biostudies-literatureJanasik DPolitechnika Slaska721-727https://www.ebi.ac.uk/biostudies/studies/S-EPMC9972467biostudies-literatureUnknown8(2)Molecular switches have become an area of great interest in recent years. They are explored as high-density data storage and organic diodes in molecular electronics as well as chemosensors due to their ability to undergo a transition between well-defined structures under the action of external stimuli. One of the types of such switches is hydrazones. They work by changing the configuration from E to Z under the influence of pH or light. The change in configuration is accompanied by a change in the absorption band and changes in the nuclear magnetic resonance (NMR) spectrum. In this publication, the structure-property relationship of fluorinated hydrazone switches was established. A linear relationship between the Hammett substituent constants and the pH where the switching occurs was found. Introduction of strong electron-donating groups allowed obtaining a hydrazone switch of p<i>K</i>_a = 6 suitable for application in ¹⁹F MRI as contrast agents.ACS sensorsTuning the pH of Activation of Fluorinated Hydrazone-Based Switches─A Pathway to Versatile ¹⁹F Magnetic Resonance Imaging Contrast Agents.PMC997246704/050/BKM22/0146Imielska PJanasik DKrawczyk TfalseTuning the pH of Activation of Fluorinated Hydrazone-Based Switches─A Pathway to Versatile ¹⁹F Magnetic Resonance Imaging Contrast Agents.Molecular switches have become an area of great interest in recent years. They are explored as high-density data storage and organic diodes in molecular electronics as well as chemosensors due to their ability to undergo a transition between well-defined structures under the action of external stimuli. One of the types of such switches is hydrazones. They work by changing the configuration from E to Z under the influence of pH or light. The change in configuration is accompanied by a change in the absorption band and changes in the nuclear magnetic resonance (NMR) spectrum. In this publication, the structure-property relationship of fluorinated hydrazone switches was established. A linear relationship between the Hammett substituent constants and the pH where the switching occurs was found. Introduction of strong electron-donating groups allowed obtaining a hydrazone switch of p<i>K</i>_a = 6 suitable for application in ¹⁹F MRI as contrast agents.2023-01-01T00:00:00Z2023 Feb2025-04-26T10:18:56.28Z2025-04-06T13:19:42.932ZS-EPMC99724673669532310.1021/acssensors.2c02251