Direct Observation of a Bent Carbonyl Ligand in a 19-Electron Transition Metal Complex
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- 作者：Justin P. Lomont ; Son C. Nguyen ; Charles B. Harris
- 刊名：The Journal of Physical Chemistry A
- 出版年：2013
- 出版时间：March 21, 2013
- 年：2013
- 卷：117
- 期：11
- 页码：2317-2324
- 全文大小：311K
- 年卷期：v.117,no.11(March 21, 2013)
- ISSN：1520-5215
文摘
The photochemistry of [CpRu(CO)2]2 in P(OMe)3/CH2Cl2 solution has been studied using picosecond time-resolved infrared (TRIR) spectroscopy. Photolysis at 400 nm leads to the formation of 17-electron CpRu(CO)2p>鈥?/sup> radicals, which react on the picosecond time scale to form 19-electron CpRu(CO)2P(OMe)3p>鈥?/sup> adducts. The TRIR spectra of this adduct display an unusually low CO stretching frequency for the antisymmetric CO stretching mode, suggesting that one carbonyl ligand adopts a bent configuration to avoid a 19-electron count at the metal center. This spectral assignment is supported by analogous experiments on [CpFe(CO)2]2 in the same solvent, combined with DFT studies on the structures of the 19-electron adducts. The DFT results predict a bent CO ligand in CpRu(CO)2P(OMe)3p>鈥?/sup>, whereas approximately linear Fe鈥揅鈥揙 bond angles are predicted for CpFe(CO)2P(OMe)3p>鈥?/sup>. The observation of a bent CO ligand in the 19-electron ruthenium adduct is a surprising result, and it provides new insight into the solution-phase behavior of 19-electron complexes. TRIR spectra were also collected for [CpRu(CO)2]2 in neat CH2Cl2, and it is interesting to note that no singly bridged [CpRu(CO)]2(渭-CO) photoproduct was observed to form following 400- or 267-nm excitation, despite previous observations of this species on longer time scales.