Structural characterization, vibrational studies and optical properties of a new luminescent organic-inorganic material [C6H20N3]BiI6·H2O

Abstract

The (C6H20N3)BiI6·H2O compound is a new crystal belonging to the large hybrid organic-inorganic compounds family, which has been synthesized by the solvent evaporation method and characterized by single crystal X-ray diffraction at room. It crystallizes in the zero-dimensional (0-D) triclinic P1¯ space group. The cell dimensions are: a = 8.572 (5) Å, b = 11.838 (5) Å, c = 12.707 (5) Å, α = 74.317 (5)°, β = 71.043 (5)° and γ = 71.419 (5)°. The crystal structure consists of a discrete ionic layer of bis(3-azaniumylpropyl)azanium cations, hexa-iodobismuthate anions and neutral water molecules linked via simple and bifurcated NH⋯I(OW) and O(W)H⋯I hydrogen bonds. The structure of the prepared compound has been investigated using the group theory and IR and Raman spectroscopic techniques. The detailed interpretation of the vibrational modes was carried out. The optical absorption measurements on a (C6H20N3)BiI6·H2O pellet have revealed two absorption bands at 2.27 and 2.78 eV. In the end, two room temperature photoluminescence emissions attributed to the excitonic transition in the [BiI6]3− anions, were observed in the red spectral range at energy values of 1.87 and 2.05 eV.