Acta Crystallographica Section B

Structural Science

Volume 62, Part 1 (February 2006)

research papers

Acta Cryst. (2006). B62, 128-134 [ doi:10.1107/S0108768105034014 ]

Monitoring structural transformations in crystals. 8. Monitoring molecules and a reaction center during a solid-state Yang photocyclization

I. Turowska-Tyrk, E. Trzop, J. R. Scheffer and S. Chen

Abstract: Structural changes taking place in a crystal during an intramolecular photochemical reaction [the Yang photocyclization of the [alpha] -methylbenzylamine salt with 1-(4-carboxybenzoyl)-1-methyladamantane] were monitored step-by-step using X-ray structure analysis. This is the first example of such a study carried out for an intramolecular photochemical reaction. During the photoreaction, both the reactant and product molecules change their orientation, but the reactant changes more rapidly after the reaction is about 80% complete. The distance between directly reacting atoms in the reactant molecule is almost constant until about 80% reaction progress and afterwards decreases. The torsion angle defined by the reactant atoms that form the cyclobutane ring also changes in the final stages of the photoreaction. These phenomena are explained in terms of the influence of many product molecules upon a small number of reacting molecules. The adamantane portion shifts more than the remaining part of the anionic reactant species during the reaction, which is explained in terms of hydrogen bonding. The structural changes are accompanied by changes in the cell constants. The results obtained in the present study are compared with analogous results published for intermolecular reactions.

Keywords: photochemical reactions; Yang photocyclization; monitoring structural changes; X-ray structure analysis.


	Structure factor file (CIF format) (198.5 kbytes) [ doi:10.1107/S0108768105034014/bk50194.4Psup2.hkl ] Contains datablock 4.4P

	Structure factor file (CIF format) (198.5 kbytes) [ doi:10.1107/S0108768105034014/bk501910.6Psup3.hkl ] Contains datablock 10.6P

	Structure factor file (CIF format) (198.6 kbytes) [ doi:10.1107/S0108768105034014/bk501926.5Psup4.hkl ] Contains datablock 26.5P

	Structure factor file (CIF format) (199.3 kbytes) [ doi:10.1107/S0108768105034014/bk501942.3Psup5.hkl ] Contains datablock 42.3P

	Structure factor file (CIF format) (199.6 kbytes) [ doi:10.1107/S0108768105034014/bk501951.8Psup6.hkl ] Contains datablock 51.8P

	Structure factor file (CIF format) (200.0 kbytes) [ doi:10.1107/S0108768105034014/bk501974.5Psup7.hkl ] Contains datablock 74.5P

	Structure factor file (CIF format) (200.5 kbytes) [ doi:10.1107/S0108768105034014/bk501980.1Psup8.hkl ] Contains datablock 80.1P

	Structure factor file (CIF format) (199.8 kbytes) [ doi:10.1107/S0108768105034014/bk501987.5Psup9.hkl ] Contains datablock 87.5P

	Structure factor file (CIF format) (200.7 kbytes) [ doi:10.1107/S0108768105034014/bk501991.0Psup10.hkl ] Contains datablock 91.0P

	Structure factor file (CIF format) (200.0 kbytes) [ doi:10.1107/S0108768105034014/bk501994.5Psup11.hkl ] Contains datablock 94.5P

	Structure factor file (CIF format) (199.7 kbytes) [ doi:10.1107/S0108768105034014/bk501995.8Psup12.hkl ] Contains datablock 95.8P

	Structure factor file (CIF format) (199.8 kbytes) [ doi:10.1107/S0108768105034014/bk501996.2Psup13.hkl ] Contains datablock 96.2P

	Structure factor file (CIF format) (199.7 kbytes) [ doi:10.1107/S0108768105034014/bk5019100Psup14.hkl ] Contains datablock 100P

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