Synthesis, Characterisation and Nonlinear Optical Properties of Two‐Dimensional Octupolar Systems Based on Phthalocyanine Compounds

Four phthalocyanine‐based compounds with pseudo D3h symmetry have been synthesised and fully characterised. Palladium cross‐coupling methodologies were employed in order to synthesise 1,3,5‐tris[(phthalocyaninyl)ethenyl]benzene (Heck) and 1,3,5‐tris[(phthalocyaninyl)ethynyl]benzene (Sonogashira) derivatives. Knoevenagel condensation conditions were then applied to the synthesis of 1,3,5‐tris[cyano(phthalocyaninyl)ethenyl]benzene and 2,4,6‐tris[(phthalocyaninyl)ethenyl]‐1,3,5‐triazine. Preliminary second‐order nonlinear optical studies, by hyper‐Rayleigh scattering measurements, revealed that the compounds containing ethenyl linkers induce a strong octupolar effect while the ethynyl‐containing compound does not show any octupolar enhancement. The introduction of a triazine central core does not modify significantly the nonlinear optical behaviour of the compound. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)