Fig. 6

Properties of chelates with N/C coordination environments. a Ultraviolet–visible (UV–vis) absorption spectra of complexes 2–5 measured in CH₂Cl₂ at room temperature. b Photoacoustic (PA) mean intensities of 4 and 5 at different concentrations (0.0625, 0.125, 0.250, 0.500, and 1.00 mg ml⁻¹) in MeCN monitored at λ = 700 nm (Inset: PA imaging). c, d Assessment of the generation of reactive oxygen species (ROS) by 4 and 5 at different concentrations (10, 20, 40, 60, 80, and 100 μg ml⁻¹ in CH₂Cl₂) when activated by ultrasound (US) (1 MHz, 0.56 W cm⁻², 50% cycle, 5 min). FL: fluorescence; DMA: 9,10-dimethylanthracene