Abstract
Several new cobalt(III) complexes incorporating 4,4,5,5-tetramethyl-2-(3- or 4-pyridyl)imidazolin-1-oxyl 3-oxide (NITnpy) (n = 3 or 4) or 4,4,5,5-tetramethyl-2-(3- or 4-pyridyl)-imidazolin-1-oxyl (IMnpy) have been prepared. The X-ray crystallographic analyses and the spectroscopic investigations have revealed that the nitronyl or imino nitroxides with the radical character are bound through the pyridyl-N atom to a CoIII center. There are some influences from the radical unpaired electron toward the CoIII complex moiety and those from the coordination of the CoIII ion toward the nature of these radicals which can be detected by 59Co NMR and UV/Vis spectroscopy. Such observed changes coincide with the proposed spin density on the N atom of the pyridyl substituent. Furthermore, it was found that trans-[Co-(acac)2(PPh3)(NIT4py)]+ in methanol was gradually converted into the corresponding IM4py complex, while free NIT4py is stable in methanol. The CoII species formed on the partial decomposition of the NIT4py complex in methanol seems to catalyze the deoxygenation of NIT4py to IM4py.
| Original language | English |
|---|---|
| Pages (from-to) | 886-894 |
| Number of pages | 9 |
| Journal | European Journal of Inorganic Chemistry |
| Issue number | 4 |
| Publication status | Published - 2002 |
| Externally published | Yes |
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Keywords
- Cobalt
- Deoxygenation
- Nitroxides
- NMR spectroscopy
- Radicals
ASJC Scopus subject areas
- Inorganic Chemistry
Cite this
Syntheses, structures, and spectroscopic properties of cobalt(III) complexes containing 3- or 4-pyridyl-substituted nitronyl and imino nitroxide ligands. / Ogita, Masahiro; Yamamoto, Youhei; Suzuki, Takayoshi; Kaizaki, Sumio.
In: European Journal of Inorganic Chemistry, No. 4, 2002, p. 886-894.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Syntheses, structures, and spectroscopic properties of cobalt(III) complexes containing 3- or 4-pyridyl-substituted nitronyl and imino nitroxide ligands
AU - Ogita, Masahiro
AU - Yamamoto, Youhei
AU - Suzuki, Takayoshi
AU - Kaizaki, Sumio
PY - 2002
Y1 - 2002
N2 - Several new cobalt(III) complexes incorporating 4,4,5,5-tetramethyl-2-(3- or 4-pyridyl)imidazolin-1-oxyl 3-oxide (NITnpy) (n = 3 or 4) or 4,4,5,5-tetramethyl-2-(3- or 4-pyridyl)-imidazolin-1-oxyl (IMnpy) have been prepared. The X-ray crystallographic analyses and the spectroscopic investigations have revealed that the nitronyl or imino nitroxides with the radical character are bound through the pyridyl-N atom to a CoIII center. There are some influences from the radical unpaired electron toward the CoIII complex moiety and those from the coordination of the CoIII ion toward the nature of these radicals which can be detected by 59Co NMR and UV/Vis spectroscopy. Such observed changes coincide with the proposed spin density on the N atom of the pyridyl substituent. Furthermore, it was found that trans-[Co-(acac)2(PPh3)(NIT4py)]+ in methanol was gradually converted into the corresponding IM4py complex, while free NIT4py is stable in methanol. The CoII species formed on the partial decomposition of the NIT4py complex in methanol seems to catalyze the deoxygenation of NIT4py to IM4py.
AB - Several new cobalt(III) complexes incorporating 4,4,5,5-tetramethyl-2-(3- or 4-pyridyl)imidazolin-1-oxyl 3-oxide (NITnpy) (n = 3 or 4) or 4,4,5,5-tetramethyl-2-(3- or 4-pyridyl)-imidazolin-1-oxyl (IMnpy) have been prepared. The X-ray crystallographic analyses and the spectroscopic investigations have revealed that the nitronyl or imino nitroxides with the radical character are bound through the pyridyl-N atom to a CoIII center. There are some influences from the radical unpaired electron toward the CoIII complex moiety and those from the coordination of the CoIII ion toward the nature of these radicals which can be detected by 59Co NMR and UV/Vis spectroscopy. Such observed changes coincide with the proposed spin density on the N atom of the pyridyl substituent. Furthermore, it was found that trans-[Co-(acac)2(PPh3)(NIT4py)]+ in methanol was gradually converted into the corresponding IM4py complex, while free NIT4py is stable in methanol. The CoII species formed on the partial decomposition of the NIT4py complex in methanol seems to catalyze the deoxygenation of NIT4py to IM4py.
KW - Cobalt
KW - Deoxygenation
KW - Nitroxides
KW - NMR spectroscopy
KW - Radicals
UR - http://www.scopus.com/inward/record.url?scp=0036214896&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0036214896&partnerID=8YFLogxK
M3 - Article
AN - SCOPUS:0036214896
SP - 886
EP - 894
JO - Chemische Berichte
JF - Chemische Berichte
SN - 0009-2940
IS - 4
ER -