ISSN:
1022-1352
Keywords:
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Physics
Notes:
1,3-Bis(4-phenoxybenzoyl)benzene (1) shows a single melting peak at T1 = 120°C when rapidly crystallized from a methanol/benzene mixture (10:1 v/v) (sample A) and a double melting peak at T1 = 120°C and T2 = 130°C when crystallized slowly (overnight) (sample B). Slow recrystallization of 1 using ethanol instead of methanol induces the formation of large single crystals which only show a single melting peak at T2 = 130°C (sample C). Analysis of powder X-ray diffractograms obtained for A, B and C samples clearly point out the coexistence of two crystalline phases in sample B: phase 1 (observed for sample A) and phase 2 (sample C). From optical microscopy and thermal (DSC) observations, it can be concluded that, upon heating, phase 1 melts at T1 and the molten material converts itself into phase 2 if some crystals of phase 2 are present. Single crystal structure determination of, both, phase 1 and 2 reveal conformational differences of the molecule in both phases which pack in an orthorhombic and a monoclinic unit cell, respectively.
Additional Material:
7 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/macp.1997.021980707
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