Photoreversible Hydrogen Migration System in a Solid Argon Matrix Formed by the Reaction of Methyl Fluoride with Laser-Ablated Titanium Atoms

The photoreversible system of titanium methylidene and methyltitanium fluoride complexes has been formed by the reaction of methyl fluoride and laser-ablated Ti atoms and isolated in a solid argon matrix. There are two major groups of absorptions based on broad-band irradiation and annealing behavior. The increase of group I is accompanied by the decrease of group II on photolysis with UV light (240 nm < λ < 380 nm) and the reverse with visible light (λ > 530 nm). The methylidene CH 2 TiHF and methyltitanium fluoride CH 3 −TiF are responsible for these absorptions, and the photochemical interconversion occurs via α-H migration between carbon and titanium atoms. The methylidene complex appears to be stabilized by an agostic hydrogen interaction. Absorptions for the higher coordinated (CH 3 ) 2 TiF 2 complex are observed to increase on UV irradiation and on annealing where CH 3 TiF spontaneously adds CH 3 F.