Structural control of μ-hydroxo-μ-peroxodicobalt(III) complex with the 6-hpa dinucleating ligand to enhance O-evolution activity in catalytic water oxidation.

The 6-hpa ligand forms a μ-hydroxo-μ-peroxodicobalt(III) complex [Co(μ-OH)(μ-O)(6-hpa)]X (X = ClO (1a) and PF (1b)) and controls the formation of configuration. Electrochemical studies revealed that the 6-hpa ligand lowers the oxidation potential of the peroxide moiety by 0.13 V and twice enhances O evolution during catalytic water oxidation by fixing the configuration.

A Doubly meso-α Linked N-Confused Porphyrin Tape Silver(III) Complex Comprising an Antiaromatic Pyrrolo[2,3-f]indole Segment.

The free base form of doubly meso-α linked N-confused porphyrin (NCP) tape 3 was successfully synthesized via Ir(I) mediated intramolecular coupling. The following silver complexation afforded the Ag(III) complex of doubly meso-α linked NCP tape 4. While 3 exhibited 38π aromatic characters, 4 exhibited not only 18π aromatic NCP-type characteristics but also a decent antiaromatic contribution of 12π pyrrolo[2,3-f]indole segment, as probed by NMR spectra, absorption spectra, and DFT calculations.

A Computational Study on the Mechanism of Catalytic Cyclopropanation Reaction with Cobalt N-Confused Porphyrin: The Effects of Inner Carbon and Intramolecular Axial Ligand.

The factors that affect acceleration and high / selectivity in the catalytic cyclopropanation reaction of styrene with ethyl diazoacetate by cobalt N-confused porphyrin (NCP) complexes were investigated using density functional theory calculations. The reaction rate was primarily related to the energy gap between the cobalt-carbene adduct intermediates, and , which was affected by the NCP skeletons and axial pyridine ligands more than the corresponding porphyrin complex. In addition, high / stereoselectivity was determined at the and, in part, in the isomerization process at the carbon-centered radical intermediates, and .

Ruthenium(iv) N-confused porphyrin μ-oxo-bridged dimers: acid-responsive molecular rotors.

Ruthenium(iv) N-confused porphyrin μ-oxo-bridged complexes were synthesized oxidative dimerization of a ruthenium(ii) N-confused porphyrin complex using 2,2,6,6-tetramethylpiperidine 1-oxyl. The deformed core planes in the dimers conferred a relatively high ring rotational barrier of 16 kcal mol. Rotation of the complexes was controlled by protonating the peripheral nitrogen.

NH Tautomerism of N-Confused Porphyrin: Solvent/Substituent Effects and Isomerization Mechanism.

The effects of substituents and solvents on the NH tautomerism of N-confused porphyrin () were investigated. The structures, electronic states, and aromaticity of NH tautomers ( and ) were studied by absorption and nuclear magnetic resonance (H, C, and N) spectroscopies, single-crystal X-ray diffraction analysis, and theoretical calculations. The relative stability of the tautomers is highly affected by solvents, with the -type tautomer being more stable in nonpolar solvents, while the -type tautomer being highly stabilized in polar solvents with high donor numbers such as ,-dimethylformamide (DMF), pyridine, and acetone.