New Polar Phases of 1,4-Diazabicyclo[2.2.2]octane Perchlorate, An NH+···N Hydrogen-Bonded Ferroelectric
Citations Over Time
Abstract
Exceptionally rich diagram of ten phases, I–X, has been revealed for ferroelectric 1,4-diazabicyclo[2.2.2]octane perchlorate, [C6H13N2]+ClO4–, dabcoHClO4. Pressure- and temperature-induced transformations of this NH+···N hydrogen bonded structure have been characterized by single-crystal X-ray diffraction, calorimetric, and dielectric measurements. At high pressure the single crystals were in situ grown in a diamond-anvil cell at isochoric conditions. There are nine phases of dabcoHClO4 between 400 and 11 K at ambient pressure, whereas phase X is formed at 1.5 GPa and 296 K. Tetragonal phase I space group P4/mmm transforms to orthorhombic phases II (Pm21n), III (Pc21n), IV (Pc2a), and V (orthorhombic-modulated) on decreasing temperature. Phase II is stable up to 0.22 GPa, at 0.6 GPa phase III is formed, and above 1.50 GPa a new phase X (Pc21a) has been obtained. At normal conditions dabcoHClO4 is isostructural with the ferroelectric crystal of dabcoHBF4; however, their phase diagrams are very different. Above 1.8 GPa dabcoHClO4 cocrystallizes with solvate molecules.
Related Papers
- → Isostructural Metal–Organic Frameworks Assembled from Functionalized Diisophthalate Ligands through a Ligand‐Truncation Strategy(2013)119 cited
- → High pressure stability of β-Zr: no evidence for isostructural phase transitions(2021)8 cited
- → Insights into isostructural and non-isostructural crystals of esters of oleanolic acid and its 11-oxo derivatives(2022)4 cited
- → Isostructurality in the Guest Free Forms and in the Clathrates of 1,3,5-Triethyl-2,4,6-tris(4-halophenoxy)methylbenzenes(2011)27 cited
- → Formation of isostructural solid solutions in 2,6-disubstitutedN-phenylformamides andN-phenylthioamides(2013)6 cited