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 t2g 6eg 1 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 |
|---|---|
| Pages (from-to) | 1344-1351 |
| Number of pages | 8 |
| Journal | Canadian Journal of Chemistry |
| Volume | 79 |
| Issue number | 9 |
| DOIs | |
| Publication status | Published - 2001 |
| Externally published | Yes |
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Keywords
- Cobalt(III/II)
- Electron transfer
- EPR study
- Kinetics
- Spin state
ASJC Scopus subject areas
- Chemistry(all)
Cite this
New low-spin Co(II) complexes with novel tripodal 1,1,1-tris(dimethylphosphinomethyl)ethane ligand : Electron transfer kinetics and spectroscopic characterization of Co(II)P6 and Co(II)P3S3 ions in aqueous solution. / Iwatsuki, S.; Obeyama, K.; Koshino, N.; Funahashi, S.; Kashiwabara, K.; Suzuki, Takayoshi; Takagi, H. D.
In: Canadian Journal of Chemistry, Vol. 79, No. 9, 2001, p. 1344-1351.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - New low-spin Co(II) complexes with novel tripodal 1,1,1-tris(dimethylphosphinomethyl)ethane ligand
T2 - Electron transfer kinetics and spectroscopic characterization of Co(II)P6 and Co(II)P3S3 ions in aqueous solution
AU - Iwatsuki, S.
AU - Obeyama, K.
AU - Koshino, N.
AU - Funahashi, S.
AU - Kashiwabara, K.
AU - Suzuki, Takayoshi
AU - Takagi, H. D.
PY - 2001
Y1 - 2001
N2 - 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 t2g 6eg 1 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.
AB - 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 t2g 6eg 1 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.
KW - Cobalt(III/II)
KW - Electron transfer
KW - EPR study
KW - Kinetics
KW - Spin state
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U2 - 10.1139/cjc-79-9-1344
DO - 10.1139/cjc-79-9-1344
M3 - Article
VL - 79
SP - 1344
EP - 1351
JO - Canadian Journal of Chemistry
JF - Canadian Journal of Chemistry
SN - 0008-4042
IS - 9
ER -