgett films.