Halogen Trimer-Mediated Hexagonal Host Framework of 2,4,6-Tris(4-halophenoxy)-1,3,5-triazine. Supramolecular Isomerism from Hexagonal Channel (X = Cl, Br) to Cage Structure (X = I)
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- 作者：Binoy K. Saha ; Ram K. R. Jetti ; L. Sreenivas Reddy ; Srinivasulu Aitipamula ; and Ashwini Nangia
- 刊名：Crystal Growth & Design
- 出版年：2005
- 出版时间：May 2005
- 年：2005
- 卷：5
- 期：3
- 页码：887 - 899
- 全文大小：347K
- 年卷期：v.5,no.3(May 2005)
- ISSN：1528-7505
文摘
The hexagonal layer structure of host atoms in chloro, bromo, and iodo derivatives of 2,4,6-tris(4-halophenoxy)-1,3,5-triazine, X-POT, is stabilized by a cyclic and cooperative halogen trimer (X···X) synthon. TheX···X distance is ~3.5 Å in isostructural channel inclusion adducts of Cl-POT and Br-POT, whereas I···I is ~3.8 Åin cage structures of I-POT with aromatic and hydrophobic guests. X-ray crystal structures of I-POT with mesitylene,collidine, tribromomesitylene, triiodomesitylene, hexachlorobenzene, hexafluorobenzene, 1-methylnaphthalene, CH2Cl2, CH2Br2, and CH2I2 guests in R
space group are reported. Host molecules are fully ordered in these isostructuralclathrates, whereas guest atoms are disordered except for C6Cl6 and C6F6. The guest molecule resides in a penta-decker sandwich surrounded by double layers of iodo trimer and triazine ring. Supramolecular isomerism fromchannel to cage framework and the persistent crystallization of trigonal X-POT molecules in high-symmetry hostnetworks (space groups P63/m, P63, R) are discussed in crystal engineering terms: halogen trimer synthon, C3i-Piedfort unit, weak C-H···O/N interactions, changes in size/polarizability of halogen atom, and CSDSymmetrystatistics. Br-POT crystallizes in a channel or cage lattice depending on the guest species. Guest release from thecage framework occurs at a higher temperature compared to the channel structure in thermal gravimetric analysis,suggesting applications in organic zeolites. This study illustrates several aspects of crystal engineering from theunderstanding of intermolecular interactions to the design of crystal structures and their utility as functional solids.
space group are reported. Host molecules are fully ordered in these isostructuralclathrates, whereas guest atoms are disordered except for C6Cl6 and C6F6. The guest molecule resides in a penta-decker sandwich surrounded by double layers of iodo trimer and triazine ring. Supramolecular isomerism fromchannel to cage framework and the persistent crystallization of trigonal X-POT molecules in high-symmetry hostnetworks (space groups P63/m, P63, R) are discussed in crystal engineering terms: halogen trimer synthon, C3i-Piedfort unit, weak C-H···O/N interactions, changes in size/polarizability of halogen atom, and CSDSymmetrystatistics. Br-POT crystallizes in a channel or cage lattice depending on the guest species. Guest release from thecage framework occurs at a higher temperature compared to the channel structure in thermal gravimetric analysis,suggesting applications in organic zeolites. This study illustrates several aspects of crystal engineering from theunderstanding of intermolecular interactions to the design of crystal structures and their utility as functional solids.