Assembly of novel organic-decorated quaternary TM-Hg-Sb-Q compounds (TM = Mn, Fe, Co; Q = S, Se) by the combination of three types of metal coordination geometries.

Four organic-decorated quaternary TM-Hg-Sb-Q compounds, namely, [Mn(phen)](2)HgSb(2)S(6) (phen = 1,10-phenanthroline) (1) and isomorphic [TM(tren)]HgSb(2)Se(5) (TM = Mn (2), Fe (3), Co (4); tren = tris(2-aminoethyl)amine) have been solvothermally prepared, and structurally characterized by single crystal X-ray diffraction analyses. 1 and 2 (3, 4) feature distinct one-dimensional neutral infinite ribbon-like structures constructed by the combination of Sb(3+), Hg(2+) and TM(2+), the latter two of which adopt different coordination modes. In compound 1, organic-decorated {[Mn(phen)](2)Sb(2)S(6)} clusters assembled by {MnS(4)N(2)} octhedra and {SbS(3)} pyramids are bridged by the {HgS(2)} groups in a linear fashion. Differently, the {SbSe(3)} pyramids, {HgSe(4)} tetrahedra and {TMSeN(4)} trigonal-bipyramids in 2 (3, 4) are combined to form novel {[TM(tren)](2)Hg(2)Sb(4)Se(12)} clusters, which are interconnected to form {[TM(tren)]HgSb(2)Se(5)}(n) ribbons. The results of optical diffuse-reflectance measurements and band structure calculations based on DFT methods indicate that 1 and 2 (3, 4) are indirect and direct semiconductors, respectively. Photocatalytic experiments have shown the ability of 2 in photodegradation of Rhodamine B (RhB).