Helical ribbons tuned by alkoxy chains in achiral twin-tapered dihydrazide derivatives

Abstract

Achiral twin-tapered dihydrazide derivatives n = 3, 4, 5, 6, 7, 8, 10) are effective gelators in ethanol. The gelling ability in ethanol, the morphologies, packing structures and intermolecular H-bonding strength were significantly influenced by the length of the alkyl chains. FH-T6 and FH-T7 showed strong gelation ability in ethanol with critical gelation concentrations of 2.1 Â 10 À3 mol L À1 and 2.1 Â 10 À3 mol L À1 , respectively. Both left-and right-handed helical ribbons with non-uniform helical pitch were observed in FH-Tn (n = 5, 6, 7) gels.

Ultrasound-induced controllable morphology and growth dimension in a dihydrazide-based self-assembly system

“…As reported in our previous work, 20 both FH-T5 and FH-T6 showed strong gelation ability only in ethanol, although slowly, in a traditional heating-cooling process (designated as the Tgel, shown in Fig. 1).…”

“…The gelators FH-T5 and FH-T6 were synthesised as described elsewhere. 20 All chemicals were of laboratory reagent grade and used without further purication.…”

“…Considering that gelators with hydrogen bonding interactions may be prone to be sonication-sensitive, in this work we choose the twin-tapered derivatives, oxalyl acid N,N-di(3,4,5trialkoxybenzoyl)-hydrazide (FH-Tn, Scheme 1), 20 which may generate multiple hydrogen bonds, as the gelators. To the best of our knowledge, this is the rst example related to ultrasoundinduced morphology and property changes due to changes of environmental parameters and this study also opens a door for the development of responsive so materials.…”

Photo-induced fiber–vesicle morphological change in an organogel based on an azophenyl hydrazide derivative

“…1 Supramolecular self-assembly is the spontaneous process of molecular aggregation into ordered nanostructures and provides a bottom-up approach to obtain structural regularity of various morphologies, 2 whereas a complete mechanism for the self-assembled supramolecular structures is still beyond our understanding. Recently, there has been a rapidly growing interest in tuning morphology by changing molecular structures, 3 the composition of a binary gel, 4 solvents, 1f,5 as well as using ultrasound, 6 light 7 and so on. For example, Nandi and co-workers reported for the first time the hierarchical tuning of one-dimensional morphology from helical bunched fibers to rods and hollow tubes, by changing the composition of riboflavinemelamine in a hydrogel system.…”

Controlled self-assembly of helical nano-ribbons formed by achiral amphiphiles

“…1,5 In general, the chirality of molecular building blocks, when forming assemblies, can be expressed in the form of helices. And the helicity of assemblies rests on the delicate design of molecular geometry, [6][7][8][9] intermolecular interactions [10][11][12][13][14] and even the mechanical field. [15][16][17] Although the building blocks can be small molecules, [18][19][20] polymers [21][22][23][24] or supramolecules, [25][26][27][28][29][30][31][32][33] a chiral centre is usually required to break the symmetry and trigger the consistent alignment of the molecules.…”