Carbon-Atom Extrusion from Halobenzenes and Its Coupling with a Methylene Ligand to Form Acetylene

Mechanistic aspects of an unusual gas-phase reaction of [LaCH2](+) with halobenzenes have been investigated using Fourier-transform ion cyclotron resonance (FTICR) mass spectrometry combined with density functional theory (DFT) calculations. In this thermal process a carbon-atom from the benzene ring, most likely the ipso-position, and the carbene ligand are coupled to form C2H2.