Phthalocyanines

Abstract

A phthalocyanine of Formula (1): ##STR1## wherein: M.sub.k PC iS a phthalocyanine nucleus of Formula (2): ##STR2## M is a metal atom, a chloro-metal group, and oxy-metal group or hydrogen; k is inverse of 1/2 valency of M; R and R.sup.1 each independently is an organic radical; R.sup.2 is H or optionally substituted alkyl; a is an average value from 15 to 8; b is an average value from 1 to 8; and a+b is from 15 to 16; and sulphonated derivatives thereof and process for their preparation. The phthalocyanines of the present invention are useful for absorbing electro-magnetic radiation from for example a laser source and may be used in a coating for optical data storage disks, or in security applications such as printing banknotes or checks, or in the preparation of lithographic printing plates or in washing powders to assist in bleaching.

Dependencies are inferred from the claim text.