Patyk-Kaźmierczak Ewa, Szymańska Kornelia, Kaźmierczak Michał
Facuty of Chemistry, Adam Mickiewicz University in Poznań, Uniwersytetu Poznańskiego 8, Poznań 61-614, Poland.
IUCrJ. 2025 Jan 1;12(Pt 1):88-96. doi: 10.1107/S2052252524011734.
Multicomponent crystals have great scientific potential because of their amenability to crystal engineering in terms of composition and structure, and hence their properties can be easily modified. More and more research areas are employing the design of multicomponent materials to improve the known or induce novel physicochemical properties of crystals, and recently they have been explored as materials with abnormal pressure behaviour. The cocrystal of 1,2-bis(4'-pyridyl)ethane and fumaric acid (ETYFUM) exhibits a negative linear compressibility behaviour comparable to that of framework and metal-containing materials, but overcomes many of their deficiencies restricting their use. Herein ETYFUM was investigated at low temperature to reveal negative thermal expansion behaviour. Additionally, a cocrystal isostructural with ETYFUM, based on 1,2-bis(4'-pyridyl)ethane and succinic acid (ETYSUC), was exposed to high pressure and low temperature, showing that its behaviour is similar in nature to that of ETYFUM, but significantly differs in the magnitude of both effects. It was revealed that the minor structural difference between the acid molecules does not significantly affect the packing under ambient conditions, but has far-reaching consequences when it comes to the deformation of the structure when exposed to external stimuli.
多组分晶体具有巨大的科学潜力，因为就组成和结构而言，它们易于进行晶体工程，因此其性质可以很容易地改变。越来越多的研究领域采用多组分材料的设计来改善已知的晶体物理化学性质或诱导新的性质，最近它们被探索作为具有异常压力行为的材料。1,2-双(4'-吡啶基)乙烷与富马酸的共晶体(ETYFUM)表现出与骨架材料和含金属材料相当的负线性压缩行为，但克服了许多限制其使用的缺点。在此研究了ETYFUM在低温下的负热膨胀行为。此外，基于1,2-双(4'-吡啶基)乙烷和琥珀酸的与ETYFUM同构的共晶体(ETYSUC)，在高压和低温下进行了研究，结果表明其行为本质上与ETYFUM相似，但在两种效应的程度上有显著差异。结果表明，酸性分子之间的微小结构差异在环境条件下对堆积没有显著影响，但在受到外部刺激时结构变形方面却有着深远的影响。
