Year: 2026
Type: article
Abstract: Forming or disrupting hydrogen-bond pairs is a powerful strategy used to achieve selective chemical transformations and functions. Here, we introduce isolable sulfonamidate-iminium Stenhouse zwitterions, a class of photoswitches featuring hydrogen-bond-accepting capabilities. Unlike prior Stenhouse photoswitches necessitating C2 heteroatomic protonation for open-form stabilization, Stenhouse zwitterions remain in their open form with a C2 sulfonamidate anion when constructed with a sufficiently electron-withdrawing sulfonyl group. The sulfonamidate inverts the traditional C2 hydrogen-bond donor functionality into a hydrogen-bond acceptor, enabling hydrogen-bonding interactions that extend beyond acidochromism. Electronic changes in the sulfonyl group can also be leveraged to alter irradiative and nonirradiative isomeric distributions. Stenhouse zwitterion, hydrogen-bound zwitterion, and Stenhouse salt structural and behavioral patterns are differentiated by X-ray crystallography, NMR, and UV-vis control experiments. The chromophoric hydrogen-bond acceptor isomerizes to a colorless cyclic adduct with up to 96% efficiency upon visible light irradiation, with disruption of the hydrogen-bond interaction when in the hydrogen-bound form. A direct correlation between the triene electronic structure, nonirradiative equilibrium, photoswitching efficiency, and hydrogen-bonding capacity demonstrates the tunability of this platform.
DOI: 10.1021/jacs.6c03702
Institution: University of Southern California
Language: English
Subfield: Materials Chemistry
Field: Materials Science
Domain: Physical Sciences
Open Access status: green
Awards: Collaborative Research: Acquisition of a 400 MHz NMR at the University of Southern California, MRI: Acquisition of a 600 Mhz NMR Spectrometer at the University of Southern California, Strategic Molecular Activations for the Selective Synthesis of 2-Deoxy-Beta-Glycosides, and for the Synthesis of Novel Donor-Acceptor Stenhouse Adducts, MRI: Acquisition of an X-ray Diffractometer at the University of Southern California, Acquisition of a 500 MHz NMR Spectrometer for the University of Southern Calif, G7818790124
OpenAlex ID: W7161563182