Dioxomolybdenum(<scp>vi</scp>) and dioxotungsten(<scp>vi</scp>) complexes chelated with the ONO tridentate hydrazone ligand: synthesis, structure and catalytic epoxidation activity
作者:Višnja Vrdoljak、Jana Pisk、Dominique Agustin、Predrag Novak、Jelena Parlov Vuković、Dubravka Matković-Čalogović
DOI:10.1039/c4nj01394h
日期:——
Synthesis of the dioxomolybdenum(VI) complexes [MoO2(L3OMe)(EtOH)] (1), [MoO2(L4OMe)(EtOH)] (2) and [MoO2(LH)(EtOH)] (3) and dioxotungsten(VI) complexes [WO2(L3OMe)(EtOH)] (4), [WO2(L4OMe)(EtOH)] (5) and [WO2(LH)]n (6a) was carried out using [MO2(C5H7O2)2] (M = Mo or W) and the corresponding aroylhydrazone ligand H2LR (3-methoxysalicylaldehyde 4-hydroxybenzhydrazone (H2L3OMe), 4-methoxysalicylaldehyde 4-hydroxybenzhydrazone (H2L4OMe), or salicylaldehyde 4-hydroxybenzhydrazone (H2LH) in ethanol. Compounds obtained upon heating of the mononuclear complexes in acetonitrile or dichloromethane, [MO2(LR)]n (1a–6a) or [MoO2(L3OMe)]2 (1b), respectively, were also investigated. Crystal and molecular structures of the mononuclear 1, 2 and 3, polynuclear 1a·MeCN and dinuclear 1b complexes were determined by the single crystal X-ray diffraction method. Powder X-ray diffraction showed isostructurality of 1 and 4, and 2 and 5. The complexes were further characterized by elemental analysis, IR spectroscopy, TG and DSC analyses, and one- and two-dimensional NMR spectroscopy. The catalytic performances of 1–5 and 6a were investigated for epoxidation of cyclooctene using aqueous tert-butyl hydroperoxide (TBHP) as the oxidant.
二氧钼(VI)配合物[MoO2(L3OMe)(EtOH)](1)、[MoO2(L4OMe)(EtOH)](2)和[MoO2(LH)(EtOH)](3)以及二氧钨(VI)配合物[WO2(L3OMe)(EtOH)](4)的合成、[MO2(C5H7O2)2](M = Mo 或 W)和相应的酰基腙配体 H2LR(3-甲氧基水杨醛 4-羟基腙 (H2L3OMe))进行了[WO2(L4OMe)(EtOH)](5)和[WO2(LH)]n(6a)的研究、乙醇中的 4-甲氧基水杨醛 4-羟基苯腙(H2L4OMe)或水杨醛 4-羟基苯腙(H2LH)。此外,还研究了单核络合物在乙腈或二氯甲烷中加热后得到的化合物,分别为[MO2(LR)]n (1a-6a) 或 [MoO2(L3OMe)]2 (1b)。单晶 X 射线衍射法测定了单核 1、2 和 3、多核 1a-MeCN 和双核 1b 复合物的晶体和分子结构。粉末 X 射线衍射显示 1 和 4 以及 2 和 5 具有同构性。通过元素分析、红外光谱、TG 和 DSC 分析以及一维和二维 NMR 光谱对这些配合物进行了进一步表征。研究了 1-5 和 6a 以水性叔丁基过氧化氢(TBHP)为氧化剂对环辛烯进行环氧化反应的催化性能。