Photocatalytic aerobic benzylic C(sp3)−H oxygenations of aromatic hydrocarbons and C3‐substituted indoles were studied by employing a co‐catalytic system of 3DDQ* (DDQ=2,3‐dichloro‐5,6‐dicyano‐1,4‐benzoquinone) and tert‐butyl nitrite. The superior efficiency of these reaction conditions was demonstrated by comparison with the analogous thermal protocol, and a range of substrates could be oxidized catalytically and selectively in good yields.

The electronic response of colloidal 2D tin sulfide crystals to the illumination with circularly polarized light has been investigated. The nanocrystals show a strong anisotropic circular photogalvanic effect.

The Cover shows a visible light‐induced benzylic C(sp3)−H photooxygenation driven by the co‐catalytic system of triplet‐excited DDQ and nitric oxides, which are generated in situ from tert‐butyl nitrite and O2. In their Communication, F. Rusch et al. report that this photocatalytic protocol offers a dramatic increase of reaction rate relative to the thermal variant of the reaction, and a range of aromatic hydrocarbons and substituted indoles could be oxidized with good selectivity. Mechanistic control experiments suggest that benzylic cations are the key intermediates in the oxygenation reaction. More information can be found in the Communication by F. Rusch et al. on page 2881 in Issue 18, 2016 (DOI: 10.1002/cctc.201600704).

The role of metal−support epitaxy on shape and size heterogeneity of nanoparticles and their response to gas atmospheres is not very well explored. Here we show that an ensemble of Pd nanoparticles, grown on MgO(001) by deposition under ultrahigh vacuum, mostly consists of two distinctly epitaxially oriented particles, each having a different structural response to redox cycles. X-ray reciprocal space patterns were acquired in situ under oxidizing and reducing environments. Each type of nanoparticle has a truncated octahedral shape, whereby the majority grows with a cube-oncube epitaxy on the substrate. Less frequently occurring and larger particles have their principal crystal axes rotated ±3.7°with respect to the substrate's. Upon oxidation, the top (001) facets of both types of particles shrink. The relative change of the rotated particles' top facets is much more pronounced. This finding indicates that a larger mass transfer is involved for the rotated particles and that a larger portion of high-index facets forms. On the main facets of the cube-on-cube particles, the oxidation process results in a considerable strain, as concluded from the evolution to largely asymmetric facet scattering signals. The shape and strain responses are reversible upon reduction, either by annealing to 973 K in vacuum or by reducing with hydrogen. The presented results are important for unraveling different elements of heterogeneity and their effect on the performance of real polycrystalline catalysts. It is shown that a correlation can exist between the particle-support epitaxy and redox-cycling-induced shape changes.