Acta Crystallographica Section C

Structural Chemistry

Volume 70, Part 2 (February 2014)

organic compounds

eg3145 scheme

Acta Cryst. (2014). C70, 202-206    [ doi:10.1107/S2053229613034232 ]

Photochemical dimerization of a fluorinated di­benzyl­ideneacetone in chloro­form solution

A. Schwarzer and E. Weber

Abstract: (1E,4E)-1,5-Bis(2,6-di­fluoro­phen­yl)penta-1,4-dien-3-one, C17H10F4O, (I), dimerizes under sunlight in chloro­form solution to form the corresponding cyclo­butane derivative, (2E,2'E)-1,1'-[2,4-bis­(2,6-di­fluoro­phen­yl)cyclo­butane-1,3-di­yl]bis­[3-(2,6-di­fluoro­phen­yl)prop-2-en-1-one], C34H20F8O2, (II). The crystal structure of (I) explains why no topochemical di­merization can occur in the solid state. In the solid, mol­ecules of dimer (II) show the `truxillic acid'-type arrangement of crystallographic centres of inversion, with half a mol­ecule per asymmetric unit and cell dimensions closely related to those of the monomer. Inter­molecular inter­actions in both solids are dominated by C-H...O and C-H...F contacts and also comprise inter­actions with aromatic systems (C-H...[pi] and [pi]-[pi]).

CCDC references: 742631 and 978150

Formula: C17H10F4O and C34H20F8O2

Keywords: crystal structure; photodimerization; di­benzyl­ideneacetone; cyclo­butane; fluorine interactions.

hkldisplay filedownload file

Structure factor file (CIF format) (142.5 kbytes)
[ doi:10.1107/S2053229613034232/eg3145Isup2.hkl ]
Contains datablock I

hkldisplay filedownload file

Structure factor file (CIF format) (124.0 kbytes)
[ doi:10.1107/S2053229613034232/eg3145IIsup3.hkl ]
Contains datablock II


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