Crystal Structure, Thermal Properties, and Shock-Wave-Induced Nucleation of 1,2-Bis(phenylethynyl)benzene

We report the single crystal structure and thermal properties of 1,2-bis(phenylethynyl)benzene (PEB), revealing that PEB forms a metastable liquid at rt, ca. 35 °C below its melting point. Accelerated nucleation of PEB from its supercooled state was induced with high reproducibility by a shock wave with ca. 15 ns duration and 1.2 GPa peak pressure. By conducting shock wave experiments with varying peak pressures, we observed a correlation between the frequency of accelerated nucleation and shock intensity. The generality of shock-induced nucleation for supercooled liquids was probed with other organic supercooled liquids bearing phenyl rings. However, accelerated nucleation after shock wave impact was only observed for PEB, possibly due to the low rotational energy barrier of the terminal phenyl rings.