Luminescent metallomesogens based on platinum complex containing triphenylene unit

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 degrees C. Both platinum complexes exhibit intense emission at about 550 nm in CH2Cl2 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 2.5x10(-4) cm(2) V-1 s(-1) and 2.99x10(-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. (C) 2014 Elsevier Ltd. All rights reserved.