Regioselective formation of peroxyquinolatocobalt(III) complexes in the oxygenation of 2,6-di-t-butylphenols with cobalt(II) Schiff-base complexes
作者:Akira Nishinaga、Haruo Tomita、Kanji Nishizawa、Teruo Matsuura、Shunichiro Ooi、Ken Hirotsu
DOI:10.1039/dt9810001504
日期:——
The oxygenation of 2,6-di-t-butylphenols with five-co-ordinate cobalt(II) Schiff-base complexes in aprotic solvents, such as CH2Cl2, thf, and dmf (thf = tetrahydrofuran, dmf = dimethylformamide), has been found to result in regioselective formation of peroxyquinolatocobalt(III) complexes. The regioselectivity depends on the nature of the substituent at the 4-position of the phenol used: 4-alkyl-2,6-di-t-butylphenols
在质子惰性溶剂(例如CH 2 Cl 2,thf和dmf(thf =四氢呋喃,dmf =二甲基甲酰胺)中,用五坐标的席夫碱钴(II)Schiff碱络合氧化2,6-二叔丁基苯酚,已发现导致过氧喹诺酮钴(III)配合物的区域选择性形成。区域选择性取决于所用苯酚的4位上取代基的性质:4-烷基-2,6-二叔丁基苯酚(1)提供过氧-对-喹啉钴(III)配合物,而过氧-邻由4-芳基-2,6-二叔丁基苯酚(4)形成喹诺酮络合物。氧合作用的起始是超氧杂钴(III)提取氢。)酚类化合物,得到相应的苯氧基自由基(10)。随后用钴(II)物种快速还原(10),生成了苯并三价酚(III)配合物中间体,其中掺入了双氧。氧化的区域选择性归因于苯酚钴(III)配合物中间体的形成。所述过氧的晶体p -quinolatocobalt(III)复合物(2a)中是斜方晶系,空间群P 2 1 2 1 2 1,具有一个= 33.749(11),b