Quercetin 2,3-Dioxygenase Mimicking Ring Cleavage of the Flavonolate Ligand Assisted by Copper. Synthesis and Characterization of Copper(I) Complexes [Cu(PPh3)2(fla)] (fla = Flav
详细信息 查看全文
- 作者：É ; va Balogh-Hergovich ; Jó ; zsef Kaizer ; Gá ; bor Speier ; Vilmos Fü ; lö ; p ; and Lá ; szló ; Pá ; rká ; nyi
- 刊名：Inorganic Chemistry
- 出版年：1999
- 出版时间：August 23, 1999
- 年：1999
- 卷：38
- 期：17
- 页码：3787 - 3795
- 全文大小：184K
- 年卷期：v.38,no.17(August 23, 1999)
- ISSN：1520-510X
文摘
Cu(PPh3)2(fla) has been prepared by reacting copper(I) chloride with sodium flavonolate in tetrahydrofuran solution.Crystallographic characterization of the complex (orthorhombic, P212121, a = 9.588(1) Å, b = 17.364(3) Å, c =24.378(3) Å, V = 4058.6(10) Å3, Z = 4, R = 0.049) has shown that the coordination geometry of the moleculeis tetrahedral. Oxygenation of Cu(PPh3)2(fla) in a methylene chloride solution at ambient conditions gives theO-benzoylsalicylato copper complex Cu(PPh3)2(O-bs) and carbon monoxide. Labeling experiments with an 18O2-16O2 mixture (1:4) evidenced the incorporation of both 18O atoms of 18O2 into the O-bs ligand. IR and MS studiesof labeled O-bs confirmed the incorporation of 18O2 while the released CO remained unlabeled. Crystallographiccharacterization of Cu(PPh3)2(O-bs) on crystals obtained as the acetone solvate (triclinic, P
f">, a = 13.154(1) Å,b = 17.991(1) Å, c = 20.495(1) Å, 
fchars/alpha.gif" BORDER=0> = 80.01(1)
f">, fchars/beta2.gif" BORDER=0 ALIGN="middle"> = 88.02(1)f">, fchars/gamma.gif" BORDER=0 > = 71.83(1)f">, V = 4537.5(5) Å3, Z = 4, R= 0.0403) shows that the molecule has a distorted tetrahedral structure. The oxygenolysis was followed byspectrophotometry, and the rate constants were determined according to the rate law -d[Cu(PPh3)2(fla)]/dt =k2[Cu(PPh3)2(fla)][O2]. The rate constant, activation enthalpy, and entropy at 363.16 K are as follows: k2/M-1s-1 = 4.16 ± 0.48, fchars/Delta.gif" BORDER=0 >H
f">/kJ mol-1 = 102 ± 7, fchars/Delta.gif" BORDER=0 >Sf">/J mol-1 K-1 = -13.0 ± 21. The reaction fits a Hammettlinear free energy relationship for 4'-substituted flavonolates, and an increase of the electron density on coppermakes the oxygenation reaction faster.
f">, a = 13.154(1) Å,b = 17.991(1) Å, c = 20.495(1) Å, fchars/alpha.gif" BORDER=0> = 80.01(1)f">, fchars/beta2.gif" BORDER=0 ALIGN="middle"> = 88.02(1)f">, fchars/gamma.gif" BORDER=0 > = 71.83(1)f">, V = 4537.5(5) Å3, Z = 4, R= 0.0403) shows that the molecule has a distorted tetrahedral structure. The oxygenolysis was followed byspectrophotometry, and the rate constants were determined according to the rate law -d[Cu(PPh3)2(fla)]/dt =k2[Cu(PPh3)2(fla)][O2]. The rate constant, activation enthalpy, and entropy at 363.16 K are as follows: k2/M-1s-1 = 4.16 ± 0.48, fchars/Delta.gif" BORDER=0 >Hf">/kJ mol-1 = 102 ± 7, fchars/Delta.gif" BORDER=0 >Sf">/J mol-1 K-1 = -13.0 ± 21. The reaction fits a Hammettlinear free energy relationship for 4'-substituted flavonolates, and an increase of the electron density on coppermakes the oxygenation reaction faster.