Cover Picture: Chromium‐Catalyzed Highly Selective Oligomerization of Ethene to 1‐Hexene with N,N‐Bis[chloro(aryl)phosphino]amine Ligands (ChemCatChem 13/2017)

The Front Cover shows an optical illusion that symbolizes the mystery in the structure–response relationship of Cr/MAO/PNP‐ligand‐catalyzed ethylene oligomerizations. It represents the not‐yet‐fully‐understood reasons for the formation of the C6/C8 ratios during the oligomerization reaction.In their Full Paper, M. Höhne et al. demonstrate that depending on the size of the substituent R, three or four molecules of ethylene can be coupled by the catalyst. Whereas a tiny ligand realizes four beams, the huge one —from a different view— counts only three. This comic‐like illustration is completed by a “scientific” blackboard depicting the “unexpected observations.” More information can be found in the Full Paper by M. Höhne et al. on page 2467 in Issue 13, 2017 (DOI: 10.1002/cctc.201700448).