A Copper(I)-Thioarsenate(III) Inorganic Framework Directed by [Ni(en)3]2.

One novel three-dimensional (3-D) copper(I)-thioarsenate(III) [Ni(en)3]Cu4As4S9 (1, en = ethylenediamine) has been solvothermally prepared with the utilization of the in situ formation of [Ni(en)3]2+ complex as structure-directing agent (SDA). 1 contains cubane-like [Cu8S12]16- clusters and rare tetrameric [As4S9]6- units, which are interconnected to generate the first example of a 3-D anionic framework [Cu4As4S9]n2n-, topologically identical to pyrite, and having large channels filled by [Ni(en)3]2+ complex cations. 1 is a potential wide-band-gap semiconductor with an energy gap of 1.91 eV that exhibits selectively photocatalytic degradation of methylene blue under visible-light irradiation. The density functional theory calculation, photocurrent response, and magnetic properties of 1 were also investigated.