Hydrazone Schiff base-manganese(II) complexes: Synthesis, crystal structure and catalytic reactivity
Hydrazone Schiff base-manganese(II) complexes: Synthesis, crystal structure and catalytic reactivity
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DOI：
10.1016/j.ica.2006.08.056
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发表时间：
2007-04-01
影响因子：
2.8
通讯作者：
Hosseini-Monfared, Hassan
中科院分区：
文献类型：
--
作者：
Pouralimardan, Omid;Chamayou, Anne-Christine;Hosseini-Monfared, Hassan
以苯甲酰肼为配体，通过水杨醛和吡啶甲醛为配体，合成了5个不对称三齿Schiff碱配体，其结构经FT-IR、H-1和C-13 NMR表征。这些配体的络合物通过用等摩尔量的MnCl 2处理适当配体和一当量Et 3 N的乙醇溶液来合成。4 H（2）O或可替代地通过更直接的途径，其中将苯甲酰肼的乙醇溶液加入到适当的水杨醛和MnCl 2的乙醇溶液中。4 H（2）O溶液中，得到[MnCl（L-1）（H2O）（2）]、[Mn（L-2）（2）（H2O）（2）]、[MnCl（L-3）]、[MnCl（L-4）]和[MnCl 2（H2O）（L-5）]。腙类Schiff碱配体及其锰配合物（HL 1 -4和L-5）（HL 1 =苯甲酸（2-羟基-3-甲氧基-亚苄基）-酰肼，HL 2 =苯甲酸（2，3-二羟基-亚苄基）-酰肼，HL 3 =苯甲酸（2-羟基-亚苄基）-酰肼，HL 4 =苯甲酸（5-溴-2-羟基-亚苄基）-酰肼，L-5 =苯甲酸吡啶-2-基亚甲基-酰肼）的红外光谱、核磁共振氢谱和碳13谱以及摩尔电导率进行了表征。测定了HL_1和[MnCl_2（H_2 O）L ~（-5）]的晶体结构。结果表明，HL 1、HL 2、HL 3和HL 4席夫碱均以一价阴离子形式与羰基、酚氧和甲亚胺氮的三齿O、N、O供体配位. L-5是一个中性的三齿Schiff碱，具有N，N，O供体。通过对配合物Mn-L-2、L-3、L-5的ESI-MS分析，证明了溶液中存在多核配合物。考察了Mn-L_（1 -5）配合物的催化性能，发现在咪唑存在下，碘酰苯在乙腈中对环己烯进行了高选择性的环氧化（>95%）。(c)2006 Elsevier B. V.保留所有权利。
Five dissymmetric tridentate Schiff base ligands, containing a mixed donor set of ONN and ONO were prepared by the reaction of benzhydrazide with the appropriate salicylaldehyde and pyridine-2-carbaldehyde and characterized by FT-IR, H-1 and C-13 NMR. The complexes of these ligands were synthesized by treating an ethanolic solution of the appropriate ligand and one equivalent Et3N with an equimolar amount of MnCl2 . 4H(2)O or alternatively by a more direct route in which an ethanolic solution of benzhydrazide was added to ethanolic solution of appropriate salicylaldehyde and MnCl2 . 4H(2)O solution to yield [MnCl(L-1)(H2O)(2)], [Mn(L-2)(2)(H2O)(2)], [MnCl(L-3)], [MnCl(L-4)] and [MnCl2(H2O)(L-5)]. The hydrazone Schiff base ligands and their manganese complexes including HL1-4 and L-5 (HL1 = benzoic acid (2-hydroxy-3-methoxy-benzylidene)-hydrazide, HL2 = benzoic acid (2,3-dihydroxy-benzylidene)-hydrazide, HL3 = benzoic acid (2-hydroxy-benzylidene)-hydrazide, HL4 = benzoic acid (5-bromo-2-hydroxy-benzylidene)-hydrazide, L-5 = benzoic acid pyridine-2-yl methylene-hydrazide) were characterized on the basis of their FT-IR, H-1 and C-13 NMR, and molar conductivity. The crystal structures of HL1 and [MnCl2(H2O)L-5] have been determined. The results suggest that the Schiff bases HL1, HL2, HL3, and HL4 coordinate as univalent anions with their tridentate O,N,O donors derived from the carbonyl and phenolic oxygen and azomethine nitrogen. L-5 is a neutral tridentate Schiff base with N,N,O donors. ESI-MS for the complexes Mn-L-2,L-3,L-5 provided evidence for the presence of multinuclear complexes in solution. Catalytic ability of Mn-L1-5 complexes were examined and found that highly selective epoxidation (>95%) of cyclohexene was performed by iodosylbenzene in the presence of these complexes and imidazole in acetonitrile. (c) 2006 Elsevier B.V. All rights reserved.