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

Abstract

Solid View of a Sigma Complex For decades, it has been clear from kinetic studies that saturated hydrocarbons can also act as weak ligands, often just prior to bond cleavage reactions. These short-lived intermediates—termed “σ complexes” because the donated electrons reside in single (sigma symmetry) C-H bonds—have been glimpsed spectroscopically but have largely eluded full structural characterization. Pike et al. (p. 1648 , published online 23 August) now present the crystallographic characterization of an alkane bound to rhodium, which they captured by direct hydrogenation of a more stable crystalline precursor incorporating an alkene.