Selective Photooxidation of Sulfides Catalyzed by Bis-cyclometalated IrIII Photosensitizers Bearing 2,2′-Dipyridylamine-Based Ligands

A new family of heteroleptic bis-cyclometalated Ir-III complexes with formula [Ir(CN)(2)(NN)]Cl(CN= 2-phenylpyridinate and NN= 2,2'-dipyridylamine or N-benzylated 2,2'-dipyridylamines, were synthesized, characterized, and successfully used as photosensitizers in the catalytic photooxidation of an array of dialkyl, dibenzyl, alkyl aryl, and diaryl sulfides, as well as sulfur-containing amino acids. Furthermore, the reactions proceeded with optimal chemoselectivity, and atom economy under mild conditions. Experimental observations support a dual mechanism in which singlet oxygen and superoxide are the actual oxidants.