1H NMR spectra were recorded on Varian Inova 300 (300 MHz) spectrometers. Low-resolution mass spectra were measured on an ESI (Electro Spray Ionization) by the ACQUITY UPLC (Waters). High-resolution mass spectra (HRMS) were measured on an ESI by micrOTOF-Q II (Bruker). Ultraviolet spectra were measured on a Varian Cary 300. Fluorescence intensities were measured on a Fluoroskan Ascent Microplate Fluorometer. The OGR1 probe was synthesized with an Applied Biosystems 394 DNA/RNA synthesizer as described.63 (link) Analytical TLC was performed on ready-to-use plates with silica gel 60 (Merck, F254). Flash column chromatography was performed over Fisher Scientific silica gel (grade 60, 230–400 mesh).