Synthesis and Structural Phase Transitions of Copper(II) and Iron(III) Complexes Containing [(C 8 H 12 NO)(18‐crown‐6)] + Supramolecular Cations

The organic‐inorganic hybrid compounds, [Cu 2 Cl 6 ] 2– ( 1 ), [Fe 2 Cl 6 O] 2– ( 2 ), and [FeCl 4 ] – ( 3 ), based on [(C 8 H 12 NO)(18‐crown‐6)] + (C 8 H 12 NO = 4‐methoxybenzylammonium) supramolecular cations, were synthesized and structurally characterized. Crystal structure analyses and thermal and dielectric studies showed that compounds 1 and 2 have similar crystal packings and undergo reversible phase transitions at 230 K and 358 K, respectively. Compound 3 shows a phase transition at 361 K, though its crystal structure is remarkably different from 1 and 2 . These results indicate that the phase transitions may arise from the [(C 8 H 12 NO)(18‐crown‐6)] + supramolecular cations. The role of the chlorometalate anions is to tune the crystal packings and thus the phase transition points and types.