Fluorescence-Enhanced Organogels and Mesomorphic Superstructure Based on Hydrazine Derivatives

New low-molecular-mass organic gelators (LMOGs) bearing hydrazine linkage and end-capped by phenyl, namely 1,4-bis[(3,4-bisalkoxyphenyl)hydrozide]phenylene (BPH-n, n = 4, 6, 8, 10), were designed and synthesized. These organogelators have shown great ability to gel a variety of organic solvents to form stable organogels with the critical gelation concentration as low as 8.7 x 10(-4) mol L-1 (0.06 wt %). The formed gel has a high gel sol transition temperature (T-gel) at low gelation concentration. Aggregation-induced emission (AIE) has been observed after gelation though conventional chromophore units not incorporated in BPH-n. The fluorescence quantum yields of xerogel are 2 orders higher than that of dilute solution. In addition, the BPH-n (n = 6, 8, 10) exhibited thermotropic hexagonal column (Col(h)) mesophase, which are stable at room temperature as revealed by differential scanning calorimetry (DSC), polarized optical microscopy (POM), and X-ray diffraction (XRD) studies.