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

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.

Solution and solid state photochromism in a family of shape persistent azobenzene tetramers functionalized with alkyloxy substituents

Shape-persistent azobenzene tetramers functionalized at the periphery with alkyloxy substituents of different lengths have been synthesized and their photochemical behaviour has been investigated.

Reversal of reaction type selectivity by Lewis acid coordination: the ortho photocycloaddition of 1- and 2-naphthaldehyde

Lewis acids, such as AlBr3, completely alter the photochemical behaviour of naphthaldehydes. Instead of typical carbonyl photochemistry, the aldehydes undergo cycloaddition reactions at the arene core upon visible-light irradiation.

Aqueous microgels modified with photosensitive wedge-shaped amphiphilic molecules: synthesis, structure and photochemical behaviour

Hydrophobic “pockets” in aqueous microgels act as a spectroscopic and kinetic probe sensing the microenvironment inside the particles.