Lead halide inorganic–organic hybrids incorporating diammonium cations

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.