Fig. 4: Absorption and photoswitching behavior of HPI 17 and hydrolyzed HPIs in water or D2O.
From: Hemiphosphoindigos as a platform for chiroptical or water soluble photoswitching
a General synthetic procedure for the hydrolysis of HPI 1, 2, 3, 11, 17 to the corresponding phosphinic acids. Substitution at the phosphorus are highlighted in purple. b, c, d Photoswitching of non-hydrolyzed HPI 17 and hydrolyzed HPI 1-OH and 11-OH in water followed by UV/vis spectroscopy in water at 23 °C. e, f, g Photoswitching of non-hydrolyzed HPI 17 and hydrolyzed HPI 1-OH and 11-OH in water followed by NMR spectroscopy in D2O at 25 °C. The parts in the spectra highlighted in red show signal regions of the E isomer.
