Chain Crossing upon Solid State Methane Photofluorination at 16 K

Photolysis of solid equimolar mixtures of CH₄ and F₂ at 16 K leads to formation of spatially isolated CH₃F, CH₂F₂ and HF, whereas in methane-diluted mixtures ([CH₄]:[F₂] = 60:1) cage formation of CH₃F^…HF complexes prevails; the observed quadratic relation between CH₂F₂ concentration and exposure dose and high quantum yield of the secondary product (per CH₃F molecule formed) means that CH₂F₂ molecules are formed from CH₃F, generated by the growth of previous chains.