journal article

Journal Article

Text

Inorganic Chemistry. 2023, 62(27), p. 10539-10547

Characterization and Reactivity Studies of Mononuclear Tetrahedral Copper(II)-Halide Complexes

American Chemical Society

English

Text

2023-07-10

https://doi.org/10.1021/acs.inorgchem.3c00320

Lan Y., Morimoto Y., Shimizu I., et al. Characterization and Reactivity Studies of Mononuclear Tetrahedral Copper(II)-Halide Complexes. Inorganic Chemistry 62, 10539 (2023); https://doi.org/10.1021/acs.inorgchem.3c00320.

Structures, physicochemical properties, and reactivity of the whole series of copper(II)-halide complexes (1X; X = F, Cl, Br, and I) were examined using a TMG3tach tridentate supporting ligand consisting of cis,cis-1,3,5-triaminocyclohexane (tach) and N,N,N′,N′-tetramethylguanidine (TMG). The tach ligand framework with the bulky and strongly electron-donating TMG substituents enforces the copper(II) complexes to take a tetrahedral geometry, as inferred from the electron paramagnetic resonance (EPR) spectra, exhibiting relatively large gz and small Az values. The electronic absorption spectra of 1X agreed with the simulation spectra obtained by time-dependent density functional theory (TD-DFT) calculations on a slightly distorted tetrahedral geometry. 1I and 1Br gradually decomposed to generate the corresponding copper(I) complex and halide radical X•, and in the case of 1Br, intramolecular hydroxylation of a methyl group of the TMG substituent took place under aerobic conditions, which may be caused by the reaction of the generated copper(I) complex and dioxygen (O2), generating a reactive oxygen species. 1X except 1I showed hydrogen atom abstraction (HAA) reactivity toward 1,4-cyclohexadiene (CHD), where 1F exhibited the highest reactivity with a second-order rate constant as 1.4 × 10-3 M-1 s-1 at 25 °C. Such an HAA reactivity can be attributed to the higher basicity of F- and/or large bond dissociation free energy of conjugate acid H-F as well as the unstable copper(II) electronic state in the tetrahedral geometry.

This document is the Accepted Manuscript version of a Published Work that appeared in final form in Inorganic Chemistry, © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see https://doi.org/10.1021/acs.inorgchem.3c00320.

94621

Characterization and Reactivity Studies of Mononuclear Tetrahedral Copper(II)-Halide Complexes

American Chemical Society

English

2023-07-10

Inorganic Chemistry

62

27

10539

10547

https://doi.org/10.1021/acs.inorgchem.3c00320

https://hdl.handle.net/11094/94621