Towards a dynamic covalent molecular switch: substituent effects in chalcone/flavanone isomerism

Abstract

Chalcone/flavanone interconversion occurs facilely under aqueous alkaline conditions making it a promising scaffold for the development of a covalent molecular switch. In this study, a single methoxy substituent is shown to have a significant impact on the equilibrium dynamics of this reaction; this impact is dependent on the site of substitution.

Layer by layer assembled films between hemoglobin and multiwall carbon nanotubes for pH-switchable biosensing

“…The study of molecular switches and memories has attracted much attention during the past decade owing to their potential function as the key component for manufacturing materials at molecular and electronics levels [1][2][3][4][5][6]. The development of the devices was mainly based on their controllable responses to external stimuli [7], such as stress [8], temperature [9], pH value [10], moisture [11], light [12], and ionic strength [13].…”

Interactions in flavanone and chalcone derivatives: Hirshfeld surface analysis, energy frameworks and global reactivity descriptors

“…Two such isomers, i.e. ortho-hydroxychalcone and flavanone, can undergo reversible isomerization in solution (Mai et al, 2013); this ortho-hydroxychalcone/flavanone pair is a good example of molecular switching, where molecules are capable of predictable and reversible conformational changes. Such compounds have become increasingly desirable targets for organic synthesis (Mai et al, 2013;Muller et al, 2016).…”

“…ortho-hydroxychalcone and flavanone, can undergo reversible isomerization in solution (Mai et al, 2013); this ortho-hydroxychalcone/flavanone pair is a good example of molecular switching, where molecules are capable of predictable and reversible conformational changes. Such compounds have become increasingly desirable targets for organic synthesis (Mai et al, 2013;Muller et al, 2016). Moreover, the physicochemical properties of chalcone and its derivatives, including their nonlinear optical and fluorescence properties, have received considerable attention owing to their associated delocalization of electronic charge distribution and overlapping -orbitals.…”

Impact of mono- and disubstitution on the colorimetric dynamic covalent switching chalcone/flavanone scaffold

“…1). 27 This system is capable of interconversion in aqueous solutions by altering the pH; the range of pH within which rapid equilibration takes place is ∼10 (where flavanone is the only observed isomer) to ∼13 (where anionic chalcone is adopted exclusively). 28 Subsequent acidification provides a kinetically stable solution of either isomer.…”

“…Previously, 27 we established and detailed a UV/Vis spectrophotometric assay for investigation of this isomerism and subsequently analyzed the impact of a single methoxy substituent in a variety of positions. Chalcones were placed in solutions of varying pH (8.5-13) and allowed to reach equilibrium with the flavanone isomer.…”