Cover Feature: Half‐Sandwich Metal‐Catalyzed Alkyne [2+2+2] Cycloadditions and the Slippage Span Model (ChemistryOpen 2/2019)

The Cover Feature shows the glacier of Marmolada, the highest Dolomite (3343 m), with superimposed the aromatic ligand of the group 9 half‐matallocene catalysts for [2+2+2] cycloadditions of unsaturated molecules. When large changes of metal slippage from the centroid of the coordinated cyclopentadienyl moiety occur during catalysis, the turnover frequency (TOF) of the catalytic cycle decreases, similar to what happens to the inexperienced climber who drifts on ice and gets away from the longed‐for TOP. (Photo credit to Foto Riva) More information can be found in the Full Paper by M. Dalla Tiezza et al. on page 143 in Issue 2, 2019 (DOI: 10.1002/open.201800191).[Image: see text]