Perylenophthalocyanines

The first perylenophthalocyanines have been synthesised using a Diels-Alder reaction between dialkylperylenes and fumaronitrile as the key step towards the dinitrile precursors. As expected the octaalkylperylenophthalocyanines show red-shifted absorption spectra. They are high melting solids that do not display mesophase behaviour at accessible temperatures. A 3:1 phthalocyanine/perylenophthalocyanine hybrid material, prepared by a mixed macrocyclisation reaction, presents an unusual board-like molecular profile. Its absorption maxima lie between those observed for the parent phthalocyanines and the symmetrical perylenophthalocyanines. The spectrum shows a characteristic split Q-band due to the reduced symmetry of the core. This material is non-mesogenic but is sufficiently soluble to permit processing and characterisation. The (1)H NMR spectrum indicates that at least two of the appended alkyl chains are displaced out of the macrocycle plane and lie in its shielding region--an arrangement that disfavours the face-to-face packing required for mesophase formation.