Solvothermal synthesis and characterization of thioindate–thioantimonates with transition-metal complexes: The first examples of the incorporation of transition metal ions into In–S–Sb frameworks

Three new thioindate–thioantimonates [Ni(en)3][In2Sb2S7] (1, en = ethylenediamine), [(Ni(en)3)]3(en)[In6Sb6S21] (2), and [Co(tren)InSbS4] (3, tren = tris(2-aminoethyl)amine) have been solvothermally synthesized and structurally characterized. Compound 1 contains dimeric [In2S7] units built of two tetrahedral [InS4] units sharing one corner and [SbS3] trigonal-pyramids, which are interconnected to form a puckered [In2Sb2S7]n2n− layer with 4-, 5- and 6-heterorings. [Ni(en)3]2+ complex cations as structure-directing and charge-balancing agents are located at the interlayer spaces. Compound 2 consists of a 3-D polymeric [In6Sb6S21]n6n− anion, [Ni(en)3]2+ cations, free en molecule and a water molecule. The 3-D polymeric [In6Sb6S21]n6n− anion is composed of [In2Sb2S8]n4n− chains and heterometallic [In2Sb2S9] clusters, which are interconnected to give 3-D frameworks with 10-ring helical channels, 14- and 20-ring channels. Compound 3 contains dimeric [In2S6] units constructed by two tetrahedral [InS4] sharing a common edge and [SbS3] trigonal-pyramids, which link to form a new [InSbS4]n2n− layer with large 10-heterorings. Each [Co(tren)]2+ group is appended within the cavity of the 10-heteroring via one Co–S–Sb bond. 3 represents the first example of the incorporation of transition metal ions into a In–S–Sb framework. Density functional theory calculation for 3 also has been performed, and the optical properties of 1–3 have been characterized by UV-vis spectra.