Hydrazine-solvothermal methods to synthesize polymeric thioarsenates from one-dimensional chains to a three-dimensional framework

Abstract

A series of polymeric Mn(II)-thioarsenates [Mn(en)₃]_n[(N₂H₄)₂Mn₆(μ₆-S)(μ-N₂H₄)₂(μ₃-AsS₃)₄]_n (1), [N₂H₅]_n[{Mn(μ-N₂H₄)₂(μ-AsS₄)}·0.5en]_n (2), [Mn(μ-trien){Mn(μ-N₂H₄)(μ-AsS₃)}₂]_n (3), [{Mn(N₂H₄)}₂(μ-N₂H₄)₂{Mn(μ-N₂H₄)₂(μ-AsS₃)₂}]_n (4), [Mn₃(μ-N₂H₄)₆(μ₃-AsS₄)(μ₂-AsS₄)]_n (5), and [Mn(NH₃)₆]_n[{Mn(NH₃)(μ-AsS₄)}₂]_n (6) were synthesized using a hydrazine-solvothermal method. The thioarsenate units AsS₃ and AsS₄ coordinate to Mn(II) ions with variable coordination modes, forming a Mn–As–S ternary cluster (1), chains (2, 4–6), and layers (3), respectively. The hydrazine molecules act as inter-cluster, intra-chain and intra-layer bridging ligands to join the Mn(II) ions, resulting in hydrazine hybrid 1-D, 2-D, and 3-D Mn(II)-thioarsenate moieties in 1–5. Compounds 1–6 exhibit tunable semiconducting band gaps varying in the range of 2.19–2.47 eV. Compound 1 displays stronger antiferromagnetic coupling interactions than that of compound 2.