Two novel lumophores based on aluminum and zinc metallo-8-hydroxyquinolates have been prepared as electroluminescent materials, and their absorbance, photoluminescence, and electroluminescence properties compared with unsubstituted versions of these same complexes. 8-Hydroxy-5-piperidinylquinolinesulfonamide (1) was synthesized in order to add an electron-withdrawing substituent at the 5-position in 8-hydroxyquinoline, increasing the solubility of the corresponding metal quinolate complexes in nonpolar solvents, and producing a blue-shift in the emission wavelength maximum, relative to complexes formed from the unsubstituted compound. The aluminum complex (Al(QS)3) and the zinc complex (Zn(QS)2) of 1 were compared with the aluminum and zinc complexes of unsubstituted 8-hydroxyquinoline (AlQ3 and ZnQ2), both as solutions and as pure thin films, or as poly(N-vinylcarbazole) (PVK) thin films doped with the metal quinolates. Ultraviolet photoelectron spectroscopy data are presented to assist in estimating the energies of the highest occupied molecular orbitals (HOMO) of AlQ3, ZnQ2, Al(QS)3, and Zn(QS)2. Electroluminescence data shows that ITO/Al(QS)3−PVK/aluminum and ITO/Zn(QS)2−PVK/aluminum devices exhibit good diode-like electrical behavior. Electroluminescence spectra mimic the photoluminescence spectra for all complexes.

Langmuir-Blodgett (LB) films of poly (5-(2-(4-((4-hexylphenyl)azo)phenoxy)ethyl) L-glutamate) (P2) and poly (5-(6-(4-((4-hexylphenyl)azo)phenoxy)hexyl) L-glutamate) (P6) polymers with a stiff backbone and flexible side chains ("hairy rods"), have been investigated at different steps of the photoisomerization and annealing process by means of X-ray reflection and U V-vis spectroscopy. From the absorption spectra the amount of aggregated chromophores was estimated using a peak-fitting procedure. The original LB structure, which is characterized by deformed "hairy rods" arranged in bilayers, is destroyed upon photoisomerization or annealing. The side chains relax to a more symmetrical distribution around the main chain helix. Furthermore the aggregation of the chromophores as well as their orientation in respect to the main chain helix is changed. The changes are more pronounced upon irradiation and depend on the length of the spacer used to tether the chromophores to the polymer backbone.

Neutron reflection and surface plasmon optical experiments have been performed to evaluate structural data of the interfacial binding reaction between the protein streptavidin and a solid-supported lipid monolayer partly functionalized by biotin moieties. Since both experimental techniques operate in a total internal reflection geometry at a substrate/solution interface, identical sample architectures allow for a direct comparison between the results obtained with these two recently developed methods. It is found that a monomolecular layer of dipalmitoyllecithin doped with 5 mol% of a biotinylated-phosphatidylethanolamine shows a thickness of d1 approximately (3.4 +/- 0.5) nm. Binding of streptavidin to the biotin groups results in an overall layer thickness of d = (5.9 + 0.5) nm that demonstrates the formation of a well-ordered protein monolayer with the (biotin+spacer) units of the functionalized lipids being fully embedded into the binding pocket of the proteins. It is demonstrated by model calculations that a more detailed picture of the internal structure of this supramolecular assembly can only be obtained if one uses deuterated lipid molecules, thus generating a high contrast between individual layers.