Jump to main content
Jump to site search

Issue 22, 2011
Previous Article Next Article

Enantiomeric crystallization of (±)-trans-1,2-diaminocyclohexane under pressure

Author affiliations


The isothermal and isochoric crystallizations of (±)-trans-1,2-diaminocyclohexane, C6H10(NH2)2, (±)-DACH, yield enantiomeric conglomerates of orthorhombic symmetry, space groupP21212, the same as obtained by isobaric crystallization. Despite the compression to 73% of ambient pressure volume, no racemic compound of DACH was formed. This contradicts for this compound the possibility of reverse causality between density and preferred enantiomorphic/racemic crystallization in Wallach's rule. The crystal structures have been determined at 0.36, 0.52, 0.65, 1.19 and 2.04 GPa at 296 K by single-crystal X-ray diffraction. It has been established that the enantiomeric-conglomerate crystallization of DACH at ambient pressure is mainly due to the molecular arrangement, governed by the close-packing rule in the crystal. High pressure enhances the close packing, and it does not change the course of crystallization of (±)-DACH. The shortest intermolecular contacts, NH⋯N and CH⋯N, become most compressed between 0.36 and 2.04 GPa, indicating that such weak hydrogen bonds are enhanced by pressure. The phase diagram of (±)-DACH has been outlined to 2.04 GPa.

Graphical abstract: Enantiomeric crystallization of (±)-trans-1,2-diaminocyclohexane under pressure

Back to tab navigation

Supplementary files

Publication details

The article was received on 12 May 2011, accepted on 12 Aug 2011 and first published on 08 Sep 2011

Article type: Paper
DOI: 10.1039/C1CE05553D
Citation: CrystEngComm, 2011,13, 6742-6746
  •   Request permissions

    Enantiomeric crystallization of (±)-trans-1,2-diaminocyclohexane under pressure

    W. Cai and A. Katrusiak, CrystEngComm, 2011, 13, 6742
    DOI: 10.1039/C1CE05553D

Search articles by author