Syntheses of Novel Triphenylene-Aminoanthraquinone Dimers and Studies on Their Mesomorphic and Fluorescence Properties

Two novel triphenylene-aminoanthraquinone dimers 4a and 4b were synthesized by reacting triphenylene carboxyl derivatives 3a or 3b with 2-aminoanthracene-9,10-dione in yields of 80% and 78%, respectively. Their structures were confirmed by 1H NMR, electrospray ionization (ESI-MS), and elemental analysis. Their mesomorphic properties were studied by diffraction scanning calorimetry (DSC), polarizing optical microscopy (POM), and x-ray diffraction (XRD). The mesomorphic results suggested that they possess excellent mesophase properties. The investigation of fluorescence properties indicated that the strong cooperating fluorescence actions exist between two structural units. The fluorescence of dimers 4a and4b are seriously quenched due to the electron transfer from donor (triphenylene unit) to acceptor (aminoanthraquinone unit).