Synthesis and Crystal Structures of (C4H12N2)[Mn(HSeO3)2Cl2] and [(C4N12N2)2Br]2[Mn(HSeO3)2Br2]—New Representatives of the Modular Family of “Layered Hydroselenites”

Abstract

Single crystals of two new complex hydroselenites with organic cations—(C₄H₁₂N₂)[Mn(HSeO₃)₂Cl₂] (1) and [(C₄N₁₂N₂)Br]₂[Mn(HSeO₃)₂Br₂] (2)—were obtained as the products of the reaction of piperazine, selenious acid, and manganese halide in an aqueous medium. The crystal structures of 1 and 2 were determined by single-crystal X-ray diffraction analysis; they are characterized by monoclinic symmetry (1: P2₁/c, a = 9.7557(7) Å, b = 7.3930(5) Å, c = 9.7660(6) Å, β = 116.839(7)°; 2: P2₁/c, a = 14.4093(3) Å, b = 7.3822(1) Å, c = 10.3051(3) Å, β = 101.553(2)°). The crystal structures of both compounds are constructed by alternating layers of the composition [Mn(HSeO₃)₂X₂]^2– (X = Cl, Br) and layers formed by piperazinium cations. Compound 1 is a structural analogue of the previously described compound (C₄H₁₂N₂)[Cd(HSeO₃)₂Cl₂], while the crystal structure of compound 2 belongs to a new structural type, is characterized by a modular structure, and contains layers including both piperazinium cations and bromine anions.