Lead halide inorganic–organic hybrids incorporating diammonium cations

Abstract

Diammonium cations of general formula (H₃N–R–NH₃) have been used as templating moieties on lead(II) halide motifs, forming a variety of inorganic–organic nanocomposites. The R group can have simple, straight alkyl chains, which if even-membered and greater than ethane, form 2-D layers based on the RbAlF₄ structure type, as found in [(H₃N(CH₂)₄NH₃)PbBr₄] (1), [(H₃N(CH₂)₄NH₃)PbI₄] (2), [(H₃N(CH₂)₈NH₃)PbI₄] (4), [(H₃N(CH₂)₁₀NH₃)PbBr₄] (5), and [(H₃N(CH₂)₁₂NH₃)PbI4] (6). If the R group has fused aromatic rings like naphthalene, the 2-D layered perovskite-type motif is still adopted, as in [(H₃NC₁₀H₆NH₃)PbI₄] (7). If the chain is odd-membered, a 0-D inorganic motif, consisting of isolated blocks of face-sharing PbI₆ octahedra and isolated iodide anions is seen, as in [(H₃N(CH₂)₇NH₃)₄Pb₃I₁₂·2I⁻] (3). 1-D motifs, which have edge-sharing twin-anionic chains of corner-sharing ribbons are also observed in the compounds [(H₃NC₂H₄NH₃)₄PbBr₄] (8) and [(H₃NC₆H₄CH₂C₆H₄NH₃)PbI₆] (9) respectively.