Details

Autor(en) / Beteiligte

• Park, Minwook
• Choi, Yu-Jin
• Kim, Dae-Yoon
• Hwang, Seok-Ho
• Jeong, Kwang-Un

Titel

Unique Monotropic Phase Transition Behaviors of a Butterfly-Shaped Diphenylpyrimidine Molecule

Ist Teil von

• Crystal growth & design, 2015-02, Vol.15 (2), p.900-906

Ort / Verlag

American Chemical Society

Erscheinungsjahr

2015

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• The physical properties of two-dimensional disc-shaped aromatic carbon molecules strongly depend on the molecular packing structures. A butterfly-shaped diphenylpyrimidine molecule (DPP-6C12) was synthesized by covalently attaching two tridodecyl benzoate tails (6C12) at the both sides of the diphenylpyrimidine (DPP) moiety. Unique phase transition behaviors of DPP-6C12 and their origins were investigated with the combined techniques of thermal, scattering, spectroscopic, and microscopic analyses. On the basis of the experimental results and analyses, it was realized that a butterfly-shaped DPP-6C12 formed three ordered phases: a plastic crystal phase (PK), a crystal phase (K), and a liquid crystal phase (Φ). By breaking the molecular symmetry and coplanarity of DPP-6C12, peculiar monotropic phase transition behaviors were observed. The stable Φ mesophase was formed either by a slow heating above the metastable PK phase or by an isothermal annealing between T Φ and T K. The stable K phase was only formed by a slow heating from the preordered Φ mesophase, and the formation of the K phase directly from the isotropic state (I) was forbidden because the nucleation barrier from I to K was too high to be overcome via thermal annealing.