2,6-Diphospha-s-indacene-1,3,5,7(2 H,6 H)-tetraone: a phosphorus analogue of aromatic diimides with the minimal core exhibiting high electron-accepting ability.

Phosphorus analogues of pyrromellitic diimides (PyDIs), which represent a family of privileged electron-accepting organic compounds, have been successfully synthesized as novel electron-accepting π-conjugated molecules. Investigation into their physicochemical properties uncovered their prominent electron-accepting abilities over the corresponding PyDI. Furthermore, theoretical studies revealed the significant contribution of σ*-π* hyperconjugation in stabilizing the LUMO+1.