铁（Ⅲ）卟啉络合物在PhIO存在下的氧化分解反应

THE STUDY ON THE OXIDATION DECOMPOSITION OF iRON(Ⅲ)PORPHYRINS WITH PhIO

利用ＵＶ光谱方法研究了７种具有不同立体结构的铁（Ⅲ）卟啉络合物在ＰｈＩＯ存在下的氧化分解反应．动力学初步研究表明铁（Ⅲ）卟啉络合物的氧化分解对铁（Ⅲ）卟啉络合物是二级反应．７种铁（Ⅲ）卟啉络合物的氧化分解速率常数（ｍｏｌ－１·Ｌ·ｍｉｎ－１）大小顺序为（Ｔｏ－ＲＰＰＦｅＣｌ，Ｒ＝）：Ｈ》Ｍｅ（７１．１）＞Ｅｔ（５９．１）＞ｎ－Ｐｒ（４２．２）＞ｔ—Ｂｕ（－２７．３）＞ｎ－Ｂｕ（２１．０）＜ｉ－Ｐｒ（９．８６）．加入某些中性有机配体能减小铁（Ⅲ）卟啉络合物的氧化分解速率．根据研究的结果提出了铁（Ⅲ）卟啉络合物氧化分解反应的可能机理为：

The studies on the oxidation doc6mposition of seven stcrically hindctcd iron (Ⅲ) porphyrins by UV spectra are reported in this paper.In the ptcscncc of PhIO this oxidation decompostion is second order for iron(Ⅲ)porphyrin.The order of the ratc constants (mol-1 ·L·min-1 )ofthe okidation decomposition for the dtherent lion')porphviins was TPPFcCI>>Me substitutediron (Ⅲ)porphyrin (71.1)>Et(59. 1)>n-Pr (42. 2)>t-Bu (27.3)>n-Bu (21. 0) >i-Pr (9. 86). Some additive organo-liqands-cyclobexanol and pyridine could decrease the rate of the oxidationdecomposition. The oxioation decomposition of TPPFeCl in eigt solvents were also investigated.Based on these resu'ts the probale mechanism for the oxidation decomposition is suggested.