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

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

doi:10.1016/j.poly.2013.12.028

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

Christopher M. Brookes, Justin P. Lomont, Son C. Nguyen, James A. Calladine, Xue Zhong Sun, Charles B. Harris, Michael W. George

Research output: Journal Publication › Article › peer-review

6 Citations (Scopus)

Abstract

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(μ-CO) ₃, with a band at 1824 cm^-1, grows in on a timescale (15-20 ps) similar to the cooling rate of many of the ν(CO) bands, and this arises from presumably the initially formed species, [CpFe(CO)(μ-CO) ₂FeCp] of which we were unable to find clear evidence. However, Cp₂Fe₂(μ-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 ν(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.

Original language	English
Pages (from-to)	130-134
Number of pages	5
Journal	Polyhedron
Volume	72
DOIs	https://doi.org/10.1016/j.poly.2013.12.028
Publication status	Published - 18 Apr 2014
Externally published	Yes

Keywords

Infrared spectroscopy
Iron carbonyls
Photochemistry
Time-resolved spectroscopy

ASJC Scopus subject areas

Physical and Theoretical Chemistry
Inorganic Chemistry
Materials Chemistry

Access to Document

10.1016/j.poly.2013.12.028

Cite this

@article{746c8f58b06b4992a39ca66aa308e93e,

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

abstract = "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(μ-CO) 3, with a band at 1824 cm-1, grows in on a timescale (15-20 ps) similar to the cooling rate of many of the ν(CO) bands, and this arises from presumably the initially formed species, [CpFe(CO)(μ-CO) 2FeCp] of which we were unable to find clear evidence. However, Cp2Fe2(μ-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 ν(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.",

keywords = "Infrared spectroscopy, Iron carbonyls, Photochemistry, Time-resolved spectroscopy",

author = "Brookes, {Christopher M.} and Lomont, {Justin P.} and Nguyen, {Son C.} and Calladine, {James A.} and Sun, {Xue Zhong} and Harris, {Charles B.} and George, {Michael W.}",

note = "Funding Information: This work was supported by Sasol Technologies UK, the EPSRC and the NSF (grant CHE-1213135). SCN acknowledges support through a VIED fellowship. JPL acknowledges support through an NSF graduate research fellowship. MWG gratefully acknowledges receipt of a Royal Society Wolfson Merit award.",

year = "2014",

month = apr,

day = "18",

doi = "10.1016/j.poly.2013.12.028",

language = "English",

volume = "72",

pages = "130--134",

journal = "Polyhedron",

issn = "0277-5387",

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TY - JOUR

T1 - New insights into the photochemistry of [CpFe(CO)2]2 using picosecond through microsecond time-resolved infrared spectroscopy (TRIR)

AU - Brookes, Christopher M.

AU - Lomont, Justin P.

AU - Nguyen, Son C.

AU - Calladine, James A.

AU - Sun, Xue Zhong

AU - Harris, Charles B.

AU - George, Michael W.

N1 - Funding Information: This work was supported by Sasol Technologies UK, the EPSRC and the NSF (grant CHE-1213135). SCN acknowledges support through a VIED fellowship. JPL acknowledges support through an NSF graduate research fellowship. MWG gratefully acknowledges receipt of a Royal Society Wolfson Merit award.

PY - 2014/4/18

Y1 - 2014/4/18

N2 - 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(μ-CO) 3, with a band at 1824 cm-1, grows in on a timescale (15-20 ps) similar to the cooling rate of many of the ν(CO) bands, and this arises from presumably the initially formed species, [CpFe(CO)(μ-CO) 2FeCp] of which we were unable to find clear evidence. However, Cp2Fe2(μ-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 ν(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.

AB - 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(μ-CO) 3, with a band at 1824 cm-1, grows in on a timescale (15-20 ps) similar to the cooling rate of many of the ν(CO) bands, and this arises from presumably the initially formed species, [CpFe(CO)(μ-CO) 2FeCp] of which we were unable to find clear evidence. However, Cp2Fe2(μ-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 ν(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.

KW - Infrared spectroscopy

KW - Iron carbonyls

KW - Photochemistry

KW - Time-resolved spectroscopy

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