Synthesis and Characterization of a Rhodium(I) σ-Alkane Complex in the Solid State

Transition metal alkane complexes—termed σ-complexes because the alkane donates electron density to the metal from a σ-symmetry C–H orbital—are key intermediates in catalytic C–H activation processes yet remain tantalizingly elusive to characterization in the solid-state by single-crystal x-ray diffraction techniques. Here we report an approach to the synthesis and characterization of transition metal alkane complexes in the solid-state by simple gas-solid reaction to produce an alkane σ-complex directly. This strategy enables the structural determination, by x-ray diffraction, of an alkane (norbornane) σ-bound to a d8–Rh(I) metal center, in which the chelating alkane ligand is coordinated to the pseudo-square planar metal center through two σ-C–H bonds.