Syntheses and crystal structures of several novel alkylammonium iodobismuthate materials containing the 1,3-bis-(4-piperidinium)propane cation

The inorganic–organic salts (H2TMDP)3(Bi2I9)2 (1), (H2TMDP)2(Bi4I16)·2EtOH (2), (H2TMDP)2(Bi6I22)·2EtOH (3), and (H2TMDP)2(Bi6I22) (4) were synthesized and structurally characterized from the solvothermal reaction of 1,3-bis-(4-piperidyl)propane (TMDP) and BiI3 by adjusting the relative ratio of the reactants. The anions of the compounds consist of 2 (1), 4 (2), or 6 (3 and 4) BiI6 polyhedra, which are joined by face- (1) or edge-sharing (2–4) to form discrete anions. The size of the discrete anion, in terms of the number of connected polyhedra, is observed to increase as the ratio of BiI3 to TMDP is increased. A related compound (H2TMDP)(Bi3I11)·(H2O) (5) was synthesized and structurally characterized using the same two reactants in the presence of HF. The anion of 5 is polymeric rather than discrete, with a trioctahedral repeat unit.