Abstract
The binding of CO2 to metal macrocycles has been determined electrochemically by using cyclic voltammetry or differential pulse polarography. The CO2 binding constants, KCO2, for a series of Co(I) tetraazamacrocycle complexes in (CH3)2SO showed a strong correlation with the Co(II/I) redox potential. Although meso and d,1 stereoisomers of [CoI(Me6[14]4,11-diene)]+ had identical redox potentials, KCO2 differed by a factor of 102 for these stereoisomers, suggesting a large steric effect on CO2 binding. Binding of CO2 to Ni(I) tetraazamacrocycles in (CH3)2SO yielded a redox potential dependence similar to that of Co(I) macrocycles. A weak correlation between KCO2 and the solvent dielectric constant was found for d,l-[Co(Me6[14]-4,11-diene)]+. In tetrahydrofuran (THF), d,l-[Co(Me6[14]4,11-diene)]+ was found to bind CO2 more strongly in the presence of 0.1 M Li+ than in the presence of 0.1 M tetrabutylammonium (TBA+). Electrochemically determined KCO2's for Co(salen)- and Co(Me2salen)- in THF indicated a strong dependence on redox potential and electrolyte cation.
| Original language | English |
|---|---|
| Pages (from-to) | 3420-3426 |
| Number of pages | 7 |
| Journal | Journal of the American Chemical Society |
| Volume | 112 |
| Issue number | 9 |
| Publication status | Published - Apr 25 1990 |
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Effects of redox potential, steric configuration, solvent, and alkali metal cations on the binding of carbon dioxide to cobalt(I) and nickel(I) macrocycles. / Schmidt, Michael H.; Miskelly, Gordon M.; Lewis, Nathan S.
In: Journal of the American Chemical Society, Vol. 112, No. 9, 25.04.1990, p. 3420-3426.Research output: Contribution to journal › Article
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TY - JOUR
T1 - Effects of redox potential, steric configuration, solvent, and alkali metal cations on the binding of carbon dioxide to cobalt(I) and nickel(I) macrocycles
AU - Schmidt, Michael H.
AU - Miskelly, Gordon M.
AU - Lewis, Nathan S
PY - 1990/4/25
Y1 - 1990/4/25
N2 - The binding of CO2 to metal macrocycles has been determined electrochemically by using cyclic voltammetry or differential pulse polarography. The CO2 binding constants, KCO2, for a series of Co(I) tetraazamacrocycle complexes in (CH3)2SO showed a strong correlation with the Co(II/I) redox potential. Although meso and d,1 stereoisomers of [CoI(Me6[14]4,11-diene)]+ had identical redox potentials, KCO2 differed by a factor of 102 for these stereoisomers, suggesting a large steric effect on CO2 binding. Binding of CO2 to Ni(I) tetraazamacrocycles in (CH3)2SO yielded a redox potential dependence similar to that of Co(I) macrocycles. A weak correlation between KCO2 and the solvent dielectric constant was found for d,l-[Co(Me6[14]-4,11-diene)]+. In tetrahydrofuran (THF), d,l-[Co(Me6[14]4,11-diene)]+ was found to bind CO2 more strongly in the presence of 0.1 M Li+ than in the presence of 0.1 M tetrabutylammonium (TBA+). Electrochemically determined KCO2's for Co(salen)- and Co(Me2salen)- in THF indicated a strong dependence on redox potential and electrolyte cation.
AB - The binding of CO2 to metal macrocycles has been determined electrochemically by using cyclic voltammetry or differential pulse polarography. The CO2 binding constants, KCO2, for a series of Co(I) tetraazamacrocycle complexes in (CH3)2SO showed a strong correlation with the Co(II/I) redox potential. Although meso and d,1 stereoisomers of [CoI(Me6[14]4,11-diene)]+ had identical redox potentials, KCO2 differed by a factor of 102 for these stereoisomers, suggesting a large steric effect on CO2 binding. Binding of CO2 to Ni(I) tetraazamacrocycles in (CH3)2SO yielded a redox potential dependence similar to that of Co(I) macrocycles. A weak correlation between KCO2 and the solvent dielectric constant was found for d,l-[Co(Me6[14]-4,11-diene)]+. In tetrahydrofuran (THF), d,l-[Co(Me6[14]4,11-diene)]+ was found to bind CO2 more strongly in the presence of 0.1 M Li+ than in the presence of 0.1 M tetrabutylammonium (TBA+). Electrochemically determined KCO2's for Co(salen)- and Co(Me2salen)- in THF indicated a strong dependence on redox potential and electrolyte cation.
UR - http://www.scopus.com/inward/record.url?scp=0025125077&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0025125077&partnerID=8YFLogxK
M3 - Article
VL - 112
SP - 3420
EP - 3426
JO - Journal of the American Chemical Society
JF - Journal of the American Chemical Society
SN - 0002-7863
IS - 9
ER -