Chemical detection of carbon-metal bonds: From distinct sigma-bonding of main-group metals to ambiguous pi-bonding with transition metals

The chemical detection of sigma-carbon-metal bonds in solutions of organometallics can be achieved by deuteriodemetallation with electrophilic D-A reagents (A = OD, OAc), but with transition metals their thermal and light sensitivity requires low temperatures in the dark. Transition metal carbenes can be detected by cycloadditions with alkynes or nitriles.