Active Ga-catalysts for the ring opening homo- and copolymerization of cyclic esters, and copolymerization of epoxide and anhydrides
作者:Swarup Ghosh、Eduard Glöckler、Christoph Wölper、Alexander Tjaberings、André H. Gröschel、Stephan Schulz
DOI:10.1039/d0dt02831b
日期:——
analysis and single crystal X-ray analysis (1, 2), proving their tetranuclear structure in the solid state. Complexes 1–3 showed good catalyticactivity in the ringopening homopolymerization (ROP) and ringopeningcopolymerization (ROcoP) of lactide (LA) and ε-caprolactone (ε-CL) in the presence of benzyl alcohol (BnOH) in toluene at 100 °C, yielding polymers with the expected average molecular weights
通过GaMe 3与席夫碱配体L的反应合成了一系列镓络合物L 1 2 Ga 4 Me 8(1),L 2 2 Ga 4 Me 8(2)和L 3 2 Ga 4 Me 8(3)。1-3 H 2(L 1 H 2 = 2,4-二叔丁基-6-[((3-羟丙基)亚氨基]甲基}苯酚; L 2 H 2 = 2,4-二氯-6- [(3-羟丙基)亚氨基]甲基}苯酚; L3 H 2 = 4-叔丁基-2-[((3-羟丙基)亚氨基]甲基}苯酚),并经1 H, 13 C NMR,IR光谱,元素分析和单晶X射线分析表征( 1, 2),证明其处于固态的四核结构。在苯甲醇(BnOH)存在下,于100℃下,丙交酯(LA)和ε-己内酯(ε-CL)的开环均聚(ROP)和开环共聚(ROcoP)中,配合物1-3显示出良好的催化活性。 °C,得到具有预期平均分子量( M n)和窄分子量分布(MWD)以及rac-丙交酯(rac -L
Structural and spectroscopic characterization of a new luminescent Ni<sup>II</sup> complex: bis{2,4-dichloro-6-[(2-hydroxypropyl)iminomethyl]phenolato-κ<sup>3</sup>
<i>O</i>,<i>N</i>,<i>O</i>′}nickel(II)
preparation of transition‐metal complexes with Schiff base ligands are of interest due to their potential applications in the fields of molecular magnetism, nonlinear optics, dye‐sensitized solar cells (DSSCs), sensing and photoluminescence. Luminescent metal complexes have been suggested as potential phosphors in electroluminescent devices. A new luminescent nickel(II) complex, [Ni(C10H10Cl2NO2)2], has
具有席夫碱配体的过渡金属配合物的设计和制备备受关注,因为它们在分子磁性,非线性光学,染料敏化太阳能电池(DSSC),传感和光致发光领域具有潜在的应用前景。发光金属络合物已被建议作为电致发光器件中的潜在磷光体。合成了一种新型的发光镍(II)络合物[Ni(C 10 H 10 Cl 2 NO 2)2 ],并通过单晶X射线衍射和元素分析,UV-Vis,FT-IR,1对其进行了表征。1 H NMR,13C NMR和光致发光光谱,以及LC-MS / MS。晶体中复合物的分子位于晶体二元旋转轴上的特殊位置。Ni II原子由两个三齿Schiff碱2,4-二氯-6-[(2-羟丙基)亚氨基甲基]酚盐配体中的两个酚酸O,两个亚胺N和两个羟基O原子六配位,形成细长的八面体几何形状。此外,从(CIE)色度图中可以看出,该复合物在室温下在固态下表现出很强的绿色发光,因此该复合物可能是正在开发中的有前途的绿色OLED(
Synthesis and Catalytic Activity of Gallium Schiff‐base Complexes in the Ring‐Opening Homo‐ and Copolymerization of Cyclic Esters
作者:Swarup Ghosh、Eduard Glöckler、Christoph Wölper、Alexander Tjaberings、André H. Gröschel、Stephan Schulz
DOI:10.1002/zaac.202100183
日期:2021.8.12
Tetranuclear Ga(III) complexes L1–32Ga4(t-Bu)8 1–3 are synthesized and characterized (elemental analysis, IR, 1H, 13C, DOSY NMR spectroscopy, XRD) and their activity in the ring-opening polymerization (ROP) of lactide (LA) and ϵ-caprolactone (ϵ-CL) is reported. Complex 1 is the most active homopolymerization catalyst in the presence of benzyl alcohol (BnOH), yielding isotactic-enriched polylactides
四核 Ga(III) 配合物 L 1–3 2 Ga 4 ( t -Bu) 8 1 – 3被合成和表征(元素分析、IR、1 H、13 C、DOSY NMR 光谱、XRD)及其在环中的活性报道了丙交酯(LA)和ε-己内酯(ε -CL)的开环聚合(ROP)。在苯甲醇 (BnOH) 存在下,配合物1是活性最高的均聚催化剂,可生成具有P m 的全同立构富聚聚乳酸 (PLA)(可能是异构现象)通过关于单体浓度的一级动力学值高达 0.72。聚合过程的活性特征通过聚合恢复实验得到证实。配合物1 - 3也是 LA 和ϵ -CL共聚的活性催化剂,两种单体的顺序添加得到了定义明确的具有窄Đ值(分子量分布)的嵌段共聚物。
Degradation of β-O-4 model lignin species by vanadium Schiff-base catalysts: Influence of catalyst structure and reaction conditions on activity and selectivity
作者:Heather J. Parker、Christopher J. Chuck、Timothy Woodman、Matthew D. Jones
DOI:10.1016/j.cattod.2015.08.045
日期:2016.7
In the pursuit of value-added products from the degradation of the abundant aromatic biopolymer lignin, homogeneous catalysis has the potential to provide a mild, selective route to monomeric phenols. Homogeneous vanadium catalysts have previously been shown to effectively cleave dimeric beta-O-4 model lignin compounds, with selectivity for C-C or C-O cleavage, or benzylic oxidation, depending on the ligand structure and oxidation state of the metal. In this study, a systematic kinetic investigation was undertaken in order to gain further understanding of the role of ligand structure and reaction conditions on the activity of vanadium Schiff-base catalysts towards a non-phenolic beta-O-4 model lignin dimer, and the selectivity of these species towards C-O bond cleavage. Catalytic activity was found to be increased by the addition of bulky, alkyl substituents at the 3'-position of the phenolate ring, whereas electron withdrawing substituents were found to dramatically reduce activity irrespective of their size. Selective depolymerization of a phenolic beta-O-4 dimer was also achieved. (C) 2015 Elsevier B.V. All rights reserved.
Sarkar, Asit R.; Chakraborty, Aniruddha, Journal of the Indian Chemical Society, 2008, vol. 85, # 2, p. 167 - 170