Abstract
Substitution-inert Co(II) complexes with tripodal 1,1,1-tris(dimethylphosphinomethyl)ethane were produced in aqueous solution by the controlled-potential electrolysis. EPR studies indicated that the Co(II)P6 and Co(II)P3S3 species are in the low-spin t2g6eg1 state. The analyses of the absorption spectra of the Co(II) species in solution indicated significant Jahn-Teller distortion in Co(II)P6 and Co(II)P3S3 ions as expected for the low-spin d7 electronic configuration, while less distortion was observed for the Co(II)S6 ion. Kinetic studies of the redox reactions involving these Co(III/II) species confirmed that the electron self-exchange reactions for the Co(III/II)P6 and Co(III/II)P3S3 couples are relatively fast (kex ∼ 1 × 104 dm3 mol-1 s-1), which is consistent with the results for other low-spin - low-spin Co(III/II) couples. It was concluded that the nephelauxetic effect of the P-donor atom stabilizes the low-spin state in Co(II), and that the rather rapid electron exchange rates for these Co(III/II) couples were explained by the lack of the spin reorganization process required for the ordinary low-spin - high-spin Co(III/II) couples.
Original language | English |
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Pages (from-to) | 1344-1351 |
Number of pages | 8 |
Journal | Canadian Journal of Chemistry |
Volume | 79 |
Issue number | 9 |
DOIs | |
Publication status | Published - Jan 1 2001 |
Externally published | Yes |
Keywords
- Cobalt(III/II)
- EPR study
- Electron transfer
- Kinetics
- Spin state
ASJC Scopus subject areas
- Catalysis
- Chemistry(all)
- Organic Chemistry