Iron(III) complexes of N2O and N3O donor ligands as functional models for catechol dioxygenase enzymes: ether oxygen coordination tunes the regioselectivity and reactivity
Sundaravel, K; Suresh, E; Saminathan, K; Palaniandavar, M
HERO ID
1555002
Reference Type
Journal Article
Year
2011
Language
English
PMID
| HERO ID | 1555002 |
|---|---|
| In Press | No |
| Year | 2011 |
| Title | Iron(III) complexes of N2O and N3O donor ligands as functional models for catechol dioxygenase enzymes: ether oxygen coordination tunes the regioselectivity and reactivity |
| Authors | Sundaravel, K; Suresh, E; Saminathan, K; Palaniandavar, M |
| Journal | Dalton Transactions (Online) |
| Volume | 40 |
| Issue | 32 |
| Page Numbers | 8092-8107 |
| Abstract | A series of mononuclear iron(III) complexes of the type [Fe(L)Cl(3)], where L is a systematically modified N(2)O or N(3)O ligand with a methoxyethyl/tetrahydrofuryl ether oxygen donor atom, have been isolated and studied as models for catechol dioxygenases. The X-ray crystal structures of [Fe(L2)Cl(3)] 2, [Fe(L6)Cl(3)] 6, [Fe(L5)(TCC)Cl] 5a, where H(2)TCC = tetrachlorocatechol, [Fe(L6)(TCC)Br] 6a, and the μ-oxo dimer [{Fe(L6)Cl}(2)O](ClO(4))(2) 6b have been successfully determined. In [Fe(L2)Cl(3)] 2 the N(2)O ligand is facially coordinated to iron(III) through the pyridine and secondary amine nitrogen atoms and the tetrahydrofuryl oxygen atom. In [Fe(L6)Cl(3)] 6, [Fe(L5)(TCC)Cl] 5a and [Fe(L6)(TCC)Br] 6a the N(3)O donor ligands L5 and L6 act as a tridentate N3 donor ligand coordinated through two pyridine and one secondary amine nitrogen atoms, whereas the ether oxygen is not coordinated. The spectral and electrochemical properties of the adducts [Fe(L)(DBC)Cl] of 1-8, where H(2)DBC = 3,5-di-tert-butylcatechol, in DMF and their solvated adduct species [Fe(L)(DBC)(Sol)](+), where Sol = DMF/H(2)O, generated in situ in dichloromethane, respectively, have been investigated. The product analysis demonstrates that the adducts [Fe(L)(DBC)Cl] effect cleavage of catechol in the presence of O(2) in DMF to give mainly the intradiol (I) product with a small amount of the extradiol (E) product (E/I, 0.2:1-0.7:1). Interestingly, the solvated species [Fe(L)(DBC)(Sol)](+) derived from 1-4 cleave H(2)DBC to provide mainly the extradiol cleavage products with lower amounts of intradiol products (E/I, 2.3:1-4.3:1) in dichloromethane. In contrast, the solvated species [Fe(L)(DBC)(Sol)](+) derived from 5-8 cleave H(2)DBC to provide both extradiol and intradiol products (E/I, 0.6:1-2.3:1) due to the involvement of the ether oxygen donor of the methoxyethyl/tetrahydrofuryl arm in the coordination to iron(III) upon removal of a chloride ion. |
| Doi | 10.1039/c0dt01598a |
| Pmid | 21766098 |
| Is Certified Translation | No |
| Dupe Override | No |
| Is Public | Yes |
| Language Text | English |