Regioselective formation of peroxyquinolatocobalt(III) complexes in the oxygenation of 2,6-di-t-butylphenols with cobalt(II) Schiff-base complexes
Regioselective formation of peroxyquinolatocobalt(III) complexes in the oxygenation of 2,6-di-t-butylphenols with cobalt(II) Schiff-base complexes
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2,6-二叔丁基苯酚与钴（II）希夫碱配合物氧化反应中过氧化喹啉钴（III）配合物的区域选择性形成
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发表时间：
1981
期刊：
影响因子：
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通讯作者：
K. Hirotsu
中科院分区：
文献类型：
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作者：
A. Nishinaga;H. Tomita;K. Nishizawa;T. Matsuura;S. Ooi;K. Hirotsu
已发现 2,6-二叔丁基苯酚与五配位钴 (II) 席夫碱络合物在非质子溶剂（例如 CH2Cl2、thf 和 dmf（thf = 四氢呋喃，dmf = 二甲基甲酰胺））中氧化，可导致区域选择性形成过氧化喹啉钴 (III) 络合物。区域选择性取决于所用酚 4 位取代基的性质：4-烷基-2,6-二叔丁基苯酚 (1) 提供过氧-对喹啉钴 (III) 络合物，而过氧-邻喹啉钴络合物由 4-芳基-2,6-二叔丁基苯酚 (4) 形成。氧化反应的起始是超氧钴(III)物质从酚中夺取氢，得到相应的苯氧基自由基(10)。随后用钴(II)物质快速还原(10)，产生酚钴钴(III)络合物中间体，其中掺入了双氧。氧化的区域选择性归因于酚钴(III)络合物中间体的形成。过氧对喹啉钴(III)配合物(2a)的晶体为斜方晶系，空间群P212121，a= 33.749(11)，b= 11.844(5)，c= 9.329(4)A，Z= 4。晶体结构已根据3 018个衍射仪数据精修至R= 0.067。
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 (1) afford peroxy-p-quinolatocobalt(III) complexes, whereas peroxy-o-quinolato-complexes are formed from 4-aryl-2,6-di-t-butyl phenols (4). The initiation of the oxygenation is hydrogen abstraction by superoxocobalt(III) species from the phenols to give the corresponding phenoxy-radicals (10). Rapid reduction of (10) with cobalt(II) species follows giving rise to a phenolatocobalt(III) complex intermediate, within which dioxygen is incorporated. The regioselectivity of the oxygenation is attributable to the formation of the phenolatocobalt(III) complex intermediate. Crystals of the peroxy-p-quinolatocobalt(III) complex (2a) are orthorhombic, space group P212121, with a= 33.749(11), b= 11.844(5), c= 9.329(4)A, and Z= 4. The crystal structure has been refined from 3 018 diffractometer data to R= 0.067.