Electrochemical properties of self-assembled monolayers (SAMs) of a 1-aminoanthraquinone derivative (1-aminoAQ) were studied using electrochemical impedance spectroscopy (EIS) and cyclic voltammetry. The results of EIS studies at different temperatures and applied potentials established that SAMs of 1-ammoniumAQ undergo proton-coupled electron transfer (PCET) in 0.1 M H2SO4 with a rate constant of 7.4 s−1. Variable-temperature studies of the charge-transfer reaction gave a high activation barrier of 69 kJ·mol−1 for the 1-ammoniumAQ redox reaction, which is attributed to cleavage of a strong intramolecular hydrogen bond; this conclusion is supported by NMR and FTIR spectroscopic analyses, as well as DFT calculations. The 1-ammoniumAQ redox reactions were found to have a reorganizational energy term of 2.7 eV, consistent with large solvent reorganization and substantial nuclear rearrangement upon reduction.

Ta oxide nanotubes (NTs) were formed by the anodization of Ta at 15 V in a solution of concentrated sulfuric acid containing 0.8-1.0 M hydrofluoric acid. To study the initial stages of NT formation, FESEM images of samples anodized for very short times were obtained. The results contradict the existing explanation of the current-time data collected during anodization, which has persisted in the literature for more than two decades. In addition to providing a first-time morphological study of Ta oxide NT formation at very early stages of anodization, we also propose a new interpretation of the i-t response, showing that pores are already present in the first few milliseconds of anodization and that NTs are formed well before present models predict. This behaviour may also extend to the anodization of other valve metals, such as Al, Ti, Zr, W, and Nb.

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Ta oxynitride (TaO x N y ) nanotubes (NTs) were synthesized by the anodization of Ta in an aqueous H 2 SO 4 + HF solution, forming Ta oxide NTs, followed by the high temperature conversion of Ta oxide to TaO x N y in ammonia. The electrochemical behavior of these nanotubular arrays was then investigated using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS), revealing a wide range of interesting properties. The Ta oxynitride NTs, which are shown to contain evenly spaced holes along their length, undergo a reversible redox process involving cation intercalation in both aqueous solutions and dry acetonitrile at potentials negative of 0.5 V, while above this, the nanotubular array is nonconducting. From the CV charges, it is possible that this reaction occurs only on the exposed TaO x N y NT surfaces, although the nanotubular array does undergo conductivity and colour switching. EIS analysis has confirmed the pseudocapacitive properties of the TaO x N y NTs at < 0.5 V, while at potentials above this, Mott-Schottky analysis shows that they are n-type semiconductors having a donor density of ca. 6  10 21 cm -3 .

Two symmetry‐independent but geometrically similar, essentially planar molecules of the title compound, C9H8INO4, are linked via C—I...O=C interactions [I...O = 2.981 (6) and 3.006 (5) Å] into infinite chains running along the b axis. The independent molecules alternate within the chain, so that only one independent chain is formed in the crystal structure.