Despite the growing interest in the synthesis of fluorinated organic compounds, few methods are able to incorporate fluoride ion directly into alkyl C-H bonds. Here, we report the C(sp 3)-H fluorination reactivity of a formally copper(III) fluoride complex. The C-H fluorination intermediate, LCuF, along with its chloride and bromide analogs, LCuCl and LCuBr, were prepared directly from halide sources with a chemical oxidant and fully characterized. While all three copper(III) halide complexes capture carbon radicals efficiently to afford C(sp 3)-halogen bonds, LCuF is two orders of magnitude more efficient at hydrogen atom abstraction (HAA) than LCuCl and LCuBr. Alongside reported kinetic data for other LCu(III) species, we established a positive correlation between ligand basicity and the rate of HAA. The capability of LCuF to perform both hydrogen atom abstraction and radical capture was leveraged to enable fluorination of allylic and benzylic C-H bonds and α-C-H bonds of ethers at room temperature.

<p>Despite the growing interest in the synthesis of fluorinated organic compounds, few methods are able to incorporate fluoride ion directly into alkyl C-H bonds. Here, we report the C(sp³)-H fluorination reactivity of a formally copper(III) fluoride complex. The C-H fluorination intermediate, <b>L</b>CuF, along with its chloride and bromide analogs, <b>L</b>CuCl and <b>L</b>CuBr, were prepared directly from halide sources with a chemical oxidant and fully characterized. While all three copper(III) halide complexes capture carbon radicals efficiently to afford C(sp³)-halogen bonds, <b>L</b>CuF is two orders of magnitude more efficient at hydrogen atom abstraction (HAA) than <b>L</b>CuCl and <b>L</b>CuBr. Alongside reported kinetic data for other <b>L</b>Cu(III) species, we established a positive correlation between ligand basicity and the rate of HAA. The capability of <b>L</b>CuF to perform both hydrogen atom abstraction and radical capture was leveraged to enable fluorination of allylic and benzylic C-H bonds and α-C-H bonds of ethers at room temperature.</p>

A formal copper(iii) cyanide complex and its C–H cyanation reactivity are reported. The redox potentials of substrates, instead of C–H bond dissociation energies, were found to be the key determinant of the rates of PCET.

Transition metal hydride complexes are key intermediates in a variety of catalytic processes. Transfer of a hydride, hydrogen atom, or proton is defined by the thermochemical parameters of hydricity, bond dissociation free energy (BDFE), and pK a, respectively. These values have been studied primarily in organic solvents to predict or understand reactivity. Despite growing interest in the development of aqueous metal hydride catalysis, BDFE measurements of transition metal hydrides in water are rare. Herein, we report two nickel hydride complexes with one or two cationic ligands that enable the measurement of BDFE values in both aqueous and organic solvents using their reduction potential and pK a values. The Ni­(I/0) reduction potentials increase anodically as more charged groups are introduced into the ligand framework and are among the most positive values measured for Ni complexes. The complex with two cationic ligands, 2-Ni­(II)–H, displays exceptional stability in water with no evidence of decomposition at pH 1 for at least 2 weeks. The BDFE of the nickel hydride bond in 2-Ni­(II)–H was measured to be 53.6 kcal/mol in water and between 50.9 and 56.2 kcal/mol in acetonitrile, consistent with prior work that indicates minimal solvent dependence for BDFEs of O–H and N–H bonds. These results indicate that transition metal hydride BDFEs do not change drastically in water and inform future studies on highly cationic transition metal hydride complexes.

Despite the growing interest in the synthesis of fluorinated organic compounds, few methods are able to incorporate fluoride ion directly into alkyl C-H bonds. Here, we report the C(sp 3 )-H fluorination reactivity of a formally copper(III) fluoride complex. The C-H fluorination intermediate, LCuF, along with its chloride and bromide analogs, LCuCl and LCuBr, were prepared directly from halide sources with a chemical oxidant and fully characterized. While all three copper(III) halide complexes capture carbon radicals efficiently to afford C(sp 3 )-halogen bonds, LCuF is two orders of magnitude more efficient at hydrogen atom abstraction (HAA) than LCuCl and LCuBr. Alongside reported kinetic data for other LCu(III) species, we established a positive correlation between ligand basicity and the rate of HAA. The capability of LCuF to perform both hydrogen atom abstraction and radical capture was leveraged to enable fluorination of allylic and benzylic C-H bonds and α-C-H bonds of ethers at room temperature.Carbon-fluorine bonds are becoming increasingly prevalent in pharmaceuticals and agrochemicals. 1 The value of fluorinated compounds in these applications stems from their enhancement of lipophilicity, metabolic stability, and receptor binding affinity. 2