Quercetinase model studies. The oxygenation of flavonol catalyzed by a cationic 2,2′-bipyridine copper(II) flavonolate complex1Dedicated to Professor Gottfried Huttner on the occasion of his 60th birthday.1
摘要:
The catalyst [Cu(II)(bpy)(fla)]ClO(4), 1, was prepared from Cu(CH(3)CN)(4)ClO(4), 2,2'-bipyridine (bpy), flavonol (flaH), and dioxygen in acetonitrile at ambient conditions. The flavonolato copper complex 1 reacts with molecular oxygen slowly at room temperature but reasonably fast at around 100 degrees C in acetonitrile or DMF to the O-benzoylsalicylato copper complex [Cu(II)(bpy)(O-bs)]ClO(4) in good yield. Kinetics of the oxygenation of 1 shows that there are two kinetically not interpretable segments of the reaction, however 1 is a good catalyst for the oxygenation of flavonol to O-benzoylsalicylic acid (O-bsH) at around 100 degrees C. Kinetic studies of the catalytic reaction resulted in the rate expression -d[flaH]/dt = k(obs)[flaH][catalyst](2)[O(2)](2). The reaction constant at 100 degrees C was found to be k(obs) = 7.20 +/- 0.13 X 10(10) mol(-4) dm(12) s(-1), with activation parameters Delta H double dagger = 80.83 +/- 3.14 kJ mol(-1), Delta S double dagger = 179.61 +/- 8.82 J mol(-1) K(-1). (C) 1998 Elsevier Science B.V.
Quercetinase model studies. The oxygenation of flavonol catalyzed by a cationic 2,2′-bipyridine copper(II) flavonolate complex1Dedicated to Professor Gottfried Huttner on the occasion of his 60th birthday.1
摘要:
The catalyst [Cu(II)(bpy)(fla)]ClO(4), 1, was prepared from Cu(CH(3)CN)(4)ClO(4), 2,2'-bipyridine (bpy), flavonol (flaH), and dioxygen in acetonitrile at ambient conditions. The flavonolato copper complex 1 reacts with molecular oxygen slowly at room temperature but reasonably fast at around 100 degrees C in acetonitrile or DMF to the O-benzoylsalicylato copper complex [Cu(II)(bpy)(O-bs)]ClO(4) in good yield. Kinetics of the oxygenation of 1 shows that there are two kinetically not interpretable segments of the reaction, however 1 is a good catalyst for the oxygenation of flavonol to O-benzoylsalicylic acid (O-bsH) at around 100 degrees C. Kinetic studies of the catalytic reaction resulted in the rate expression -d[flaH]/dt = k(obs)[flaH][catalyst](2)[O(2)](2). The reaction constant at 100 degrees C was found to be k(obs) = 7.20 +/- 0.13 X 10(10) mol(-4) dm(12) s(-1), with activation parameters Delta H double dagger = 80.83 +/- 3.14 kJ mol(-1), Delta S double dagger = 179.61 +/- 8.82 J mol(-1) K(-1). (C) 1998 Elsevier Science B.V.
3-Hydroxyflavone coordinates to Cu-II together with the auxiliary ligand 2,2'-bipyridine to form a stable cationic flavonolato-copper(II) complex, [Cu(C15H9O3)(C10H8N2)]ClO4. The complex has distorted square pyramidal geometry. Two O atoms of the flavonol and the N atoms of the chelating bpy ligand are in the basal position, while a perchlorate O atom occupies the apical position.