Orthorhombic polymorph of (2E)-2-(2,3-dihydro-1H-inden-1-ylidene)-2,3-dihydro-1H-inden-1-one

Hairong Li,Steven F Watkins,Frank R Fronczek

doi:10.1107/s1600536812035994

Abstract

The title compound, C18H14O, is polymorphic at 123 K. The orthorhombic form reported herein has two independent molecules in the asymmetric unit, with molecular volume 313.5 Å3. The previously reported triclinic (P-1) form [Raston & Scott (2000 ▶). Green Chem., 2, 49–52] has molecular volume 309.6 Å3 at the same temperature. All three molecules deviate significantly and systematically from the putative Cs symmetry (δr.m.s. = 0.0265, 0.0256, 0.0497 Å). Comparison of the two molecules in the orthorhombic polymorph shows that 16 of the 19 equivalent pairs of framework atoms have a mirror-image pattern of deviations (above/below plane), suggesting that the two are quasi-enantiomorphs. The pattern of deviations in the triclinic form is nearly the same (13 of 19 atom pairs) as the orthorhombic form.

Highlights

The title compound, C18H14O, is polymorphic at 123 K
Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: JJ2149)
The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry

Summary

Data collection

Refinement R[F 2 > 2(F 2)] = 0.057 wR(F 2) = 0.110 S = 1.05 4236 reflections 344 parameters H-atom parameters constrained. The orthorhombic form reported has two independent molecules in the asymmetric unit, with molecular volume 313.5 A 3. The previously reported triclinic (P1) form [Raston & Scott (2000). Green Chem., 2, 49–52] has molecular volume 309.6 A 3 at the same temperature. All three molecules deviate significantly and systematically from the putative Cs symmetry Comparison of the two molecules in the orthorhombic polymorph shows that 16 of the 19 equivalent pairs of framework atoms have a mirror-image pattern of deviations (above/below plane), suggesting that the two are quasi-enantiomorphs. The pattern of deviations in the triclinic form is nearly the same (13 of 19 atom pairs) as the orthorhombic form

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