Abstract
Reactions of BiI(3)/CuI mixtures with tetrahydrothiophene (THT) in toluene produce 2-D sheet networks BiCu(3)I(6)(THT)(n) (n = 2, 3, or 4), depending on reaction conditions. All three structures are based on BiI(6) octahedra, which share pairs of (μ(2)-I)(2) with Cu(3)(THT)(n) units. BiCu(3)I(6)(THT)(2) features Cu(2)(μ(2)-I)(2) rhombs with close Cu···Cu interactions and is accompanied by formation of the very complex HBi(3)Cu(12)I(22)(THT)(8). Reactions of SbI(3)/CuI with THT in toluene produced a SbCu(3)I(6)(THT)(2) network shows Cu(3)(μ(2)-THT)(2) units, like its Bi congener, but Cu(6)(μ(2)-I)(6) barrels rather than rhombs. Isolated SbI(3) units are stacked above the Cu(6)I(6) barrels. A molecular compound, Sb(3)Cu(3)I(12)(THT)(6) consists of a face-sharing Sb(3)I(12) stack, in which the Cu-THT units are bonded in asymmetric fashion about the central SbI(6). Metal-halide bonds were investigated via QTAIM and NLMO analyses, demonstrating that these bonds are largely ionic and occur between the Bi/Sb and I p orbitals. Hirshfeld analysis shows significant H···H and H···I interactions. Diffuse reflectance spectroscopy (DRS) reveals band edges for the Bi species of 1.71-1.82 eV, while those for the neutral Sb complexes are in the range of 1.94-2.06 eV. Mapping of the electronic structure via density of state calculations indicates population of antibonding Bi/Sb-I orbitals in the excited state.