An aza-cyclophane stacked in racemic columnar assemblies: whole-molecule disorder in a two-dimensional solid solution

• Published in: Acta crystallographica. Section B, Structural science Structural science, 2009-04, Vol.65 (2), p.223-229
• Main Authors: Zeller, Matthias, Lutz Jr, Marlon R., Becker, Daniel P.
• Format: Article
• Language: English
• Subjects: Beckmann rearrangement; Chemistry; columnar assemblies; Crystal structure; Crystallography; Crystallography, X-Ray; cyclotriveratrylene; Geometry; Models, Molecular; Molecular Conformation; Molecules; Oximes - chemistry; Polycyclic Compounds - chemical synthesis; Polycyclic Compounds - chemistry; solid solution; Solutions; Stereoisomerism; whole-molecule disorder
• ISSN: 0108-7681; 2052-5192; 1600-5740; 2052-5206
• DOI: 10.1107/S0108768109002134

The oxime derivative of [1.1.1]cyclophane cyclotriveratrylene (CTV) was ring expanded utilizing a Beckmann rearrangement to provide a ten‐membered N‐acetyl macrocyclic amide that crystallizes as a chloroform monosolvate in columnar assemblies manifesting an unusual disorder within the crystal. Columns made up of this structure consist of infinite columnar assemblies of alternating d and l enantiomers and therefore necessarily are made up of a racemate, yet the chiralities of individual molecules in adjacent columns are independent of one another, leading to the overall formation of a two‐dimensional solid solution. The random arrangement of the columns within the structure leads to the emergence of a crystallographic mirror plane not reflected by the molecular symmetry, to a change of symmetry from Pna21 to Pnma and to whole‐molecule disorder of the bowl‐shaped molecules within the columns.