No abstract

The structural chemistry of hybrid organic-inorganic lead iodide materials has become of increasing significance for energy applications since the discovery and development of perovskite solar cells based on methylammonium lead iodide. Seven new hybrid lead iodide compounds have been synthesized and structurally characterized using single-crystal X-ray diffraction. The lead iodide units in materials templated with bipyridyl, 1,2-bis(4-pyridyl)ethane, 1,2-di(4-pyridyl)ethylene and imidazole adopt one-dimensional chain structures, while crystallization from solutions containing piperazinium cations generates a salt containing isolated [PbI6](4-) octahedral anions. Templating with 4-chlorobenzylammonium lead iodide adopts the well known two-dimensional layered perovskite structure with vertex shared sheets of composition [PbI4](2-) separated by double layers of organic cations. The relationships between the various structures determined, their compositions, stability and hydrogen bonding between the protonated amine and the iodide ions of the PbI6 octahedra are described.

Eleven first row transition metal fluoride sulfates synthesised in hydrofluorothermal conditions have been structurally characterised by single crystal X-ray diffraction and exhibit a wide variety of structural motifs. The polyionic structures containing Ti, V, Mn and Fe vary from discrete polyhedral units in Na4TiF4(SO4)2 and [N2C10H12] TiF4SO4, through one dimensional chains in (K2FeF3SO4, Li3FeF2(SO4)2·H2O, Li1.87Ti1.13O0.39F1.61(SO4)2, [N2C10H12]TiF2(SO4)2, [N2C6H16]Fe(SO4)2F and [N2C6H16]V(SO4)2F), and to two dimensional layers in ([N2C6H16](2+)Mn2F2(SO4)2, Na2VF3SO4 and Na3CrF2(SO4)2).

Three different cationic species, [NH4]+, [H-piperazine]+ and [H-1,4-diaminocyclohexane]+, can be incorporated between the inorganic square-net layers of the composition [Cu4Cl(PO3F)4]−.

Abstract. Three new titanium-based network structures and an organic tetraazapentacenium [TiF 6 ] 2-salt were synthesized under high fluoride-concentration, hydrothermal conditions utilizing hexafluorotitanic acid as a starting material.