New mercury-contained cationic frameworks stabilized by (GaCl4)− unit via weak electrostatic forces in supramolecular compounds (Hg11P4)(GaCl4)4 and (Hg3AsS)(GaCl4)

Abstract

Two new inorganic supramolecular compounds, (Hg₁₁P₄)(GaCl₄)₄ (1) and (Hg₃AsS)(GaCl₄) (2), have been prepared by the solid-state reactions. Their structures are characterized by mercury-containing cationic hosts and discrete (GaCl₄)⁻ guests, which is a derivative of a very strong Lewis acid. The three-dimensional cationic framework of 1, (Hg₁₁P₄)⁴⁺, is marvellously extended by Hg₂²⁺ and Hg₃²⁺ groups as well as Hg²⁺ ions to form two large tunnels with different sizes each embedded with two columns of (GaCl₄)⁻ anions. Compound 2 features a layered structure with (GaCl₄)⁻ tetrahedra being intercalated between two-dimensional (Hg₃AsS)⁺ layers and it is the first mercury pnictidechalcohalide. It is found that the weak electrostatic forces between hosts and guests play a key role in the stabilization of the whole structures of 1 and 2, which is strikingly different from almost all the reported metal pnictidehalide and chalcohalide supramolecular compounds. Optical dielectric constants calculations show that both 1 and 2 possess strong dielectric anisotropy.