Catalytic Reduction of 1,6-Dihalohexanes by Nickel(I) Salen Electrogenerated at Glassy Carbon Cathodes in Dimethylformamide
Catalytic Reduction of 1,6-Dihalohexanes by Nickel(I) Salen Electrogenerated at Glassy Carbon Cathodes in Dimethylformamide
复制标题
二甲基甲酰胺中在玻碳阴极上电解的镍 (I) Salen 催化还原 1,6-二卤代己烷
DOI：
10.1149/1.1928168
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发表时间：
2005
影响因子：
3.9
通讯作者：
D. Peters
中科院分区：
文献类型：
--
作者：
Parichatr Vanalabhpatana;D. Peters
在含有0.10 M四氟硼酸四甲基铵的二甲基甲酰胺中，化学计量的1，6-二卤代己烷和电生成的镍（I）salen之间的反应以高达78%的产率提供环己烷。通过自由基途径产生的ω-卤代烷基镍（II）物种是这些还原的提议中间体，其中还产生烷烃、1-烯烃和醛。在5-25 mV s - 1的扫描速率下的循环伏安研究中，在碳阴极表面上形成钝化膜对1，6-二卤代己烷的催化还原具有显著影响，但这种电极结垢可以通过向介质中加入乙酸来克服。对于控制电位电解涉及减少的1，6-dihalohexane与催化量的电生成的镍（I）salen在过量的乙酸的存在下，大部分的基板被转化为三种不同的酯（乙酸己酯，1，6-diacetoxyhexane，和十二烷基乙酸酯），这是通过亲核（SN 2）攻击的乙酸根离子上的二卤代烷。
Reaction between stoichiometric amounts of 1,6-dihalohexanes and electrogenerated nickel(I) salen in dimethylformamide containing 0.10 M tetramethylammonium tetrafluoroborate affords cyclohexane in up to 78% yield. Arising via a radical pathway, an ω-haloalkylnickel(II) species is a proposed intermediate for these reductions in which alkanes, 1-alkenes, and aldehydes are also produced. In cyclic voltammetric studies at scan rates of 5-25 mV s - 1 , formation of a passivating film on the surface of the carbon cathode has a dramatic effect on the catalytic reduction of 1,6-dihalohexanes, but this electrode fouling can be overcome by addition of acetic acid to the medium. For controlled-potential electrolyses involving the reduction of a 1,6-dihalohexane with catalytic amounts of electrogenerated nickel(I) salen in the presence of excess acetic acid, most of the substrate is converted into three different esters (hexyl acetate, 1,6-diacetoxyhexane, and dodecyl acetate) which arise via nucleophilic (S N 2) attack of acetate ion on the dihaloalkane.