Syntheses, crystal structures, and characterization of As(III) and As(V) thioarsenates, [Mn2(phen)(AsIII2S5)]n and [Mn3(phen)3(AsvS4)2]n.nH2O

The hydrothermal reactions of As, Mn, S, phen (phen=1,10-phenanthroline), and en (en=ethylenediamine) yield two manganese As(III) and As(V) thioarsenates, [Mn2(phen)(AsIII2S5)]n (1) and [Mn3(phen)3(AsVS4)2]n.nH2O (2), respectively. Single-crystal X-ray diffraction analyses reveal that compound 1 is a two-dimensional (2D) layer of (6,3) topology. The 18-membered rings within the 2D porous layers are formed by corner-, edge-, and face-sharing cubane-like [Mn2As2S4] units along the [100] direction. Whereas compound 2 is a one-dimensional (1D) chain structure. They are both characterized by IR, elemental analysis, EDS, and X-ray powder diffraction. The thermogravimetric analysis of 1 and 2 are discussed. Both the compounds are semiconductors with the band gap of Eg (compound 1)=2.01 eV (617 nm) and Eg (compound 2)=1.97 eV (629 nm), respectively. In addition, the variable-temperature magnetic susceptibility data suggest weak antiferromagnetic interactions between the Mn2+ ions in these two compounds. - Graphical abstract: Two manganese As(III) and As(V) thioarsenates, namely, [Mn2(phen)(AsIII2S5)]n (1) (top structure) and [Mn3(phen)3(AsVS4)2]n.nH2O (2) (bottom structure), have been isolated under hydrothermal conditions. Compound 1 is a 2D layer of (6,3) topology, while that of 2 is a 1D chain structure. The oxidation-state of arsenic might be related to the molar ratio of the reactants. They are both characterized by IR, elemental analysis, X-ray powder diffraction, and EDS. The thermogravimetric analysis and magnetism of 1 and 2 are discussed. Both the compounds are semiconductors.