Coordination Polymer Gels with Modular Nanomorphologies, Tunable Emissions, and Stimuli-Responsive Behavior Based on...

The recent upsurge in research on coordination polymer gels (CPGs) stems from their synthetic modularity, nanoscale processability, and versatile functionalities. Here we report self-assembly of an amphiphilic, tripodal low-molecular weight gelator (L) that consists of 4,4',4-[1,3,5-phenyl-tri(methoxy)]-tris-benzene core and 2,2':6',2″-terpyridyl termini, with different metal ions toward the formation of CPGs that show controllable nanomorphologies, tunable emission, and stimuli-responsive behaviors. L can also act as a selective chemosensor for Zn^II with very low limit of detection (0.18 ppm) in aqueous medium. Coordination-driven self-assembly of L with Zn^II in H₂O/MeOH solvent mixture results in a coordination polymer hydrogel (ZnL) that exhibits sheet like morphology and charge-transfer emission. On the other hand, coordination of L with Tb^III and Eu^III in CHCl₃/tetrahydrofuran solvent mixture results in green- and red-emissive CPGs, respectively, with nanotubular morphology. Moreover, precise stoichiometric control of L/Eu^III/Tb^III ratio leads to the formation of bimetallic CPGs that show emissions over a broad spectral range, including white-light-emission. We also explore the multistimuli responsive properties of the white-light-emitting CPG by exploiting the dynamics of Ln^III-tpy coordination.