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.