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The Cu-O-Cu core has been proposed as a potential site for methane oxidation in particulate methane monooxygenase. In this work, we used density functional theory (DFT) to design a mixed-valent Cu III -O-Cu II species from an experimentally known peroxo-dicopper complex supported by N-donor ligands containing phenolic groups. We found that the transfer of two-protons and two-electrons from phenolic groups to peroxo-dicopper core takes place, which results to the formation of a bis-μ-hydroxo-dicopper core. The bis-μ-hydroxo-dicopper core converts to a mixed-valent Cu III -O-Cu II core with the removal of a water molecule. The orbital and spin density analyses unravel the mixed-valent nature of Cu III -O-Cu II . We further investigated the reactivity of this mixed-valent core for aliphatic C-H hydroxylation. Our study unveiled that mixed-valent Cu III -O-Cu II core follows a hydrogen atom transfer mechanism for C-H activation. An in-situ generated water molecule plays an important role in C-H hydroxylation by acting as a proton transfer bridge between carbon and oxygen. Furthermore, to assess the relevance of a mixed-valent Cu III -O-Cu II core, we investigated aliphatic C-H activation by a symmetrical Cu II -O-Cu II core. DFT results show that the mixed-valent Cu III -O-Cu II core is more reactive toward the C-H bond than the symmetrical Cu II -O-Cu II core., (© 2024 Wiley-VCH GmbH.)

Context: The structures of Ag 2n-1 S n - (n = 2-11) clusters are obtained by the combination of genetic algorithm (GA) and density functional theory (DFT). All the global minimum structures prefer hollow polyhedral structures, in which S-Ag-S element, triangular Ag 3 S 3 and tetragonal Ag 4 S 4 units present to stabilize the structures. The S atoms in the structures appear in μ 3 -S or μ 4 -S form. Adiabatic and vertical electron affinities of the clusters have been obtained, which reveals that they increases as cluster size. Stability analysis shows that Ag 9 S 5 - and Ag 19 S 10 - have special stability. The HOMO, LUMO orbitals of the clusters are obtained and the orbital components of them are calculated. The HOMO orbitals are mainly from the p orbitals of S atoms, whereas the s, p and d orbitals of Ag atoms contribute much bigger than the p orbitals of S atoms for LUMO orbitals. The orbital delocalization indexes (ODI) of the HOMOs and LUMOs are calculated, and the small ODIs of the HOMOs and LUMOs for n = 4-10 reveal that these orbitals are highly delocalized. By studying the projected density of states and molecular orbitals of Ag 9 S 5 - and Ag 19 S 10 - clusters, it is found that their molecular orbitals have superatomic properties. Superatomic properties play an important role in stabilizing clusters., Methods: This work used combined genetic algorithm and density functional theory (GA-DFT), and PBE0/Lanl2tz(Ag)/6-311G(d,p)(S) method to optimize the structures. Gaussian 16 program, Gauss view 6.0.16 program and Multiwfn 3.8 code are the softwares used., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)