Luminescent metallomesogens based on platinum complex containing triphenylene unit

Abstract To explore the influence of mesogenic unit on the liquid crystals and luminescence properties of metal complex, two novel triphenylene-based platinum complexes of TppyPtacac and TppyPtPhacac featuring donor–acceptor framework have been designed and synthesized, in which Tppy is triphenylene–phenylpyridine skeleton and acac/Phacac is pentane-2,4-dione derivative. Differential scanning calorimetry (DSC), polarized optical microscopy (POM) and X-ray diffraction (XRD) techniques demonstrate the complex TppyPtPhacac shows a column mesophase in the region of 55–110 °C. Both platinum complexes exhibit intense emission at about 550 nm in CH 2 Cl 2 solution. Compared to the analogous platinum complexes without triphenylene unit, TppyPtacac and TppyPtPhacac display a remarkable red-shifted emission profiles (ca. 50 nm) due to strong intramolecular charge transfer. Furthermore, the hole mobilities up to 2.5×10 −4  cm 2  V −1  s −1 and 2.99×10 −5  cm 2  V −1  s −1 are achieved for the annealed film of TppyPtacac and TppyPtPhacac, respectively, which is one of the highest hole mobility with respect to cyclometalated platinum complexes.