5 pagesInternational audienceFourfold 2,3,6,10-alkoxycarbonyl-substituted triphenylenes are synthesised in five concise steps from 4-methylcyclohexanone by selective monoformylation of 2,6,10-trimethyltriphenylene, followed by oxidation in aqueous dichromate solution. Their low symmetry leads to mesogenic self assembly in a columnar liquid-crystalline state at or near room temperature, depending on the choice of alkyl group. These materials unite several properties that are desirable in charge-transporting thin films for organic optoelectronics: room-temperature self assembly into structures of good charge mobility and high viscosity, low electron density in the aromatic core, smooth synthetic access, optical transparenc

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Metal-free and metal(II) all-endo-tetraalkoxy-phthalocyanines of C4h symmetry are synthesised regiospecifically from 3-(2-butyloctyloxy)phthalonitrile with lithium octanolate and subsequent metal ion exchange. The voluminous, yet not overly large, and racemically disordered alkoxy substituent not only renders the cyclotetramerisation regiospecific, but also leads to liquid crystalline self-assembly with attainable clearing temperatures and persisting columnar organisation at room temperature. A rare hexagonal mesophase with twelve columns per hexagonal unit cell is found in the metal-free homologue, whereas the metal complexes show rectangular mesophases. The clearing temperature increases with increasing axial component of the metal ion coordination sphere. At low temperature, significant antiferromagnetic exchange between magnetic centres is observed for the Co(II) homologue, whereas the magnetic centres are magnetically independent in the Cu(II) derivative, in line with the observed higher clearing temperature in the Co(II) case that testifies of stronger interdisk interactions.