Peripherally Dimethyl Isophthalate-Functionalized Poly(benzyl ether) Dendrons: A New Kind of Unprecedented Highly Efficient Organogelators

Abstract

A series of poly(benzyl ether) dendrons, up to the fourth generation, decorated in their periphery with dimethyl esters were divergently synthesized and fully characterized. These dendrons were found to be unprecedented highly efficient organogelators toward various aromatic and polar organic solvents with the critical gelator concentration (CGC) approaching 2.2 mg/mL. The gelation ability was found to be highly dependent on the nature of the peripheral groups, dendron generation, and the dendritic architecture. The large monodisperse dendron G(4) with a globular shape could also form stable gels in several aromatic solvents with relatively high CGCs. A number of experiments (SEM, TEM and AFM imaging, X-ray crystal structure analysis, concentration- and temperature-dependent (1)H NMR spectroscopy, fluorescence spectroscopy, and powder X-ray diffraction) confirmed the self-aggregation of these dendrons, despite the lack of any conventional gelating motifs such as amides, long alkyl side chains, and steroidal groups. The multiple strong pi-pi stacking interactions due to the peripheral dimethyl isophthalate rings and the internal benzyl rings are found to be the key contributor in forming the self-assembled gel.

Augmenting Photoinduced Charge Transport in a Single‐Component Gel System: Controlled In Situ Gel–Crystal Transformation at Room Temperature

“…Therefore, extending this concept to any potential application is hitherto unknown. Unlike molecular gelators having traditional long alkyl chains, the structural uniqueness of acyl hydrazine‐linked lower generation of poly(aryl ether) (PAE) dendrons (Frèchet type) can pre‐program the molecular self‐assembly to well‐control the desired maximal electronic coupling of o ‐benzoxy rings, driven through H‐bonding interactions . Despite being used for diverse applications in soft matter research, the optoelectronic response of novel poly(aryl ether) dendron‐based gel systems remains untouched till date.…”

Poly(benzyl ether) dendrons without conventional gelation motifs as a new kind of effective organogelators

“…Based on all the above experimental evidences and our previous study on peripherally dimethyl isophthalate-functionalized dendritic analogues [24], the extended aromatic plane consisting of the IPN ring and the benzyl ring at the periphery of the dendritic gelators could be served as a new type of gelation "motif " to improve multi-intermolecular interactions. Thus, the principal multiple strong - aromatic stacking interactions, together with hydrogen bonding and solvophobic interactions, might best explain the origin of this unique gelation capability of these poly(benzyl ether) dendrons without bearing any conventional gelation motifs.…”

“…The dendrons G n -CH 2 OH (n=0,1) were synthesized according to previously reported synthetic procedures [24,30]. The synthesis route of G m -CN (m=1,2) is shown in Scheme 1.…”

“…According to our previous methods [24,30], a series of peripherally isophthalonitrile-functionalized poly(benzyl ether) dendrons were divergently synthesized by using Mitsunobu reaction between the first-and second-generation dendritic alcohols with commercially available 5-hydroxyisophthalonitrile in 70% and 85% yields, respectively. Their chemical structures and purities were confirmed by 1 H NMR, 13 C NMR and HR-ESI mass spectroscopy as well as elemental analysis.…”

“…However, it remains a great challenge to date in the design of effective dendritic organogelators with no conventional gelation motifs such as peptide and long alkyl chains [22,23]. We previously reported a series of peripherally dimethyl isophthalate-functionalized poly(benzyl ether) dendrons, which could act as a highly efficient dendritic organogelator despite the lacking of any conventional gelating motifs [24,25]. The multiple strong - stacking interactions due to the peripheral dimethyl isophthalate motifs and non-typical hydrogen bonding were found to be the key contributor in forming the self-assembled gel.…”