Acta Crystallographica Section C

Crystal Structure Communications

Volume 65, Part 8 (August 2009)

organic compounds

sk3332 scheme

Acta Cryst. (2009). C65, o381-o384 [ doi:10.1107/S0108270109024457 ]

Polymorphism and phase transition behavior of 6,6'-bis(chloromethyl)-1,1',4,4'-tetramethyl-3,3'-(p-phenylenedimethylene)bis(piperazine-2,5-dione)

N. W. Polaske, G. S. Nichol and B. Olenyuk

Abstract: A crystallographic investigation of the title compound, C₂₂H₂₈Cl₂N₄O₄, using crystals obtained under different crystallization conditions, revealed the presence of two distinct polymorphic forms. The molecular conformation in the two polymorphs is very different: one adopts a `C' shape, whereas the other adopts an `S' shape. In the latter, the molecule lies across a crystallographic twofold axis. The `S'-shaped polymorph undergoes a reversible orthorhombic-to-monoclinic phase transition on cooling, whereas the structure of the `C'-shaped polymorph is temperature insensitive.

Formula: Three polymorphs of C₂₂H₂₈Cl₂N₄O₄


	Structure factor file (CIF format) (81.2 kbytes) [ doi:10.1107/S0108270109024457/sk33321sup2.hkl ] Contains datablock 1

	Structure factor file (CIF format) (112.5 kbytes) [ doi:10.1107/S0108270109024457/sk33322rtsup3.hkl ] Contains datablock 2rt

	Structure factor file (CIF format) (143.2 kbytes) [ doi:10.1107/S0108270109024457/sk33322ltsup4.hkl ] Contains datablock 2lt

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