Understanding the mechanism of H+-induced demetalation as a design strategy for robust iron(III) peroxide-activating catalysts
Understanding the mechanism of H+-induced demetalation as a design strategy for robust iron(III) peroxide-activating catalysts
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DOI：
10.1021/ja0367344
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发表时间：
2003-10-15
影响因子：
15
通讯作者：
Collins, TJ
中科院分区：
文献类型：
--
作者：
Ghosh, A;Ryabov, AD;Collins, TJ
FeIII-TAML（四氨基大环配体）活化剂1（Y = Cl）和2（Y = H2O），a（R = Me，X = H），B（Me，Cl），c（Me，MeO），d（Et，Cl），e（F，H），f（F，Cl），在固态（X射线晶体学）中为五配位，但在水中为六配位，具有两个H2O轴向配体。水性配体的第一pKa在9.5 - 10.5的范围内。2的酸诱导脱金属遵循方程kobs =k1*[H+] +k3*[H+]3。速率常数sk 1 * 和k 3 * 随取代基R的性质变化5和11个数量级。对于R = F，实现了对脱金属的最高稳定性。
The FeIII-TAML (tetra-amido macrocyclic ligand) activators1(Y = Cl) and2(Y = H2O),a(R = Me, X = H),b(Me, Cl),c(Me, MeO),d(Et, Cl),e(F, H),f(F, Cl), are five-coordinated in the solid state (X-ray crystallography) but are six-coordinated species in water with two H2O axial ligands. The first pKa's of aqueous ligands are in the range of 9.5−10.5. The acid-induced demetalation of2follows the equationkobs=k1*[H+] +k3*[H+]3. The rate constantsk1* andk3* vary by 5 and 11 orders of magnitude depending on the nature of substituents R. The highest stabilization against the demetalation is achieved for R = F.