Chiral self-assembly of bolaamphiphilic sugar-terphenyl-sugar constructs

Bag, K and Naresh, K and Jayaraman, N (2022) Chiral self-assembly of bolaamphiphilic sugar-terphenyl-sugar constructs. In: Materials Today Chemistry, 26 .

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Abstract

A study of the bolaamphiphilic constructs constituted with α-D-mannopyransoide-terphenyl-α-D-mannopyranoside and α-L-rhamnopyranoside-terphenyl-α-L-rhamnopyranoside is reported. The p,p’-bis-formyl-functionalities of p-terphenyl are derivatized with pyranosides with the aid of the reductive amination to secure the water-soluble bolaamphiphiles. Aq. solutions of the bolaamphiphiles undergo self-assembly above critical aggregation concentration (CAC) of 0.9 and 0.6 mM, for α-D-mannopyranoside and α-L-rhamnopyranoside, respectively. Dynamic light scattering measurements show the formation of larger aggregates of hydrodynamic diameter 600–850 nm for concentration up to CAC, and the hydrodynamic diameter reduces to 200–350 nm upon increasing the solution concentration above the CAC. Circular dichroism (CD) spectral assessment shows the emergence of a left-handed helicity to the mannopyranoside bolaamphiphile, where the helicity reverses to a right-handed with α-L-rhamnopyranoside, thereby illustrating configurational control in the chirality emergence. The helical structure dissociates upon heating and the assembly reverts back upon cooling, the transition of aggregate-to-monomer occurs at ∼40 °C for the mannopyranoside bolaamphiphile. Atomic force (AFM) and scanning electron microscopies (SEM) reveal concentration-dependent morphological changes in bolaamphiphiles. Presence of helical, lamelle, hemi-circular and circular rings are seen for concentrations below CAC, and at higher concentrations, the morphology transforms to well-defined vesicles.

Item Type:	Journal Article
Publication:	Materials Today Chemistry
Publisher:	Elsevier Ltd
Additional Information:	The copyright for this article belongs to the Elsevier Ltd.
Keywords:	Aggregates; Amines; Hydrodynamics; Light scattering; Scanning electron microscopy; Self assembly, Bolaamphiphiles; Chiral self assembly; Critical aggregation concentration; Helicities; Hydrodynamic diameter; Mannopyranosides; P-terphenyl; Pyranosides; Terphenyls; Vesicle, Dichroism
Department/Centre:	Division of Chemical Sciences > Organic Chemistry
Date Deposited:	10 Aug 2022 05:20
Last Modified:	10 Aug 2022 05:20
URI:	https://eprints.iisc.ac.in/id/eprint/75758

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