Acta Crystallographica Section B

Structural Science

Volume 56, Part 4 (August 2000)

Acta Cryst. (2000). B56, 682-689 [doi:10.1107/S0108768100002329]

Crystal-to-crystal photodimerization of trans-cinnamamides

H. Hosomi, Y. Ito and S. Ohba

Abstract: In the crystals of trans-4-methylcinnamamide, C₁₀H₁₁NO (I), trans-4-chlorocinnamamide, C₉H₈ClNO (II), trans-3-(2-thienyl)acrylamide, C₇H₇NOS (III), and trans-cinnamamide, C₉H₉NO (IV), the shortest intermolecular C $\cdots$ C distances between the C=C double bonds are 3.670 (2), 3.632 (2), 3.762 (3) and 4.120 (2) Å, respectively, for the pair of molecules related by a center of symmetry. The structure analysis was also carried out for trans-2-(p-chlorophenyl)-cis-4-(p-chlorophenyl)-1-trans-3-diamidocyclobutane, C₁₈H₁₆Cl₂N₂O₂ (V), which is the [alpha] -type photodimer of (II). The N-H $\cdots$ O hydrogen-bond networks in (I)-(III) are composed of two-dimensional pleated sheets, and those in (IV) and (V) of one-dimensional flat ribbons. The single crystals of (I), (II) and (IV) were photoirradiated with a 250 W ultra-high-pressure mercury lamp through a band-pass filter or a long-pass filter for 2-5 h. The photodimer was produced in each crystal with retention of the single-crystal form. The populations of the dimers were converged to 86.2 (4), 48.4 (6) and 4.5 (2)% in the refinement of the crystals after photoirradiation, (I $^{\prime}$ ), (II $^{\prime}$ ) and (IV $^{\prime}$ ), respectively. Although the intermolecular N-H $\cdots$ O hydrogen-bond network remained in (I $^{\prime}$ ) and (II $^{\prime}$ ), the network was partly broken in (IV $^{\prime}$ ) in the process of photoreaction.

Online 1 August 2000


	Structure factor file (CIF format) (99.4 kbytes) Contains datablock I

	Structure factor file (CIF format) (104.0 kbytes) Contains datablock I'

	Structure factor file (CIF format) (96.6 kbytes) Contains datablock II

	Structure factor file (CIF format) (98.1 kbytes) Contains datablock II'

	Structure factor file (CIF format) (107.0 kbytes) Contains datablock III

	Structure factor file (CIF format) (87.5 kbytes) Contains datablock IV

	Structure factor file (CIF format) (87.7 kbytes) Contains datablock IV'

	Structure factor file (CIF format) (144.7 kbytes) Contains datablock V

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