This article reports on the activation of dioxygen on nickel(I) dispersed inside the nanopores of the ZSM-5 zeolite, which can be regarded as a heterogeneous mimetic system (zeozyme) for Ni-bearing enzymes. The side-on η(2)-coordination of the resulting nickel-bound superoxo adduct was ascertained by detailed analysis of the EPR spectra of both (16)O(2) and (17)O(2) species supported by computer simulations of the spectra and relativistic DFT calculations of the EPR signatures. Molecular analysis of the g and A((17)O) tensors (g(xx) = 2.0635, g(yy) = 2.0884, g(zz) = 2.1675; |A(xx)| ≈ 1.0 mT, |A(yy)| = 5.67 mT, |A(zz)| ≈ 1.3 mT) and quantum chemical modeling revealed an unusual electronic and magnetic structure of the observed adduct (with g(zz)(g(max)) > g(yy)(g(mid)) > g(xx)(g(min)) and the largest O-17 hyperfine splitting along the g(mid) direction) in comparison to the known homogeneous and enzymatic nickel-superoxo systems. It is best described as a mixed metalloradical with two supporting oxygen donor ligands and even triangular spin-density redistribution within the η(2)-{NiO(2)}(11) magnetophore. The semioccupied molecular orbital (SOMO) is constituted by highly covalent δ overlap between the out-of-plane 2p(π(g)*) MO of dioxygen and the 3d(x(2)(-y(2))) MO of nickel. By means of the extended transition state-natural orbitals for the chemical valence approach (ETS-NOCV), three distinct orbital channels (associated with σ, π, and δ overlap) of congruent and incongruent charge and spin density flows within the η(2)-{NiO(2)}(11) unit, contributing jointly to activation of the attached dioxygen, were identified. Their individual energetic relevance was quantified, which allowed for explaining the oxygen binding mechanism with unprecedented accuracy. The nature and structure sensitivity of the g tensor was rationalized in terms of the contributions due to the magnetic field-induced couplings of the relevant molecular orbitals that control the g-tensor anisotropy. The calculated O-17 hyperfine coupling constants correspond well with the experimental parameters, supporting assignment of the adduct. To the best of our knowledge, the η(2)-{NiO(2)}(11) superoxo adducts have not been observed yet for digonal mononuclear nickel(I) centers supported by oxygen donor ligands.

Heavy pnictogen chalcohalides offer various shades from the same palette, like “Paysage” by Nicolas de Staël. Their versatility and tunability lead to a new world of possible applications.

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Materials exhibiting excitation-wavelength-dependent photoluminescence, PL, are useful in a range of biomedical and optoelectronic applications. This paper describes a nanoparticulate material whose PL is tunable across the entire visible range and is achieved without adjusting particle size, any postsynthetic doping, or surface modification. A straightforward thermal decomposition of rhenium (VII) oxide precursor yields nanoparticles that comprise Re atoms at different oxidation states. Studies of time-resolved emission spectra and DFT calculations both indicate that tunable PL of such mixed-valence particles originates from the presence of multiple emissive states that become "active" at different excitation wavelengths. In addition, the nanoparticles exhibit photocatalytic activity that, under visible-light irradiation, is superior to that of TiO nanomaterials.