Ternary Complexes of BiI 3 /CuI and SbI 3 /CuI with Tetrahydrothiophene.

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.