The Synthesis and Crystal Structure of [BiI2(tpy)2][Bi2I7(tpy)]: A New Metal Halide Material

Abstract

[BiI2(tpy)2][Bi2I7(tpy)] (1) (tpy = 2,2′:6′2′′-terpyridine), a new compound containing a discrete bismuth halide anion, has been synthesized solvothermally and characterized by single crystal X-ray diffraction. The solvothermal reaction between BiI3, Zn(NO3)2 · 6H2O, and 2,2′:6′2′′-terpyridine in an ethanol/water solvent mixture resulted in the title compound. The anion and cation of this compound both contain bismuth, iodide ligands, and the organic ligand. The anion is composed of two face-sharing bismuth polyhedra, one of which is coordinated in a tridentate fashion to a disordered tpy ligand; and the remaining coordination sites at each Bi center are occupied by iodide ligands. The cation of the compound is a distorted, eight-coordinate polyhedron with a bismuth center, two iodide ligands, and six nitrogen atoms from two, tridentate tpy ligands. [BiI2(tpy)2][Bi2I7(tpy)] crystallizes in the triclinic space group P $$ \overline{1} $$ with the following lattice parameters: a = 10.0744(5) A, b = 16.6115(8) A, c = 18.5333(9) A, α = 102.6490(10)°, β = 101.0850(10)°, and γ = 93.9160(10)°. The title compound, [BiI2(tpy)2][Bi2I7(tpy)], was synthesized solvothermally by the reaction between BiI3 and 2,2′:6′2′′-terpyridine. Single crystal X-ray diffraction analysis reveals that the molecular structure contains one anion and one cation, both of which contain bismuth, iodine, and the tpy ligand, a situation not typically observed in these types of compounds.