Foiling Normal Patterns of Crystallization by Design. Polymorphism of Phosphangulene Chalcogenides
作者:Alice Heskia、Thierry Maris、James D. Wuest
DOI:10.1021/acs.cgd.9b00907
日期:2019.9.4
Phosphangulene (1) has a well-defined hexacyclic structure with a distinctive conical shape and an electron-rich aromatic surface. Molecules of phosphangulene are disposed to crystallize in parallel π-stacks. This preference can be thwarted by adding a single atom and converting phosphangulene into the corresponding oxide (2a), sulfide (2b), and selenide (2c). This change creates an awkward molecular shape that prevents effective stacking. As a consequence, the formation of optimal intermolecular interactions is inhibited, and multiple polymorphs with high values of Z and Z′ are formed. The high polymorphism of chalcogenides 2a–c is particularly noteworthy because the compounds have little flexibility. Analysis of the structures of phosphangulene, chalcogenides 2a–c, and related compounds provides deeper understanding of crystallization, including how to design molecules that cannot pack efficiently, are unable to achieve normal patterns of association, and are therefore predisposed to form multiple polymorphs, structures with high values of Z and Z′, solvates, solid solutions, and cocrystals.
磷杂富瓦烯(1)具有一种明确的六环结构,具有独特的锥形形态和富电子的芳香表面。磷杂富瓦烯分子倾向于以平行的π堆积方式结晶。通过添加一个原子并将其转化为相应的氧化物(2a)、硫化物(2b)和硒化物(2c),这种倾向可以被打破。这一变化产生了一种不协调的分子形态,从而阻止了有效的堆积。因此,最优的分子间相互作用形成受阻,形成了具有高Z值和高Z′值的多种多晶型物。2a-c的硫族化合物高度多晶型性尤其值得注意,因为这些化合物几乎没有灵活性。对磷杂富瓦烯、2a-c硫族化合物及相关化合物的结构分析为进一步理解结晶学提供了深入见解,包括如何设计不能有效堆积、无法实现正常结合模式的分子,因此易于形成多种多晶型结构、具有高Z值和高Z′值的结构、溶剂化物、固溶体和共晶体。