Stepwise formation of a chemodynamic therapy agent of {Cu 8 } macrocyclic complex recognized by iodide ions.

An atomically precise Cu(I) macrocyclic complex Cu8I was developed for chemodynamic therapy (CDT) research. The {Cu 8 } macrocyclic skeleton gradually forms with the selective recognition of iodide ions, and the monitoring of intermediate fragments during Cu8I formation using time-dependent electrospray ionization mass spectrometry indicates the following possible formation process: [Cu 1 ] → [Cu 2 ] → [Cu 3 ] → [Cu 4 ] → [Cu 5 I] → [Cu 6 I] → [Cu 7 I] → [Cu 8 I] when recognized by iodide ions. Furthermore, the Cu(I)-mediated Fenton-like reaction in Cu8I catalyzes the production of toxic ˙OH from H 2 O 2 , which results in efficient tumor suppression.