Remote-Controlled Exchange Rates by Photoswitchable Internal Catalysis of Dynamic Covalent Bonds

Year: 2022

Type: article

Abstract: The transesterification rate of boronate esters with diols is tunable over 14 orders of magnitude. Rate acceleration is achieved by internal base catalysis, which lowers the barrier for proton transfer. Here we report a photoswitchable internal catalyst that tunes the rate of boronic ester/diol exchange over 4 orders of magnitude. We employed an acylhydrazone molecular photoswitch, which forms a thermally stable but photoreversible intramolecular H-bond, to gate the activity of the internal base catalyst in 8-quinoline boronic ester. The photoswitch is bidirectional and can be cycled repeatedly. The intramolecular H-bond is found to be essential to the design of this photoswitchable internal catalyst, as protonating the quinoline with external sources of acid has little effect on the exchange rate.

Source: Journal of the American Chemical Society

DOI: 10.1021/jacs.2c04658

Authors: David N. Barsoum, Viraj C. Kirinda, Boyeong Kang, Julia A. Kalow

Institution: Northwestern University

Language: English

Topic: Photochromic and Fluorescence Chemistry

Subfield: Materials Chemistry

Field: Materials Science

Domain: Physical Sciences

Open Access status: green

Funders: National Science Foundation, Northwestern University, Materials Research Science and Engineering Center, Harvard University, International Institute for Nanotechnology, Northwestern University, Division of Materials Research, Division of Electrical, Communications and Cyber Systems, Division of Chemistry

OpenAlex ID: W4281766978