Conformational space of cinchonidine has been explored by means of ab initio potential and free energy surfaces, and the temperature-induced changes of conformational populations were studied by a combined NOESY-DFT analysis. The DFT-derived potential energy surface investigation identified four new conformers. Among them, Closed(7) is substantially relevant to fully understand the conformational behavior. The energy surfaces gave access to the favored transformation pathways at different temperatures (280-320 K). They also revealed the reasons for the negligible presence of energetically stable conformers and explained the experimentally observed temperature dependence of the populations.

Allylpalladium complexes with chiral bis(dihydrooxazole) ligands were studied as catalysts for the enantioselective allylic substitution reaction of rac‐1,3‐diphenylprop‐2‐enyl acetate (rac‐5) with the anion of dimethyl malonate (Scheme 1). Using enantiomerically pure (S,E)‐1‐(4‐tolyl)‐3‐phenylprop‐2‐enyl acatete ((S)‐25) as substrate, the reaction was shown to proceed by a clean ‘syn’ displacement of acetate by dimethyl malonate (Scheme 6). The [Pd11(η3‐allyl)] complex 18 and the analogous [Pd(η3‐1,3‐diphenylallyl)] complex 20, both containing the same bis(dihydrooxazole) ligand, were characterized by X‐ray structure analysis and by NMR spectroscopy in solution. The structural data reveal that steric interactions of the allyl system with the chiral ligand result in selective electronic activation of one of the allylic termini. The higher reactivity of one allylic terminus toward nucleophilic attack is reflected in a significantly longer PdC bond and a shift of the corresponding 13C‐NMR resonance to higher frequency.

The feasibility of using surfactant vesicles as soft templates for the peroxidase-triggered polymerization of aniline was investigated. It was found that mixed anionic vesicles (diameter approximately 80 nm) composed of sodium dodecylbenzenesulfonate (SDBS) and decanoic acid (1:1, molar ratio) are promising templates. In the presence of the vesicles and horseradish peroxidase/hydrogen peroxide (H2O2) as initiator system, aniline polymerizes under optimized conditions at pH=4.3 to the desired conductive emeraldine form of polyaniline (PANI). The optimal polymerization conditions were elaborated, and some of the chemical and physicochemical aspects of the reaction system were investigated. After addition of aniline and peroxidase to the vesicles, aniline is only loosely associated with the vesicles, as shown by NOESY-NMR and zeta potential measurements. In contrast, the peroxidase strongly binds to the vesicle surface, as shown by fluorescence measurements using TNS (2-(p-toluidino)naphthalene-6-sulfonate) as vesicle membrane probe. This binding of the enzyme to the vesicle surface indicates that the polymerization reaction is initiated predominantly on the surface of the vesicles. Cryo-transmission electron microscopy indicates that the polymerization product remains associated with the vesicles on their surface. For short reaction times (30 s

Compounds including the free or coordinated gas-phase cations [Ag(eta(2)-C(2)H(4))(n)](+) (n = 1-3) were stabilized with very weakly coordinating anions [A](-) (A = Al{OC(CH(3))(CF(3))(2)}(4), n = 1 (1); Al{OC(H)(CF(3))(2)}(4), n = 2 (3); Al{OC(CF(3))(3)}(4), n = 3 (5); {(F(3)C)(3)CO}(3)Al-F-Al{OC(CF(3))(3)}(3), n = 3 (6)). They were prepared by reaction of the respective silver(I) salts with stoichiometric amounts of ethene in CH(2)Cl(2) solution. As a reference we also prepared the isobutene complex [(Me(2)C=CH(2))Ag(Al{OC(CH(3))(CF(3))(2)}(4))] (2). The compounds were characterized by multinuclear solution-NMR, solid-state MAS-NMR, IR and Raman spectroscopy as well as by their single crystal X-ray structures. MAS-NMR spectroscopy shows that the [Ag(eta(2)-C(2)H(4))(3)](+) cation in its [Al{OC(CF(3))(3)}(4)](-) salt exhibits time-averaged D(3h)-symmetry and freely rotates around its principal z-axis in the solid state. All routine X-ray structures (2theta(max.) < 55 degrees) converged within the 3sigma limit at C=C double bond lengths that were shorter or similar to that of free ethene. In contrast, the respective Raman active C=C stretching modes indicated red-shifts of 38 to 45 cm(-1), suggesting a slight C=C bond elongation. This mismatch is owed to residual librational motion at 100 K, the temperature of the data collection, as well as the lack of high angular data owing to the anisotropic electron distribution in the ethene molecule. Therefore, a method for the extraction of the C=C distance in [M(C(2)H(4))] complexes from experimental Raman data was developed and meaningful C=C distances were obtained. These spectroscopic C=C distances compare well to newly collected X-ray data obtained at high resolution (2theta(max.) = 100 degrees) and low temperature (100 K). To complement the experimental data as well as to obtain further insight into bond formation, the complexes with up to three ligands were studied theoretically. The calculations were performed with DFT (BP86/TZVPP, PBE0/TZVPP), MP2/TZVPP and partly CCSD(T)/AUG-cc-pVTZ methods. In most cases several isomers were considered. Additionally, [M(C(2)H(4))(3)] (M = Cu(+), Ag(+), Au(+), Ni(0), Pd(0), Pt(0), Na(+)) were investigated with AIM theory to substantiate the preference for a planar conformation and to estimate the importance of sigma donation and pi back donation. Comparing the group 10 and 11 analogues, we find that the lack of pi back bonding in the group 11 cations is almost compensated by increased sigma donation.