The photochemistry of Fe(CO)5 (5) has been studied in heptane, supercritical (sc) Ar, scXe, and scCH4 using time-resolved infrared spectroscopy (TRIR). 3Fe(CO)4 (34) and Fe(CO)3(solvent) (3) are formed as primary photoproducts within the first few picoseconds. Complex 3 is formed via a single-photon process. In heptane, scCH4, and scXe, 34 decays to form 14·L (L = heptane, CH4, or Xe) as well as reacting with 5 to form Fe2(CO)9. In heptane, 3 reacts with CO to form 14·L. The conversion of 34 to 14·L has been monitored directly for the first time (L = heptane, kobs = 7.8(±0.3) x 107 s-1; scCH4, 5(±1) x 106 s-1; scXe, 2.1(±O.1) x 107 s-1). In scAr, 34 and 3 react with CO to form 5 and 34, respectively. We have determined the rate constant (kCO = 1.2 x 107 dm3 mol -1 s-1) for the reaction of 34 with CO in scAr, and this is very similar to the value obtained previously in the gas phase. Doping the scAr with either Xe or CH4 resulted in 34 reacting with Xe or CH4 to form 14·Xe or 14·CH4. The relative yield, : decreases in the order heptane > scXe > scCH4 ≫ scAr, and pressure-dependent measurements in scAr and scCH4 indicate an influence of the solvent density on this ratio.
ASJC Scopus subject areas
- Colloid and Surface Chemistry