An aza-cyclophane stacked in racemic columnar assemblies: whole-molecule disorder in a two-dimensional solid solution.
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 Pna2(1) to Pnma and to whole-molecule disorder of the bowl-shaped molecules within the columns.
Zeller
Matthias
M
Youngstown State University, Department of Chemistry, 1 University Plaza, Youngstown, OH 44555-3663, USA. mzeller@cc.ysu.edu
Lutz
Marlon R
MR
Becker
Daniel P
DP
D018360:Crystallography, X-Ray; D008958:Models, Molecular; D008968:Molecular Conformation; D010091:Oximes / Q000737:chemistry*; D011083:Polycyclic Compounds / Q000138:chemical synthesis / Q000737:chemistry*; D012996:Solutions; D013237:Stereoisomerism
D010091:Oximes; D011083:Polycyclic Compounds; D012996:Solutions; C483859:cyclotriveratrylene