biostudies-literatureUnknown16(48)Dolinski NDThe wide availability, ease of manipulation, and access to spatiotemporal control make light an attractive stimulus for controlling dynamic covalent chemistries/networks. In this work, a series of photo-isomerizable benzalisoxazolone (BIOx) thia-Michael (tM) acceptors were developed that exhibit an increase in thiol-bonding during irradiation with visible light (455-470 nm). <i>In situ</i> photo-NMR experiments demonstrate significant increases in the overall system <i>K</i> _eq (extent of bonding) for a variety of electronically-substituted BIOx tM acceptors. A combination of experimental and computational studies show that steric interactions between the β-phenyl ring and substituent on the isoxazolone in the <i>E</i>-isomer serve as a driving force for the increased <i>K</i> _eq. In addition, it is demonstrated that the power/intensity of the light can be used to tune the system's response. Incorporation of these photoisomerizable motifs into dynamic polymer networks gives access to organogels that exhibit reversible, on-demand, light-triggered stiffening.Chemical science23019-23025https://www.ebi.ac.uk/biostudies/studies/S-EPMC12590959biostudies-literatureManipulating dynamic covalent bonds through direct photoisomerization.PMC12590959Snyder SACrolais AEBoynton NRDolinski NDChen Cde Pablo JJRowan SJfalseManipulating dynamic covalent bonds through direct photoisomerization.The wide availability, ease of manipulation, and access to spatiotemporal control make light an attractive stimulus for controlling dynamic covalent chemistries/networks. In this work, a series of photo-isomerizable benzalisoxazolone (BIOx) thia-Michael (tM) acceptors were developed that exhibit an increase in thiol-bonding during irradiation with visible light (455-470 nm). <i>In situ</i> photo-NMR experiments demonstrate significant increases in the overall system <i>K</i> _eq (extent of bonding) for a variety of electronically-substituted BIOx tM acceptors. A combination of experimental and computational studies show that steric interactions between the β-phenyl ring and substituent on the isoxazolone in the <i>E</i>-isomer serve as a driving force for the increased <i>K</i> _eq. In addition, it is demonstrated that the power/intensity of the light can be used to tune the system's response. Incorporation of these photoisomerizable motifs into dynamic polymer networks gives access to organogels that exhibit reversible, on-demand, light-triggered stiffening.2025-01-01T00:00:00Z2025 Dec2026-06-06T01:13:26.925Z2026-05-24T03:12:17.805ZS-EPMC125909594121028410.1039/d5sc06704a