Braga Dario, Grepioni Fabrizia, Maini Lucia, Polito Marco, Rubini Katia, Chierotti Michele R, Gobetto Roberto
Dipartimento di Chimica G. Ciamician, Università degli studi di Bologna, Via Selmi 2, 40126 Bologna, Italy.
Chemistry. 2009;15(6):1508-15. doi: 10.1002/chem.200800381.
Para-methyl benzyl alcohol (p-MeBA II) and para-chloro benzyl alcohol (p-ClBA) are quasi-isostructural and share the same hydrogen-bond patterns, but their crystals are not isomorphous. No new polymorphs could be obtained by conventional polymorph screening based on different solvents and different crystallization conditions. Formation of a new polymorph of p-MeBA named p-MeBA I, isomorphous with the crystal of p-ClBA, was induced by hetero-seeding with a small quantity of powdered p-ClBA added to a supersaturated solution of p-MeBA in hexane, while seeding of p-ClBA with p-MeBA II failed to give a new phase of p-ClBA isomorphous with known crystalline p-MeBA II. Mixed crystals of p-MeBA and p-ClBA were also prepared with different p-MeBA/p-ClBA ratios to understand the role of the different functional groups in the crystal structure. Crystal phases were characterized by combined use of single-crystal and powder X-ray diffraction, differential scanning calorimetry, and solid-state NMR spectroscopy.
对甲基苄醇（p-MeBA II）和对氯苄醇（p-ClBA）具有准同构结构且氢键模式相同，但它们的晶体并非同构。基于不同溶剂和不同结晶条件的传统多晶型筛选无法获得新的多晶型物。通过向对甲基苄醇在己烷中的过饱和溶液中加入少量粉末状对氯苄醇进行异质晶种诱导，形成了一种名为对甲基苄醇I的新多晶型物，它与对氯苄醇的晶体同构，而用对甲基苄醇II对氯苄醇进行晶种接种未能得到与已知结晶对甲基苄醇II同构的对氯苄醇新相。还制备了不同对甲基苄醇/对氯苄醇比例的对甲基苄醇和对氯苄醇混合晶体，以了解不同官能团在晶体结构中的作用。通过结合使用单晶和粉末X射线衍射、差示扫描量热法和固态核磁共振光谱对晶相进行了表征。
