Controlling the Optical and Catalytic Properties of Artificial Metalloenzyme Photocatalysts Using Chemogenetic Engineering

Visible light photocatalysis enables a broad range of organic transformations that proceed via single electron or energy transfer. Metal polypyridyl complexes are among the most commonly employed visible light photocatalysts. The photophysical properties of these complexes have been extensively studied and can be tuned by modifying the substituents on the pyridine ligands. On the other hand, ligand modifications that enable substrate binding to control reaction selectivity remain rare. Given the exquisite control that enzymes exert over electron and energy transfer processes in nature, we envisioned that artificial metalloenzymes (ArMs) created by incorporating Ru(II) polypyridyl complexes into a suitable protein scaffold could provide a means to control photocatalyst properties. This study describes approaches to create covalent and non-covalent ArMs from a variety of Ru(II) polypyridyl cofactors and a prolyl oligopeptidase scaffold. A panel of ArMs with enhanced photophysical properties were engineered, and the nature of the scaffold/cofactor interactions in these systems was investigated. These ArMs provided higher yields and rates than Ru(Bpy)32+ for the reductive cyclization of dienones and the [2+2] photocycloaddition between C-cinnamoyl imidazole and 4-methoxystyrene, suggesting that protein scaffolds could provide a means to improve the efficiency of visible light photocatalysts.

Controlling One-Electron vs Two-Electron Pathways in the Multi-Electron Redox Cycle of Nickel Diethyldithiocarbamate

This manuscript describes electrochemical experiments in which a Nickel(III) intermediate is kinetically trapped by the addition of derivatized pyridine ligands to the electrolyte solution. EPR and DFT studies support the conclusion that pyridine coordinates in a trans- configuration and contains a small equilibrium between mono- and bis-pyridine structures. Electrochemical kinetic data provides evidences for decomposition pathways which ultimately result in Ni(IV) complexes.

Controlling One-Electron vs Two-Electron Pathways in the Multi-Electron Redox Cycle of Nickel Diethyldithiocarbamate

This manuscript describes electrochemical experiments in which a Nickel(III) intermediate is kinetically trapped by the addition of derivatized pyridine ligands to the electrolyte solution. EPR and DFT studies support the conclusion that pyridine coordinates in a trans- configuration and contains a small equilibrium between mono- and bis-pyridine structures. Electrochemical kinetic data provides evidences for decomposition pathways which ultimately result in Ni(IV) complexes.

Synthesis, Crystallographic Structure, Hirshfeld Surface Analysis, Drug-likeness Properties and Molecular Docking Studies of New Oxime-pyridine Compounds

A detailed description of the two new pyridine ligands, (2E,3Z)-3-[2-(3-chloropyridin-2-yl)hydrazinylidene]-N-hydroxybutan-2-imine and 3-chloro-2-{(2Z)-2-[1-(4 nitrophenyl)ethylidene]hydrazinyl}, is reported. The synthesized compounds were characterized by spectroscopic studies, spectral features were performed by TD-DFT calculations. New-generation pyridine ligand of HL2 was also determinate by single-crystal X-ray diffraction and Hirshfeld surface analysis with two-dimensional fingerprint plots was used to analyze intermolecular interactions in crystals. Molecular-docking was performed to investigate the binding areas of chemical compounds, and the results showed the inhibitory activity of the studied HL1 and HL2 against E. coli. The results of the current study revealed the drug-likeness and bioactive properties of the ligands.