We report on the observation of chirality induced spin selectivity for electrons transmitted through monolayers of oligopeptides, both for energies above the vacuum level as well as for bound electrons and for electrons conducted through a single molecule. The dependence of the spin selectivity on the molecular length is measured in an electrochemical cell for bound electrons and in a photoemission spectrometer for photoelectrons. The length dependence and the absolute spin polarization are similar for both energy regimes. Single molecule conductance studies provide an effective charge transport barrier between the two spin channels and it is found to be on the order of 0.5 eV

Four helical peptides with the general formula (Boc)-Cys-(S-Acm)-(Ala-Leu)(n)-NH-(CH(2))(2)-SH (n = 4-7) were synthesized and further used for the preparation of self-assembled monolayers (SAMs) on gold substrates. The electron-transfer behavior of these systems was probed using current-sensing atomic force microscopy (CS-AFM). It was found that the electron transmission through SAMs of helical peptides trapped between an AFM conductive tip and a gold substrate occurs very efficiently and that the distance dependence obeys the exponential trend with a decay constant of 4.6 nm(-1). This result indicates that the tunneling mechanism is operative in this case. Conductance measurements under mechanical stress show that peptide-mediated electron transmission occurs with the possible contribution of intermolecular electron tunneling between adjacent helices. It was also demonstrated that an external electric field applied between metallic contacts can affect the structure of the peptide SAM by changing its thickness. This explains the asymmetry of the current-voltage response of metal-monolayer-metal junction.

Spreading of small unilamellar vesicles on solid surfaces is one of the most common ways to obtain supported lipid bilayers. Although the method has been used successfully for many years, the details of this process are still the subject of intense debate. Particularly controversial is the mechanism of bilayer formation on metallic surfaces like gold. In this work, we have employed scanning probe microscopy techniques to evaluate the details of lipid vesicles spreading and formation of the lipid bilayer on a Au(111) surface in a phosphate-buffered saline solution. Nanoscale imaging revealed that the mechanism of this process differs significantly from that usually assumed for hydrophilic surfaces such as mica, glass, and silicon oxide. Formation of the bilayer on gold involves several steps. Initially, the vesicles accumulate on a gold surface and release lipid molecules that adsorb on a Au(111) surface, giving rise to the appearance of highly ordered stripelike domains. The latter serve as a template for the buildup of a hemimicellar film, which contributes to the increased hydrophilicity of the external surface and facilitates further adsorption and rupture of the vesicles. As a result, the bilayer is spread over a hemimicellar film, and then it is followed by slow fusion between coupled layers leading to formation of a single bilayer supported on a gold surface. We believe that the results presented in this work may provide some new insights into the area of research related to supported lipid bilayers.

The tetragonal compound FeF3(H2O)3 is synthesized through a facile liquid‐phase method. FeF3(H2O)3/C is prepared by mechanical milling with carbon black and investigated for its application as a cathode material. This material exhibits two types of thermodynamic lithiation scheme, at 3.0 and 1.5 V, which correspond to a Li+‐intercalation process (1 Li+) and a conversion reaction (>1 Li+), respectively. A reversible capacity of about 300 mAh g−1 can be achieved at a current density of 10 mAg−1. In particular, the intercalation/deintercalation process above 2.0 V exhibits good cycling performance and rate properties. The relatively high diffusion coefficients (Dcv=7.27×10−13–1.07×10−12 m2 s−1) of Li+ through the FeF3(H2O)3 lattice are calculated by using the Randles–Sevcik equation, which reveal fast Li+‐ion migration in this process. In contrast, the conversion reaction is strongly dependent on the current density. Electrochemical impedance spectroscopy indicates that the FeF3(H2O)3/C cathode forms a relatively stable solid electrolyte interphase film, with a low Schottky contact resistance in comparison with that of the FeF3/C cathode, which makes it a potential candidate for cathode applications.

A series of thioacetyl-functionalized fullerene-C 60 derivatives were synthesized using the Prato reaction of fullerene-C 60 with six different 4-(S-acetylthioalkyl)benzaldehydes. The structures of the synthesized compounds were characterized by FT-IR, 1 H NMR and ESI-MS techniques. The LUMO-HOMO band gaps, derived from DFT B3LYP/6-31G* calculations, for the azomethine ylides corresponding to each 4-(S-acetylthioalkyl)benzaldehyde and fullerene-C 60 were correlated with the efficiency of the Prato reaction. The compounds were deposited onto gold electrodes via self-assembly following an in situ deprotection procedure which transformed the thioacetyl-functionalized compounds into their thiolated derivatives. The redox properties of the C 60 derivatives in solution were characterized using Voltammetry. The LUMO-HOMO band gaps obtained from the electrochemical data were compared with the density functional theory (DFT) values for the optimized structures. The thioacetylfunctionalized C 60 derivatives were employed for the catalytic reduction of halogenated hydrocarbons. Following deprotection, they were also employed for the modification of gold substrates. The solvent dependent barrier properties of the thiolated fullerene films were investigated using Cyclic Voltammetry (CV) and Electrochemical Impedance Spectroscopy (EIS). The topography of the C 60 derivative modified electrode was investigated using X-ray Photoelectron Spectroscopy (XPS) and Atomic Force Microscopy (AFM), which confirmed stable modification of the Au support with a three dimensional (3D) film of worm-like fullerene aggregates.