Characterization and Reactivity Studies of Mononuclear Tetrahedral Copper(II)–Halide Complexes
In: Inorganic Chemistry, Jg. 62 (2023-07-10), Heft 27, S. 10539-10547
Online
serialPeriodical
Zugriff:
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 gzand small Azvalues. The electronic absorption spectra of 1Xagreed with the simulation spectra obtained by time-dependent density functional theory (TD-DFT) calculations on a slightly distorted tetrahedral geometry. 1Iand 1Brgradually 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. 1Xexcept 1Ishowed hydrogen atom abstraction (HAA) reactivity toward 1,4-cyclohexadiene (CHD), where 1Fexhibited the highest reactivity with a second-order rate constant as 1.4 × 10–3M–1s–1at 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.
Titel: |
Characterization and Reactivity Studies of Mononuclear Tetrahedral Copper(II)–Halide Complexes
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Autor/in / Beteiligte Person: | Lan, Yang ; Morimoto, Yuma ; Shimizu, Ikuma ; Sugimoto, Hideki ; Itoh, Shinobu |
Link: | |
Zeitschrift: | Inorganic Chemistry, Jg. 62 (2023-07-10), Heft 27, S. 10539-10547 |
Veröffentlichung: | 2023 |
Medientyp: | serialPeriodical |
ISSN: | 0020-1669 (print) ; 1520-510X (print) |
DOI: | 10.1021/acs.inorgchem.3c00320 |
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