Pyrene-tethered bismoviologens for visible light-induced C(sp3)–P and C(sp2)–P bonds formation

Developing efficient photosensitizers for C–P bond construction is highly important and remains a challenge due to the urgently needed for the synthesis of modified nucleosides,nucleotides,and other phosphine-containing ligands.Herein,two pyrene-tethered bismoviologen derivatives (Py-BiV2+) were designed and synthesized for visible-light-induced C–P bonds formation.The photochemical and electrochemical properties of Py-BiV2+were studied systemically,certifying fine-tunable opto-electronic properties through the number of pyrene groups (4,n=1;6,n=2).The prepared Py-BiV2+showed strong light absorption,while retaining good redox features and chromic response features that were inherent to viologens.4 exhibited accelerated photoinduced electron transfer in the presence of the electron donor(pyrene) and the generated 4 (radical cation) showed higher stability.Accordingly,Py-BiV2+directly served as photosensitizers for the first time in the visible-light-induced C(sp3)–P and C(sp2)–P bonds formation.As expected,these novel viologen derivatives exhibited good catalytic performance and good substrate expansibility under ambient conditions.