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3-Pentadecylphenol (PDP) belongs to a natural group of amphiphilic phenols and plays a lot of different interesting functions. Effects on the phase behavior of bilayer mixtures of DPPC (dipalmitoyl phosphatidylcholine) or MPPC (l-myristoyl-2-palmitoyl-phosphatidylcholine) and PDP has been investigated using electron microscopy, differential scanning calorimetry (DSC) and fluorescence spectroscopy. Addition of 3-pentadecylphenol increases the phase transition temperature T m . Above 20 mole % PDP in DPPC the phase behavior becomes increasingly complex. Coexistence of various phases within the bilayer with different composition and structural properties is suggested and is responsible for the changes of the physico-chemical properties of the lipid bilayer. Excellent analogy between fluorescence and calorimetric data demonstrate that phase effects are primarily caused by the abundance of the large phenolic headgroup. DPPC and MPPC bilayers are similarly affected but MPPC is more sensitive to added PDP.

Supramolecular host–guest complexes formed between dye molecules, which are absorbing and fluorescing in the visible range, and cyclodextrin molecules are studied with the aim to generate a self-assembled nanostructured layer on a surface. Studies in solution show that an aminocoumarin dye, i.e. coumarin-6, binds strongly to β-cyclodextrin and yields fluorescent structures. The complex formation is substantiated by 17 nm blue shift of the fluorescence spectrum. The binding of thiolated cyclodextrin, 6-monodeoxy-6-monothio-β-cyclodextrin, to gold surface is then studied by induced change in the second-harmonic signal intensity generated from the surface. The saturation times of surface adsorption, as a measure of binding kinetics, are estimated for thiolated cyclodextrin as well as hexadecanethiol. The results support formation of self-assembled layers of the host molecules, which can serve as basis for the formation of supramolecular host–guest surface layers.

The photophysical properties of 10-decyl- and 10-propenyl-9-acridones, important emitters in electro- and chemiluminescence, are investigated in dependence of the solvent polarity and its hydrogen bonding ability at room temperature as well as in frozen matrix at 77 K. Fluorescence is inefficient in non-polar solvents at room temperature due to fast intersystem crossing but increases with solvent polarity due to the inversion of the S 1 (ππ ∗ ) and the T (nπ ∗ ) states. In the case of 9-[10-(1-propenyl)]-acridone the dependencies of the fluorescence spectrum and quantum yield on the ET(30) solvent parameters indicate that intermolecular hydrogen bonded solute-solvent complexes are formed in the excited state, inducing efficient non-radiative deactivation.

For the purpose of modelling medium effects on the lowest Rydberg transitions of amines, ab initio calculations on excited clusters of ammonia and helium were performed. As the excited state surface is strongly repulsive, shifts of the transitions to higher energies are reproduced. As charge is accumulated around the perturber atom, the spatial charge distribution is considerably altered. The diffuse character of the Rydberg orbitals is not principally changed after clustering.