A pilot study into the use of phosphorescent sand in glass transfer studies.

Phosphorescent sand is proposed as a model system to study the behaviour of glass particles and support their activity level interpretation. Pilot experiments into the properties of the phosphorescent particles indicate that they are comparable to glass. Phosphorescent particles are charged effectively using ultraviolet illumination.

Fast photo-processes in triazole-based push-pull systems.

Electron donor-acceptor compounds 1 (asymmetrical push-pull derivative) and 2 (symmetrical push-pull-push derivative) were studied in which one (push-pull) or two aniline units (push-pull-push) are connected to a biphenyl group via triazole linkers, made by "click" chemistry. Steady-state and time-resolved spectroscopies indicate that highly dipolar charge separated excited states are populated in moderately polar solvents. The very similar photophysical behavior of both compounds implies symmetry breaking in the excited state of 2.

A push-pull aromatic chromophore with a touch of merocyanine.

The solvatochromic behavior of N-(2,5-di-tert-butylphenyl)-9-pyrrolidinoperylene-3,4-dicarboximide () was investigated by measuring the excitation and emission spectra over a wide range of temperature in 2-methyltetrahydrofuran (MTHF). The temperature induced spectral changes can be compared with the changes caused by changing solvent polarity using different solvents at room temperature. In both cases a strong positive solvatochromism is observed both in absorption/excitation and in emission.

Paradoxical solvent effects on the absorption and emission spectra of amino-substituted perylene monoimides.

In N-(2,5-di-tert-butylphenyl)-9-pyrrolidinoperylene-3,4-dicarboximide (5PI) the absorption and emission spectra display large solvatochromic shifts, but, remarkably, the Stokes shift is practically independent of solvent polarity. This unique behavior is caused by the extraordinarily large ground-state dipole moment of 5PI, which further increases upon increasing the solvent polarity, whereas the excited-state dipole moment is less solvent dependent. In the corresponding piperidine compound, 6PI, this effect is much less important owing to the weaker coupling between the amino group and the aromatic imide moiety, and in the corresponding naphthalimide, 5NI, it is absent.