Dendritic Effect on Supramolecular Self-Assembly: Organogels with Strong Fluorescence Emission Induced by Aggregation

Abstract

A novel class of dumbbell-shaped dendritic molecules with a p-terphenylene core was synthesized, and their self-assembling properties were investigated. The incorporation of bulky dendritic wedges to the central stiff aromatic scaffolds could finely tune their solubility in many organic solvents. Unlike the self-assembly behavior of p-terphenylen-1,4"-ylenebis(dodecanamide), the p-terphenylene cored different generation dendritic molecules could form gels in several kinds of organic solvents through a cooperative effect of the pi-pi stacking, hydrogen-bonding, and van der Waals forces. Interestingly, significant fluorescence enhancement was observed after gelation. Extensive investigations with atomic force microscopy (AFM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), theological measurements, UV-vis absorption spectroscopy, FT-IR spectroscopy, 1H NMR, and X-ray powder diffraction (XRD) revealed that these dendritic molecules self-assembled into elastically interpenetrating one-dimensional nanostructures in organogels.

Twisted Helical Microfibers by Hierarchical Self‐Assembly of an Aromatic Oligoamide Foldamer

“…These three samples all revealed a peak at 0.42 nm, which supported a less compact stacking mode, as reported in other stacked supramolecular aggregates. [19] In addition, a strong peak was all exhibited at 0.99 nm from those three compounds, which is consistent with the size of the folded frameworks by the crystal data of quinoline tetramer as we got before. [14] The rest two peaks at around 1.67 and 0.86 nm for 1a could correspond to inter-sheet and inter-strand separations respectively, [20] which is also in accordance with the fact that the corresponding distances increased for 1b (1.73, 0.87 nm) and even further for 1c (1.91, 0.90 nm), due to the longer aliphatic chains.…”

Aggregation-induced blue shift of fluorescence emission due to suppression of TICT in a phenothiazine-based organogel

“…[10][11][12][13][14][15]. Notably, the microenvironment around the gelator molecules in the gel phase is very different from that in the solution, so the aggregation-induced novel optical and electrical properties in the gel states based on p-conjugated systems can be expected, such as enhanced charge transfer [16,17], excitation energy transfer [18], and enhanced fluorescence emission [19]. It is well-known that the twisted intramolecular charge transfer (TICT) probe molecules may give color-tunable fluorescence emission depending on the polarity of solvents [20][21][22].…”

Polypeptide dendrimers: Self-assembly and drug delivery

“…For instance, phase behavior of dendritic block copolymers is significantly different from the linear block copolymers [17]. With the functionalization of the peripheral groups, the solubility of dendritic block copolymers was improved, thus led to the improvement of the physical and chemical properties of their aggregates [18]. The worm-like nanoparticles were fabricated by self-assembled dendron/linear/dendron triblock copolymers and used as vectors for drug delivery [19].…”