Selective photocatalytic oxidation of sulfides with dioxygen over carbazole-fluorene conjugated microporous polymers.

One sustainable concept emerges to implement the selective oxidation of sulfides with dioxygen (O ₂ ) at ambient conditions and has received increasing attention. As such, three donor-acceptor (D-A) type conjugated microporous polymers (CMPs) were connected via robust CC bonds prepared from FeCl ₃ -promoted polymerization of monomers of 3,6-di(9H-carbazol-9-yl)-9H-fluorene with the 9H position of the fluorene moiety occupied by 1,1'-biphenyl-, difluoro-, or keto- group, furnishing 9,9'-(9,9'-spirobi[fluorene]-2,7-diyl)-bis-9H-carbazole-CMP (SFC-CMP), 9,9'-(9,9-difluoro-9H-fluorene-2,7-diyl)bis(9H-carbazole)-CMP (FFC-CMP), and 2,7-di(carbazol-9-yl)-fluoren-9-one-CMP (OFC-CMP), respectively. These three carbazole-fluorene CMPs could implement blue light-driven highly selective oxidation of sulfides into sulfoxides with O ₂ in methanol (CH ₃ OH). Intriguingly, the SFC-CMP imparted the best photocatalytic activity for selective oxidation of sulfides in a broad scope. Besides, the SFC-CMP photocatalyst could be fully recovered even outperforming the fresh one. This work highlights that the properties of CMPs could be regulated by the D-A units like carbazole-fluorene to execute selective chemical transformations ambiently.
Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
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