Synthesis, Characterization, and Spectroscopic Studies of 2,6-Dimethylpyridyl-Linked Cu(I)-CNC Complexes: The Electronic Influence of Aryl Wingtips on Copper Centers.

Six new Cu(I) complexes containing pincer ligands of the type 2,6-bis(3-alkyl/arylimidazol-2-ylidene) methylpyridine I(R/Ar) , where R = trifluoroethyl (TFE) and R' = 4-CF, 4-NO, 4-CN, 4-H, and 4-CH, have been synthesized. These complexes, namely, [Cu(I(TFE))]PF, ; [Cu(IAr ]PF, ; [Cu(IAr )]PF, ; [Cu(IAr ]PF, ; [Cu(IAr )](PF), ; and [Cu(IAr )](PF), , were fully characterized by H, C, and HMBC NMR spectroscopy, elemental analysis, electrochemical studies, and single-crystal X-ray crystallography. The crystallographic data revealed different structures and copper nuclearities for the complexes bearing aryl wingtips with electron-withdrawing (, , and ) and electron-donating ( and ) substituents.

pH Changes That Induce an Axial Ligand Effect on Nonheme Iron(IV) Oxo Complexes with an Appended Aminopropyl Functionality.

Nonheme iron enzymes often utilize a high-valent iron(IV) oxo species for the biosynthesis of natural products, but their high reactivity often precludes structural and functional studies of these complexes. In this work, a combined experimental and computational study is presented on a biomimetic nonheme iron(IV) oxo complex bearing an aminopyridine macrocyclic ligand and its reactivity toward olefin epoxidation upon changes in the identity and coordination ability of the axial ligand. Herein, we show a dramatic effect of the pH on the oxygen-atom-transfer (OAT) reaction with substrates.

Computational studies of DNA base repair mechanisms by nonheme iron dioxygenases: selective epoxidation and hydroxylation pathways.

DNA base repair mechanisms of alkylated DNA bases is an important reaction in chemical biology and particularly in the human body. It is typically catalyzed by an α-ketoglutarate-dependent nonheme iron dioxygenase named the AlkB repair enzyme. In this work we report a detailed computational study into the structure and reactivity of AlkB repair enzymes with alkylated DNA bases.

C-X (X = N, O) Cross-Coupling Reactions Catalyzed by Copper-Pincer Bis(N-Heterocyclic Carbene) Complexes.

Over the last two decades, N-heterocyclic carbene (NHC)-copper catalysts have received considerable attention in organic synthesis. Despite the popularity of copper complexes containing monodentate NHC ligands and recent development of poly(NHC) platforms, their application in C-C and C-heteroatom cross-coupling reactions has been limited. Recently, we reported an air-assisted Sonogashira-type cross-coupling catalyzed by well-defined cationic copper-pincer bis(NHC) complexes.