Zero-obliquity twin lattice quasi-symmetry threefold twinning in 1-{(R)-1-[(3-oxo-2-isoindolinoyl)methyl]-2-propenyl}-5-methyl-2,3-indolinedione

Massimo Nespolo, Rebecca W. Smaha, Sean Parkin

Research output: Contribution to journalArticlepeer-review

2 Scopus citations


Threefold twinning in 1-{(R)-1-[(3-oxo-2-isoindolinoyl)methyl]-2-propenyl}-5-methyl-2,3-indolinedione, C21H16N2O4, has been reported recently [Trost et al. (2020). Org. Lett. 22, 2584-2589] but the twin characterization was not published. This twinning presents several interesting features. The crystal structure is monoclinic, but its lattice is metrically strongly pseudo-orthorhombic and underpins a strongly pseudo-hexagonal sublattice. Several possible twin laws are compatible with these metric specializations, among which the one found experimentally corresponds to a trichromatic point group. Twinning is by reticular pseudo-merohedry with twin index 2 and zero obliquity but a non-zero twin misfit. The twin lattice coincides with the pseudo-hexagonal sublattice of the individual domain, which justifies the adoption of the unconventional setting B21 of the space group.

Original languageEnglish
Pages (from-to)643-649
Number of pages7
JournalActa Crystallographica Section B: Structural Science, Crystal Engineering and Materials
StatePublished - Aug 1 2020


  • chromatic symmetry
  • twin misfit
  • twinning
  • zero-obliquity twin lattice quasi-symmetry

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Atomic and Molecular Physics, and Optics
  • Metals and Alloys
  • Materials Chemistry


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