Binding and activation of small molecules by a quintuply bonded chromium dimer

The quintuply bonded [(LCr)-L-H-Cr-iPr](2) reacts with various small molecules, revealing a pattern of two kinds of transformations. Unsaturated molecules that are neither polar nor oxidizing form binuclear [2+n] cyclo-addition products retaining Cr-Cr quadruple bonds. In contrast, polar or oxidizing molecules effect the complete cleavage of the Cr-Cr bond.