Reactions of Methane with Titanium Atoms: CH3TiH, CH2=TiH2, Agostic Bonding, and (CH3)2TiH2

Laser-ablated titanium atoms react with methane to form the insertion product CH3TiH, which undergoes a reversible photochemical (alpha)-H transfer to give the methylidene complex CH2=TiH2. On annealing a second methane activation occurs to produce (CH3)2TiH2. These molecules are identified from matrix infrared spectra by isotopic substitution (CH4, 13CH4, CD4, CH2D2) and comparison to DFT frequency calculations. The computed planar structure for singlet ground-state CH2=TiH2 shows CH2 distortion and evidence for agostic bonding (H-C-Ti, 91.4°), which is supported by the spectra for CHD=TiHD.