Photoswitchable electron-rich phosphines: using light to modulate the electron-donating ability of phosphines

Buss, Florenz; Das, Mowpriya; Janssen-Mueller, Daniel; Sietmann, Alexander; Das, Ankita; Wilm, Lukas F. B.; Freitag, Matthias; Seidl, Michael; Glorius, Frank; Dielmann, Fabian

Abstract

The synthesis and properties of photoswitchable electron-rich phosphines containing N-heterocyclic imines equipped with a photochromic dithienylethene unit are reported. Heteronuclear NMR spectroscopy and UV/vis studies reveal that the imine substituents undergo reversible electrocyclic ring-closing and ring-opening reactions upon exposure to UV and visible light, respectively. The photoisomerization alters the electron-donating ability of the phosphines by up to ΔTEP = 8 cm−1.