Name: heterogeneous removal of water-soluble ruthenium olefin metathesis catalyst from aqueous media via host-guest interaction
Uploaded: 2018-08-23T14:00:00.000+00:00
Duration: 10 min 39 s
Description: Watch this Scientific Journal Video about Heterogeneous Removal of Water-Soluble Ruthenium Olefin Metathesis Catalyst from Aqueous Media Via Host-Guest Interaction at JoVE.com

这项工作得到佛罗里达州立大学能源和材料招聘倡议和 FSU 化学和生物医学工程部的支持。

注: 我们介绍了合成 4-(97-(adamantan-1-氧)-25, 81114172023262932353841444750535659626568717477808386899295-dotriacontaoxaheptanonacontyl)-13-dimesityl-45-氢-1 h-咪-3-ium四氟硼酸盐 (鎓) 和宿主复合物, β镉接枝二氧化硅, 在我们以前的论文38。在该协议中, 我们描述了我们的水溶性钌烯烃置换催化剂和置换反应 (RCM 和嬉戏) 的合成。
1. 合成 (4-(97-(adamantan 1 基) 氧)-25, 81114172023262932353841444750535659626568717477808386899295-dotriacontaoxaheptanonacontyl)-13-dimesitylimidazolidinylidene) 二氯 ( o -isopropoxyphenylmethylene) 钌 (催化剂 1)
<ol><li>用搅拌棒、20毫升瓶和烤箱里的刮刀烘干25毫升的圆底烧瓶。</li>
	<li>在4毫升瓶中放入118毫克的鎓盐a (0.060 毫摩尔)。</li>
	<li>将准备好的鎓盐a放入干燥的玻璃器皿、隔膜和在手套箱室中的刮刀中, 真空度为2小时。</li>
	<li>在把手套箱内的空气完全取出后, 将惰性气体吹入燃烧室, 然后将其移入手套箱。</li>
	<li>在手套盒中, 把54毫克的 Hoveyda-格拉布斯 (H G) 1st世代 (0.090 毫摩尔, 1.5 equiv) 在20毫升瓶。</li>
	<li>将所制备的鎓盐溶解在2.0 毫升的甲苯中, 然后用搅拌棒将其转化为50毫升的圆底烧瓶。</li>
	<li>将0.18 毫升的钾双 (三甲基硅) 酰胺 (KHMDS) 溶液 (0.5 米甲苯溶液, 0.090 毫摩尔, 1.5 equiv) 加入鎓盐溶液中。</li>
	<li>旋转烧瓶混合试剂。</li>
	<li>在3.0 毫升甲苯中溶解 H-G 1st世代, 然后将此溶液加入反应瓶中。</li>
	<li>用隔膜封住瓶子, 然后从手套箱中取出。</li>
	<li>搅拌反应混合物3小时在80摄氏度。</li>
	<li>3小时后, 用中性氧化铝色谱法提纯催化剂, 洗脱 EtOAc/甲醇 = 15/1。收集深绿色解决方案。 注: 在色谱前不需要溶剂的蒸发。Rf 值是0.46 在中性氧化铝, 洗脱与 EtOAc/甲醇 = 15/1。</li>
	<li>在减压的情况下去除溶剂。</li>
	<li>真空的最后残留物获得深绿色的蜡质固体。</li>
</ol>2. 水介质中催化剂残留的置换反应及脱除
<ol><li>在2小时内用氮气泡 d2O 或去离子水, 制备脱气氘氧化物 (D2O) 或去离子水。</li>
	<li>在每个2毫升瓶中放入4.4 毫克的催化剂1 (0.0020 毫摩尔) 和41毫克0.20 烯丙基n,n,n-trimethylpent-4-en-1-aminium 氯化物 (tetraalkyl 铵基板) (4.0 毫摩尔)。</li>
	<li>将 tetraalkyl 铵基体溶解在0.5 毫升的脱气 D2o (或2o), 然后将溶液加入催化剂1。</li>
	<li>密封反应瓶, 然后加热反应混合物24小时在45摄氏度。用1小时核磁共振仪监测反应转化。 注: 监控1h 核磁共振峰值转换从 3.25 ppm (双峰,-nch2ch 基板) 到 3.52 ppm (双,-nch2CH) 产品)。</li>
	<li>反应完成后, 在室温下冷却反应瓶。</li>
	<li>在反应混合物中加入150毫克的β镉接枝二氧化硅。 注: 通过热重分析 (TGA) 计算了 1.57 10-4毫摩尔/毫克的硅凝胶上接枝β镉单元。</li>
	<li>在室温下将反应混合物搅拌10小时。</li>
	<li>通过棉塞过滤反应混合物。</li>
	<li>在冷冻干燥机中取出溶剂。</li>
</ol>3. 开环置换聚合和脱除水介质中催化剂残留物
<ol><li>在2小时内用氮气泡 d2o 或去离子水, 制备脱气 d2o 或去离子水。</li>
	<li>把4.4 毫克的催化剂1 (0.0020 毫摩尔) 和17.1 毫克的 2-(3 aR*, 4s*, 7R*, 7as*)-13-dioxo-13, 3 a, 47, 7 a-六氢-2H-47-methanoisoindol-2-基)-n,n,n-trimethylethan-1-aminium 氯 (单体,图 5) (0.060 毫摩尔) 在每4.0 毫升瓶。</li>
	<li>将单体溶解在0.5 毫升的脱气 D2o (或 H2o) 中, 然后将溶液加入催化剂1。</li>
	<li>密封反应瓶, 然后加热反应混合物2小时在45摄氏度。用1小时核磁共振仪监测反应转化。 注: 监测1小时核磁共振峰值消失在 6.14 ppm (-ch= ch在单体)。</li>
	<li>反应完成后, 在室温下冷却反应瓶。</li>
	<li>用0.1 毫升乙烯基醚淬火反应。 注: 从高分子链端子中分离钌催化剂需要淬火。</li>
	<li>在反应混合物中加入150毫克的β镉接枝二氧化硅。</li>
	<li>在室温下将反应混合物搅拌10小时。</li>
	<li>通过棉塞过滤反应混合物。</li>
	<li>在冷冻干燥机中取出溶剂。</li>
</ol>4. 从 CH2氯2置换反应和脱除催化剂残渣
<ol><li>在每个0.20 毫升瓶中放入4.4 毫克的催化剂1 (0.0020 毫摩尔) 和48毫克的 diallylmalonate (4.0 毫摩尔)。</li>
	<li>在0.5 毫升的 CH2氯2中溶解 diallylmalonate 二乙酯, 然后将溶液加入催化剂1。</li>
	<li>密封反应瓶, 然后在室温下保持反应混合物1小时. 用1h 核磁共振对反应转化进行监测。 注: 监控1h 核磁共振峰值转换从 2.63 ppm (双,-cch2ch = CH2在基板) 到 3.01 ppm (单线,-ccH2CH = CHCH2C-在产品)。</li>
	<li>反应完成后, 将产生的反应混合物转化为30毫升瓶。</li>
	<li>用15毫升乙醚稀释反应溶液。</li>
	<li>用15毫升水冲洗有机溶液五次。</li>
	<li>用 MgSO4干燥有机层, 然后通过棉塞过滤溶液, 去除 MgSO4粒子。</li>
	<li>在所得到的溶液中加入60毫克活性炭, 然后在室温下搅拌24小时的混合物。</li>
	<li>通过棉塞过滤溶液, 除去活性炭, 然后在减压下去除溶剂。</li>
</ol>

<ol>
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H., Grubbs, R. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Efficient+Removal+of+Ruthenium+Byproducts+from+Olefin+Metathesis+Products+by+Simple+Aqueous+Extraction.">Efficient Removal of Ruthenium Byproducts from Olefin Metathesis Products by Simple Aqueous Extraction.</a> Organic Letters. 9 (10), 1955-1957 (2007).</li><li>Kim, C., Ondrusek, B. A., Chung, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Removable+Water-Soluble+Olefin+Metathesis+Catalyst+via+Host-Guest+Interaction.">Removable Water-Soluble Olefin Metathesis Catalyst via Host-Guest Interaction.</a> Organic Letters. 20 (3), 736-739 (2018).</li><li>Hong, S. H., Wenzel, A. G., Salguero, T. T., Day, M. W., Grubbs, R. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Decomposition+of+Ruthenium+Olefin+Metathesis+Catalysts.">Decomposition of Ruthenium Olefin Metathesis Catalysts.</a> Journal of the American Chemical Society. 129 (25), 7961-7968 (2007).</li><li>Qi, M., Chew, B. K. J., Yee, K. G., Zhang, Z. X., Young, D. J., Hor, T. S. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+catch-release+catalysis+system+based+on+supramolecular+host-guest+interactions.">A catch-release catalysis system based on supramolecular host-guest interactions.</a> RSC Advances. 6 (28), 23686-23692 (2016).</li></ol>

作者声明没有竞争的财政利益。

本文介绍了可拆卸均质钌烯烃置换催化剂的合成及其从水和有机溶液中的脱除。同质催化剂相比, 均相催化具有反应性高、反应速度快等优点;然而, 从产品中去除所用的催化剂比异质催化剂3的难度更大。合成催化剂的主要特点是 NHC 配体, 它具有金刚烷基拴系水溶性寡核苷酸 (乙二醇)。所提出的催化剂在水溶液和有机溶液中均表现出均质反应, 并利用主-客互动<sup class="xref...

从产品中去除同类有机金属催化是现代化学1、2中的一个重要问题。残留催化剂不仅是其重金属元素的毒性问题, 而且是产物从其潜在反应性中产生的不期望的转化。均质催化剂具有活性高、反应速度快、chemoselectivity3等优点, 但其从产品中去除的难度要远远大于非均匀催化剂, 只需过滤或迁.均质和异质催化剂的优点,即均相反应和异质去除, 是高活性、易移动有机金属催化剂的重要概念。图 1说明了同质反应的工作原理, 并通过宿客相互作用的异构去除催化剂。
宿客化学是在超分子化学4、5、6、7、8中, 宿主分子与 noncovalent 分子识别之间的结合。环糊精 (CDs), 循环寡糖, 是代表性的宿主分子9,10,11,12, 它们已经应用于广泛的科学领域, 如高分子科学13,14、催化15、16、生物医学应用6、10和分析化学17。一个客人分子, adamatane, 强烈绑定到β CD (宿主, 7-元循环糖类) 的疏水腔与高协会常数, Ka (日志ka = 5.04)18。这种超分子结合亲和性足够强, 可以从含固体β镉的水反应溶液中去除残留的催化剂复合物。
在许多符合主客搬迁条件的催化剂中, 钌烯烃置换催化剂由于实用性强, 对空气和湿气的稳定性高而受到研究。烯烃置换反应是合成化学中的重要工具, 在过渡金属催化剂19、20、21、22的存在下形成碳-碳双键。稳定钌烯烃置换催化剂的研制触发置换作为合成化学的主要领域 (如RCM 和十字置换 (CM)) 以及高分子科学 (例如, 嬉戏和无环二烯置换 (ADMET))。特别是, RCM 综合了大环化合物和中型环, 这是很难建设23。
尽管钌催化烯烃置换合成实用, 但从所需产品中完全去除所用的钌催化剂是许多实际应用的一个重大挑战24。例如, 在硅胶柱层析法25中, 在环合置换产品中观察到了钌渣的 1912 ppm。残留钌可能会引起诸如烯烃异构化、分解、着色和药物毒性等问题26。国际协调会议 (ICH) 发表了药物残留金属试剂指南。药剂产品中的最大允许钌含量为 10 ppm27。出于这些原因, 试图从产品解决方案28、29、30、31、32、33中去除汝渣。并研究了可摘钌催化剂在反应后无特殊处理的情况下进行提纯。在各种纯化方法中, 对催化剂配体改性进行了改进, 提高了硅胶过滤和液体萃取的效率。例如, 在苄叉34或 NHC 配体35、36的主干上引入离子标记, 可以实现高效硅胶过滤。NHC 配体上的催化剂轴承聚乙二醇37或离子标记35可提高钌催化剂的水萃取效率。
近年来, 我们报道了一种高水溶性钌烯烃置换催化剂, 它不仅表现出高反应性, 而且具有较高的催化剂去除率。此外, 置换和催化剂的去除发生在水和二氯甲烷34,35,36,37。新的催化剂的主要特点是新的 NHC 金刚烷基栓寡核苷酸 (乙二醇)。寡核苷酸 (乙二醇) 提供了整个催化剂复合物的高水溶性。此外, 寡核苷酸 (乙二醇) 拥有金刚烷基端组, 可用于与外部β CD 的宿客互动。
在这里, 我们描述了催化剂合成, 置换反应, 以及在水和二氯甲烷脱除催化剂的协议。

<table><tbody><tr><td>Hoveyda-Grubbs Catalyst 1st Generation</td><td>Sigma-Aldrich</td><td>577944</td><td>Air sensitivie. Light sensitivie.</td></tr><tr><td>Diethyl diallylmalonate</td><td>Sigma-Aldrich</td><td>283479</td><td></td></tr><tr><td>Ethyl vinyl ether</td><td>Sigma-Aldrich</td><td>422177</td><td>Air sensitive.</td></tr><tr><td>Aluminum oxide</td><td>Sigma-Aldrich</td><td>06300</td><td>Activated, neutral, Brockmann Activity I</td></tr><tr><td>Potassium bis(trimethylsilyl)amide solution (0.5 M in toluene)</td><td>Sigma-Aldrich</td><td>277304</td><td>Moisture sensitive.</td></tr><tr><td>Etyhl acetate</td><td>VWR</td><td>BDH1123</td><td>Flammable liquid.</td></tr><tr><td>Methanol</td><td>VWR</td><td>BDH1135</td><td>Flammable liquid. Toxic.</td></tr><tr><td>Deuterium Oxide 99.8%D</td><td>TCI</td><td>W0002</td><td></td></tr><tr><td>Methylene Chloride-D2 (D, 99.8%)</td><td>Cambridge Isotope Laboratories, Inc.</td><td>DLM-23</td><td>Flammable liquid. Toxic.</td></tr><tr><td>Activated carbon</td><td>Sigma-Aldrich</td><td>242276</td><td></td></tr><tr><td>Magnesium sulfate</td><td>EMD Millipore</td><td>MX0075</td><td></td></tr><tr><td>Ethyl ether</td><td>EMD Millipore</td><td>EX0190</td><td>Flammable liquid.</td></tr></tbody></table>

heterogeneous removal of water-soluble ruthenium olefin metathesis catalyst from aqueous media via host-guest interaction

研制了一种高效的过渡金属催化剂脱除方法。水溶性催化剂中含有一种新设计的 NHC 配体, 可通过宿主-来宾相互作用来去除催化剂。新的 NHC 配体拥有一个金刚烷基 (客) 栓线性乙烯乙二醇单位为疏水性包裹入β-环糊精 (β CD) 宿主化合物的腔内。将新型 NHC 配体应用于钌基烯烃置换催化剂中。钌催化剂在水介质中具有代表性环合置换 (RCM) 和环开置换聚合 (嬉戏) 反应的优良活性, 以及有机溶剂, CH2氯2。反应完成后, 用不溶性二氧化硅接枝β-镉 (寄主) 之间的主-客相互作用, 从水溶液中去除 99% (53 ppm) 的水溶性钌渣, 并对其进行简单过滤。金刚烷基基团 (客人) 在催化剂上。在有机溶剂中, 通过将粗反应混合物划分为二乙基醚与水之间的混合反应, 新的钌基催化剂也表现出高的去除效率。这样, 催化剂只停留在水层中。在有机层中, 在二烯丙基化合物的 RCM 反应中, 残余钌含量仅为 0.14 ppm。

图 2描述了我们的催化剂1的配体交换反应。1H 核磁共振谱如图 3所示。
图 4显示了在水溶液中的 RCM, 以及随后从反应混合物中去除使用的催化剂的主-客交互作用,表 1总结了水介质中的 rcm。将季铵基板完全转化为相应的产物, 催...

Watch this Scientific Journal Video about Heterogeneous Removal of Water-Soluble Ruthenium Olefin Metathesis Catalyst from Aqueous Media Via Host-Guest Interaction at JoVE.com

Heterogeneous Removal of Water-Soluble Ruthenium Olefin Metathesis Catalyst from Aqueous Media Via Host-Guest Interaction

开发了一种可移动的水溶性n-杂环卡宾 (NHC) 配体在水介质中的宿主-来宾相互作用。我们在水中和二氯甲烷中表现出了代表性的烯烃置换反应。通过主-客交互或萃取, 在反应后, 残余钌 (钌) 催化剂的低至 0.14 ppm。

水介质中水溶性钌烯烃置换催化剂的异质化去除与寄主交互作用

A highly efficient transition metal catalyst removal method is developed. The water-soluble catalyst contains a newly-designed NHC ligand for the catalyst ...

heterogeneous-removal-water-soluble-ruthenium-olefin-metathesis

Universidad San Sebastian

Research

JoVE Journal

Chemistry

7.8K 次观看.  Florida State University. 开发了一种可移动的水溶性n-杂环卡宾 (NHC) 配体在水介质中的宿主-来宾相互作用。我们在水中和二氯甲烷中表现出了代表性的烯烃置换反应。通过主-客交互或萃取, 在反应后, 残余钌 (钌) 催化剂的低至 0.14 ppm。

视频: Heterogeneous Removal of Water-Soluble Ruthenium Olefin Metathesis Catalyst from Aqueous Media Via Host-Guest Interaction

Mizoroki-Heck Cross-coupling Reactions Catalyzed by Dichloro{bis[1,1',1''-(phosphinetriyl)tripiperidine]}palladium Under Mild Reaction Conditions

Dichloro-bis(aminophosphine) complexes of palladium with the general formula of [(P{(NC5H10)3-n(C6H11)n})2Pd(Cl)2] (where n = 0-2), belong to a new family of easy accessible, very cheap, and air stable, but highly active and universally applicable C-C cross-coupling catalysts with an excellent functional group tolerance. Dichloro{bis[1,1',1''-(phosphinetriyl)tripiperidine]}palladium [(P(NC5H10)3)2Pd(Cl)2] (1), the least stable complex within this series towards protons; e.g. in the form of water, allows an eased nanoparticle formation and hence, proved to be the most active Heck catalyst within this series at 100 &#176;C and is a very rare example of an effective and versatile catalyst system that efficiently operates under mild reaction conditions. Rapid and complete catalyst degradation under work-up conditions into phosphonates, piperidinium salts and other, palladium-containing decomposition products assure an easy separation of the coupling products from catalyst and ligands. The facile, cheap, and rapid synthesis of 1,1',1"-(phosphinetriyl)tripiperidine and 1 respectively, the simple and convenient use as well as its excellent catalytic performance in the Heck reaction at 100 &#176;C make 1 to one of the most attractive and greenest Heck catalysts available.
We provide here the visualized protocols for the ligand and catalyst syntheses as well as the reaction protocol for Heck reactions performed at 10 mmol scale at 100 &#176;C and show that this catalyst is suitable for its use in organic syntheses.

Mizoroki-Heck Cross-coupling Reactions Catalyzed by Dichloro{bis[1,1',1''-phosphinetriyltripiperidine]}palladium Under Mild Reaction Conditions

Dichloro{bis[1,1',1''-(phosphinetriyl)tripiperidine]}palladium [(P(NC5H10)3)2Pd(Cl)2] (1) is an easy accessible, cheap, and air stable, but highly active Heck catalyst with an excellent functional group tolerance that efficiently operates under mild reaction conditions to give the coupling products in very high yields.

Mizoroki-哎呀交叉偶联反应由二氯{双[1,1&#39;，1&#39;&#39;  - （phosphinetriyl）tripiperidine]}钯催化在温和的反应条件

Dichloro-bis(aminophosphine) complexes of palladium with the general formula of [(P{(NC5H10)3-n(C6H11)n})2Pd(Cl)2] (where n = 0-2), belong to a new family ...

科研

化学

The Synthesis, Characterization and Reactivity of a Series of Ruthenium N-triphosPh Complexes

Herein we report the synthesis of a tridentate phosphine ligand N(CH2PPh2)3 (N-triphosPh) (1) via a phosphorus based Mannich reaction of the hydroxylmethylene phosphine precursor with ammonia in methanol under a nitrogen atmosphere. The N-triphosPh ligand precipitates from the solution after approximately 1 hr of reflux and can be isolated analytically pure via simple cannula filtration procedure under nitrogen. Reaction of the N-triphosPh ligand with [Ru3(CO)12] under reflux affords a deep red solution that show evolution of CO gas on ligand complexation. Orange crystals of the complex [Ru(CO)2{N(CH2PPh2)3}-&#954;3P] (2) were isolated on cooling to RT. The 31P{1H} NMR spectrum showed a characteristic single peak at lower frequency compared to the free ligand. Reaction of a toluene solution of complex 2 with oxygen resulted in the instantaneous precipitation of the carbonate complex [Ru(CO3)(CO){N(CH2PPh2)3}-&#954;3P] (3) as an air stable orange solid. Subsequent hydrogenation of 3 under 15 bar of hydrogen in a high-pressure reactor gave the dihydride complex [RuH2(CO){N(CH2PPh2)3}-&#954;3P] (4), which was fully characterized by X-ray crystallography and NMR spectroscopy. Complexes 3 and 4 are potentially useful catalyst precursors for a range of hydrogenation reactions, including biomass-derived products such as levulinic acid (LA). Complex 4 was found to cleanly react with LA in the presence of the proton source additive NH4PF6 to give [Ru(CO){N(CH2PPh2)3}-&#954;3P{CH3CO(CH2)2CO2H}-&#954;2O](PF6) (6).

The Synthesis, Characterization and Reactivity of a Series of Ruthenium N-triphosPh Complexes

Ruthenium phosphine complexes are widely used for homogeneous catalytic reactions such as hydrogenations. The synthesis of a series of novel tridentate ruthenium complexes bearing the N-triphos ligand N(CH2PPh2)3 is reported. Additionally, the stoichiometric reaction of a dihydride Ru&#8211;N-triphos complex with levulinic acid is described.

一系列钌的合成，表征和反应<em&gt;Ñ</em&gt; -triphos<sup&gt;博士</sup&gt;配合

Herein we report the synthesis of a tridentate phosphine ligand N(CH2PPh2)3 (N-triphosPh) (1) via a phosphorus based Mannich reaction of the ...

Synthesis of a Water-soluble Metal&#8211;Organic Complex Array

We demonstrate a method for the synthesis of a water-soluble multimetallic peptidic array containing a predetermined sequence of metal centers such as Ru(II), Pt(II), and Rh(III). The compound, named as a water-soluble metal-organic complex array (WSMOCA), is obtained through 1) the conventional solution-chemistry-based preparation of the corresponding metal complex monomers having a 9-fluorenylmethyloxycarbonyl (Fmoc)-protected amino acid moiety and 2) their sequential coupling together with other water-soluble organic building units on the surface-functionalized polymeric resin by following the procedures originally developed for the solid-phase synthesis of polypeptides, with proper modifications. Traces of reactions determined by mass spectrometric analysis at the representative coupling steps in stage 2 confirm the selective construction of a predetermined sequence of metal centers along with the peptide backbone. The WSMOCA cleaved from the resin at the end of stage 2 has a certain level of solubility in aqueous media dependent on the pH value and/or salt content, which is useful for the purification of the compound.

A potential general method for the synthesis of water-soluble multimetallic peptidic arrays containing a predetermined sequence of metal centers is presented.

一个水溶性金属 - 有机络合物阵列合成

We demonstrate a method for the synthesis of a water-soluble multimetallic peptidic array containing a predetermined sequence of metal centers such as ...

Synthesis and Evaluation of a Ruthenium-based Mitochondrial Calcium Uptake Inhibitor

We detail the synthesis and purification of a mitochondrial calcium uptake inhibitor, [(OH2)(NH3)4Ru(&#181;-O)Ru(NH3)4(OH2)]5+. The optimized synthesis of this compound commences from [Ru(NH3)5Cl]Cl2 in 1 M NH4OH in a closed container, yielding a green solution. Purification is accomplished with cation-exchange chromatography. This compound is characterized and verified to be pure by UV-vis and IR spectroscopy. The mitochondrial calcium uptake inhibitory properties are assessed in permeabilized HeLa cells by fluorescence spectroscopy.

A protocol for the synthesis, purification, and characterization of a ruthenium-based inhibitor of mitochondrial calcium uptake is presented. A procedure to evaluate its efficacy in permeabilized mammalian cells is demonstrated.

钌线粒体钙吸收抑制剂的合成与评价

We detail the synthesis and purification of a mitochondrial calcium uptake inhibitor, [(OH2)(NH3)4Ru(&#181;-O)Ru(NH3)4(OH2)]5+. The optimized synthesis of ...

Photogeneration of N-Heterocyclic Carbenes: Application in Photoinduced Ring-Opening Metathesis Polymerization

We report a method to generate the N-heterocyclic carbene (NHC) 1,3-dimesitylimidazol-2-ylidene (IMes) under UV-irradiation at 365 nm to characterize IMes and determine the corresponding photochemical mechanism. Then, we describe a protocol to perform ring-opening metathesis polymerization (ROMP) in solution and in miniemulsion using this NHC-photogenerating system. To photogenerate IMes, a system comprising 2-isopropylthioxanthone (ITX) as the sensitizer and 1,3-dimesitylimidazolium tetraphenylborate (IMesH+BPh4-) as the protected form of NHC is employed. IMesH+BPh4- can be obtained in a single step by anion exchange between 1,3-dimesitylimidazolium chloride and sodium tetraphenylborate. A real-time steady-state photolysis setup is described, which hints that the photochemical reaction proceeds in two consecutive steps: 1) ITX triplet is photo-reduced by the borate anion and 2) subsequent proton transfer takes place from the imidazolium cation to produce the expected NHC IMes. Two separate characterization protocols are implemented. Firstly, CS2 is added to the reaction media to evidence the photogeneration of NHC through formation of the IMes-CS2 adduct. Secondly, the amount of NHC released in situ is quantified using acid-base titration. The use of this NHC photo-generating system for the ROMP of norbornene is also discussed. In solution, a photopolymerization experiment is conducted by mixing ITX, IMesH+BPh4-, [RuCl2(p-cymene)]2 and norbornene in CH2Cl2, then irradiating the solution in a UV reactor. In a dispersed medium, a monomer miniemulsion is first formed then irradiated inside an annular reactor to produce a stable poly(norbornene) latex.

We describe a protocol to photogenerate N-heterocyclic carbenes (NHCs) by UV irradiation of a 2-isopropylthioxanthone/imidazolium tetraphenylborate salt system. Methods to characterize the photoreleased NHC and elucidate the photochemical mechanism are proposed. The protocols for ring-opening metathesis photopolymerization in solution and miniemulsion illustrate the potential of this 2-component NHC photogenerating system.

n-杂环卡本的光生成在光致环开环转移聚合中的应用

We report a method to generate the N-heterocyclic carbene (NHC) 1,3-dimesitylimidazol-2-ylidene (IMes) under UV-irradiation at 365 nm to characterize IMes ...

Multiscale Sampling of a Heterogeneous Water/Metal Catalyst Interface using Density Functional Theory and Force-Field Molecular Dynamics

A significant number of heterogeneously-catalyzed chemical processes occur under liquid conditions, but simulating catalyst function under such conditions is challenging when it is necessary to include the solvent molecules. The bond breaking and forming processes modeled in these systems necessitate the use of quantum chemical methods. Since molecules in the liquid phase are under constant thermal motion, simulations must also include configurational sampling. This means that multiple configurations of liquid molecules must be simulated for each catalytic species of interest. The goal of the protocol presented here is to generate and sample trajectories of configurations of liquid water molecules around catalytic species on flat transition metal surfaces in a way that balances chemical accuracy with computational expense. Specifically, force field molecular dynamics (FFMD) simulations are used to generate configurations of liquid molecules that can subsequently be used in quantum mechanics-based methods such as density functional theory or ab initio molecular dynamics. To illustrate this, in this manuscript, the protocol is used for catalytic intermediates that could be involved in the pathway for the decomposition of glycerol (C3H8O3). The structures that are generated using FFMD are modeled in DFT in order to estimate the enthalpies of solvation of the catalytic species and to identify how H2O molecules participate in catalytic decompositions.

The goal of the protocol presented here is to generate and sample trajectories of configurations of liquid water molecules around catalytic species on a flat transition metal surface. The sampled configurations can be used as starting structures in quantum mechanics-based methods.

利用密度泛函理论和力场分子动力学对多相水-金属催化剂接口进行多尺度采样

A significant number of heterogeneously-catalyzed chemical processes occur under liquid conditions, but simulating catalyst function under such conditions ...

Imine Metathesis by Silica-Supported Catalysts Using the Methodology of Surface Organometallic Chemistry

With this protocol, a well-defined singlesite silica-supported heterogeneous catalyst [(&#8801;Si-O-)Hf(=NMe)(&#951;1-NMe2)] is designed and prepared according to the methodology developed by surface organometallic chemistry (SOMC). In this framework, catalytic cycles can be determined by isolating crucial intermediates. All air-sensitive materials are handled under inert atmosphere (using gloveboxes or a Schlenk line) or high vacuum lines (HVLs, &#60;10-5 mbar). The preparation of SiO2-700 (silica dehydroxylated at 700 &#176;C) and subsequent applications (the grafting of complexes and catalytic runs) requires the use of HVLs and double-Schlenk techniques. Several well-known characterization methods are used, such as Fourier-transform infrared spectroscopy (FTIR), elemental microanalysis, solid-state nuclear magnetic resonance spectroscopy (SSNMR), and state-of-the-art dynamic nuclear polarization surface enhanced NMR spectroscopy (DNP-SENS). FTIR and elemental microanalysis permit scientists to establish the grafting and its stoichiometry. 1H and 13C SSNMR allows the structural determination of the hydrocarbon ligands coordination sphere. DNP SENS is an emerging powerful technique in solid characterization for the detection of poorly sensitive nuclei (15N, in our case). SiO2-700 is treated with about one equivalent of the metal precursor compared to the amount of surface silanol (0.30 mmol&#183;g-1) in pentane at room temperature. Then, volatiles are removed, and the powder samples are dried under dynamic high vacuum to afford the desired materials [(&#8801;Si-O-)Hf(&#951;2&#960;-MeNCH2)(&#951;1-NMe2)(&#951;1-HNMe2)]. After a thermal treatment under high vacuum, the grafted complex is converted into metal imido silica complex [(&#8801;Si-O-)Hf(=NMe)(&#951;1-NMe2)]. [(&#8801;Si-O-)Hf(=NMe)(&#951;1-NMe2)] effectively promotes the metathesis of imines, using the combination of two imine substrates, N-(4-phenylbenzylidene)benzylamine, or N-(4-fluorobenzylidene)-4-fluoroaniline, with N-benzylidenetert-butylamine as substrates. A significantly lower conversion is observed with the blank runs; thus, the presence of the imido group in [(&#8801;Si-O-)Hf(=NMe)(&#951;1-NMe2)] is correlated to the catalytic performance.

A new group IV metal catalyst for imine metathesis is prepared by grafting amine metal complex onto dehydroxylated silica. Surface metal fragments are characterized using FT-IR, elemental microanalysis, and solid-state NMR spectroscopy. Further dynamic nuclear polarization surface enhanced NMR spectroscopy experiments complement the determination of the coordination sphere.

利用表面有机金属化学方法，利用硅支持的催化剂进行Imine金属分析

With this protocol, a well-defined singlesite silica-supported heterogeneous catalyst [(&#8801;Si-O-)Hf(=NMe)(&#951;1-NMe2)] is designed and prepared ...

Tuning the Acidity of Pt/ CNTs Catalysts for Hydrodeoxygenation of Diphenyl Ether

We herein present a method for the synthesis of HNbWO6, HNbMoO6, HTaWO6 solid acid nanosheet modified Pt/CNTs. By varying the weight of various solid acid nanosheets, a series of Pt/xHMNO6/CNTs with different solid acid compositions (x = 5, 20 wt%; M = Nb, Ta; N = Mo, W) have been prepared by carbon nanotube pretreatment, protonic exchange, solid acid exfoliation, aggregation and finally Pt particles impregnation. The Pt/xHMNO6/CNTs are characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and NH3-temperature programmed desorption. The study revealed that HNbWO6 nanosheets were attached on CNTs, with some edges of the nanosheets being bent in shape. The acid strength of the supported Pt catalysts increases in the following order: Pt/CNTs &#60; Pt/5HNbWO6/CNTs &#60; Pt/20HNbMoO6/CNTs &#60; Pt/20HNbWO6/CNTs &#60; Pt/20HTaWO6/CNTs. In addition, the catalytic hydroconversion of lignin-derived model compound: diphenyl ether using the synthesized Pt/20HNbWO6 catalyst has been investigated.

A protocol for the synthesis of HNbWO6, HNbMoO6, HTaWO6 solid acid nanosheet modified Pt/CNTs is presented.

调整二苯醚氢氧化的Pt/CNT催化剂的酸度

We herein present a method for the synthesis of HNbWO6, HNbMoO6, HTaWO6 solid acid nanosheet modified Pt/CNTs. By varying the weight of various solid acid ...

Development of Heterogeneous Enantioselective Catalysts using Chiral Metal-Organic Frameworks (MOFs)

Substrate size discrimination by the pore size and homogeneity of the chiral environment at the reaction sites are important issues in the validation of the reaction site in metal-organic framework (MOF)&#8211;based catalysts in an enantioselective catalytic reaction system. Therefore, a method of validating the reaction site of MOF-based catalysts is necessary to investigate this issue. Substrate size discrimination by pore size was accomplished by comparing the substrate size versus the reaction rate in two different types of carbonyl-ene reactions with two kinds of MOFs. The MOF catalysts were used to compare the performance of the two reaction types (Zn-mediated stoichiometric and Ti-catalyzed carbonyl-ene reactions) in two different media. Using the proposed method, it was observed that the entire MOF crystal participated in the reaction, and the interior of the crystal pore played an important role in exerting chiral control when the reaction was stoichiometric. Homogeneity of the chiral environment of MOF catalysts was established by the size control method for a particle used in the Zn-mediated stoichiometric reaction system. The protocol proposed for the catalytic reaction revealed that the reaction mainly occurred on the catalyst surface regardless of the substrate size, which reveals the actual reaction sites in MOF-based heterogeneous catalysts. This method for reaction site validation of MOF catalysts suggests various considerations for developing heterogeneous enantioselective MOF catalysts.

Development of Heterogeneous Enantioselective Catalysts using Chiral Metal-Organic Frameworks MOFs

Here, we present a protocol for active site validation of metal-organic framework catalysts by comparing stoichiometric and catalytic carbonyl-ene reactions to find out whether a reaction takes place on the inner or outer surface of metal-organic frameworks.

使用气性金属-有机框架 （MoF） 开发异构异构选择性催化剂

Substrate size discrimination by the pore size and homogeneity of the chiral environment at the reaction sites are important issues in the validation of ...

Catalytic Reactions at Amine-Stabilized and Ligand-Free Platinum Nanoparticles Supported on Titania During Hydrogenation of Alkenes and Aldehydes

Ligands like amines are used in the colloidal synthesis approach to protect platinum nanoparticles (Pt NP&#39;s) from agglomeration. Normally, ligands like amines are removed by diverse pre-treatment procedures before use in heterogeneous catalysis as amines are considered as a catalyst poison. However, a possible beneficial influence of these surface modifiers on hydrogenation reactions, which is known from spectator species on metal surfaces, is often neglected.
Therefore, amine-stabilized Pt nanoparticles supported by titania (P25) were used without any pre-treatment in order to elucidate a possible influence of the ligand in liquid phase hydrogenation reactions. The catalytic activity of amine-stabilized Pt nanoparticles of two different sizes was investigated in a double-walled stirring tank reactor at 69 &#176;C to 130 &#176;C and 1 atm hydrogen pressure. The conversion of cyclohexene to cyclohexane was determined by gas chromatography (GC) and was compared to ligand-free Pt particles. All catalysts were checked before and after reaction by transmission electron spectroscopy (TEM) and X-ray photoelectron spectroscopy (XPS) for possible changes in size, shape, and ligand shell. The hydrogenation of cyclohexene in liquid phase revealed a higher conversion for amine-stabilized Pt nanoparticles on titania than the ligand-free particles. The hydrogenation of 5-methylfurfural (5-MF) was chosen for a further test reaction, since the hydrogenation of &#945;, &#946;-unsaturated aldehydes is more complex and exhibits various reaction paths. However, XPS and infrared spectroscopy (IR) proved that 5-MF acts as catalyst poison at the given reaction conditions.

This protocol shows a convenient method for comparing the catalytic properties of supported platinum catalysts, synthesized by deposition of nanosized colloids or by impregnation. The hydrogenation of cyclohexene serves as a model reaction to determine the catalytic activity of the catalysts.

烯烃和醛加氢过程中负载在二氧化钛上的胺稳定和无配体铂纳米颗粒的催化反应

Ligands like amines are used in the colloidal synthesis approach to protect platinum nanoparticles (Pt NP&#39;s) from agglomeration. Normally, ligands ...

水介质中水溶性钌烯烃置换催化剂的异质化去除与寄主交互作用

摘要

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此视频中的章节

Mizoroki-哎呀交叉偶联反应由二氯{双[1,1'，1'' - （phosphinetriyl）tripiperidine]}钯催化在温和的反应条件

一系列钌的合成，表征和反应

一个水溶性金属 - 有机络合物阵列合成

钌线粒体钙吸收抑制剂的合成与评价

n-杂环卡本的光生成在光致环开环转移聚合中的应用

利用密度泛函理论和力场分子动力学对多相水-金属催化剂接口进行多尺度采样

利用表面有机金属化学方法，利用硅支持的催化剂进行Imine金属分析

调整二苯醚氢氧化的Pt/CNT催化剂的酸度

使用气性金属-有机框架（MoF）开发异构异构选择性催化剂

烯烃和醛加氢过程中负载在二氧化钛上的胺稳定和无配体铂纳米颗粒的催化反应

水介质中水溶性钌烯烃置换催化剂的异质化去除与寄主交互作用

摘要

探索更多视频

此视频中的章节

Mizoroki-哎呀交叉偶联反应由二氯{双[1,1'，1'' - （phosphinetriyl）tripiperidine]}钯催化在温和的反应条件

一系列钌的合成，表征和反应

一个水溶性金属 - 有机络合物阵列合成

钌线粒体钙吸收抑制剂的合成与评价

n-杂环卡本的光生成在光致环开环转移聚合中的应用

利用密度泛函理论和力场分子动力学对多相水-金属催化剂接口进行多尺度采样

利用表面有机金属化学方法，利用硅支持的催化剂进行Imine金属分析

调整二苯醚氢氧化的Pt/CNT催化剂的酸度

使用气性金属-有机框架 （MoF） 开发异构异构选择性催化剂

烯烃和醛加氢过程中负载在二氧化钛上的胺稳定和无配体铂纳米颗粒的催化反应

使用气性金属-有机框架（MoF）开发异构异构选择性催化剂