Acta Crystallographica Section C

Crystal Structure Communications

Volume 62, Part 9 (September 2006)

organic compounds

hj3016 scheme

Acta Cryst. (2006). C62, o557-o560    [ doi:10.1107/S0108270106025819 ]

4-Dimethyl­amino-[beta]-nitro­styrene and 4-dimethyl­amino-[beta]-ethyl-[beta]-nitro­styrene at 100 K

L. Hamdellou, O. Hernandez and J. Meinnel

Abstract: The structures of 4-dimethyl­amino-[beta]-nitro­styrene (DANS), C10H12N2O2, and 4-dimethyl­amino-[beta]-ethyl-[beta]-nitro­styrene (DAENS), C12H16N2O2, have been solved at T = 100 K. The structure solution for DANS was complicated by the presence of a static disorder, characterized by a misorientation of 17% of the mol­ecules. The mol­ecule of DANS is almost planar, indicating significant conjugation, with a push-pull effect through the styrene skeleton extending up to the terminal substituents and enhancing the dipole moment. As a consequence of this conjugation, the hexa­gonal ring displays a quinoidal character; the lengths of the C-N [1.3595 (15) Å] and C-C [1.448 (2) Å] bonds adjacent to the benzene ring are shorter than single bonds. The mol­ecules are stacked in dimers with anti­parallel dipoles. In contrast, the mol­ecule of DAENS is not planar. The ethyl substituent pushes the nitro­propene group out of the benzene plane, with a torsion angle of -21.9 (3). Nevertheless, the mol­ecule remains conjugated, with a shortening of the same bonds as in DANS.

Formula: C10H12N2O2 and C12H16N2O2

hkldisplay filedownload file

Structure factor file (CIF format) (107.1 kbytes)
[ doi:10.1107/S0108270106025819/hj3016Isup2.hkl ]
Contains datablock I

hkldisplay filedownload file

Structure factor file (CIF format) (253.5 kbytes)
[ doi:10.1107/S0108270106025819/hj3016IIsup3.hkl ]
Contains datablock II


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