KCS

We report direct structural determination of photodissociation of 1,2-diiodotetrafluoroethane (C₂F₄I₂) in polar solution, obtained using time-resolved liquid-phase x-ray diffraction. Ultrashort laser pulses were used to initiate the cleavage of an iodine atom from C₂F₄I₂ dissolved in methanol, and x-ray pulses from a third generation synchrotron probed the structural dynamics with ~100 picosecond time-resolution. The bond-rupture of C₂F₄I₂ leads to the formation of transient CF₂ICF₂· radical and I atom as well as complete dissociation to the C₂F₄ and 2I. Then I atom binds another I atom and eventually makes I₂ in cage via non-geminate recombination. Solvent dynamics, which are explained by heating and thermal expansion, were also extracted from time-resolved x-ray diffraction data.