Bioinspired Five‐Coordinate Iron(III) Complexes for Stabilization of Phenoxyl Radicals

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

“…At higher surface pressures, the film becomes rougher owing to material aggregation. With an estimated 12 between the catechol-like oxygen atoms and the bulky terminal tertbutyl groups, [14,16] these results are in excellent agreement with the notion of a true monolayer. The thickness of a single monolayer was determined on quartz substrates containing one to fifteen layers by blade-scratching the film and measuring the scratch depth in the tapping mode ( Figure 3 c; Figure S16 and Table S3).…”

“…This phenomenon has been observed for organic materials and is tentatively explained by the reorganization of dipole moments in the presence of high electric fields to attain a stable monolayer by decreasing their energy. Although further considerations will be necessary, DFT calculations for similar systems [14] suggest that partially occupied metal-based SOMOs might be energetically accessible. Although the exact origin of the rectifying behavior is not certain, unimolecular contribution can be assumed as viable, and a description of the possible [DA] and [D + A À ] states becomes relevant.…”

“…[2] Usually, donor and acceptor are separated by a s-or p-bridge to decrease electronic coupling, [3] and if the requirements are fulfilled, rectification occurs with contributions from Schottky, asymmetric, and/or unimolecular mechanisms. [14] Herein, a new iron(III) species [Fe III L 1 ] (1; Scheme 1) is reported. [4] Asymmetric and unimolecular mechanisms rely on the use of frontier molecular orbitals of the molecule; whereas the former relies on an asymmetric placement of the HOMO or the LUMO in the electrode j molecule j electrode assembly, the latter is based on small HOMO-LUMO gaps that allow for through-molecule current flow.…”

“…[14] Herein, a new iron(III) species [Fe III L 1 ] (1; Scheme 1) is reported. We recently reported on the redox and electronic behavior of five-coordinate complexes where the iron(III) ion is bound to low-symmetry, phenolaterich, [N 2 O 3 ] environments, and it was shown that geometric and electronic constraints determine the sequence by which the metal and each of the phenolate substituents gets oxidized.…”

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

“…Our group is engaged in an effort to integrate bioinspired asymmetry principles into new molecular materials, with the aim of developing redox‐responsive metallosurfactants with topologies that display unique structural, spectroscopic, and surface patterning behavior. We recently reported on the redox and electronic behavior of five‐coordinate complexes where the iron(III) ion is bound to low‐symmetry, phenolate‐rich, [N 2 O 3 ] environments, and it was shown that geometric and electronic constraints determine the sequence by which the metal and each of the phenolate substituents gets oxidized 14. Herein, a new iron(III) species [Fe III L 1 ] ( 1 ; Scheme ) is reported.…”