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Accessible ring opening metathesis and atom transfer radical polymerization catalysts based on dimethyl sulfoxide ruthenium(II) complexes bearing N-heterocyclic carbene ligands
Molecular Catalysis ( IF 3.9 ) Pub Date : 2018-02-08 , DOI: 10.1016/j.mcat.2018.01.032
André H.S. Idehara , Patrik D.S. Gois , Henrique Fernandez , Beatriz E. Goi , Antonio E.H. Machado , Benedito S. Lima-Neto , Valdemiro P. Carvalho

Dimethyl sulfoxide ruthenium(II) complexes of N-heterocyclic carbenes derived from cycloalkylamines (cycloalkyl = cyclopentyl (1a), cyclohexyl (1b), cycloheptyl (1c), and cyclooctyl (1d)) were synthesized: [RuCl2(S-dmso)2(IPent)] (2a), [RuCl2(S-dmso)2(IHex)] (2b), [RuCl2(S-dmso)2(IHept)] (2c), and [RuCl2(S-dmso)2(IOct)] (2d). The imidazolium salts 1a-1d were characterized by FTIR, UV–vis, and 1H and 13C NMR spectroscopy, while their respective dimethyl sulfoxide ruthenium(II) complexes (2a-2d) were characterized by elemental analysis, FTIR, UV–vis, 1H and 13C NMR, and cyclic voltammetry. The complexes 2a-2d were evaluated as catalytic precursors for ROMP of norbornene (NBE) and for ATRP of methyl methacrylate (MMA). The polynorbornene (polyNBE) syntheses via ROMP using the complexes 2a-2d as pre-catalysts were evaluated under reaction conditions of [EDA]/[Ru] = 28 (5 μL), [NBE]/[Ru] = 5000 at 50 °C as a function of time. The polymerization of MMA via ATRP was conducted using the complexes 2a-2d in the presence of ethyl 2-bromoisobutyrate (EBiB) as the initiator. All tests were using the molar ratio [MMA]/[EBiB]/[Ru] = 1000/2/1 and conducted at 85 °C. The linear correlation of ln([MMA]0/[MMA]) and time clearly indicates that the concentration of radicals remains constant during the polymerization and that the ATRP of MMA mediated by 2a-2d proceeds in a controlled manner.



中文翻译:

基于带有N-杂环卡宾配体的二甲基亚砜钌(II)配合物的可及的开环复分解和原子转移自由基聚合催化剂

合成了环烷基胺(环烷基=环戊基(1a),环己基(1b),环庚基(1c)和环辛基(1d))的N-杂环卡宾的二甲基亚砜钌(II)配合物:[RuCl 2(S-dmso)2(IPent)](2a),[RuCl 2(S-dmso)2(IHex)](2b),[RuCl 2(S-dmso)2(IHept)](2c)和[RuCl 2(S- dmso)2(IOct)](2d)。咪唑鎓盐1a - 1d用FTIR,UV-vis和1 H和13 C NMR光谱表征,而它们各自的二甲基亚砜钌(II)配合物(2a - 2d)用元素分析,FTIR,UV-vis,1 H和13 C表征。NMR和循环伏安法。评价了络合物2a - 2d作为降冰片烯ROMP(NBE)和甲基丙烯酸甲酯(MMA)ATRP的催化前体。使用配合物2a - 2d通过ROMP合成聚降冰片烯(polyNBE)在[EDA] / [Ru] = 28(5μL),[NBE] / [Ru] = 5000的反应条件下,于50°C的条件下,对前催化剂的反应时间进行了评估。在2-溴异丁酸乙酯(EB i B)作为引发剂的情况下,使用配合物2a - 2d通过ATRP进行MMA聚合。所有测试均使用摩尔比[MMA] / [EB i B] / [Ru] = 1000/2/1并在85°C下进行。ln([MMA] 0 / [MMA])和时间的线性关系清楚地表明,自由基的浓度在聚合过程中保持恒定,并且由2a - 2d介导的MMA的ATRP以受控方式进行。

更新日期:2018-02-08
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