Abstract
The redox chemistry of oxo (7,8,12,13-tetraethyl-2,3,17,18-tetramethylcorrolato)chromium(V), [Cr(O) (tetmc)], and the (5,10,15,20-tetraphenylporphinato) chromium(III) complexes, [Cr(tpp)X] (X = OMe or Cl), was investigated by means of cyclic voltammetry and controlled-potential electrolysis in the presence of tetrabutylammonium perchlorate at 25 ± 2 °C. Dichloromethane and NN-dimethylformamide were used as solvents for [Cr(O)(tetmc)] and [Cr(tpp)X] respectively. The compound [Cr(O)(tetmc)] underwent metal reduction more readily than [Mo(O)(tetmc)]. This was attributed to an extensive interaction between chromium dxy and ligand orbitals which tends to reduce the d-electron density at the chromium site (nephelauxetic effect) and to raise the dxy level. As for the tpp complexes, the first reduction took place at the ligand (tpp) site for [Cr(tpp)(OMe)] but at the metal site for [Cr(tpp)Cl]. The less ready reduction of the former complex at the metal site was attributed to effective covalent character of the Cr-OMe bond. Redox behaviour of the tpp complexes was discussed on the basis of the energy-level diagram of d orbitals under C4v co-ordination symmetry and π-orbital interactions between chromium and tpp.
| Original language | English |
|---|---|
| Pages (from-to) | 855-861 |
| Number of pages | 7 |
| Journal | Journal of the Chemical Society, Dalton Transactions |
| Issue number | 3 |
| DOIs | |
| Publication status | Published - Dec 1 1981 |
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All Science Journal Classification (ASJC) codes
- Chemistry(all)
Cite this
Transition-metal complexes of pyrrole pigments. Part 20. Redox behaviour of chromium complexes with macrocyclic tetrapyrroles. / Murakami, Yukito; Matsuda, Yoshihisa; Yamada, Sunao.
In: Journal of the Chemical Society, Dalton Transactions, No. 3, 01.12.1981, p. 855-861.Research output: Contribution to journal › Article
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TY - JOUR
T1 - Transition-metal complexes of pyrrole pigments. Part 20. Redox behaviour of chromium complexes with macrocyclic tetrapyrroles
AU - Murakami, Yukito
AU - Matsuda, Yoshihisa
AU - Yamada, Sunao
PY - 1981/12/1
Y1 - 1981/12/1
N2 - The redox chemistry of oxo (7,8,12,13-tetraethyl-2,3,17,18-tetramethylcorrolato)chromium(V), [Cr(O) (tetmc)], and the (5,10,15,20-tetraphenylporphinato) chromium(III) complexes, [Cr(tpp)X] (X = OMe or Cl), was investigated by means of cyclic voltammetry and controlled-potential electrolysis in the presence of tetrabutylammonium perchlorate at 25 ± 2 °C. Dichloromethane and NN-dimethylformamide were used as solvents for [Cr(O)(tetmc)] and [Cr(tpp)X] respectively. The compound [Cr(O)(tetmc)] underwent metal reduction more readily than [Mo(O)(tetmc)]. This was attributed to an extensive interaction between chromium dxy and ligand orbitals which tends to reduce the d-electron density at the chromium site (nephelauxetic effect) and to raise the dxy level. As for the tpp complexes, the first reduction took place at the ligand (tpp) site for [Cr(tpp)(OMe)] but at the metal site for [Cr(tpp)Cl]. The less ready reduction of the former complex at the metal site was attributed to effective covalent character of the Cr-OMe bond. Redox behaviour of the tpp complexes was discussed on the basis of the energy-level diagram of d orbitals under C4v co-ordination symmetry and π-orbital interactions between chromium and tpp.
AB - The redox chemistry of oxo (7,8,12,13-tetraethyl-2,3,17,18-tetramethylcorrolato)chromium(V), [Cr(O) (tetmc)], and the (5,10,15,20-tetraphenylporphinato) chromium(III) complexes, [Cr(tpp)X] (X = OMe or Cl), was investigated by means of cyclic voltammetry and controlled-potential electrolysis in the presence of tetrabutylammonium perchlorate at 25 ± 2 °C. Dichloromethane and NN-dimethylformamide were used as solvents for [Cr(O)(tetmc)] and [Cr(tpp)X] respectively. The compound [Cr(O)(tetmc)] underwent metal reduction more readily than [Mo(O)(tetmc)]. This was attributed to an extensive interaction between chromium dxy and ligand orbitals which tends to reduce the d-electron density at the chromium site (nephelauxetic effect) and to raise the dxy level. As for the tpp complexes, the first reduction took place at the ligand (tpp) site for [Cr(tpp)(OMe)] but at the metal site for [Cr(tpp)Cl]. The less ready reduction of the former complex at the metal site was attributed to effective covalent character of the Cr-OMe bond. Redox behaviour of the tpp complexes was discussed on the basis of the energy-level diagram of d orbitals under C4v co-ordination symmetry and π-orbital interactions between chromium and tpp.
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U2 - 10.1039/DT9810000855
DO - 10.1039/DT9810000855
M3 - Article
SP - 855
EP - 861
JO - Dalton Transactions
JF - Dalton Transactions
SN - 1470-479X
IS - 3
ER -