Formation of Grignard Species from the Reaction of Methyl Halides with Laser-Ablated Magnesium Atoms. A Matrix Infrared Study of CH₃MgF, CH₃MgCl, CH₃MgBr, and CH₃MgI

Magnesium atoms generated by laser ablation were reacted with methyl halides diluted (0.5% to 0.1%) in argon. Reaction products were trapped in a cryogenic argon matrix and analyzed by infrared spectroscopy. The primary reaction product, isolated Grignard molecule CH 3 MgX, and the secondary reaction products MgX, MgX 2, MgH, MgH 2, CH 4, C 2 H 6, CH 2 X, CH 3 MgCH 3, XMgCH 2, HMgCH 3, and HMgCH 2 X were identified by isotopic ( 13 C, D, and 26 Mg) substitution and by correlation with B3LYP and BP86 isotopic frequency calculations. This investigation reports the first experimental evidence for the fluoride Grignard species, CH 3 MgF. Infrared absorptions were also observed for associated Grignard species.