Superoxo complexes of copper are primary adducts in several O2-activating Cu-containing metalloenzymes as well as in other Cu-mediated oxidation and oxygenation reactions. Because of their intrinsically high reactivity, however, isolation of Cu x (O2 •–) species is challenging. Recent work (J. Am. Chem. Soc. 2017, 139, 9831; 2019, 141, 12682) established fundamental thermochemical data for the H atom abstraction reactivity of dicopper­(II) superoxo complexes, but structural characterization of these important intermediates was so far lacking. Here we report the first crystallographic structure determination of a superoxo dicopper­(II) species (3) together with the structure of its 1e– reduced peroxo congener (2; a rare cis-μ-1,2-peroxo dicopper­(II) complex). Interconversion of 2 and 3 occurs at low potential (−0.58 V vs Fc/Fc+) and is reversible both chemically and electrochemically. Comparison of metric parameters (d(O–O) = 1.441(2) Å for 2 vs 1.329(7) Å for 3) and of spectroscopic signatures (ν̃(16O–16O) = 793 cm–1 for 2 vs 1073 cm–1 for 3) reflects that the redox process occurs at the bridging O2-derived unit. The CuII–O2 •––CuII complex has an S = 1/2 spin ground state according to magnetic and EPR data, in agreement with density functional theory calculations. Computations further show that the potential associated with changes of the Cu–O–O–Cu dihedral angle is shallow for both 2 and 3. These findings provide a structural basis for the low reorganization energy of the kinetically facile 1e– interconversion of μ-1,2-superoxo/peroxo dicopper­(II) couples, and they open the door for comprehensive studies of these key intermediates in Cu x /O2 chemistry.

Our work on ligand field theory—an automated fitting procedure for Angular Overlap Model (AOM) parameters—is reflected by Van Gogh's Field with Irises near Arles. We showcase the capabilities of this procedure with a two‐dimensional spectrochemical series with the metals manganese, iron, cobalt, nickel and copper and the halides fluoride, chloride, bromide and iodide. The perspective in van Gogh's field resembles a correlation we found between the halide ligands’ AOM parameters and their chemical hardness. More information can be found in the Research Article by V. Krewald et al. (DOI: 10.1002/chem.202103775). Original image credit: Van Gogh Museum, Amsterdam (Vincent van Gogh Foundation).

An upscalable chemical vapor deposition setup has been built‐up and employed in producing methylammonium lead iodide (MAPI) thin film perovskite solar cells, leading to a maximum efficiency of 12.9%. The method makes use of methylamine gas and hydrogen iodide gas to transform a predeposited layer of lead(II)iodide (PbI2) into MAPI. Although the reaction mechanism includes the intermediate phases lead oxide (PbO) and lead hydroxide (Pb(OH)2), indicated at least on the surface of the samples by XPS, neither species could be observed in XRD measurements of the stepwise reaction, which show a mixture of highly oriented cubic and tetragonal MAPI perovskite lattice systems.

Ammonia and amine ligands are commonly assumed to be σ-only ligands in coordination chemistry, i.e. they are not expected to interact significantly with a metal via a π-path. Ligand field...

The properties and reactivities of transition metal complexes are often discussed in terms of Ligand Field Theory (LFT), and with ab initio LFT a direct connection to quantum chemical wavefunctions was recently established. The Angular Overlap Model (AOM) is a widely used, ligandspecific parameterization scheme of the ligand field splitting that has, however, been restricted by the availability and resolution of experimental data. Using ab initio LFT, we present here a generalised, symmetry-independent and automated fitting procedure for AOM parameters that is even applicable to formally underdetermined or experimentally inaccessible systems. This method allows quantitative evalua-tions of assumptions commonly made in AOM applications, for example, transferability or the relative magnitudes of AOM parameters, and the response of the ligand field to structural or electronic changes. A two-dimensional spectrochemical series of tetrahedral halido metalates ([M II X 4 ] 2À , M = MnÀ Cu) served as a case study. A previously unknown linear relationship between the halide ligands' chemical hardness and their AOM parameters was found. The impartial and automated procedure for identifying AOM parameters introduced here can be used to systematically improve our understanding of ligand-metal interactions in coordination complexes.