MESOMORPHIC PROPERTIES OF SOME ,8,11,15,18,22,25-OCTA-ALKOXYMETHYLPHTHALOCYANINES

The mesophase behaviour of a number of non-peripherally octa-substitut ed phthalocyanine derivatives has been studied by optical microscopy, differential scanning calorimetry (DSC) and X-ray diffraction. A homol ogous series of straight chain alkoxymethyl derivatives has exhibited both rectangular and hexagonal columnar mesophases, with the rectangul ar phases being favoured by the shorter chains. Two branched chain der ivatives were found to give rectangular columnar phases at room temper ature. A detailed analysis of the X-ray data has shown some difference s from the analogous n-alkyl compounds. It has been deduced that the i ncreased polarizability and flexibility of the ether linkage allows th e disc-like molecules to approach more closely face to face with corre spondingly thicker columns.