A rotaxane mimic of the photoactive yellow protein chromophore environment: effects of hydrogen bonding and mechanical interlocking on a coumaric amide derivative

Abstract

Hydrogen bonding in a [2]rotaxane is shown to stabilise the phenolate anion of a coumaric amide chromophore by almost 3 pK_a units; however, the effect on the UV spectral shift in the anion is small and, significantly given the photochemistry of PYP, despite the hydrogen bonding olefin photoisomerisation in the anionic rotaxane remains heavily suppressed.