Characterization of a Rhodium(I) σ-Methane Complex in Solution

Abstract

Methane Loosely Bound For the most part, molecular bonds involve sharing of electrons between two discrete atoms. In certain cases, however, a third atom can also attract a portion of the electron density without fully cleaving the bond. Such loose complexes between C-H bonds and transition metals are often invoked as short-lived intermediates in metal-catalyzed reactions of hydrocarbons, though they are rarely observed directly. Bernskoetter et al. (p. 553 ) glimpse this coordination motif for methane (CH 4 ) and rhodium (Rh) using low-temperature nuclear magnetic resonance spectroscopy after protonation of an Rh-CH 3 precursor. Kinetics measurements revealed a half-life of just over 80 minutes at −87°C.