Synthesis, structure and red-light emission of a manganese halide directed by a methyldiphenylphosphine oxide complex.

Controlling the optical activity of halide perovskite materials through modulation of the coordination configurations of the metal ions is important. Herein, a novel manganese-based halide, specifically diaquatetrakis(methyldiphenylphosphine oxide)manganese(II) tetrachloridomanganate(II), [Mn(CHOP)(HO)][MnCl] or [Mn(MDPPO)(HO)][MnCl] (MDPPO is methyldiphenylphosphine oxide), was synthesized through the solvothermal reaction of MnCl with the neutral molecule MDPPO. In this compound, [Mn(MDPPO)(HO)] acts as the cation, while [MnCl] serves as the anion, enabling the co-existence of tetrahedral and octahedral structures within the same system. Remarkably, the compound exhibits efficient red-light emission at 662 nm, distinct from the green-light emission typically observed in MnX-based halides. Theoretical calculations show that the red emission comes from the charge transfer from the MDPPO to the Mn of [MnCl]. This work provides a new perspective for the design and synthesis of red-light-emitting manganese-based halides with unique structures.