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 photo-induced transformations in crystals of 2,6-difluorocinnamic acid under ambient conditions

2016 ◽  
Vol 72 (7) ◽  
pp. 593-599 ◽  
Author(s):  
Tomasz Galica ◽  
Julia Bąkowicz ◽  
Piotr Broda ◽  
Ilona Turowska-Tyrk
Keyword(s):  
Dicarboxylic Acid ◽  
Photochemical Reaction ◽  
Uv Light ◽  
Unit Cell ◽  
Initial Increase ◽  
Geometrical Parameters ◽  
Ambient Conditions ◽  
Unit Cell Parameters ◽  
Cell Parameters

Several conditions need to be fulfilled for a photochemical reaction to proceed in crystals. Some of these conditions, for example, geometrical conditions, depend on the particular type of photochemical reaction, but the rest are common for all reactions. The mutual directionality of two neighbouring molecules determines the kind of product obtained. The influence of temperature on the probability of a photochemical reaction occurring varies for different types of photochemical reaction and different compounds. High pressure imposed on crystals also has a big influence on the free space and the reaction cavity. The wavelength of the applied UV light is another factor which can initiate a reaction and sometimes determine the structure of a product. It is possible, to a certain degree, to control the packing of molecules in stacks by using fluoro substituents on benzene rings. The crystal and molecular structure of 2,6-difluorocinnamic acid [systematic name: 3-(2,6-difluorophenyl)prop-2-enoic acid], C9H6F2O2, (I), was determined and analysed in terms of a photochemical [2 + 2] dimerization. The molecules are arranged in stacks along theaaxis and the values of the intermolecular geometrical parameters indicate that they may undergo this photochemical reaction. The reaction was carried outin situand the changes of the unit-cell parameters during crystal irradiation by a UV beam were monitored. The values of the unit-cell parameters change in a different manner,viz.cell lengthaafter an initial increase starts to decrease,bafter a decrease starts to increase,cincreases and the unit-cell volumeVafter a certain increase starts to decrease. The structure of a partially reacted crystal,i.e.containing both the reactant and the product, namely 2,6-difluorocinnamic acid–3,4-bis(2,6-difluorophenyl)cyclobutane-1,2-dicarboxylic acid (0.858/0.071), 0.858C9H6F2O2·0.071C18H12F4O4, obtainedin situ, is also presented. The powder of compound (I) was irradiated with UV light and afterwards crystallized [as 3,4-bis(2,6-difluorophenyl)cyclobutane-1,2-dicarboxylic acid toluene hemisolvate, C18H12F4O4·0.5C7H8] in a space group different from that of the crystal containing thein-situdimer.

The crystal and molecular structure of sodium 4-(2,4,6-triisopropylbenzoyl)benzoate in terms of the photochemical behaviour of the anion

2015 ◽  
Vol 71 (5) ◽  
pp. 410-414 ◽  
Author(s):  
Krzysztof Konieczny ◽  
Julia Bąkowicz ◽  
Ilona Turowska-Tyrk
Keyword(s):  
Molecular Structure ◽  
Intermolecular Interactions ◽  
Photochemical Reaction ◽  
Crystalline State ◽  
Crystal And Molecular Structure ◽  
Hirshfeld Surface ◽  
Geometrical Parameters ◽  
Photochemical Behaviour

Contrary to the known 4-(2,4,6-triisopropylbenzoyl)benzoate salts, di-μ-aqua-bis[tetraaquasodium(I)] bis[4-(2,4,6-triisopropylbenzoyl)benzoate] dihydrate, [Na2(H2O)10](C23H27O3)2·2H2O, (1), does not undergo a photochemical Norrish–Yang reaction in the crystalline state. In order to explain this photochemical inactivity, the intermolecular interactions were analyzed by means of the Hirshfeld surface and intramolecular geometrical parameters describing the possibility of a Norrish–Yang reaction were calculated. The reasons for the behaviour of the title salt are similar crystalline environments for both theo-isopropyl groups in the anion, resulting in similar geometrical parameters and orientations, and that these interaction distances differ significantly from those found in salts where the photochemical reaction occurs.

Hydrogen bonding in liquid methanol at ambient conditions and at high pressure

2000 ◽  
Vol 98 (3) ◽  
pp. 125-134 ◽  
Author(s):  
T. Weitkamp, J. Neuefeind, H. E. Fisch
Keyword(s):  
High Pressure ◽  
Hydrogen Bonding ◽  
Ambient Conditions
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