Ferroxime(II)-catalysed oxidation of 3,5-di-tert-butylcatechol by O2. Kinetics and mechanism †
作者:Tatiana L. Simándi、László I. Simándi
DOI:10.1039/a907373f
日期:——
intermediate to form a superoxo complex. The latter abstracts an H atom from H2dbcat via a hydrogen-bonded ternary active intermediate, affording the semiquinone anion radical dbsq˙– and [FeIII(Hdmg)2(MeIm)(O2H)]. Utilising an electron and a proton from H2dbcat, the latter undergoes heterolytic cleavage to yield a ferryl species, which rapidly oxidises a second H2dbcat. Complexation of dbsq˙– with [FeII(Hdmg)2(MeIm)]
发现络合物[Fe(Hdmg)2(MeIm)2 ] 1,称为亚铁肟(II),是用于3,5-二叔丁基邻苯二酚(H 2)氧化脱氢的选择性催化剂的前体。dbcat)在室温和大气压下将其转化为相应的1,2-苯醌(dtbq)。在MeOH中观察到的动力学行为与一种MeIm配体的溶剂分解以及双氧与五坐标中间物的结合形成超氧配合物相一致。后者通过氢键键合的三元活性中间体从H 2 dbcat提取H原子,得到半醌阴离子自由基dbsq q-和[Fe III(Hdmg)2(MeIm)(O 2 H)]。利用来自H 2 dbcat的电子和质子,后者进行杂解裂解以产生小环物种,其快速氧化第二个H 2 dbcat。dbsq˙-与[Fe II(Hdmg)2(MeIm)]的络合提供了强烈着色的顺磁性物质[Fe II(Hdmg)2(MeIm)(dbsq˙-)],其在整个催化反应中持续存在,充当缓冲剂对于dbsq ˙–。拟议的机制