Photoactivity and UV Absorption Spectroscopy of RCo(CO)4 (R = H, CH3) Organometallic Complexes
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- 作者：David Ambrosek ; Sebastien Villaume ; Chantal Daniel ; Leticia Gonzá ; lez
- 刊名：Journal of Physical Chemistry A
- 出版年：2007
- 出版时间：June 7, 2007
- 年：2007
- 卷：111
- 期：22
- 页码：4737 - 4742
- 全文大小：206K
- 年卷期：v.111,no.22(June 7, 2007)
- ISSN：1520-5215
文摘
The photoactivity of RCo(CO)4 (R = H, CH3) complexes has been investigated and compared by means ofstate correlation diagrams connecting the low-lying singlet 1E (dCo 
*Co-R and dCo 
*CO) and 1A1 (dCo *CO) electronic states accessible through UV irradiation, and the low-lying triplet states (3E and 3A1), tothe corresponding states of the primary products R + Co(CO)4 and COax + RCo(CO)3. The electronic absorptionspectra have been calculated by time-dependent wave packet propagations on two-dimensional potential energysurfaces describing both channels of dissociation, namely the homolysis of the R-Co and the COax-Cobonds. It is shown that the absorption spectrum of HCo(CO)4 is characterized by two peaks; the most intensepeaks for each set are located respectively at 42 659 and 45 001 cm-1. The CH3Co(CO)4 absorption spectrumalso gives two sets of signals with maximum intensities found at 42 581 and 51 515 cm-1 These bands forboth molecules are assigned to the two metal-to-ligand-charge-transfer (MLCT; dCo *CO) states. Threephotoactive states have been determined in both molecules, namely the singlet metal-to--bond-charge-transfer(MSBCT) states (a1E and b1E), simultaneously dissociative for both the homolysis of CO and the R-Cobond, and the 3A1 (Co-R *Co-R), dissociative along the R-Co bond.
*Co-R and dCo *CO) and 1A1 (dCo *CO) electronic states accessible through UV irradiation, and the low-lying triplet states (3E and 3A1), tothe corresponding states of the primary products R + Co(CO)4 and COax + RCo(CO)3. The electronic absorptionspectra have been calculated by time-dependent wave packet propagations on two-dimensional potential energysurfaces describing both channels of dissociation, namely the homolysis of the R-Co and the COax-Cobonds. It is shown that the absorption spectrum of HCo(CO)4 is characterized by two peaks; the most intensepeaks for each set are located respectively at 42 659 and 45 001 cm-1. The CH3Co(CO)4 absorption spectrumalso gives two sets of signals with maximum intensities found at 42 581 and 51 515 cm-1 These bands forboth molecules are assigned to the two metal-to-ligand-charge-transfer (MLCT; dCo *CO) states. Threephotoactive states have been determined in both molecules, namely the singlet metal-to--bond-charge-transfer(MSBCT) states (a1E and b1E), simultaneously dissociative for both the homolysis of CO and the R-Cobond, and the 3A1 (Co-R *Co-R), dissociative along the R-Co bond.