Crystal Engineering: Some Further Strategies

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• 作者：Anthony ; A. ; Desiraju ; G.R. ; Jetti ; R.K.R. ; Kuduva ; S.S. ; Madhavi ; N.N.L. ; Nangia ; A. ; Thaimattam ; R. ; et. al.
• 关键词：A. microporous materials ; A. organic compounds ; C. X-ray diffraction ; D. crystal structure
• 刊名：Materials Research Bulletin
• 出版年：1998
• 期刊代码：60_00255408
• 类别：ms
• 出版时间：June, 1998
• 卷：33
• 期：6, Supplement 1
• 页码：1-18
• 文件大小：504 K

摘要

Structural studies currently underway in our group are reported in this paper. Molecular symmetry is rarely carried over into the crystal, posing problems when high-symmetry networks are desired. This is illustrated by the low-symmetry structure of 2,4,6-trinitromesitylene. However, the involvement of the Cl₃ supramolecular synthon ensures a hexagonal network structure for 2,4,6-tris-(4-chlorophenoxy)-1,3,5-triazine. Arguments following from the equivalence between molecular and supramolecular synthons lead to the tetragonal network structure of the 1:1 complex of tetraphenylmethane and CCl₄. With a similar reasoning, 4-(triphenylmethyl)benzoic acid is identified as a precursor of a supramolecular wheel-and-axle host substance. The study of novel and weaker intermolecular interactions is often useful. In N,N′-dibenzyl-1,4-cubanedicarboxamide, the acidity of the cubyl C-H groups leads to the formation of C-H···O hydrogen bonds. Polymorphism is a difficult challenge for the crystal engineer and, in its most intriguing manifestation, two crystalline forms of a substance appear in the same crystallization batch. This is observed for 4,4-diphenyl cyclohexadienone. The ultimate frontier in the subject is an understanding of the phenomenon of crystallization, and the unexpected crystal structure of quinoxaline, with five symmetry-independent molecules, could possibly represent a case of arrested crystallization.