Intense photo- and tribo-luminescence of three tetrahedral manganese(ii) dihalides with chelating bidentate phosphine oxide ligand

Abstract

Three air-stable tetrahedral manganese(II) dihalide complexes [MnX₂(DPEPO)] (DPEPO = bis[2-(diphenylphosphino)phenyl]ether oxide; X = Cl, Br and I) were prepared. All of the obtained compounds were structurally characterized by single-crystal X-ray diffraction analyses, which reveal that they crystallize in centrosymmetric space groups and feature an isolated mononuclear structure with Mn²⁺ in a tetrahedral environment. Interestingly, these complexes show excellent photoluminescent performance in neat solid form, with the highest total quantum yield (Φ_total) of up to 70% recorded for the dibromide complex. Intense green flashes of light could be observed by the naked eye when rubbing the manganese(II) complexes.