Synthesis, crystal structures and catalytic activity of Cu(II) and Mn(III) Schiff base complexes: Influence of additives on the oxidation catalysis of cyclohexane and 1-phenylehanol

IF 5.062

Journal of Molecular Catalysis A: Chemical Pub Date : 2017-01-01 DOI:10.1016/j.molcata.2016.09.005

Oksana V. Nesterova , Dmytro S. Nesterov , Agnieszka Krogul-Sobczak , M. Fátima C. Guedes da Silva , Armando J.L. Pombeiro

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引用次数: 39

Abstract

The complexes of copper [Cu(κONN’-HL)(NO₃)(DMF)](NO₃)∙H₂O (1) and [Cu(κONN’-HL)Cl₂]∙½DMSO (2), and of manganese [Mn(κON-HL)₂Cl₂]Cl (3) and [Mn(κON-HL)₂(NO₃)₂](NO₃)∙H₂O (4) were synthesized by reactions of the respective chloride or nitrate salt with a non-aqueous solutions of the Schiff base aminoalcohol HL (product of condensation of salicylic aldehyde and aminoethylpiperazine) and characterized by X-ray diffraction analysis. The catalytic investigations disclosed a prominent activity of the copper compounds 1 and 2 towards oxidation of cyclohexane with hydrogen peroxide in the presence of various promoters (nitric, hydrochloric, oxalic acids and pyridine), under mild conditions. The unusual promoting effect of pyridine on the catalytic activity of the copper catalysts allowed to achieve yields up to 21% based on cyclohexane. Chromatographic studies revealed that cyclohexyl hydroperoxide is a main reaction product and chlorocyclohexane (in the presence of HCl as promoter) was also detected, suggesting a free radical reaction pathway with hydroxyl radicals as attacking species. Complexes 1 and 2 act also as catalysts in the oxidation of 1-phenylethanol with tert-butylhydroperoxide, showing acetophenone yields up to 62% and TON (turnover numbers) up to 620 in the presence of the K₂CO₃ promoter.

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Cu(II)和Mn(III)希夫碱配合物的合成、晶体结构和催化活性:添加剂对环己烷和1-苯乙醇氧化催化的影响

分别用氯盐或硝酸盐与希夫碱氨基醇HL(水杨醛与氨基乙基哌嗪缩合产物)的非水溶液反应合成了铜[Cu(κONN ' -HL)(NO3)(DMF)](NO3)∙H2O(1)和[Cu(κONN ' -HL)Cl2]∙½DMSO(2)和锰[Mn(κON-HL)2Cl2]Cl(3)和[Mn(κON-HL)2(NO3)2](NO3)∙H2O(4)配合物，并用x射线衍射分析对其进行了表征。催化研究表明，铜化合物1和2在各种促进剂(硝酸、盐酸、草酸和吡啶)存在下，在温和条件下对环己烷的过氧化氢氧化具有显著的活性。吡啶对铜催化剂的催化活性有不同寻常的促进作用，使得以环己烷为基础的铜催化剂的产率达到21%。色谱研究表明，环己基过氧化氢是反应的主要产物，氯环己烷(HCl作为启动子存在)也被检测到，提示自由基反应途径以羟基自由基为攻击种。配合物1和2在1-苯乙醇与过氧化叔丁基氧化过程中也起到催化剂的作用，在K2CO3促进剂的存在下，苯乙酮的产率高达62%，TON(周转数)高达620。

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来源期刊

Journal of Molecular Catalysis A: Chemical 化学-物理化学

自引率

0.00%

发文量

审稿时长

2.8 months

期刊介绍： The Journal of Molecular Catalysis A: Chemical publishes original, rigorous, and scholarly full papers that examine the molecular and atomic aspects of catalytic activation and reaction mechanisms in homogeneous catalysis, heterogeneous catalysis (including supported organometallic catalysis), and computational catalysis.