Polymorphism and Structure in a Pentamorphic Guest-Host Material: The Tris(5-acetyl-3-thienyl) Methane (TATM) Inclusion Compound with 1,3-Dichloropropane
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- 作者：Paul S. Sidhu ; Gary D. Enright ; Konstantin A. Udachin ; and John A. Ripmeester
- 刊名：Crystal Growth & Design
- 出版年：2004
- 出版时间：November 2004
- 年：2004
- 卷：4
- 期：6
- 页码：1249 - 1257
- 全文大小：473K
- 年卷期：v.4,no.6(November 2004)
- ISSN：1528-7505
文摘
In this work, we describe the preparation and structural properties of five polymorphs of the 1G:2H,1,3-dichloropropane/tris (5-acetyl-3-thienyl) methane (TATM) inclusion compound. A number of different preparativemethods were used to give products whose structures were solved by single-crystal X-ray diffraction. In addition,solid-state 13C NMR spectroscopy and powder X-ray diffraction (PXRD) were used for bulk phase identification. Onthe basis of the unit cell parameters determined from single crystal X-ray diffraction experiments, the PXRD resultswere used to resolve the products as being from either pure or mixed phases. In four of the five forms, the hostTATM molecules have similar torsional conformations and share a common layered motif. The guest molecules aredisordered and reside in cages or channels that are formed from the stacking of these layers. In the fifth form, theconformation of the TATM host molecules differ significantly, and the disordered guests reside in a pronouncedzigzag channel. Apparently, slightly different conformations for the host and the flexile guest give structures thatdiffer little in energy. The results suggest that minor changes in synthetic procedures can have a profound effect onthe structure of the resulting crystalline product. Some of the structures presented here are closely related to otherstructures previously reported for TATM inclusion compounds with a variety of guests, suggesting that this may bea particularly rich area for studying polymorphism.