scholarly journals Structural transformations in crystals induced by radiation and pressure. Part 5. The influence of pressure on the course of the photochemical reaction in crystals of 2,6-difluorocinnamic acid

CrystEngComm ◽  
2016 ◽  
Vol 18 (46) ◽  
pp. 8871-8879 ◽  
Author(s):  
T. Galica ◽  
J. Bąkowicz ◽  
K. Konieczny ◽  
I. Turowska-Tyrk
Keyword(s):  
Photochemical Reaction ◽  
Structural Transformations ◽  
Pressure Part

scholarly journals Structural Transformations in Crystals Induced by Radiation and Pressure. Part 10. The Crystallographic Picture of Photochemical Behaviour of bi(anthracene-9,10-dimethylene) under High Pressure

Crystals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1031
Author(s):  
Julia Bąkowicz ◽  
Ilona Turowska-Tyrk
Keyword(s):  
High Pressure ◽  
Intermolecular Interactions ◽  
Photochemical Reaction ◽  
Molecular Orientation ◽  
Reaction Path ◽  
Structural Transformations ◽  
Initial Increase ◽  
Ambient Conditions ◽  
Photochemical Behaviour ◽  
Pressure Part

The results of the monitoring of the [4 + 4] photocycloaddition reaction path in single crystals of bi(anthracene-9,10-dimethylene) at high pressure are presented. The crystal structures for several steps of the phototransformation at 0.3 GPa and 1.0 GPa were determined and analysed. The applied high pressure did not halt the photochemical reaction and almost 100% of the product molecules were obtained, although the reaction was very slowly reversible similarly to that of ambient conditions. During the crystal phototransformation the intramolecular geometry, molecular orientation and intermolecular interactions of the reactant changed more and more towards the values observed for the product. The initial increase in the unit cell volume brought about by the photochemical reaction was diminished by high pressure. High pressure itself did not significantly influence the intramolecular geometry of the reactant and product molecules, but it influenced the intermolecular interactions.

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

2006 ◽  
Vol 62 (1) ◽  
pp. 128-134 ◽  
Author(s):  
Ilona Turowska-Tyrk ◽  
Elżbieta Trzop ◽  
John R. Scheffer ◽  
Shuang Chen
Keyword(s):  
Hydrogen Bonding ◽  
Solid State ◽  
Photochemical Reaction ◽  
Structural Changes ◽  
Structural Transformations ◽  
Reaction Progress ◽  
X Ray ◽  
Intermolecular Reactions ◽  
Reactant Molecule ◽  
Cyclobutane Ring

Structural changes taking place in a crystal during an intramolecular photochemical reaction [the Yang photocyclization of the α-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.

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