Organogel Formation by Self-assembly of Ag(I) and Mono-urea Derivatives Containing Pyridyl Group

Abstract

The mono-urea derivative 3 derived from 4-(2-aminoethyl)pyridine and dodecyl isocyanate gelled aromatic solvents, such as p-xylene, tetralin, and benzene, in the presence of Ag(I). The complex formation by the coordination of two equivalents of mono-urea 3 to Ag(I) and the intermolecular hydrogen bonding between urea groups plays important roles for the fibrous self-assembly followed by the gelation.

Rheology and silver nanoparticle templating in a bis(urea) silver metallogel

“…5,6 One elegant way of realising this potential is the design of LMWGs responsive to chemical and physical stimuli, and especially the ''tuning'' of these systems by binding of metal ions and anions is currently gaining momentum. [7][8][9] We have been investigating the combination of urea functionalities (which are well known to afford gelation and anion modulation through the urea a-tape motif) [10][11][12][13][14][15][16] and pyridyl groups (which allow the formation of metallogels) [17][18][19][20] in new gelators with the potential of reversible chemical tuning. 9,21 There has been a considerable recent interest in the templating of metallic and semiconductor nanoparticles by using the gel network not only as a coordinating substrate for pre-prepared nanoparticles, but also as a directing medium for the in situ synthesis of the nanosized materials.…”

Metal-induced gelation in dipyridyl ureas

“…Metal and anion binding can make use of self-assembly in the formation of the gelators themselves, and can also tune gel properties such as photophysics, catalytic activity, redox response and rheology. [7][8][9][10] In our group, we have focused on metal and anion tuning [11][12][13][14][15][16][17] of the rheological properties of the versatile bis(urea) [18][19][20][21][22][23][24][25][26][27][28] class of gelators. By appending metal-binding pyridyl groups to bis(ureas), the primary urea tape hydrogen bonding motif (Fig.…”

Shear induced gelation in a copper(ii) metallogel: new aspects of ion-tunable rheology and gel-reformation by external chemical stimuli

“…[6][7][8] The use of bis(ureas) is well recognized in this context since the urea a-tape motif affords gelation, while at the same time being receptive to modulation of the inter-gelator interactions by anion binding. [9][10][11][12][13][14] Similarly the use of pyridyl groups as metal-binding moieties is a simple way to access metallogels, [15][16][17][18][19][20] amidst a wide range of other metallogel-forming systems. [21][22][23][24][25][26][27][28] However, the combination of these two motifs for potential reversible chemical gel tuning is still quite rare.…”