Pyrene-based macrocyclic system with tetramethoxy resorcinarene functionalization: applications in liquid crystals and bioimaging study

The development of multifunctional fluorescent materials is of growing interest for advanced bioimaging applications, where stability, permeability, and high signal intensity are critical. This work reports the design and synthesis of tetramethoxy resorcinarene-based macrocycles (TMRP 1 –TMRP 4 ) bearing four-side substituted aroylhydrazone groups at the lower rim. The key synthetic step leading to these macrocycles proceeded in good yields (70–76 %), and the compounds were fully characterized by IR, 1H and 13C NMR, MALDI-TOF, and elemental analysis. All four macrocycles adopt a crown conformation and exhibit enantiotropic nematic liquid crystalline phases with broad mesophase ranges and higher thermal stability. A detailed structure property investigation highlights the influence of variable alkyl side chain on mesogenic behavior. The photophysical investigations demonstrate high fluorescence intensities in solution, thin film, and AIE state. Among them, the nonyl-substituted derivative TMRP 4 demonstrated excellent performance in nematode cell imaging, showing high cellular uptake, strong fluorescence intensity, and good selectivity without interference from crystallization or precipitation. These findings establish pyrene-functionalized resorcinarene macrocycles as promising candidates for bioimaging, combining robust mesophase stability with advantageous optical properties.