Integrating sphere detector

All reagents used in the reaction were purchased from commercial suppliers without further purification unless otherwise stated. The ¹H NMR and ¹³C NMR spectra were measured by Bruker Ascend ΙΙΙ 400 and Avance ΙΙΙ 600 instruments at 298.6 K using CDCl₃ and DMSO (d₆) as solvents. ESI-MS data were collected on Agilent Technologies 6230 TOF LC/MS with ESI source. The UV and fluorescent measurements were performed on a HITACHI U-3900 spectrophotometer and an Edinburgh FLS980 spectrophotometer, respectively. The photodynamic experiment was carried out using an FLS980 with a 450 W xenon lamp. The absolute quantum yield method was carried out using an integrating sphere detector from Edinburgh Instruments. The ultrapure water was obtained by the Direct-Q5 purification instrument. The analysis for the reaction mixture of mito-ACS with NaClO was performed by using a Shimadzu LC-20A HPLC with a C-18 reversed-phase column. A Leica SP 8 confocal laser scanning microscope was used for fluorescence imaging. HeLa Cells were purchased from the Type Culture Collection of the Chinese Academy of Sciences, Shanghai, China.