Rectification in Nanoscale Devices Based on an Asymmetric Five-Coordinate Iron(III) Phenolate Complex

Electron transport through a (terpyridine)ruthenium metallo-surfactant containing a redox-active aminocatechol derivative

Aiming to develop a new class of metallosurfactants with unidirectional electron transfer properties, a (terpyridine) ruthenium complex containing a semiquinone derivative L², namely [Ru^III(L^terpy)(L²)Cl]PF₆ (1), was synthesized and structurally characterized as a solid and in solution. The electronic and redox behaviour of 1 was studied experimentally as well as by means of DFT methods, and is indicative of significant orbital mixing and overlap between metal and ligands. The complex forms stable Pockels-Langmuir films at the air-water interface and allows for the formation of thin films onto gold electrodes to prepare nanoscale Au|LB 1|Au junctions for current-voltage (I/V) analysis. Complex 1 shows asymmetric electron transfer with a maximum rectification ratio of 32 based on tunnelling through MOs of the aminocatechol derivative.

A Molecular Approach for Mitigation of Aluminum Pitting based on Films of Zinc(II) and Gallium(III) Metallosurfactants

The use of metallosurfactants to prevent pitting corrosion of aluminum surfaces is discussed based on the behavior of the metallosurfactants [Zn^II (L^N2O2 )H₂ O] (1) and [Ga^III (L^N2O3 )] (2). These species were deposited as multilayer Langmuir-Blodgett films and characterized by IR reflection absorption spectroscopy and UV/Vis spectroscopy. Scanning electron microscopy images, potentiodynamic polarization experiments, and electrochemical impedance spectroscopy were used to assess corrosion mitigation. Both metallosurfactants demonstrate superior anticorrosion activity due to the presence of redox-inactive 3d¹⁰ metal ions that enhance the structural resistance of the ordered molecular films and limit chloride mobility and electron transfer.

Molecular rectifiers based on five-coordinate iron(iii)-containing surfactants

The state-of-the-art of metallorganic-based molecular rectification is reviewed with an emphasis on asymmetric five-coordinate Fe^III-containing surfactants in electrode|LB film|electrode assemblies.

Ligand transformations and efficient proton/water reduction with cobalt catalysts based on pentadentate pyridine-rich environments

A series of cobalt complexes with pentadentate pyridine-rich ligands is studied. An initial Co(II) amine complex 1 is prone to aerial oxidation yielding a Co(III) imine complex 2 that is further converted into an amide complex 4 in presence of adventitious water. Introduction of an N-methyl protecting group to the ligand inhibits this oxidation and gives rise to the Co(II) species 5. Both the Co(III) 4 and Co(II) 5 show electrocatalytic H2 generation in weakly acidic media as well as in water. Mechanisms of catalysis seem to involve the protonation of a Co(II)-H species generated in situ.