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Synthesis of polymer-supported metal-ion complexes and evaluation of their catalytic activities

机译：聚合物负载的金属离子配合物的合成及其催化活性的评价

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摘要

Polymer-supported transition-metal-ion complexes of the N,N'-bis(o-hydroxy acetophenone) propylenediamine (HPPn) Schiff base were prepared by the complexation of iron(III), cobalt(II), and nickel(II) ions on a polymer-anchored N,N'-bis(5-amino-o-hydroxy acetophenone) propylenediamine Schiff base. The complexation of iron(III), cobalt(II), and nickel(II) ions on the polymer-anchored HPPn Schiff base was 83.44, 82.92, and 89.58 wt %, respectively, whereas the unsupported HPPn Schiff base showed 82.29, 81.18, and 87.29 wt % complexation of these metal ions. The iron(III) ion complexes of the HPPn Schiff base showed octahedral geometry, whereas the cobalt(II) and nickel(II) ion complexes were square planar in shape, as suggested by spectral and magnetic measurements. The thermal stability of the HPPn Schiff base increased with the complexation of metal ions, as evidenced by thermogravimetric analysis. The HPPn Schiff base showed a weight loss of 51.0 wt % at 500 degrees C, but its iron(III), cobalt(II), and nickel(II) ion complexes showed weight losses of 27.0, 35.0, and 44.7 wt % at the same temperature. The catalytic activity of the unsupported and supported metal-ion complexes was analyzed by the study of the oxidation of phenol and epoxidation of cyclohexene in the presence of hydrogen peroxide. The supported HPPn Schiff base complexes of iron(III) ions showed a 73.0 wt % maximum conversion of phenol and 90.6 wt % epoxidation of cyclohexene, but unsupported complexes of iron(III) ions showed 63.8 wt % conversion of phenol and 83.2 wt % epoxidation of cyclohexene. The product selectivity for catechol (CTL) and epoxy cyclohexane (ECH) was 93.1 wt % and 98.1 wt % with the supported HPPn Schiff base complexes of iron(Ill) ions, but it was low with the supported Schiff base complexes of cobalt(II) and nickel(II) ions. The selectivity for CTL and ECH varied with the molar ratio of the metal ions but remained unaffected by the molar ratio of hydrogen peroxide to the substrate. The energy of activation for the epoxidation of cyclohexene and oxidation of phenol with the polymer-supported Schiff base complexes of iron(III) ions was 10.0 and 12.7 kJ/mol, respectively, but it was found to be higher with the supported HPPn Schiff base complexes of cobalt(II) and nickel(II) ions and with the unsupported HPPn Schiff base complexes of iron(III), cobalt(II), and nickel(II) ions. (C) 2008 Wiley Periodicals, Inc.
机译：通过铁（III），钴（II）和镍（II）的络合制备N，N'-双（邻羟基苯乙酮）丙二胺（HPPn）席夫碱的聚合物负载的过渡金属离子络合物聚合物固定的N，N'-双（5-氨基-邻-羟基苯乙酮）丙二胺席夫碱上的离子聚合物锚定的HPPn Schiff碱上的铁（III），钴（II）和镍（II）离子的络合物分别为83.44、82.92和89.58 wt％，而未负载的HPPn Schiff碱显示为82.29、81.18，和这些金属离子的87.29 wt％的络合。 HPPn Schiff碱的铁（III）离子络合物呈八面体几何形状，而钴（II）和镍（II）离子络合物呈方形平面形状，这是通过光谱和磁测量得出的。热重分析表明，HPPn Schiff碱的热稳定性随着金属离子的络合而增加。 HPPn Schiff碱在500摄氏度时显示出51.0 wt％的重量损失，但其铁（III），钴（II）和镍（II）离子络合物在25°C时的重量损失为27.0、35.0和44.7 wt％。相同的温度。通过在过氧化氢存在下苯酚的氧化和环己烯的环氧化的研究，分析了未负载和负载的金属离子配合物的催化活性。铁（III）离子的负载型HPPn Schiff碱配合物显示最大73.0 wt％的苯酚转化率和90.6 wt％的环己烯环氧化，但未负载的铁（III）离子的络合物显示63.8 wt％的苯酚转化率和83.2 wt％环氧化环己烯。负载铁（III）离子的HPPn席夫碱配合物对儿茶酚（CTL）和环氧环己烷（ECH）的产物选择性为93.1 wt％和98.1 wt％，但负载钴（II）的席夫碱配合物时产物选择性低）和镍（II）离子。 CTL和ECH的选择性随金属离子的摩尔比而变化，但不受过氧化氢与底物摩尔比的影响。聚合物负载的铁（III）离子席夫碱络合物的环己烯环氧化活化反应和苯酚氧化的活化能分别为10.0和12.7 kJ / mol，但负载的HPPn席夫碱则更高钴（II）和镍（II）离子的配合物，以及铁（III），钴（II）和镍（II）离子的不受支持的HPPn Schiff碱配合物。 （C）2008 Wiley期刊公司

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