Kulla Hannes, Michalchuk Adam A L, Emmerling Franziska
BAM Federal Institute for Materials Research and Testing, Richard-Willstätter-Strasse 11, 12489 Berlin, Germany.
Chem Commun (Camb). 2019 Aug 13;55(66):9793-9796. doi: 10.1039/c9cc03034d.
The mechanism of ternary cocrystal formation, and the potential role of intermediate binary phases, has been debated for some time. We report here the first in situ real-time monitoring of two prototypic ternary cocrystals. Our results suggest that the question is more complicated than previously considered. The mechanism of mechanochemical ternary cocrystal formation depends on the milling conditions, here the milling frequency and addition of liquid. Binary phases can form under certain conditions, but do not act as intermediates in the formation of the ternary cocrystals. Rather, binary phases are competitive with the ternary phase, and their formation appears to compete with that of the ternary components. The presence of binary phases leads to an increase in the overall reaction time. The results reported here offer the first insights into the true complexities of mechanochemical multi-component synthesis of higher order multi-component crystals and demonstrate a new understanding of the influence of milling condition for the study of mechanisms and kinetics.
三元共晶形成的机制以及中间二元相的潜在作用，已经争论了一段时间。我们在此报告首次对两种典型三元共晶进行原位实时监测。我们的结果表明，这个问题比之前认为的更为复杂。机械化学三元共晶形成的机制取决于研磨条件，这里指的是研磨频率和液体的添加。二元相在某些条件下可以形成，但在三元共晶的形成过程中并不充当中间体。相反，二元相与三元相相互竞争，它们的形成似乎与三元组分的形成相互竞争。二元相的存在导致整体反应时间增加。这里报告的结果首次揭示了机械化学多组分合成高阶多组分晶体的真正复杂性，并展示了对研磨条件影响机制和动力学研究的新理解。
