Multiple Stimuli-responsive Gel Of Small Organic Molecules And Functional Complexes

In this paper, we investigatived multi-stimuli-responsive behavior of multi-stimuli-responsive materials by using organic small molecular gel and functional complexes. In first part, we synthesized a series of chiral aryl amide compounds bearing peptide pendants which have been investigated as low molecular weight gelators. A mechanistic study revealed that complementary hydrogen bonding from peptide pendants was the main driving force for the formation of organogels. This new class of organogels could exhibit multi-stimuli-responsive behavior upon applying (1) thermal, (2) pH, (3) enantiomeric purity, and (4) fluoride anion stimuli. Enantiomeric purity as a new external stimulus displays sensitive stimuliresponsiveness; only 0.02 equiv. of the enantiomer can completely disassemble the gel aggregate. They will serve as excellent smart materials with potential applications in chiral sensors, recognition, and separation. In second part, we report the investigation of a mononuclear spin-crossover complex [Fe?L2][ClO4]2 (L= 2,6-bis-{4,4-dimethyl-4,5-dihydrooxazol-2-yl}pyri-dine). This compound undergoes a structural phase transition around 173 K, accompanying with an abrupt spin-transition process. Interestingly, it exhibits a multi-induced spin-crossover behavior mediated by heat, light, pressure and solvent.