Photochemistry of [Re(bipy)(CO)3(PPh3)]+ (bipy = 2,2′-bipyridine) in the presence of triethanolamine associated with photoreductive fixation of carbon dioxide: participation of a chain reaction mechanism
- 1 January 1997
- journal article
- research article
- Published by Royal Society of Chemistry (RSC) in J. Chem. Soc., Dalton Trans.
- No. 6,p. 1019-1024
- https://doi.org/10.1039/a607058b
Abstract
The complex fac-[Re(bipy)(CO) 3 (PPh 3 )] + 1 + (bipy = 2,2′-bipyridine) was converted into a formate complex fac-[Re(bipy)(CO) 3 {OC(O)H}] 2 in a 52.2% yield by irradiation in the presence of triethanolamine (teoa) and CO 2 . This photochemical fixation of CO 2 proceeds via a unique reaction mechanism: (i) irradiation of 1+ in teoa–dimethylformamide (dmf) resulted in the efficient formation of fac-[Re(bipy)(CO) 3 (teoa)] + 3 + and fac-[Re(bipy)(CO) 3 (dmf)] + 4+ in a quantum yield of 16.9; (ii) the ligand substitution was explained in terms of a chain mechanism involving an initial electron transfer from teoa to excited 1+, followed by substitution of the PPh 3 ligand of 1 with teoa and dmf to give 3 and 4; subsequent electron exchange of 3 and 4 with 1+ leads to the formation of 3+ and 4+ accompanied by the regeneration of 1; (iii) the formate complex 2 was formed in a quantum yield of 1.1 × 10 -3 upon excitation of 3+ and 4+ in the presence of CO 2 ; (iv) further irradiation after the formation of 2 resulted in the photocatalytic reduction of CO 2 to CO in a quantum yield of 0.05.Keywords
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