Designing a Hexanickel Cluster-Functionalized Polyoxometalate Hybrid for Photothermally Driven P(O)-S Bond Formation.

Abstract

The widespread applications of sulfur-containing organophosphorus compounds across organic synthesis, medicinal chemistry, and agricultural chemistry necessitate efficient methodologies for the formation of P(O)-S bonds. Herein, we developed a protocol for the cross-dehydrogenative coupling (CDC) of thiols and P(O)H compounds using H2O as a green solvent under mild conditions. A hexanuclear nickel cluster-substituted polyoxometalate-based hybrid, [(Dpa)Ni6(μ3-OH)3(H2O)10(PW9O34)]2·9H2O (Ni6PW9-Dpa), was assembled by a deliberate strategy. Compared with the secondary building unit {Ni6PW9}, Ni6PW9-Dpa exhibits high photogenerated electron-hole separation efficiency, a wide light absorption range, and excellent photothermal catalytic effect. Notably, Ni6PW9-Dpa can efficiently synthesize P(O)-S bonds under low-oxygen-concentration conditions with H2O as the eco-friendly solvent without any cocatalyst. Mechanistic studies showed that the synergistic effect of {Ni6PW9} and di-9,10-(pyridin-4-yl)-anthracene (Dpa) produces superoxide radicals (•O2-) to promote the formation of sulfur-centered radicals that are critical for the reaction. In addition, Ni6PW9-Dpa not only demonstrates facile recovery and exceptional stability but also serves as a highly efficient heterogeneous photothermal catalyst with gram-scale reactivity.