Synthesis of probe 1
The synthesis of target chemodosimeter 1 is shown in Scheme 1. The intermediates 3-hydroxy-4-cyano-1,8-naphthaleneimide (2) and 4-(tert-Butyldiphenylsilyloxy)benzylbromide (3) were synthesized according to the literature[29–30]. To a solution of 3-hydroxy- 4-cyano-1, 8-naphthaleneimide (2, 0.20 g, 0.68 mmol) in CH3CN (20 mL) was added 3.0 equiv. of potassium carbonate (0.28 g, 2.04 mmol), and the mixture was stirred at 50 oC for 1 h. After adding 3.0 equiv. of 4-(tert-Butyldiphenylsilyloxy)benzylbromide (3, 0.87 g, 2.04 mmol), then the mixture was further refluxed for 24 h. After cooling of the reaction mixture, the residue was poured into dilute hydrochloric acid, and then extracted with ethyl acetate (20 mL×3), then the organic layer was further washed with brine, then dried with Na2SO4 and filtered. After the removal of solvent in vacuo, the residue was purified by chromatography (PE:EA = 10:1) to afford the probe 1 (0.21 g, 48%) as a white solid. 1H NMR (500 MHz, CDCl3) δ 8.51 (d, J = 7.0 Hz, 1 H), 8.40 (d, J = 8.5 Hz, 1 H), 8.34 (s, 1 H), 7.88 (t, J = 8.0 Hz, 1 H), 7.70 (d, J = 7.0 Hz, 4 H), 7.41 (t, J = 7.0 Hz, 2 H), 7.36 (t, J = 7.0 Hz, 4 H), 7.24 (s, 2 H), 6.80 (d, J = 8.0 Hz, 2 H), 5.34 (s, 2 H), 4.16 (t, J = 7.5 Hz, 2 H), 1.72–1.66 (m, 2 H), 1.09 (s, 9 H), 0.98 (t, J = 7.5 Hz, 3 H), 0.89 − 0.82 (m, 2 H); 13C NMR (125 MHz, CDCl3) δ 163.3, 162.8, 160.8, 156.1, 135.6, 132.7, 132.7, 130.1, 123.0, 129.9, 129.9, 129.8, 128.9, 127.9, 127.8, 127.6, 127.2, 123.0, 122.9, 120.2, 119.8, 117.3, 114.2, 101.4, 71.8, 40.7, 30.2, 27.0, 26.6, 20.4, 19.5, 13.9; HRMS-ESI (m/z): [M + H]+ Calcd. for (C40H38N2O4Si): 639.2674; Found:639.2680.