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When choosing between two options, a sensible strategy is to choose the highest value option. To do this, both options must be evaluated and compared. The way value is judged and utility is perceived therefore has strong effects on which option is chosen. Traditionally, value was considered absolute. However, research on human decision-making suggests that, for us, utility is relative and based on past experiences or expectations. The study of successive contrast effects suggests that the same might be true for animals. Here we show that ants which had previously experienced a low quality food source showed higher acceptance of medium quality food (e.g. 0.1M then 0.5M; positive contrast) than if they had received the medium food all along (e.g. 0.5M then 0.5M; control). Ants also showed lower acceptance of medium food when previously offered high quality food (e.g. 2M then 0.5M; negative contrast). Further experiments demonstrate that these contrast effects arise from psychological, not physiological or psychophysical, causes. Pheromone deposition also correlates with perceived reward value, and ants also showed successive contrasts in their pheromone deposition. Contrast effects occurred not only when ants collected private information outside the nest, but also when information was received through trophallactic interactions in the nest. Relative value perception can therefore be expected to have strong effects not only on individual behaviour, but also on collective decision-making.

Methods of surface analysis and micromodification using the scanning electrochemical microscope (SECM) are described. An ultramicroelectrode (UME) is scanned in a liquid electrolyte a few microns above a sample's surface. The principles of SECM are explained. Local surface conductivity and reactivity can be imaged in the feedback and collector/generator mode. The same set-up allows micromodification processes as well. The degree of doping of polyaniline deposited on a PETG film was increased locally. The generated structure formed an interdigital array consisting of doped and undoped polyaniline. Its local conductivity was successfully analysed in a second step. To fabricate a polymer microstructure the monomer 2,5-bis(1-methyl-pyrrol-2yl)-thiophene was deposited by evaporation on an ITO substrate. Polymerisation was induced by the tip via an oxidation reaction. The remaining monomer was easily removed by organic solvents. A new method for the microdeposition of silver on a gold substrate is described. Silver cations were complexated in an aqueous solution of ammonia. Protons locally generated by the tip shifted the complexation equilibrium to create free silver cations. When the sample is held on an adequate potential they were deposited on the gold surface.

The reaction of 1,1′-ferrocenylene-bis(methylenepyridinium) tosylate chloride (1) with aza-x-crown-y (x/y = 12/4; 15/5; 18/6) gives the three novel ferrocene biscrown ethers 1,1′-ferrocenylene-bis(methylene-aza-x-crown-y) (x/y = 12/4, 2; 15/5, 3; 18/6, 4). The reaction of 1 with diaza-18-crown-6 represents a new and simple route to the known ferrocene cryptands 1,1′-zacyclooctadecane)] (5) and 1,1″:1′,1″-bisferrocenylene-bis-[bis-7,16-methylene(1,4,10,13-tetraoxa-7,16-diazacyclooctadecane)] (6). The solid-state structure of 5 is described. The ferrocene bridge compresses the diaza crown ether leading to an internitrogen distance of 458 pm. The stoichiometry of Na+ and K+ complexes with 2 and 3 in CD3CN determined in NMR titration experiments suggests the formation of Na+ and K+ crown ether sandwich complexes in solution. Cyclic voltammograms of 2 and 5 in the presence of varying amounts of H+ and Na+ have been recorded. The redox potential of ferrocene is shifted by +180 mV in the case of 5 · Na+ and up to +600 mV in the case of 5 · H+H+ relative to 5, but only by + 70 mV with 2 · Na+ and 2. The protonation of 5 give rises to several isomers (exo and endo protonation) which differ significantly in their redox potential. The extremely large positive shift of the oxidation potential of the diprotonated ferrocene cryptand corresponds to an increase in the acidity of 5 · H+H+ upon oxidation by more than ten orders of magnitude and makes this system a candidate for the directed membrane transport of protons.

Mono- and dibenzoannelated [2.2]paracyclophanes 12 and 1 were synthesized by palladium-catalyzed twoand four-fold alkenylation of vicinal di- and tetrabromides 5 and 6, respectively, and subsequent electrocyclization/ dehydrogenation of the resulting (E,Z,E)-trienes. Further extensions of the annelated ring systems, leading to the tetrahydronaphthalene derivative 15, the bis-terphenylene derivative 16, and the benzobis[2.2]paracyclophane 18, were achieved through derivatization of suitable substituents introduced with the alkene coupling component. Mono- and polyanions of some derivatives were generated and studied by ESR, ENDOR, and NMR spectroscopy, as well as by cyclic voltammetry. The assembly of mutually orthogonal r-systems in arene annelated [2.2]paracyclophanes allows the reversible incorporation of up to six additional electrons per molecule, which is the upper limit for hydrocarbons reported to date.

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