X‐ray‐Irradiated Polarized Emission in Mn(II) Bromide Hybrids with Chain‐Like Alignment of Halopyridine and Polar MnBr₄²⁻ Units

Mn(II) halide hybrid crystals possess exceptional emission properties and pronounced anisotropic optoelectronic characteristics, making them highly promising for diverse applications. In this study, we present five structurally distinct Mn(II) hybrids, which either form the one-dimensional (1D) [(MnBr₃)^-]_∞ chains or a hybrid structure combining both 1D [(MnBr₃)^-]_∞ chains and a quasi-1D chains. These quasi-1D chains are composed of polar MnBr₄ ^2- tetrahedra and halogen-substituted pyridine ligands. Of particular interest is the mixed-polyhedral compound [3-IPy]₃[MnBr₃][MnBr₄]. It exhibits dominant antiparallel alignment of dipole moment between quasi-1D chains, while 1D [(MnBr₃)^-]_∞ chains display zero dipole moment. The highly-distorted MnBr₄ ^2- tetrahedra owing to strong hydrogen bonding with halopyridine introduces large inherent structural anisotropy. Under X-ray excitation, it gives rise to a pronounced and fascinating polarization-sensitive emission. These findings underscore the promising potential of mixed-polyhedral Mn(II) halide hybrids in polarized photonic applications and provide valuable insights for the rational design of polarization-sensitive functional materials.