Name: palladium n-heterocyclic carbene complexes: synthesis from benzimidazolium salts and catalytic activity in carbon-carbon bond-forming reactions
Uploaded: 2017-07-30T14:00:00.000+00:00
Duration: 19 min 58 s
Description: Watch this Scientific Journal Video about Palladium N-Heterocyclic Carbene Complexes: Synthesis from Benzimidazolium Salts and Catalytic Activity in Carbon-carbon Bond-forming Reactions at JoVE.com

我们承认药学院（悉尼大学），Erciyes大学研究基金和TUBITAK（1059B141400496）的财务支持。我们感谢Tim Harland（悉尼大学）编辑视频。

注意:使用许多挥发性溶剂作为下面详述的方案的一部分，以便在工作通风橱中进行所有实验。在使用前请穿戴适当的个人防护装备，并咨询各试剂的MSDS;在此提供有关危险试剂和步骤的简要信息。 苯并咪唑盐的合成和纯化（化合物1-4） <ol><li>立即将100mL Schlenk管夹紧，并将搅拌棒，1mmol苯并咪唑，1mmol氢氧化钾和60mL乙醇作为溶剂。 注意:氢氧化钾可能有害。避免吸入灰尘并远离水分。 注意:乙醇易挥发和易燃。远离明火或点火源。 注意:如果没有氢氧化钾，可以使用氢氧化钠。咨询在进行此建议修改前，请先进行氢氧化钠的MSDS。 </li><li>将Schlenk管放入油浴中，以在搅拌步骤中均匀和安全地加热反应混合物。将管连接到冷凝器，以防止搅拌过程中溶剂蒸发。确保玻璃配件部分已充分润滑且安装正确。 </li><li>将反应混合物在25℃下搅拌1小时，以使所有固体完全溶解，以及在苯并咪唑分子中破坏氮 - 氢键。 注意:使用冷凝器进行该搅拌步骤并不是必需的，但是由于在下面的步骤1.5中必须使用冷凝器进行回流，所以在此步骤中可以方便地安装冷凝器，并将其用于两个步骤。否则，该步骤可以通过用带油的塞子密封Schlenk管来进行。 </li><li> 1小时后，从冷凝器中取出Schlenk管，并缓慢加入1mmol所选择的a卤化物至混合物。 注意:芳基卤化物是刺激物，可能是有害的。在进行之前，请咨询相关MSDS。 </li><li>将Schlenk管重新连接到冷凝器，并将混合物在78℃（接近乙醇沸点）下回流6小时，以使反应达到完成。让混合物在回流结束后冷却至25℃。 </li><li>从冷凝器中取出Schlenk管，并使用一些纸巾擦拭管口的油脂。然后，使用漏斗和滤纸过滤反应混合物以除去反应期间形成的氯化钾沉淀。在烧杯中收集滤液。 </li><li>将含有N-烷基苯并咪唑产物的滤液转移到干净的Schlenk管中。用油脂塞子密封管，并用真空除去滤液中的乙醇溶剂。 注意:对于协议中的所有步骤使用中等强度的真空以及连接真空的管的轻微和连续的振动。 </li><li>一旦除去所有溶剂，开启Schlenk管，加入5 mL乙醚洗涤留下的N-烷基苯并咪唑产物。轻轻摇动管子进行洗涤。 <ol><li>洗完后，用一些纸巾擦拭管子的嘴唇上的油脂，并将乙醚倒入烧杯中。重复此洗涤步骤几次，加入5 mL乙醚，每次滗析。 注意:二乙醚易挥发，易燃。远离明火或点火源。 注意:对于方案中的所有洗涤步骤，可以使用另一种溶剂:1）不与被洗涤物质反应，2）不溶解被洗涤物质，3）容易蒸发。 </li></ol></li><li>在最后的洗涤步骤之后，用一个密封Schlenk管润滑塞子并用真空干燥洗涤的N-烷基苯并咪唑产物。干燥后，使用一些纸巾擦拭管口上的油脂，然后将产品转移到一个小瓶中，用于下一个反应。 注意:协议可以在此暂停并在以后恢复。 </li><li>将干净的Schlenk管夹紧并用氩气吹扫，将其内部的空气排出。在管道的侧臂引入气体，并在此过程中保持管子的口部未密封。氩气比空气重，因此从下往上填充管将排出空气。在下一步加入试剂时，继续用氩气吹扫管。 </li><li>将缓慢加入搅拌棒，1mmol N-烷基苯并咪唑，1mmol所选择的烷基卤和4mL无水N ， N-二甲基甲酰胺（DMF）作为溶剂加入到Schlenk管中。一旦添加所有试剂，快速密封管的口用润滑塞子，然后转动旋塞将其侧臂密封，然后关闭氩气。 注意:烷基卤化物是刺激物，可能是有害的。在进行之前，请咨询相关MSDS。 注意: DMF易燃。远离明火或点火源。 </li><li>将密封的Schlenk管放入油浴中，并将反应混合物在80℃下搅拌24小时以使反应完成。 注意:该反应需要在惰性气氛中进行，因此需要谨慎地进行上述涉及氩气的清洗步骤。 </li><li> 24小时后，真空除去混合物中部分DMF溶剂;大约1-2分钟的抽真空应该是足够的。 注意:如果需要， 请从润滑脂混合物中取出所有DMF溶剂，但这不是必需的。 </li><li>开启Schlenk管并加入15 mL乙醚。搅拌哩直到苯并咪唑盐产物沉淀出来。 注意:如果没有乙醚，可以使用石油醚。在进行此建议修改之前，请咨询石油醚的MSDS。 </li><li>沉淀发生后，使用适当的过滤方法除去二乙醚。 注意:我们使用了带有侧臂，内部过滤器和两个开口端的特殊玻璃管，Schlenk管可以连接到该开口端;由于该管上的侧臂和Schlenk管上的侧臂可以附着在真空下，所以该过滤管提供了极大的便利:1）沉淀步骤后的过滤以及洗涤步骤，以及2）洗涤后的干燥脚步。 <ol><li>如果使用类似的东西，将填充的Schlenk管连接到过滤管的一端，另一端将空的Schlenk管连接。然后将空的Schlenk管连接到真空中，并小心地逐渐地翻转设备二乙醚通过过滤器到这个空的Schlenk管。但是，如果不能找到这样的管，请使用其他方法，如用漏斗和滤纸进行过滤。 </li></ol></li><li>用15mL乙醚洗涤盐产物，并使用与步骤1.15中相同的过滤方法除去二乙醚。重复此洗涤步骤几次，使用15 mL乙醚，每次过滤。 </li><li>在最后的洗涤步骤之后，将洗涤后的盐产物干燥（此处，真空干燥过滤管内），然后通过重结晶收集进一步纯化。 注意:协议可以在此暂停并在以后恢复。 </li><li>将盐和乙醇 - 乙醚混合物（12mL:4mL）加入到干净的Schlenk管中。使用热枪加热混合物，直到盐完全溶解。 </li><li>然后，用油脂塞子密封管，并将其夹在几乎水平的位置。离开t他盐在室温下重结晶。 </li><li>一旦盐重结晶，使用一些纸巾擦拭管口的油脂，然后使用漏斗和滤纸过滤混合物以分离盐晶体。 </li><li>洗涤盐晶体，同时仍然在漏斗中的滤纸上，加入15mL二乙醚。重复这个洗涤步骤几次。 </li><li>在最后的洗涤步骤之后，让晶体在滤纸上的空气中干燥。收集纯化的盐进行表征和合成钯NHC复合物。 注意:协议可以在此暂停并在以后恢复。 </li><li>表征盐如前所述18 。 </li></ol> 2.钯NHC配合物的合成和纯化（化合物5-8） <ol><li>将75mL Schlenk管立即夹紧，并加入搅拌棒，1mmol所选择的苯并咪唑盐，1mmol氯化铝，5mmol碳酸钾作为碱和3mL 3-氯吡啶。 注意:氯化钯有毒，可能是刺激性的。 注意:碳酸钾可能是有害的。避免吸入灰尘并远离水分。 注意: 3-氯吡啶极其有害。有毒，有腐蚀性。避免皮肤接触并呼吸其烟雾。 </li><li>用油封塞密封管，并将其放入油浴。将反应混合物在80℃下搅拌16小时，以使钯NHC复合物合成达到完成。 </li><li> 16小时后，让混合物冷却至室温并开启管。向混合物中加入10mL二氯甲烷，以提高下面步骤2.4和2.5中所述的过滤效率;这是可选的，如果需要可以跳过。 注意:二氯甲烷有毒，有刺激性发现疑似致癌物质。避免皮肤接触并呼吸其烟雾。 </li><li>组装以下过滤装置以从反应混合物中除去未反应的氯化钯和苯并咪唑盐:使用不带水龙头的玻璃过滤管。 <ol><li>首先，将四个过滤剂（例如Celite）的铲子添加到管中，以在管的中间的过滤器上方形成过滤剂层。然后，在过滤剂层上方加入四个硅胶粉末。最后，在硅胶层之上挤压一小块棉布，使过滤剂和二氧化硅层固定在过滤器和棉絮之间。 </li></ol></li><li>通过过滤剂和硅胶垫过滤反应混合物如下:将含有反应混合物的Schlenk管连接到玻璃过滤管上，使得Schlenk管与棉絮面对着过滤管的末端。然后，将一个空的Schlenk管连接到另一端过滤管。 <ol><li>将空的Schlenk管连接到真空，小心地逐渐倒置装置，使反应混合物通过（顺序）棉花，二氧化硅，过滤剂和过滤层过滤。未反应的氯化钯和苯并咪唑盐将保留在层中，而含有NHC复合物的滤液将进入空的Schlenk管。 注意:如果将二氯甲烷加入到反应混合物（步骤2.3）中，则可能在过滤管内部产生一些压力，这可能导致液体在反转时从填充的Schlenk管和过滤管之间的连接部分渗出。为了防止这种情况，重要的是在设备倒置之前将空的Schlenk管连接到真空（如上所述），使得在反转时，反应混合物没有足够的时间从上述连接部分渗出。 </li></ol></li><li>分离Schlenk管含有来自上述过滤装置的滤液并用油脂塞子密封。真空除去滤液中的溶剂。 </li><li>一旦除去所有溶剂，开启Schlenk管并加入5mL乙醚洗涤留下的钯NHC复合物产物。轻轻摇动管子进行洗涤。洗完后，用一些纸巾擦拭管子的嘴唇上的油脂，并将乙醚倒入烧杯中。重复此洗涤步骤几次，加入5 mL乙醚，每次滗析。 </li><li>在最后的洗涤步骤之后，用油脂塞子密封Schlenk管，并用真空干燥洗涤的钯NHC复合物产物。干燥后，使用一些纸巾擦拭管口的油脂，然后通过重结晶收集产品进一步净化。 注意:协议可以在此暂停并在以后恢复。 </li><li>对于重结晶，找到一个适用于特定的钯NHC络合物的溶剂（即，该络合物在室温下不容易溶解，但在加热时不易溶解），并按照上述盐相同的步骤（步骤1.18至1.22）。之后，收集纯化的复合物进行表征。 注意:协议可以在此暂停并在以后恢复。 </li><li>表征复杂如前所述18 。 </li></ol>复合物（5-8）在芳基化反应中的催化活性<ol><li>在通风柜内进行空气下的所有催化反应。 </li><li>不经进一步纯化即可使用购买的试剂进行碳 - 碳键形成反应。 </li><li>夹紧25mL Schlenk管，向其中加入搅拌棒，2mmol 2- 正丁基噻吩或2- 正丁基呋喃和1mmol所选择的芳基溴。 注意: 2- 正丁基呋喃和2- 正丁基噻吩均为急性毒性。避免皮肤接触并呼吸其烟雾。 </li><li>然后向管中加入1mmol乙酸钾，0.01mmol所选择的钯NHC配合物和2mL N ， N-二甲基乙酰胺（DMA）。 注意: DMA有毒。避免皮肤接触并呼吸其烟雾。 </li><li>用油封塞密封管，并将其放入油浴。将反应混合物搅拌各种时间并在各种温度下，以找到导致给定反应产物产率最大的时间和温度条件。 注意:反应进程之后可以进行薄层层析（TLC），但是如果只比较不同反应条件对产率的影响（包括用于催化的钯NHC配合物）的影响，则不需要进行反应。在这些情况下，请将反应运行时间少于所需时间完成并改变测试的反应条件。一旦反应进行了所需的时间，通过从反应混合物中除去溶剂来停止反应，如下一步所述。 <ol><li>为了跟随TLC的反应进程，比较反应混合物通过TLC板与反应物的运动;如果混合物仍然产生反应物的斑点，这意味着反应还没有完成。为了在给定的时间后得到反应混合物的样品，在反应仍然运行的同时，开启Schlenk管，并使用毛细管快速获得TLC测试的滴。为了通过TLC板运行混合物和反应物，为特定情况找到合适的溶剂（流动相）。 </li></ol></li><li>一旦反应完成或运行了所需的时间，用真空除去反应混合物中的溶剂。 </li><li>开启Schlenk管，加入己烷 - 乙醚m将混合物（10mL:2mL）加入其中。该溶剂混合物将在下面的步骤3.8和3.9中用于快速柱色谱法的流动相。大力摇动混合物，确保产品溶于流动相，不留在管中。 注意事项:己烷易挥发，易燃。避免吸入烟雾，并远离明火或点火源。 </li><li>如下组装快速色谱柱以净化产品:使用玻璃滴管。首先，将一小块棉花插入滴管中，然后将其推入，直到其紧紧靠在玻璃室开始变薄的地方。然后，将硅胶添加到棉布的顶部，使得三分之二的滴管的厚部分被填充。 </li><li>将硅胶柱直立夹紧并使用玻璃滴管将反应混合物逐渐转移到其中。将混合物通过柱洗脱，并在干净的烧杯或试验中收集含有纯化产物的洗脱液管。 注意:协议可以在此暂停并在以后恢复。 </li><li>将洗脱液转移到可以附着到真空的干净的管子上，并用油脂塞子密封管子。用真空除去洗脱液中的溶剂。 注意:协议可以在此暂停并在以后恢复。 </li><li>一旦除去所有溶剂，开启管并加入1.5mL二氯甲烷。轻轻摇动管子以溶解产物，从而允许其用GC或GC / MS分析。计算使用GC或GC / MS 19，20，21，22，23的产率。 注意:如果二氯甲烷不可用，可以使用氯仿。在进行此建议修改之前，请咨询氯仿的MSDS。 </li></ol> 4.公司的催化活性铃木 - Miyaura交叉偶联反应中的复合物（5-8） <ol><li>根据先前报道的协议18，24进行所有的催化反应。 </li><li>立即将25mL Schlenk管夹紧，向其中加入搅拌棒，1.5mmol苯基硼酸或选择的硼酸衍生物，1mmol所选择的芳基氯和2mmol叔丁醇钠作为碱。 注意事项:苯硼酸及其衍生物是刺激物，有毒。避免皮肤接触。在进行之前，请咨询相关MSDS。 注意:氯化亚芳基是有害的，根据具体化学物质的不同，可能有毒且易燃。在进行之前，请咨询相关MSDS。 注意:叔丁醇钠是易燃固体。在溶液中与水和苛性碱具有高反应性。远离明火或点火源，避免皮肤接触注意:如果没有叔丁醇钠，可以使用氢氧化钾，氢氧化钠，碳酸钾，碳酸钠，乙酸钾，乙酸钠或叔丁醇钾。在进行这些建议的修改之前，请咨询这些基础的MSDS。 </li><li>向管中加入0.01mmol所选择的钯NHC复合物。 </li><li>将DMF-水混合物（2mL:2mL）加入管中。 注意:如果需要，使用较高比例的DMF与水或自己使用DMF。 </li><li>用油封塞密封管，并将其放入油浴。将反应混合物搅拌各种时间并在各种温度下，以找到导致给定反应产物产率最大的时间和温度条件。 注意:反应的进展可以通过TLC进行，但是如果仅比较不同反应条件对产率的影响（包括用于猫的钯NHC复合物分解），然后运行反应完成是没有必要的。在这些情况下，运行反应持续时间小于完成所需的时间，并改变测试的反应条件。一旦反应运行了所需的时间，停下来，继续下一步。为了跟随TLC的反应进程，请参阅步骤3.5.1了解一些细节。 </li><li>一旦反应完成或已经运行所需的时间，就可以将混合物冷却到室温。开启Schlenk管，并向反应混合物中加入己烷 - 乙酸乙酯混合物（5mL:1mL）。重新密封管并将新混合物剧烈摇动数分钟，使合成的产物迁移到己烷 - 乙酸乙酯相。 注意:乙酸乙酯易挥发，易燃，造成严重的眼睛损伤。避免吸入烟雾，并远离明火或点火源。 </li><li>夹住Sch直立管，并使混合物在几分钟的时间内沉淀成两个不同的相。 </li><li>使用玻璃滴管小心地提取顶部有机相，并将其转移到含有1g无水硫酸镁的干净的烧杯中。硫酸镁粉末有助于从提取的有机相中除去任何残留的水。 </li><li>重复步骤4.6至4.8至少一次以最大限度地提取合成产物。 </li><li>按照步骤3.8和3.9，用快速柱色谱纯化产物。提取的有机相中存在的己烷 - 乙酸乙酯混合物将用作该纯化步骤的流动相。在干净的烧杯或试管中收集含有纯化产物的洗脱液。 注意:协议可以在此暂停并在以后恢复。 </li><li>分析产品，并使用GC或GC / MS 19,20计算出产量，21，22，23。 </li></ol>

<ol>
	<li>Akkoc, S., Gok, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Synthesis+and+characterization+of+1-phenyl-3-alkylbenzimidazol-2-ylidene+salts+and+their+catalytic+activities+in+the+Heck+and+Suzuki+cross-coupling+reactions.">Synthesis and characterization of 1-phenyl-3-alkylbenzimidazol-2-ylidene salts and their catalytic activities in the Heck and Suzuki cross-coupling reactions.</a> J. Coord. Chem. 66 (8), 1396-1404 (2013).</li><li>Aktas, A., Akkoc, S., Gok, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Palladium+catalyzed+Mizoroki-Heck+and+Suzuki-Miyaura+reactions+using+naphthalenomethyl-substituted+imidazolidin-2-ylidene+ligands+in+aqueous+media.">Palladium catalyzed Mizoroki-Heck and Suzuki-Miyaura reactions using naphthalenomethyl-substituted imidazolidin-2-ylidene ligands in aqueous media.</a> J. Coord. Chem. 66 (16), 2901-2909 (2013).</li><li>Cetinkaya, B., Alici, B., Ozdemir, I., Bruneau, C., Dixneuf, P. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=2-imidazoline+and+1,4,5,6-tetrahydropyrimidine-ruthenium(II)+complexes+and+catalytic+synthesis+of+furan.">2-imidazoline and 1,4,5,6-tetrahydropyrimidine-ruthenium(II) complexes and catalytic synthesis of furan.</a> J. Organomet. Chem. 575 (2), 187-192 (1999).</li><li>Chouthaiwale, P. V., Rawat, V., Sudalai, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Pd-catalyzed+selective+hydrosilylation+of+aryl+ketones+and+aldehydes.">Pd-catalyzed selective hydrosilylation of aryl ketones and aldehydes.</a> Tetrahedron Lett. 53 (2), 148-150 (2012).</li><li>Herrmann, W. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=N-heterocyclic+carbenes:+A+new+concept+in+organometallic+catalysis.">N-heterocyclic carbenes: A new concept in organometallic catalysis.</a> Angew. Chem. Int. Ed. 41 (8), 1290-1309 (2002).</li><li>Jensen, T. R., Schaller, C. P., Hillmyer, M. A., Tolman, W. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Zinc+N-heterocyclic+carbene+complexes+and+their+polymerization+of+D,L-lactide.">Zinc N-heterocyclic carbene complexes and their polymerization of D,L-lactide.</a> J. Organomet. Chem. 690 (24-25), 5881-5891 (2005).</li><li>Lai, Y. B., Lee, C. S., Lin, W. J., Naziruddin, A. R., Hwang, W. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Bis-chelate+N-heterocyclic+tetracarbene+Ru(II)+complexes:+Synthesis,+structure,+and+catalytic+activity+toward+transfer+hydrogenation+of+ketones.">Bis-chelate N-heterocyclic tetracarbene Ru(II) complexes: Synthesis, structure, and catalytic activity toward transfer hydrogenation of ketones.</a> Polyhedron. 53, 243-248 (2013).</li><li>Savka, R. D., Plenio, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+hexahydro-s-indacene+based+NHC+ligand+for+olefin+metathesis+catalysts.">A hexahydro-s-indacene based NHC ligand for olefin metathesis catalysts.</a> J. Organomet. Chem. 710, 68-74 (2012).</li><li>Yigit, M., Yigit, B., Gok, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Synthesis+of+novel+palladium(II)+N-heterocyclic+carbene+complexes+and+their+catalytic+activities+in+the+direct+C5+arylation+reactions.">Synthesis of novel palladium(II) N-heterocyclic carbene complexes and their catalytic activities in the direct C5 arylation reactions.</a> Inorg. Chim. Acta. 453, 23-28 (2016).</li><li>Yasar, S., Sahin, C., Arslan, M., Ozdemir, I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Synthesis,+characterization+and+the+Suzuki-Miyaura+coupling+reactions+of+N-heterocyclic+carbene-Pd(II)-pyridine+(PEPPSI)+complexes.">Synthesis, characterization and the Suzuki-Miyaura coupling reactions of N-heterocyclic carbene-Pd(II)-pyridine (PEPPSI) complexes.</a> J. Organomet. Chem. 776, 107-112 (2015).</li><li>Ozdemir, I., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=N-Heterocyclic+carbenes:+Useful+ligands+for+the+palladium-catalysed+direct+C5+arylation+of+heteroaromatics+with+aryl+bromides+or+electron-deficient+aryl+chlorides.">N-Heterocyclic carbenes: Useful ligands for the palladium-catalysed direct C5 arylation of heteroaromatics with aryl bromides or electron-deficient aryl chlorides.</a> Eur. J. Inorg. Chem. 12 (12), 1798-1805 (2010).</li><li>Clavier, H., Nolan, S. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=N-heterocyclic+carbene+and+phosphine+ruthenium+indenylidene+precatalysts:+A+comparative+study+in+Olefin+metathesis.">N-heterocyclic carbene and phosphine ruthenium indenylidene precatalysts: A comparative study in Olefin metathesis.</a> Chem. Eur. J. 13 (28), 8029-8036 (2007).</li><li>Johnson, J. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Catalyzed+reactions+of+acyl+anion+equivalents.">Catalyzed reactions of acyl anion equivalents.</a> Angew. Chem. Int. Ed. 43 (11), 1326-1328 (2004).</li><li>Marion, N., Diez-Gonzalez, S., Nolan, S. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=N-heterocyclic+carbenes+as+organocatalysts.">N-heterocyclic carbenes as organocatalysts.</a> Angew. Chem. Int. Ed. 46 (17), 2988-3000 (2007).</li><li>Perry, M. C., Burgess, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Chiral+N-heterocyclic+carbene-transition+metal+complexes+in+asymmetric+catalysis.">Chiral N-heterocyclic carbene-transition metal complexes in asymmetric catalysis.</a> Tetrahedron: Asymmetry. 14 (8), 951-961 (2003).</li><li>Zeitler, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Extending+mechanistic+routes+in+heterazolium+catalysis-promising+concepts+for+versatile+synthetic+methods.">Extending mechanistic routes in heterazolium catalysis-promising concepts for versatile synthetic methods.</a> Angew. Chem. Int. Ed. 44 (46), 7506-7510 (2005).</li><li>Schwarz, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=N-Heterocyclic+carbenes,+part+25+-+Polymer-supported+carbene+complexes+of+palladium:+Well-defined,+air-stable,+recyclable+catalysts+for+the+Heck+reaction.">N-Heterocyclic carbenes, part 25 - Polymer-supported carbene complexes of palladium: Well-defined, air-stable, recyclable catalysts for the Heck reaction.</a> Chem. Eur. J. 6 (10), 1773-1780 (2000).</li><li>Akkoc, S., Gok, Y., Ilhan, I. O., Kayser, V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=N-Methylphthalimide-substituted+benzimidazolium+salts+and+PEPPSI+Pd-NHC+complexes:+synthesis,+characterization+and+catalytic+activity+in+carbon-carbon+bond-forming+reactions.">N-Methylphthalimide-substituted benzimidazolium salts and PEPPSI Pd-NHC complexes: synthesis, characterization and catalytic activity in carbon-carbon bond-forming reactions.</a> Beilstein J. Org. Chem. 12, 81-88 (2016).</li><li>Karaca, E. O., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Palladium+complexes+with+tetrahydropyrimidin-2-ylidene+ligands:+Catalytic+activity+for+the+direct+arylation+of+furan,+thiophene,+and+thiazole+derivatives.">Palladium complexes with tetrahydropyrimidin-2-ylidene ligands: Catalytic activity for the direct arylation of furan, thiophene, and thiazole derivatives.</a> Organometallics. 34 (11), 2487-2493 (2015).</li><li>Ozdemir, I., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=N-Heterocyclic+carbene-palladium+catalysts+for+the+direct+arylation+of+pyrrole+derivatives+with+aryl+chlorides.">N-Heterocyclic carbene-palladium catalysts for the direct arylation of pyrrole derivatives with aryl chlorides.</a> Beilstein J. Org. Chem. 9, 303-312 (2013).</li><li>Senocak, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Synthesis,+crystal+structures,+magnetic+properties+and+Suzuki+and+Heck+coupling+catalytic+activities+of+new+coordination+polymers+containing+tetracyanopalladate(II)+anions.">Synthesis, crystal structures, magnetic properties and Suzuki and Heck coupling catalytic activities of new coordination polymers containing tetracyanopalladate(II) anions.</a> Polyhedron. 49 (1), 50-60 (2013).</li><li>Akkoc, S., Gok, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dichlorido(3-chloropyridine-N)+1,3-dialkylbenzimidazol-2-ylidene+palladium(II)+complexes:+Synthesis,+characterization+and+catalytic+activity+in+the+arylation+reaction.">Dichlorido(3-chloropyridine-N) 1,3-dialkylbenzimidazol-2-ylidene palladium(II) complexes: Synthesis, characterization and catalytic activity in the arylation reaction.</a> Inorg. Chim. Acta. 429, 34-38 (2015).</li><li>Akkoc, S., Gok, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Catalytic+activities+in+direct+arylation+of+novel+palladium+N-heterocyclic+carbene+complexes.">Catalytic activities in direct arylation of novel palladium N-heterocyclic carbene complexes.</a> Appl. Organomet. Chem. 28 (12), 854-860 (2014).</li><li>Akkoc, S., Gok, Y., Ilhan, I. O., Kayser, V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=In+situ+Generation+of+Efficient+Palladium+N-heterocyclic+Carbene+Catalysts+Using+Benzimidazolium+Salts+for+the+Suzuki-Miyaura+Cross-coupling+Reaction.">In situ Generation of Efficient Palladium N-heterocyclic Carbene Catalysts Using Benzimidazolium Salts for the Suzuki-Miyaura Cross-coupling Reaction.</a> Curr. Org. Synth. 13 (5), 761-766 (2016).</li></ol>

作者没有什么可以披露的。

合成和纯化四种苯并咪唑鎓盐，随后他们的钯NHC络合物的方案被故意地提供给最大的细节，以帮助年轻的科学家或那些新的现场掌握他们。考虑到同样的目标，还详细介绍了在芳基化和铃木 - 宫古反应中测试四种络合物的催化活性的方案。此外，我们试图将方案呈现为尽可能一般的形式，以允许其他人容易地适应它们用于许多其它/新的钯NHC复合物的催化活性的合成，纯化和测试。 <p class="jove_c...

N-杂环碳烯（NHC）引起了极大的关注，尤其是其催化各种重要反应的能力，如复分解，呋喃的生成，聚合，氢化硅烷化，氢化，芳基化，铃木 - 宫崎交联和Mizoroki-Heck交联1，2，3，4，5，6，7，8，9，10，11。 NHC可与金属结合;这种金属- NHC络合物作为辅助配体的过渡金属催化的反应被广泛使用和有机催化剂12，13，14， </SUP&gt; 15，16。通常，由于金属 - 碳配位键17的高解离能，其对空气，水分和热量非常稳定。 这里，四个苯并咪唑盐（化合物1 - 4）先前示出的合成和纯化的协议及其钯NHC络合物（化合物5 -分别为8，）是详细18。先前使用各种技术来表征盐和络合物18 。由于用于芳基化和Suzuki-Miyaura交叉偶联反应9，10，11的催化相似的化合物，用于测试复合物的催化活性在芳基化和铃木-宫浦反应的类型，它们在还详细。重要的是，用于合成，纯化和测试复合物的催化活性的方案一般足够容易地适应新的钯NHC络合物。

<table><tbody><tr><td>1-chloro-4-nitrobenzene</td><td>Sigma-Aldrich (Interlab A.S., USA)</td><td></td><td></td></tr><tr><td>2,5-dimethoxyphenylboronic acid</td><td>Sigma-Aldrich (Interlab A.S., USA)</td><td></td><td></td></tr><tr><td>2-&lt;em&gt;n&lt;/em&gt;-butylfuran</td><td>Sigma-Aldrich (Interlab A.S., USA)</td><td></td><td></td></tr><tr><td>2-&lt;em&gt;n&lt;/em&gt;-butylthiophene</td><td>Sigma-Aldrich (Interlab A.S., USA)</td><td></td><td></td></tr><tr><td>3-chloropyridine</td><td>Merck (Darmstadt, Germany)</td><td></td><td></td></tr><tr><td>4-bromoacetophenone</td><td>Merck (Darmstadt, Germany)</td><td></td><td></td></tr><tr><td>4-bromoanisole</td><td>Sigma-Aldrich (Interlab A.S., USA)</td><td></td><td></td></tr><tr><td>4-chlorotoluene</td><td>Sigma-Aldrich (Interlab A.S., USA)</td><td></td><td></td></tr><tr><td>4-methoxy-1-chlorobenzene</td><td>Merck (Darmstadt, Germany)</td><td></td><td></td></tr><tr><td>4-tert-butylphenylboronic acid</td><td>Sigma-Aldrich (Interlab A.S., USA)</td><td></td><td></td></tr><tr><td>Benzimidazole</td><td>Merck (Darmstadt, Germany)</td><td></td><td></td></tr><tr><td>Bromobenzene</td><td>Merck (Darmstadt, Germany)</td><td></td><td></td></tr><tr><td>Celite</td><td>Merck (Darmstadt, Germany)</td><td></td><td></td></tr><tr><td>Dichloromethane</td><td>Merck (Darmstadt, Germany)</td><td></td><td></td></tr><tr><td>Diethyl ether</td><td>Sigma-Aldrich (Interlab A.S., USA)</td><td></td><td></td></tr><tr><td>Ethyl acetate</td><td>Sigma-Aldrich (Interlab A.S., USA)</td><td></td><td></td></tr><tr><td>Ethyl alcohol</td><td>Merck (Darmstadt, Germany)</td><td></td><td></td></tr><tr><td>Hexane</td><td>Merck (Darmstadt, Germany)</td><td></td><td></td></tr><tr><td>Magnesium sulfate</td><td>Scharlau (Barcelona, Spain)</td><td></td><td></td></tr><tr><td>&lt;em&gt;N,N&lt;/em&gt;-dimethylacetamide</td><td>Merck (Darmstadt, Germany)</td><td></td><td></td></tr><tr><td>&lt;em&gt;N&lt;/em&gt;,&lt;em&gt;N&lt;/em&gt;-dimethylformamide</td><td>Merck (Darmstadt, Germany)</td><td></td><td></td></tr><tr><td>Palladium chloride</td><td>Merck (Darmstadt, Germany)</td><td></td><td></td></tr><tr><td>Phenylboronic acid</td><td>Sigma-Aldrich (Interlab A.S., USA)</td><td></td><td></td></tr><tr><td>Potassium acetate</td><td>Merck (Darmstadt, Germany)</td><td></td><td></td></tr><tr><td>Potassium carbonate</td><td>Scharlau (Barcelona, Spain)</td><td></td><td></td></tr><tr><td>Potassium hydroxide</td><td>Merck (Darmstadt, Germany)</td><td></td><td></td></tr><tr><td>Silica gel</td><td>Merck (Darmstadt, Germany)</td><td></td><td></td></tr><tr><td>Sodium tert-butoxide</td><td>Merck (Darmstadt, Germany)</td><td></td><td></td></tr><tr><td>Thianaphthene-2-boronic acid</td><td>Sigma-Aldrich (Interlab A.S., USA)</td><td></td><td></td></tr></tbody></table>

palladium n-heterocyclic carbene complexes: synthesis from benzimidazolium salts and catalytic activity in carbon-carbon bond-forming reactions

给出了用于合成和随后从苯并咪唑鎓盐中纯化四种钯N-杂环卡宾络合物的详细和一般化方案。还提供了详细的和一般的方案用于测试这种络合物在芳基化和铃木 - Miyaura交叉偶联反应中的催化活性。显示了四种配合物在芳基化和铃木 - 宫崎型反应中的催化活性的代表性结果。对于所研究的每个反应，四种配合物中的至少一种成功地催化了反应，使它们成为催化许多碳 - 碳键形成反应的有希望的候选物。所提出的方案一般足以适应于新的钯N-杂环卡宾络合物的合成，纯化和催化活性测试。

苯并咪唑的盐（1 - 4）（ 图1）在无水DMF使用N- -alkylbenzimidazoles和各种烷基卤化物，然后纯化和表征合成为前18，24日报道。它们是白色或奶油色固体，产率在62％至97％之间。钯络合物NHC（5 - 8）（ 图2）然后，从盐，纯化的合成...

Watch this Scientific Journal Video about Palladium N-Heterocyclic Carbene Complexes: Synthesis from Benzimidazolium Salts and Catalytic Activity in Carbon-carbon Bond-forming Reactions at JoVE.com

Palladium N-Heterocyclic Carbene Complexes: Synthesis from Benzimidazolium Salts and Catalytic Activity in Carbon-carbon Bond-forming Reactions

给出了用于合成和随后从苯并咪唑鎓盐中纯化四种钯N-杂环卡宾络合物的详细和一般化方案。在芳基化和Suzuki-Miyaura反应中测试复合物的催化活性。对于所研究的每个反应，四种配合物中的至少一种成功地催化了反应。

钯<em&gt;ñ</em&gt; - 杂环碳烯配合物:苯并咪唑盐的合成和碳 - 碳键合反应中的催化活性

Detailed and generalized protocols are presented for the synthesis and subsequent purification of four palladium N-heterocyclic carbene complexes from ...

palladium-n-heterocyclic-carbene-complexes-synthesis-from

Universidad de Cartagena UDEC

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Palladium N-Heterocyclic Carbene Complexes: Synthesis from Benzimidazolium Salts and Catalytic Activity in Carbon-carbon Bond-forming Reactions

Chemical Bonding: Basic Concepts

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9.6K 次观看.  The University of Sydney. 给出了用于合成和随后从苯并咪唑鎓盐中纯化四种钯N-杂环卡宾络合物的详细和一般化方案。在芳基化和Suzuki-Miyaura反应中测试复合物的催化活性。对于所研究的每个反应，四种配合物中的至少一种成功地催化了反应。 

视频: Palladium N-Heterocyclic Carbene Complexes: Synthesis from Benzimidazolium Salts and Catalytic Activity in Carbon-carbon Bond-forming Reactions

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 ...

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Amide Coupling Reaction for the Synthesis of Bispyridine-based Ligands and Their Complexation to Platinum as Dinuclear Anticancer Agents

Amide coupling reactions can be used to synthesize bispyridine-based ligands for use as bridging linkers in multinuclear platinum anticancer drugs. Isonicotinic acid, or its derivatives, are coupled to variable length diaminoalkane chains under an inert atmosphere in anhydrous DMF or DMSO with the use of a weak base, triethylamine, and a coupling agent, 1-propylphosphonic anhydride. The products precipitate from solution upon formation or can be precipitated by the addition of water. If desired, the ligands can be further purified by recrystallization from hot water. Dinuclear platinum complex synthesis using the bispyridine ligands is done in hot water using transplatin. The most informative of the chemical characterization techniques to determine the structure and gross purity of both the bispyridine ligands and the final platinum complexes is 1H NMR with particular analysis of the aromatic region of the spectra (7-9 ppm). The platinum complexes have potential application as anticancer agents and the synthesis method can be modified to produce trinuclear and other multinuclear complexes with different hydrogen bonding functionality in the bridging ligand.

This protocol describes the use of amide coupling reactions of isonicotinic acid and diaminoalkanes to form bridging ligands suitable for use in the synthesis of multinuclear platinum complexes, which combine aspects of the anticancer drugs BBR3464 and picoplatin.

酰胺偶联反应为双吡啶基配体及其络合合成，以白金为双核抗癌药物

Amide coupling reactions can be used to synthesize bispyridine-based ligands for use as bridging linkers in multinuclear platinum anticancer drugs. ...

Preparation and Use of Carbonyl-decorated Carbenes in the Activation of White Phosphorus

Here we present a protocol for the synthesis of two distinct carbonyl-decorated carbenes. Both carbenes can be prepared using nearly identical procedures in multi-gram scale quantities. The goal of this manuscript is to clearly detail how to handle and prepare these unique carbenes such that a synthetic chemist of any skill level can work with them. The two carbenes described are a diamidocarbene (DAC, carbene 1) and a monoamidoaminocarbene (MAAC 2). These carbenes are highly electron-deficient and as such display reactivity profiles that are atypical of more traditional N-heterocyclic carbenes. Additionally, these two carbenes only differ in their electrophilic character and not their steric parameters, making them ideal for studying how carbene electronics influence reactivity. To demonstrate this phenomenon, we are also describing the activation of white phosphorus (P4) using these carbenes. Depending on the carbene used, two very different phosphorus-containing compounds can be isolated. When the DAC 1 is used, a tris(phosphaalkenyl)phosphane can be isolated as the exclusive product. Remarkably however, when MAAC 2 is added to P4 under identical reaction conditions, an unexpected carbene-supported P8&#160;allotrope of phosphorus is isolated exclusively. Mechanistic studies demonstrate that this carbene-supported P8allotrope forms via a [2+2] cycloaddition dimerization of a transient diphosphene which has been trapped by treatment with 2,3-dimethyl-1,3-butadiene.

Here, we present a protocol for the synthesis of two carbonyl-decorated carbenes. The protocol makes these interesting compounds readily available to chemists of all skill levels. In addition to the synthesis of these two carbenes, their use in the activation of white phosphorus is also described.

羰基饰卡宾的白色磷的活化制备方法和用途

Here we present a protocol for the synthesis of two distinct carbonyl-decorated carbenes. Both carbenes can be prepared using nearly identical procedures ...

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 ...

Achieving Moderate Pressures in Sealed Vessels Using Dry Ice As a Solid CO2 Source

Herein is presented a general strategy to perform reactions under mild to moderate CO2 pressures with dry ice. This technique obviates the need for specialized equipment to achieve modest pressures, and can even be used to achieve higher pressures in more specialized equipment and sturdier reaction vessels. At the end of the reaction, the vials can be easily depressurized by opening at room temperature. In the present example CO2 serves as both a putative directing group as well as a way to passivate amine substrates, thereby preventing oxidation during the organometallic reaction. In addition to being easily added, the directing group is also removed under vacuum, obviating the need for extensive purification to remove the directing group. This strategy allows the facile &#947;-C(sp3)-H arylation of aliphatic amines and has the potential to be applied to a variety of other amine-based reactions.

Achieving Moderate Pressures in Sealed Vessels Using Dry Ice As a Solid CO2 Source

Here we present a protocol for performing reactions in simple reaction vessels under low-to-moderate pressures of CO2. The reactions can be performed in a variety of vessels simply by administering the carbon dioxide in the form of dry ice, without the need for costly or elaborate equipment or set-ups.

用干冰作为固体 CO2源实现密封容器中的适度压力

Herein is presented a general strategy to perform reactions under mild to moderate CO2 pressures with dry ice. This technique obviates the need for ...

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 ...

Isolating Free Carbenes, their Mixed Dimers and Organic Radicals

Protocols for the isolation of the commonly employed cyclic (alkyl)(amino) carbene (CAAC) and N-heterocyclic carbene (NHC) are reported. Furthermore, the synthesis of their mixed CAAC&#8211;NHC &#8220;Wanzlick&#8221; dimer and the synthesis of the related stable organic &#8220;olefin&#8221; radical are presented. The main goal of this manuscript is to give a detailed and general protocol for the synthetic chemist of any skill level on how to prepare free heterocyclic carbenes by deprotonation using filter cannulas. Due to the air-sensitivity of the synthesized compounds, all experiments are performed under inert atmosphere using either Schlenk technique or a dinitrogen filled glovebox. Controlling Wanzlick&#8217;s equilibrium (i.e., the dimerization of free carbenes), is a crucial requirement for the application of free carbenes in coordination chemistry or organic synthesis. Thus, we elaborate on the specific electronic and steric requirements favoring the formation of dimers, heterodimers, or monomers. We will show how proton catalysis allows for the formation of dimers, and how the electronic structure of carbenes and their dimers affects the reactivity with either moisture or air. The structural identity of the reported compounds is discussed based on their NMR spectra.

We present protocols for the isolation of stable heterocyclic carbenes. The synthesis of a cyclic (alkyl)(amino) carbene (CAAC) and an N-heterocyclic carbene (NHC) is demonstrated using filter cannulas and Schlenk technique. We furthermore present the synthesis of the related oxygen-sensitive, electron-rich mixed &#8220;Wanzlick dimer&#8221; and the reduced stable organic radical.

分离游离卡本内斯、其混合二聚体和有机自由基

Protocols for the isolation of the commonly employed cyclic (alkyl)(amino) carbene (CAAC) and N-heterocyclic carbene (NHC) are reported. Furthermore, the ...

[(DPEPhos)(bcp)Cu]PF6: A General and Broadly Applicable Copper-Based Photoredox Catalyst

Our group recently reported the use of [(DPEPhos)(bcp)Cu]PF6 as a general copper-based photoredox catalyst which proved efficient to promote the activation of a broad variety of organic halides, including unactivated ones. These can then participate in various radical transformations such as reduction and cyclization reactions, as well as in the direct arylation of several (hetero)arenes. These transformations provide a straightforward access to a range of small molecules of interest in synthetic chemistry, as well as to biologically active natural products. Altogether, [(DPEPhos)(bcp)Cu]PF6 acts as a convenient photoredox catalyst which appears to be an attractive, cheap and complementary alternative to the state-of-the-art iridium- and ruthenium-based photoredox catalysts. Here, we report a detailed protocol for the synthesis of [(DPEPhos)(bcp)Cu]PF6, as well as NMR and spectroscopic characterizations, and we illustrate its use in synthetic chemistry for the direct arylation of (hetero)arenes and radical cyclization of organic halides. In particular, the direct arylation of N-methylpyrrole with 4-iodobenzonitrile to afford&#160;4-(1-methyl-1H-pyrrol-2-yl)benzonitrile and the radical cyclization of N-benzoyl-N-[(2-iodoquinolin-3-yl)methyl]cyanamide to afford natural product luotonin A are detailed. The scope and limitations of this copper-based photoredox catalyst are also briefly discussed.

[DPEPhosbcpCu]PF6: A General and Broadly Applicable Copper-Based Photoredox Catalyst

Detailed and general protocols are presented for the synthesis of [(DPEPhos)(bcp)Cu]PF6, a general copper-based photoredox catalyst, and for its use in synthetic chemistry for the direct arylation of C-H bonds in (hetero)arenes and radical cyclization of organic halides.

[(Dpepphos) (bcp) Cu]PF6: 一种通用的、广泛适用的铜基光氧催化剂

Our group recently reported the use of [(DPEPhos)(bcp)Cu]PF6 as a general copper-based photoredox catalyst which proved efficient to promote the ...

Preparation of Silver-Palladium Alloyed Nanoparticles for Plasmonic Catalysis under Visible-Light Illumination

Localized surface plasmon resonance (LSPR) in plasmonic nanoparticles (NPs) can accelerate and control the selectivity of a variety of molecular transformations. This opens possibilities for the use of visible or near-IR light as a sustainable input to drive and control reactions when plasmonic nanoparticles supporting LSPR excitation in these ranges are employed as catalysts. Unfortunately, this is not the case for several catalytic metals such as palladium (Pd). One strategy to overcome this limitation is to employ bimetallic NPs containing plasmonic and catalytic metals. In this case, the LSPR excitation in the plasmonic metal can contribute to accelerate and control transformations driven by the catalytic component. The method reported herein focuses on the synthesis of bimetallic silver-palladium (Ag-Pd) NPs supported on ZrO2 (Ag-Pd/ZrO2) that acts as a plasmonic-catalytic system. The NPs were prepared by co-impregnation of corresponding metal precursors on the ZrO2 support followed by simultaneous reduction leading to the formation of bimetallic NPs directly on the ZrO2 support. The Ag-Pd/ZrO2 NPs were then used as plasmonic catalysts for the reduction of nitrobenzene under 425 nm illumination by LED lamps. Using gas chromatography (GC), the conversion and selectivity of the reduction reaction under the dark and light irradiation conditions can be monitored, demonstrating the enhanced catalytic performance and control over selectivity under LSPR excitation after alloying non-plasmonic Pd with plasmonic metal Ag. This technique can be adapted to a wide range of molecular transformations and NPs compositions, making it useful for the characterization of the plasmonic catalytic activity of different types of catalysis in terms of conversion and selectivity.

Presented here is a protocol for the synthesis of silver-palladium (Ag-Pd) alloy nanoparticles (NPs) supported on ZrO2 (Ag-Pd/ZrO2). This system allows for harvesting energy from visible light irradiation to accelerate and control molecular transformations. This is illustrated by nitrobenzene reduction under light irradiation catalyzed by Ag-Pd/ZrO2 NPs.

在可见光照射下为质子催化准备银-铂合金纳米粒子

Localized surface plasmon resonance (LSPR) in plasmonic nanoparticles (NPs) can accelerate and control the selectivity of a variety of molecular ...

Introduction to Catalysis

Source: Laboratory of Dr. Ryan Richards &#8212; Colorado School of Mines
Catalysis is among the most important fields of modern technology and presently accounts for approximately 35% of the gross domestic product (GDP) and sustenance of approximately 33% of the global population through fertilizers produced via the Haber process.1 Catalysts are systems that facilitate chemical reactions by lowering the activation energy and influencing the selectivity. Catalysis will be a central technology in addressing the energy and environmental challenges of modern times.

Catalysis: Homogeneous and Heterogeneous Catalysts

催化导论

Source: Laboratory of Dr. Ryan Richards &#8212; Colorado School of Mines
Catalysis is among the most important fields of modern technology and presently ...

钯

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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

酰胺偶联反应为双吡啶基配体及其络合合成，以白金为双核抗癌药物

羰基饰卡宾的白色磷的活化制备方法和用途

一系列钌的合成，表征和反应

用干冰作为固体 CO₂源实现密封容器中的适度压力

n-杂环卡本的光生成在光致环开环转移聚合中的应用

分离游离卡本内斯、其混合二聚体和有机自由基

[(Dpepphos) (bcp) Cu]PF₆: 一种通用的、广泛适用的铜基光氧催化剂

在可见光照射下为质子催化准备银-铂合金纳米粒子

催化导论