11 Layered Hydrogen-Bonded Organic …
207
Fig. 11.8 Crystal structures of LA-H-HexNets: a, e Tp-1, b, f T18-1, c, g T18, d, h Ex-1. a–
d H-HexNet sheet. e–h Packing diagrams of stacked neighboring three layers. Solvent molecules
accommodated in the voids are omitted for clarity
diffraction contrast provided by the low density H-HexNet frameworks composed of
no metal but low-weight elements and highly disordered solvent molecules within
the frameworks. However, the diffraction peaks became unambiguous upon heating
as the solvent molecules were removed. Tp and T18 showed PXRD pattern changes
in two or three steps, indicating formation of intermediate phases. After completing
removal of the solvents, the materials still exhibit obvious PXRD patterns, which
are not in agreement with the original patterns of the solvate crystals, indicating
that crystal structure of LA-H-HexNets changes to other crystalline forms upon
desolvation. Further increase of the temperature revealed that frameworks of Tp,
T12, T18, and Ex decomposed at 323 °C, 360 °C, 242 °C, and 249 °C, respectively.
By using PXRD pattern after desolvation, we attempted to identify the crystal
structures of activated forms and successfully estimated or solved the reasonable
207
Fig. 11.8 Crystal structures of LA-H-HexNets: a, e Tp-1, b, f T18-1, c, g T18, d, h Ex-1. a–
d H-HexNet sheet. e–h Packing diagrams of stacked neighboring three layers. Solvent molecules
accommodated in the voids are omitted for clarity
diffraction contrast provided by the low density H-HexNet frameworks composed of
no metal but low-weight elements and highly disordered solvent molecules within
the frameworks. However, the diffraction peaks became unambiguous upon heating
as the solvent molecules were removed. Tp and T18 showed PXRD pattern changes
in two or three steps, indicating formation of intermediate phases. After completing
removal of the solvents, the materials still exhibit obvious PXRD patterns, which
are not in agreement with the original patterns of the solvate crystals, indicating
that crystal structure of LA-H-HexNets changes to other crystalline forms upon
desolvation. Further increase of the temperature revealed that frameworks of Tp,
T12, T18, and Ex decomposed at 323 °C, 360 °C, 242 °C, and 249 °C, respectively.
By using PXRD pattern after desolvation, we attempted to identify the crystal
structures of activated forms and successfully estimated or solved the reasonable