New insights into the photochemistry of [CpFe(CO)(2)](2) using picosecond through microsecond time-resolved infrared spectroscopy (TRIR)

作者：Brookes Christopher M; Lomont Justin P; Nguyen Son C; Calladine James A; Sun Xue Zhong; Harris Charles B; George Michael W^*

来源：Polyhedron, 2014, 72: 130-134.

DOI：10.1016/j.poly.2013.12.028

• Photochemistry
• Time-resolved spectroscopy
• Infrared spectroscopy
• Iron carbonyls

Picosecond to microsecond time-resolved infrared spectroscopy (TRIR) has been used to investigate the photochemistry of [CpFe(CO)(2)](2). The early-time TRIR spectra are dominated by vibrationally hot transient species and this leads to spectra with broad featureless bands. The majority (84%) of the well characterized Cp2Fe2(mu-CO)(3), with a band at 1824 cm-1, grows in on a timescale (1520 ps) similar to the cooling rate of many of the nu(CO) bands, and this arises from presumably the initially formed species, [CpFe(CO)(mu-CO)(2)FeCp] of which we were unable to find clear evidence. However, Cp2Fe2(mu-CO)(3) is formed by two different processes and under CO the remaining slower formation (16%) occurs at the same rate (46 +/- 2 ns) as a transient band at 1908 cm(-1) decays. The 1908 cm(-1) had been previously observed in an earlier study but its identity remained unclear. We find that this 1908 cm(-1) intermediate has no corresponding bridging nu(CO) band and is formed by a 1-photon process. This band is assigned to a dicarbonyl-loss photoproduct, [CpFe(CO)](2) and is a rare example of double CO loss occurring following a single-photon excitation in the condensed phase.

• 出版日期2014-4-10