Tunable Emission Properties of Manganese Chloride Small Single Crystals by Pyridine Incorporation

[Image: see text] Pure transition-metal compounds seldom produce luminescence because of electron correlation and spin–spin coupling. The Pb-free perovskite materials, C(10)H(12)N(2)MnCl(4) and C(5)H(6)NMnCl(3)·H(2)O, were obtained by using pyridine-implanted manganese chloride lattices. The single-crystal X-ray diffraction indicates their different crystal structures. In C(10)H(12)N(2)MnCl(4), MnCl(4) cocoordinated with two pyridine molecules forms a lattice composed of independent mononuclear structures with paramagnetic behavior, which shows a clear emission band at 518 nm from the lowest d–d transition of a single Mn(II) ion in the octahedral crystal field. In C(5)H(6)NMnCl(5)·H(2)O crystal, MnCl(5)·(H(2)O)(x) octahedron-cocoordinated with less pyridine molecules than 2 lead to formation arris-share linear chains of Mn-ion octahedra, which give emission band at 620 nm due to the ferromagnetic Mn pair, and ferromagnetism. Pyridine incorporations in the transition-metal halide lattice provide a new channel to modulate the electron correlation and obtain materials with both luminescence and ferromagnetic properties.