Synthesis, spectral and mesomorphic properties of octa-alkoxy substituted phthalocyanine ligands and lanthanide complexes

By functionalizing the phthalocyanine (Pc) ring with long aliphatic chains, liquid-crystalline compounds can be obtained. In order to investigate the influence of chain length on mesophase behaviour, we prepared a series of h omologous peripherally octa-alkoxy substituted phthalocyanines. The alkoxy chain length was varied from CH3O to C20H41O. Trivalent lanthanide ions for m with phthalocyanine ligand complexes of the type Pc,Ln, where the lanthan ide ion is sandwiched between two phthalocyanine rings. Hitherto, most of t he mesomorphic Pc(2)Ln complexes described in literature have WHO as the ce ntral metal ion. We prepared lanthanide complexes of peripheral octa-alkoxy substituted phthalocyanines in order to investigate the influence of lanth anide ion on thermal behaviour. The thermal properties of ligands and compl exes were investigated by hot-stage polarising optical microscopy and by di fferential scanning calorimetry (DSC). The metallomesogens exhibit a column ar mesophase. Solution absorption and MCD spectra were also investigated. ( C) 2001 Elsevier Science B.V. All rights reserved.