Synthesis, structure and spectroscopic investigations of two new organic-inorganic hybrids NH₃(C₆H₄)₂NH₃CuCl₄ and NH₃(C₆H₄)₂NH₃HgCl₄

Two metal organic-inorganic hybrid compounds, NH₃(C₆H₄)₂NH₃CuCl₄, 1, and NH₃(C₆H₄)₂NH₃HgCl₄, 2, have been synthesized and structurally characterized by single-crystal X-ray diffraction. The two compounds crystallize in the monoclinic space groups P2₁/c and C2/c, respectively, with a = 14.3774 (7), b = 7.3472 (4), c = 7.1669 (3), β = 96.589 (3)°, Z = 2 and R1 = 0.037 for 1, and a = 6.2986 (4), b = 18.2911 (12), c = 28.5854 (17), β = 91.836 (2)°, Z = 8 and R1 = 0.049 for 2. The organic-inorganic layered perovskite structure of compound 1 features well-ordered sheets of corner-sharing distorted CuCl₆ octahedra, due to the presence of Jahn-Teller effect in the d⁹ electronic system of Cu(II), separated by layers of benzidinium cations. The structure of compound 2 consists of anionic parallel layers built up from discrete tetrahedral HgCl₄²- species, alternating with layers of organic molecules [NH₃(C₆H₄)₂NH₃]²⁺. The structures of the two compounds are stabilized by an extensive network of N-H...C1 hydrogen bonds. These compounds are also investigated by IR spectroscopy.