Achim Ecker

Supramolecular Organization of Dye Molecules in Zeolite L Channels: Synthesis, Properties, and Composite Materials.

Sequential insertion of different dyes into the 1D channels of zeolite L (ZL) leads to supramolecular sandwich structures and allows the formation of sophisticated antenna composites for light harvesting, transport, and trapping. The synthesis and properties of dye molecules, host materials, composites, and composites embedded in polymer matrices, including two- and three-color antenna systems, are described. Perylene diimide (PDI) dyes are an important class of chromophores and are of great interest for the synthesis of artificial antenna systems. They are especially well suited to advancing our understanding of the structure-transport relationship in ZL because their core fits tightly through the 12-ring channel opening. The substituents at both ends of the PDIs can be varied to a large extent without influencing their electronic absorption and fluorescence spectra. The intercalation/insertion of 17 PDIs, 2 terrylenes, and 1 quaterrylene into ZL are compared and their interactions with the inner surface of the ZL nanochannels discussed. ZL crystals of about 500 nm in size have been used because they meet the criteria that must be respected for the preparation of antenna composites for light harvesting, transport, and trapping. The photostability of dyes is considerably improved by inserting them into the ZL channels because the guests are protected by being confined. Plugging the channel entrances, so that the guests cannot escape into the environment is a prerequisite for achieving long-term stability of composites embedded in an organic matrix. Successful methods to achieve this goal are described. Finally, the embedding of dye-ZL composites in polymer matrices, while maintaining optical transparency, is reported. These results facilitate the rational design of advanced dye-zeolite composite materials and provide powerful tools for further developing and understanding artificial antenna systems, which are among the most fascinating subjects of current photochemistry and photophysics.

Eine kettenförmige η5-Cp*Bi-Verbindung mit 11fach koordiniertem Bismut

Bei der Umsetzung von (Cp*Al)4 mit BiI3 in Toluol bei Raumtemperatur werden rote Kristalle der Verbindung (η5-CpAl)(η5-Cp*Bi)(μ-AlI4)(AlI4)2 · 2 C7H8 gebildet, deren Festkorperstruktur eine kettenformige Anordnung von Cp*Bi-Einheiten aufweist, die uber Tetraiodoaluminat-Ionen verbruckt werden. Diese Strukturmerkmale werden mit denen von Aromaten-Komplexen der schweren Elementen der 14. Gruppe (Zinn, Blei) verglichen. A Chain-like η5-Cp*Bi Compound with Bismuth elevenfold coordinated The reaction of (Cp*Al)4 with BiI3 in toluene at room temperature affords red crystals of the new compound (η5-CpAl)(η5-Cp*Bi)(μ-AlI4)(AlI4)2 · 2 C7H8. The solid state structure exhibits a chain-like arrangement of Cp*Bi units that are bridged by tetraiodoaluminate ions. These structural features are compared with some arene complexes of the heavy group 14 elements (tin, lead).

Zwei strukturell verschiedenartige Stibocenium-Kationen

Abstract After most recent results in alkali metal cyclopentadienide chemistry we succeded in preparing two structurally different sandwich compounds of antimony: [Cp 2 ‴Sb] + AlCl 4 − 1 and [Cp 2 ∗ Sb] + All 4 − 2 (Cp‴ = 1,2,4-tri( tert -butyl)cyclopentadienyl; Cp ∗ = pentamethylcyclopentadienyl). The cations of 1 and 2 , which are isoelectronic with stannocene and similar to their lighter group homologue [Cp 2 ∗ As] + , are the first structurally characterized representatives of the stibocenium-species.

Enantioselective synthesis of calcitriol a-ring fragments

Abstract Commercial (S)-(+)-carvone is transformed to a calcitriol A-ring synthon in 24% overall yield by a highly efficient 11-step sequence. The route is designed to enable the large scale production of enantiopure A-ring precursors for the synthesis of calcitriol analogues

Influence of the Operating Mode of the Excitation Laser in Thermal Lens Spectrometry of Erythrosin in Water

This paper describes the behavior of erythrosin in thermal lens spectrometry. It is shown that the recovery of thermal energy released by the sample in aqueous solutions depends on the operating mode of the excitation laser (cw or pulsed). The results are discussed with respect to the time scales of sample irradiation and thermal lens formation.

International Relations at Universities of Applied Sciences.

An overview of international relations at the Universities of Applied Sciences in Switzerland is presented.An overview of international relations at the Universities of Applied Sciences in Switzerland is presented.

PAT at the Universities of Applied Sciences.

An overview of activities in the field of Process Analytical Technologies (PAT) at the Universities of Applied Sciences in Switzerland is presented.An overview of activities in the field of Process Analytical Technologies (PAT) at the Universities of Applied Sciences in Switzerland is presented.