Sulfamide-Lattice Restructuring To Form Dimensionally Controlled Molecular Arrays and Gel-Forming Systems

Photoirradiation-generated radicals in two-component supramolecular gel for polymerization

While supramolecular gels have been attracting great interest due to their easy design and fabrication, development of new applications based on these gels is always a challenging topic. Here, we report a two-component supramolecular gel that can generate and stabilize radicals through photo-irradiation, which can be subsequently used for polymerization. It has been found that the electrostatic interactions between a cationic amphiphile and anionic sulfonate could afford co-assembly into a two-component supramolecular gel. Upon photo-irradiation, the gel changed colour and produced the radicals, as verified from the EPR measurements. The radical thus formed in the supramolecular gel is relatively stable and could be used to polymerize acrylic acid directly without deoxygenation. In contrast, acrylic acid could not be polymerized in solution under the same conditions. This work expands the application scope of supramolecular gels.

From helical supramolecular arrays to gel-forming networks: lattice restructuring and aggregation control in peptide-based sulfamides to integrate new functional attributes

While supramolecular organisation is central to both crystallization and gelation, the latter is more complex considering its dynamic nature and multifactorial dependence. This makes the rational design of gelators an extremely difficult task. In this report, the assembly preference of a group of peptide-based sulfamides was modulated by making them part of an acid-amine two-component system to drive the tendency from crystallization to gelation. Here, the peptide core directed the assembly while the long-chain amines, introduced through salt-bridges, promoted layering and anisotropic development of primary aggregates. This proved to be very successful, leading to gelation of a number of solvents. Apart from this, it was possible to fine-tune their aggregation using an amphiphilic polymer like F-127 as an additive to get honey-comb-like 3D molecular architectures. These gels also proved to be excellent matrices for entrapping silver nanoparticles with superior emissive properties.

Gel-based supramolecular ON-OFF switch from aryl-triazolyl peptides with excellent chiro-optical, thixotropic, and self-healing characteristics

Systematic structure-property optimization of an achiral gelator (aryl-triazolyl homo dipeptide, 1.0) through a fragment replacement approach led to the identification of a new chiral system (aryl-triazolyl dipeptide 1.4 having leucine as the C-terminal residue) which exhibits consistent and perfectly reversible chiro-optical responses on sol-gel transition that can work like an ON-OFF switch. The gelator 1.4 could also direct the assembly of 1.0 in a sergeant-soldier mode to give similar CD responses. In addition, its gels are mouldable, self-healing and highly thixotropic, making it important from an application standpoint.

Towards a fragment-based approach in gelator design: halogen effects leading to thixotropic, mouldable and self-healing systems in aryl-triazolyl amino acid-based gelators!

A simple replacement of a H atom by Br transformed non-gelating aryl triazolyl amino acid benzyl ester to a versatile gelator, which formed shape-persistent, self-healing and mouldable gels.