| Title: | Photochemistry of (eta(6)-Arene)Cr(CO)(3) (Arene = Methylbenzoate, Naphthalene, or Phenanthrene) in n-Heptane Solution: Population of Two Excited States Following 400 nm Excitation As Detected by Picosecond Time-Resolved Infrared Spectroscopy
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| Authors: | Clark, Ian P. George, Michael W. Greetham, Gregory M. Harvey, Emma C. Long, Conor Manton, Jennifer C. Pryce, Mary T., 2011 |
| Abstract: | The photochemistry of (eta(6)-methylbenzoate)Cr(CO)(3),
(eta(6)-naphthalene)Cr(CO)(3), and (eta(6)-phenanthrene)Cr(CO)(3) in
n-heptane solution was investigated by picosecond time-resolved infrared
spectroscopy (TRIR). The observation of two transient IR features in the
organic carbonyl region at 1681 and 1724 cm(-1) following 400 nm
excitation of (eta(6)-methylbenzoate)Cr(CO)(3) confirms formation of two
excited states which are classified as metal-to-arene charge transfer
(MACT) and metal-to-CO charge transfer (MCCT), respectively.
Time-dependent density functional theory calculations have been used to
support these assignments. Population of the MCCT excited state results
in a slow (150 ps) expulsion of one CO ligand. Excitation of
(eta(6)-naphthalene)Cr(CO)(3) or (eta(6)-phenanthrene)Cr(CO)(3) at
either 400 or 345 nm produced two excited states: the MCCT state results
in CO loss, while the MACT excited state results in a change to the
coordination mode of the polyaromatic ligands before relaxing to the
parent complex. A comparison of the infrared absorptions observed
following the population of the MACT excited state with those calculated
for nonplanar polyaromatic intermediates provides a model for the
reduced hapticity species. |
| ICHEC Project: | Estimating the potential energy surfaces around pi-coordinated arene ligands in (eta-Arene)Cr(CO)3 complexes |
| Publication: | J. Phys. Chem. A, 2011, 115 (14), pp 2985–2993 |
| URL: | http://pubs.acs.org/doi/abs/10.1021/jp112168u |
| Status: | Published |
