UV Laser-Induced Photolysis of Fe(CO)₅ in Argon Matrix

The 280 nm pulsed laser-induced photolysis of Fe(CO)₅ in Ar matrix at 10K was studied by FT-IR spectroscopy. Due to the matrix effect, the structures of Fe(CO)₅ and Fe(CO)_x(x=4, 3) in argon matrix are distorted which makes their IR bands shift, split and change slightly in relative intensity as compared with those in gas phase. The Photofragments CO, FeCO)₄ and Fe(CO)₃ are found after laser irradiation, but no Fe(CO)₂ and lower carbonyl fragments are obsearved, which implies that the photofragments Fe(CO)₂ and CO can be recombined by "cage effect" during the interval of two laser pulses. Furthermore, the photofragment Fe(CO)₄ can combine with the Ar matrix to form a new complex Fe(CO)₄Ar under certain conditions. A Photochemical scheme which accounts for all observed products can therefore be summarized as follow: