Structural, vibrational and optical properties of a new organic–inorganic material: (C5H8N3)2[BiCl5]

Abstract Single crystal of a new organic–inorganic hybrid material [C 5 H 8 N 3 ] 2 BiCl 5 has been synthesized by slow evaporation at room temperature and characterized by X-ray single crystal diffraction, Infrared and Raman spectroscopy coupled with DFT calculation, optical absorption and photoluminescence measurements. The single X-ray diffraction results have revealed that the compound crystallizes in the triclinic system with P 1 ¯ space group with the following parameters a = 8.744(5)A, b = 10.623(5)A, c = 10.980(5)A, α = 101.692(5)°, β = 97.826(5)°, γ = 105.280(5)°, Z = 2 and V = 943.8(8) A 3 . The structure is built up from bioctahedral [Bi 2 Cl 10 ] 4− sharing one edge and independent protonated cations inserted between anions. The cohesion between these entities is performed via N H⋯Cl hydrogen bonds. The optimized molecular structure and vibrational frequencies were calculated by the Density Functional Theory (DFT) method using the B3LYP function with the LanL2DZ basis set. A satisfactory agreement has been found between the calculated and the experimental vibrational frequencies. The photoluminescence measurements show two blue peaks which are attributed to band to band (free electron-hole transitions) and excitonic (bound electron-hole transitions) emissions within the chlorobismuthate inorganic part.