TY - JOUR
T1 - Iron-catalyzed C2-C3 bond cleavage of phenylpyruvate with O2
T2 - Insight into aliphatic C-C bond-cleaving dioxygenases
AU - Paine, Tapan Kanti
AU - England, Jason
AU - Que, Lawrence
PY - 2007
Y1 - 2007
N2 - Iron(II)-phenylpyruvate complexes of tetradentate tris(6-methyl-2- pyridylmethyl)amine (6-Me3-TPA) and tridentate benzyl bis(2-quinolinylmethyl)amine (Bn-BQA) were prepared to gain insight into C-C bond cleavage catalyzed by dioxygenase enzymes. The complexes we have prepared and characterized are [Fe(O-Me3-tpa)(prv)] [BPh4] (1), [Fe2(O-Me3-tpa)2(pp)][(BPh4) 2] (2), and [Fe2(6-Me3-tpa) 2(2′-NO2-pp)][(BPh4)2] (3), [Fe(6-Me3-tpa)(pp-Me)][BPh4] (4), [Fe(6-Me 3-tpa)(CN-pp-Et)][BPh4] (5), and [Fe(Bn-bqa)(pp)] (8), in which PRV is pyruvate, PP is the enolate form of phenylpyruvate, 2′-NO2-PP is the enolate form of 2′-nitrophenylpyruvate, PP-Me is the enolate form of methyl phenylpyruvate, and CN-PP-Et is the enolate form of ethyl-3-cyanophenylpyruvate. The structures of mononuclear complexes 1 and 5 were determined by single-crystal X-ray diffraction. Both the PRV ligand in 1 and the CN-PP-Et ligand in 5 bind to the iron(II) center in a bidentate manner and form 5-membered chelate rings, but the a-keto moiety is in the enolate form in 5 with concomitant loss of a C-Hβ proton. The PP ligands of 2, 3, 4, and 8 react with dioxygen to form benzaldehyde and oxalate products, which indicates that the C2-C3 PP bond is cleaved, in contrast to cleavage of the C1-C2 bond previously observed for complexes that do not contain α-ketocarboxylate ligands in the enolate form. These reactions serve as models for metal-containing dioxygenase enzymes that catalyze the cleavage of aliphatic C-C bonds.
AB - Iron(II)-phenylpyruvate complexes of tetradentate tris(6-methyl-2- pyridylmethyl)amine (6-Me3-TPA) and tridentate benzyl bis(2-quinolinylmethyl)amine (Bn-BQA) were prepared to gain insight into C-C bond cleavage catalyzed by dioxygenase enzymes. The complexes we have prepared and characterized are [Fe(O-Me3-tpa)(prv)] [BPh4] (1), [Fe2(O-Me3-tpa)2(pp)][(BPh4) 2] (2), and [Fe2(6-Me3-tpa) 2(2′-NO2-pp)][(BPh4)2] (3), [Fe(6-Me3-tpa)(pp-Me)][BPh4] (4), [Fe(6-Me 3-tpa)(CN-pp-Et)][BPh4] (5), and [Fe(Bn-bqa)(pp)] (8), in which PRV is pyruvate, PP is the enolate form of phenylpyruvate, 2′-NO2-PP is the enolate form of 2′-nitrophenylpyruvate, PP-Me is the enolate form of methyl phenylpyruvate, and CN-PP-Et is the enolate form of ethyl-3-cyanophenylpyruvate. The structures of mononuclear complexes 1 and 5 were determined by single-crystal X-ray diffraction. Both the PRV ligand in 1 and the CN-PP-Et ligand in 5 bind to the iron(II) center in a bidentate manner and form 5-membered chelate rings, but the a-keto moiety is in the enolate form in 5 with concomitant loss of a C-Hβ proton. The PP ligands of 2, 3, 4, and 8 react with dioxygen to form benzaldehyde and oxalate products, which indicates that the C2-C3 PP bond is cleaved, in contrast to cleavage of the C1-C2 bond previously observed for complexes that do not contain α-ketocarboxylate ligands in the enolate form. These reactions serve as models for metal-containing dioxygenase enzymes that catalyze the cleavage of aliphatic C-C bonds.
KW - Bioinorganic chemistry
KW - C-C bond cleavage
KW - Enzymes
KW - Iron
KW - O-O activation
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U2 - 10.1002/chem.200601844
DO - 10.1002/chem.200601844
M3 - Article
C2 - 17469086
AN - SCOPUS:34547145888
SN - 0947-6539
VL - 13
SP - 6073
EP - 6081
JO - Chemistry - A European Journal
JF - Chemistry - A European Journal
IS - 21
ER -