The influence of the core extension of perylene tetracarboxdiimides on the thermotropic behavior has been investigated. A homologous series of alkyl substituted tetracarboxdiimides, namely, perylene diimide, terrylene diimide, quaterrylene diimide, and coronene diimide, was synthesized. These compounds display absorption maxima in the region of 430-760 nm with high extinction coefficients and show a high thermal stability up to 450 °C. Structural evaluation revealed an identical columnar self-organization for the derivatives below their isotropization temperature. An intracolumnar packing of the disks with a lateral rotation of 45°to each other resulted in a helical pitch containing four molecules. The phase transition to the isotropic phase is shifted to higher temperatures for larger aromatic cores within this series of compounds. On the other hand, differences in the self-assembly during crystallization from the isotropic phase were observed. While perylene tetracarboxdiimide and terrylene tetracarboxdiimide formed large and highly ordered domains with arranged edge-on molecules, the coronene tetracarboxdiimide disks self-organized face-on leading to a homeotropic phase. The different molecular orientation on surfaces was correlated with diversified substitution patterns of the aromatic cores. The manipulation of the molecular architecture opens thus the opportunity to control the spontaneous self-alignment. This improvement of the macroscopic organization ensures an undisturbed percolation pathway for charge carriers between electrodes in field-effect transistors or in photovoltaic cells.

A systematic approach towards highly fluorescent, water-soluble perylene-3,4:9,10-tetracarboxylic acid diimide chromophores is presented. Water solubility was introduced first through the attachment of four hydrophilic substituents onto the bay region of the perylene dye. Positively and negatively charged groups were then applied to the chromophore, and their number and their distance from the aromatic scaffold were systematically varied. To suppress aggregation, the chromophore was further isolated within a dendritic shell. Such variation of structural features and a thorough investigation of the resulting optical properties facilitated the first synthesis of perylene-3,4:9,10-tetracarboxylic acid diimides combining the properties of water solubility and fluorescence quantum yields (FQYs) close to unity, which makes them attractive as high-performance fluorescence probes in aqueous media.

Sphingosine-1-phosphate (S1P) is a widespread lysophospholipid which displays a wealth of biological effects. Extracellular S1P conveys its activity through five specific G-protein coupled receptors numbered S1P(1) through S1P(5). Agonists of the S1P(1) receptor block the egress of T-lymphocytes from thymus and lymphoid organs and hold promise for the oral treatment of autoimmune disorders. Here, we report on the discovery and detailed structure-activity relationships of a novel class of S1P(1) receptor agonists based on the 2-imino-thiazolidin-4-one scaffold. Compound 8bo (ACT-128800) emerged from this series and is a potent, selective, and orally active S1P(1) receptor agonist selected for clinical development. In the rat, maximal reduction of circulating lymphocytes was reached at a dose of 3 mg/kg. The duration of lymphocyte sequestration was dose dependent. At a dose of 100 mg/kg, the effect on lymphocyte counts was fully reversible within less than 36 h. Pharmacokinetic investigation of 8bo in beagle dogs suggests that the compound is suitable for once daily dosing in humans.

Two new synthetic approaches to terrylenediimides, highly photostable fluorescent dyes, are described. For the first time terrylenediimide has been synthesised in a straightforward procedure that makes large quantities available. The second route includes an efficient cross-coupling reaction followed by a cyclodehydrogenation. Monofunctionalisation of the imide structure allows terrylenediimides now to be coupled with a variety of compounds, for example, by Suzuki cross-coupling, which can lead to an array of terrylenediimides with new functional groups such as hydroxy, amino, or carboxy groups needed to link up with other molecules. The functionalisation in the bay region is used to tune the properties of terrylenediimides and extend the range of applications, for example, by introducing water solubility. These tetrasubstituted terrylenediimides offer, depending on the substituents used, exciting features such as good solubility in common organic solvents, water solubility, or NIR absorption.