Synthesis, crystal structures and characterization of two novel organic-inorganic hybrid compounds (C5NH6)6Bi4Br18 and [C(NH2)3]3BiI6

Two novel organic-inorganic compounds (C5NH6)6Bi4Br18 (1) and [C(NH2)3]3BiI6 (2) have been synthesized and characterized by elemental analysis, measured by DSC and single-crystal X-ray diffraction at room temperature. The crystal structure of (1) crystallizes in the monoclinic space group C2/m, with a = 17.12 (3), b = 15.3939 (1), c = 13.412 (2) Å, β = 123.702 (7)°, V = 3042.2 (8) Å3 and Z = 2. The crystal structure consists of discrete quad-core [Bi4Br18]6- anions and [C5NH6]+ cations. 2 crystallizes in triclinic space group P-1, with the following unit cell parameters: a = 9.3435 (2), b = 15.583 (4), c = 17.200 (4) Å, α = 86.383 (1), β = 75.689 (1), γ = 89.918 (6)°, V = 2421.5 (10) Å3 and Z = 4. The crystal lattice is composed of discrete [BiI6]3- anions surrounded by [C(NH2)3]+ cations. The DSC experiment of 1 clearly displays that a phase transition occurred at 124.7 K, while 2 undergoes a phase transition at 192.5 K.