A modified route to unsymmetrically substituted triphenylenes, new functionalised derivatives and twins, and the smallest reported triphenylene mesogen

We report the unexpected observation of columnar mesophase formation in a simple 2,7-dibromotetramethoxytriphenylene – by far the most lightly substituted discotic mesogen in this class. This derivative was prepared alongside the 3,6-dibromotriphenylene isomer to demonstrate an alternative, modified synthetic strategy that permits late-stage interchange of alkyl chain substituents. The new method is employed alongside the original route to deliver several new materials, including a conjugated ferrocene-triphenylene-ferrocene triad, a BODIPY-triphenylene-BODIPY triad and a new nematic twin linked through imine bridges.