这项工作得到了美国国家科学基金会化学部的资助，奖励号为CHE-2153240。

1. 设置舒伦克生产线
<ol><li>确保所有水龙头均已关闭，然后使用O形圈将冷阱固定到舒伦克生产线上（我们的设置中使用了229号，尽管尺寸可能因所使用的特定舒伦克生产线而异）并夹紧。</li>
	<li>打开真空泵（气镇关闭），然后打开舒伦克管线的水龙头，使整个设备打开真空。 注意：请勿打开软管的任何水龙头或任何其他对空气开放的水龙头;该设备应为动态真空下的封闭系统。</li>
	<li>等待至少5分钟，舒伦克线的大气被疏散。 注意：一些舒伦克管线可能装有气压计，以确定设备在动态真空下将达到的最低压力。如果在 5 分钟之前已达到该压力，请继续下一步。</li>
	<li>通过在舒伦克系列周围放置一个装满液氮的杜瓦瓶来冷却它的冷阱。在实验过程中用毛巾盖住杜瓦瓶的顶部，减缓液氮的蒸发。 注意：与液氮接触会对皮肤和眼睛造成严重伤害，只能由经过安全使用培训的人员处理。佩戴皮肤和眼睛防护装置。 注意：通常，首先将空杜瓦瓶放在冷阱周围，然后使用第二个杜瓦瓶用液氮填充疏水阀杜瓦瓶会更容易、更安全。</li>
	<li>打开起泡器，使其产生惰性气体（N 2（g）或Ar（g）） 的轻微流动（约3个气泡/秒）。</li>
</ol>2. 测量固体试剂
<ol><li>在反应瓶中加入四（三苯基膦）钯（0）和三苯基膦调节剂。<ol><li>将一张称量纸卷入锥体中用作固体加成漏斗，并将其放入 10 mL 烧瓶的取样口中。确保锥体底部插入的距离足以使其超出软管附件。 注意：使用空的NMR管或类似的小管状物体滚动称量纸有助于达到适合水龙头开口所需的小直径。</li>
		<li>按差异称取四（三苯基膦）钯（0）（0.084 g，0.073 mmol，1 当量）放入 10 mL 烧瓶中。 注意：四（三苯基膦）钯（0）对身体有害，特别是如果吞咽，如果细分散在空气中可能会点燃。避免灰尘形成和各种形式的接触，并穿戴个人防护装备。 注意：可以轻轻敲击烧瓶和称量纸锥，以确保将所有固体转移到烧瓶底部。</li>
		<li>用三苯基膦（1.23克，4.67毫摩尔，64当量）重复步骤2.1.2。 注意：三苯基膦对身体和中枢神经系统有害。避免一切形式的接触，并穿戴个人防护设备，包括耐化学手套。</li>
		<li>处理好称量纸锥，将聚四氟乙烯 （PTFE） 水龙头拧到 10 mL 烧瓶上。</li>
	</ol></li>
	<li>将四位膦接头测量到单独的 10 mL 烧瓶中。<ol><li>用第二个10 mL烧瓶重复步骤2.1.1。</li>
		<li>使用第二个 10 mL 烧瓶，用四位膦接头 Sn1 （0.085 g，0.073 mmol，1 当量）重复步骤 2.1.2。 注意： Sn1 的危险特性是未知的。由于它是Sn（IV）化合物和叔膦，因此假设它具有急性毒性，并避免所有形式的接触。穿戴个人防护装备，包括耐化学手套。</li>
		<li>用第二个10 mL烧瓶重复步骤2.1.4。</li>
	</ol></li>
</ol>3. 将试剂置于惰性气氛下
<ol><li>将舒伦克管线的软管（黑色橡胶真空管，内径 3/16 x 壁厚 3/16）连接到每个 10 mL 烧瓶。</li>
	<li>打开PTFE水龙头，使容器对软管开放。 注意： 如果水龙头打开得太开，则在抽真空过程中可能会将固体拉入软管中。</li>
	<li>将两个 10 mL 烧瓶打开真空。等待5分钟。</li>
	<li>关闭每个 10 mL 烧瓶上的水龙头，然后将每根软管关闭到真空中。将软管切换到惰性气体，然后慢慢打开每个 10 mL 烧瓶上的水龙头，用惰性气体回注。 注意：从真空切换到惰性气体时，请确保惰性气体的气泡流量足够高以防止油被吸入舒伦克管路，但又足够低以不会干扰烧瓶中的固体。切勿同时打开系统以抽真空和惰性气体。</li>
	<li>再重复步骤3.3-3.4两次，总共三个周期。</li>
</ol>4. 在惰性气氛下向试剂中添加溶剂
<ol><li>在足以防止空气进入烧瓶的惰性气体正压下，取出PTFE水龙头，并为每个10 mL烧瓶更换隔膜。</li>
	<li>将甲苯和二氯甲烷加入钯和膦混合物中。<ol><li>使用注射器和针头将 1.5 mL 干燥和脱氧甲苯转移到含有四（三苯基膦）钯 （0） 和三苯基膦的烧瓶中。 注意：甲苯既有毒又易燃。避免一切形式的接触，远离热源，在通风橱中工作，并穿戴个人防护装备。 注意：溶剂可以通过在惰性气体下通过活化的铝柱来干燥，并通过用惰性气体喷射30分钟来脱氧。在抽取溶液之前，请务必用惰性气体吹扫注射器和针头三次。</li>
		<li>用 1.5 mL 干燥和脱氧的二氯甲烷重复步骤 4.2.1。 注意：二氯甲烷有毒且致癌。避免任何形式的接触，在通风橱中工作，并穿戴个人防护装备。</li>
		<li>旋转烧瓶直到所有固体溶解（约30秒）。</li>
	</ol></li>
	<li>将二氯甲烷添加到四位膦接头中。<ol><li>使用注射器和针头将 3.0 mL 干燥和脱氧甲苯转移到含有四位膦接头 Sn1 的烧瓶中。</li>
		<li>旋转烧瓶直到所有固体溶解（约30秒）。</li>
	</ol></li>
</ol>5. 将接头剂添加到钯和膦混合物中
<ol><li>使用注射器和针头将整个 Sn1 接头溶液转移到含有四（三苯基膦）钯（0）和三苯基膦的烧瓶中。</li>
	<li>将溶液旋转30秒以彻底混合，然后在足以防止空气进入烧瓶的惰性气体正压下用PTFE水龙头替换隔膜，并密封烧瓶。</li>
	<li>超声处理（40kHz）反应溶液再30秒。</li>
</ol>6. 加热反应
<ol><li>将密封烧瓶放入60°C的预热油浴中，放置24小时而不搅拌。</li>
</ol>7. 隔离 MOF 产品
<ol><li>从油浴中取出烧瓶，使其冷却至室温。 注意：处理热玻璃器皿和/或表面时，请务必戴上耐热手套。</li>
	<li>使用小型Buchner漏斗和滤纸（8μm孔径）设置真空过滤设备。</li>
	<li>从烧瓶中取出PTFE水龙头，然后使用移液器将悬浮液的总体积转移到过滤器中。 注意：过滤器顶部的惰性气体的轻微流动有助于避免氧敏MOF产品的分解。</li>
	<li>用 2 mL 脱氧 3：1 二氯甲烷/甲苯溶液冲洗固体。再重复此步骤两次，让固体在滤纸上干燥3分钟。</li>
	<li>将固体刮入预先称重的小瓶中，然后称量小瓶以获得 Sn1-Pd的产量。 注意：将LVMOF 材料存放在惰性气体或动态真空下，以避免在空气中有氧气的情况下分解。</li>
</ol>8. 粉末X射线衍射（PXRD）表征MOF产物
<ol><li>将大约20-30mg的结晶固体转移到硅PXRD样品架上。 注意：虽然 Sn1-Pd 在空气中足够稳定，可以通过PXRD进行表征，但对空气更敏感的LVMOF材料可以转移到惰性气氛手套箱中，并装入可密封的毛细管PXRD样品架中。</li>
	<li>将样品架放入衍射仪中，然后关闭仪器的门。</li>
	<li>收集从4到40 2θ的PXRD图谱（扫描速度为0.5 s/步，步长为0.0204° 2θ），并将数据与 Sn1-Pd的模拟粉末图案进行比较。</li>
</ol>

从多主题膦接头合成低价 MOF

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作者没有什么可透露的。

协议中必须遵循几个关键步骤，才能获得具有足够结晶度的所需膦基LVMOF产品。首先是金属前驱体和调节剂混合物（在这种情况下，分别为四（三苯基膦）钯（0）和三苯基膦）必须独立于多主题膦接头（在本例中为 Sn1）溶解。这是为了避免快速和不可逆地形成无定形配位聚合物，当调节剂相对于接头的有效浓度太低或根本不存在调节剂时，就会发生这种情况15。相?...

金属有机骨架（MOF）是一类结晶多孔材料1。MOF由金属离子或金属离子簇节点（通常称为二级建筑单元（SBU））和多主题有机接头构成，以提供二维和三维网络结构2。在过去的三十年中，由于MOFs在气体储存3 和分离4，生物医学5和催化6中的潜在用途，MOFs得到了广泛的研究。报道的绝大多数MOFs由高氧化态金属节点和坚硬的阴离子供体接头组成，例如羧酸盐2。然而，许多均相催化剂利用软的低价金属与软供体配体（如膦7）结合使用。因此，扩大含有低价金属的MOF的范围可以增加MOFs可以应用的催化转化范围。
使用嵌入软供体位点将低价金属掺入MOFs的既定策略范围有限，并且减少了母体MOF结构6，8，9，10的自由孔体积。另一种方法是直接使用低价金属作为节点或SBU，结合多主题软供体配体作为接头来构建MOF。该策略不仅在MOF中提供了低价金属位点的高负载量，而且由于框架结构的稳定性，还可以减少或防止金属浸入溶液中11。例如，Figueroa及其同事使用多位异腈配体作为软供体接头，使用Cu（I）12或Ni（0）13作为低价金属节点来产生二维和三维MOF。同样，Pederson及其同事使用吡嗪作为接头14合成了含有零价基团6金属节点的MOF。最近，我们的实验室报道了四位膦配体作为构建含有Pd（0）或Pt（0）节点的MOF的接头（图1）15。由于磷化氢连接低价金属配合物在均相催化中普遍存在，这些MOFs特别有趣7。然而，低价MOFs（LVMOFs）作为一类通用材料在MOF文献中的探索相对不足，但在叠氮化物-炔烃偶联16、铃木-宫浦偶联17，18、加氢17等反应的非均相催化中具有很大的应用前景11。
<img alt="Figure 1" class="xfigimg" src="/files/ftp_upload/65317/65317fig01v2.jpg"> 图1：使用磷化氢接头合成LVMOF。 Sikma和Cohen15 报道了三维LVMOFs的合成， E1-M使用四位膦配体E1作为接头， Pd（0）和Pt（0）作为节点，三苯基膦作为调节剂。中心原子 E可以是Si或Sn. <a href="https://www.jove.com/files/ftp_upload/65317/65317fig01largev2.jpg" target="_blank">请点击这里查看此图的大图。</a>
虽然与传统MOF材料相比，LVMOF接头和节点的性质差异可能赋予它们独特的性能，但这些差异也带来了合成挑战。例如，MOF文献中常用的许多金属前驱体和接头可用于空气2。相比之下，成功合成基于磷化氢的LVMOF需要排除空气和水15。同样，与大多数MOF文献中使用的调节剂类型相比，用于促进结晶度的调节剂类型和用于合成膦基LVMOF的溶剂是不寻常的15。因此，这些材料的合成需要设备和实验技术，即使是经验丰富的MOF化学家也可能不太熟悉。因此，为了尽量减少这些障碍的影响，这里提供了一种合成这种新型材料的分步方法。这里概述的方案涵盖了合成磷化氢基LVMOF的所有方面，包括整体实验程序，无空气技术，所需设备，LVMOF的正确储存和处理以及表征方法。还讨论了金属前驱体、调节剂和溶剂的选择。使新研究人员能够进入该领域将有助于加速发现用于催化应用的新型LVMOF和相关材料。

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>2800 Ultrasonic Cleaner, 3/4 Gallon, 40 kHz</td>
			<td>Branson</td>
			<td>CPX2800H</td>
			<td>Used for sonicating</td>
		</tr>
		<tr>
			<td>Argon, Ultra High Purity</td>
			<td>Matheson</td>
			<td>G1901101</td>
			<td>Used as inert gas source</td>
		</tr>
		<tr>
			<td>D8 ADVANCE Powder X-Ray Diffractometer</td>
			<td>Bruker</td>
			<td></td>
			<td>Used to collect PXRD patterns</td>
		</tr>
		<tr>
			<td>Dewar Flask</td>
			<td>Chemglass Life Sciences</td>
			<td>CG159303</td>
			<td>Dewar used for liquid nitrogen</td>
		</tr>
		<tr>
			<td>Flask,&#160;High Vacuum Valve, Capacity (mL) 10, Valve Size 0-4 mm</td>
			<td>Synthware Glass</td>
			<td>F490010</td>
			<td>Reaction vessel referred to as &#34;10 mL flask&#34;</td>
		</tr>
		<tr>
			<td>Grade 2 Qualitative Filter Paper, Standard, 42.5 mm circle</td>
			<td>Whatman</td>
			<td>1002-042</td>
			<td>Used for product isolation</td>
		</tr>
		<tr>
			<td>Methylene Chloride (HPLC)</td>
			<td>Fisher Scientific</td>
			<td>MFCD00000881</td>
			<td>Dried and deoxygenated prior to use</td>
		</tr>
		<tr>
			<td>Sn1 (tetratopic phosphine linker)</td>
			<td></td>
			<td></td>
			<td>Prepared according to literature procedure (ref. 15)</td>
		</tr>
		<tr>
			<td>SuperNuova+ Stirring Hotplate</td>
			<td>Thermo Fisher Scientific</td>
			<td>SP88850190</td>
			<td>Used to heat oil bath</td>
		</tr>
		<tr>
			<td>Tetrakis(triphenylphosphine) palladium(0), 99% (99.9+%-Pd)</td>
			<td>Strem Chemicals</td>
			<td>46-2150</td>
			<td>Commercial Pd(0) source</td>
		</tr>
		<tr>
			<td>Toluene (HPLC)</td>
			<td>Fisher Scientific</td>
			<td>MFCD00008512</td>
			<td>Dried and deoxygenated prior to use</td>
		</tr>
		<tr>
			<td>Triphenylphosphine, &#8805;95.0% (GC)</td>
			<td>Sigma-Aldrich</td>
			<td>93092</td>
			<td>Used as a modulator</td>
		</tr>
		<tr>
			<td>Weighing Paper</td>
			<td>Fisher Scientific</td>
			<td>09-898-12B</td>
			<td>Used for solid addition</td>
		</tr>
	</tbody>
</table>

experimental approaches for the synthesis of low-valent metal-organic frameworks from multitopic phosphine linkers

金属有机骨架（MOF）因其在气体储存和分离、生物医学、能源和催化方面的潜在应用而成为人们关注的焦点。最近，人们探索了低价MOFs（LVMOFs）作为非均相催化剂的潜在用途，多位磷化氢接头已被证明是形成LVMOF的有用构建块。然而，使用磷化氢接头合成LVMOF需要与大多数MOF合成文献不同的条件，包括排除空气和水以及使用非常规调节剂和溶剂，这使得获取这些材料更具挑战性。这项工作是用磷化氢接头合成LVMOF的一般教程，包括以下内容的信息：1）金属前驱体、调节剂和溶剂的明智选择;2）实验程序、无气技术和所需设备;3）正确储存和处理由此产生的LVMOF;4）这些材料的有用表征方法。本报告的目的是降低MOF研究这一新子领域的门槛，并促进新型催化材料的进步。

Metal-organic frameworks, or MOFs, are a class of crystalline, porous materials1. MOFs are constructed from metal ions or metal ion cluster nodes, often referred to as secondary building units (SBUs), and multitopic organic linkers to give two- and three-dimensional network structures2. Over the past three decades, MOFs have been studied extensively due to their potential use in gas storage3 and separation4, biomedicine5, and catalysis6. The overwhelming majority of MOFs reported are composed of high-oxidation state metal nodes and hard, anionic donor linkers, such as carboxylates2. However, many homogeneous catalysts utilize soft, low-valent metals in combination with soft donor ligands, such as phosphines7. Therefore, expanding the scope of MOFs that contain low-valent metals can increase the range of catalytic transformations to which MOFs can be applied.
The established strategies for the incorporation of low-valent metals into MOFs using embedded soft donor sites are limited in scope and reduce the free pore volume of the parent MOF structure6,8,9,10. An alternative approach is to use low-valent metals directly as nodes or SBUs in combination with multitopic soft donor ligands as linkers to construct the MOF. This strategy not only provides a high loading of low-valent metal sites in the MOF but may also reduce or prevent metal leaching into the solution as a result of the stability of the framework structure11. For example, Figueroa and co-workers used multitopic isocyanide ligands as soft donor linkers and Cu(I)12 or Ni(0)13 as low-valent metal nodes to produce two- and three-dimensional MOFs. Similarly, Pederson and co-workers synthesized MOFs containing zero-valent group 6 metal nodes using pyrazine as a linker14. More recently, our laboratory reported tetratopic phosphine ligands as linkers for the construction of MOFs containing Pd(0) or Pt(0) nodes (Figure 1)15. These MOFs are particularly interesting due to the prevalence of phosphine-ligated low-valent metal complexes in homogeneous catalysis7. Nevertheless, low-valent MOFs (LVMOFs) as a general class of materials are relatively underexplored in the MOF literature but have great promise for applications in heterogeneous catalysis for reactions such as azide-alkyne coupling16, Suzuki-Miyaura coupling17,18, hydrogenation17, and others11.
<img alt="Figure 1" class="xfigimg" src="/files/ftp_upload/65317/65317fig01v2.jpg" /> 
Figure 1: Synthesis of LVMOFs using phosphine linkers. Sikma and Cohen15 reported the synthesis of three-dimensional LVMOFs, E1-M, using tetratopic phosphine ligands, E1, as linkers, Pd(0) and Pt(0) as nodes, and triphenylphosphine as a modulator. The central atom, E, can be Si or Sn. <a href="https://www.jove.com/files/ftp_upload/65317/65317fig01largev2.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
While the differences in the nature of the linkers and nodes of LVMOFs may give them unique properties compared to conventional MOF materials, these differences also introduce synthetic challenges. For example, many of the metal precursors and linkers that are commonly used in the MOF literature can be used in air2. In contrast, the successful synthesis of phosphine-based LVMOFs requires the exclusion of both air and water15. Similarly, the types of modulators used to promote crystallinity and the solvents used in the synthesis of phosphine-based LVMOFs are unusual compared to those used in most of the MOF literature15. As a result, the synthesis of these materials requires equipment and experimental techniques that even experienced MOF chemists may be less familiar with. Therefore, in an effort to minimize the impact of these obstacles, a step-by-step method for the synthesis of this new class of materials is provided here. The protocol outlined here covers all aspects of the synthesis of phosphine-based LVMOFs, including the overall experimental procedure, air-free techniques, the required equipment, the proper storage and handling of LVMOFs, and characterization methods. The choice of the metal precursor, modulator, and solvent are also discussed. Enabling the entry of new researchers into this field will help accelerate the discovery of novel LVMOFs and related materials for applications in catalysis.

作者聚焦：从多主题膦接头合成低价金属有机框架的实验方法  

多位膦接头合成低价金属有机骨架的实验方法

Our research aims to explore the synthesis and properties of metal organic frameworks constructed from low-valent metal ions. How to prepare these materials and their characteristics are not widely understood, but they likely hold tremendous opportunities for solid-state catalysis and other applications. Beyond our own work, there have been only a handful of reports on MOFs prepared from low-valent metal ions.Perhaps the most notable are those by Professor Joshua Figueroa here at UC San Diego who has described MOFs prepared from bulky isocyanate ligands and zero or monovalent metals. Because there are so few descriptions of low-valent MOFs, our protocol is providing a first baseline protocol that works for making these materials. That stated, our protocol is specifically designed for phosphine ligands and may not be readily translatable to different ligand systems such as isocyanates.Our findings open up opportunities to explore MOF materials with distinct characteristics from most MOFs described to date. For example, we have a new paper in press reporting a solid-state analog of Vaska's complex, which binds oxygen reversibly in a unique manner compared to the few other MOFs that do this. We are interested in opening up new opportunities to make low-valent MOFs, particularly as new solid-state catalysts.We want to answer questions such as:What other low-valent metal ions can be used to make LV MOFs, and can we mimic the reactivity of low-valent compounds using these solid-state materials?

成功合成Sn1-Pd产生亮黄色结晶固体。使用类似四位膦接头的Pd（0）MOF产物也是黄色的。确定反应是否成功的最有效方法是收集PXRD图谱并评估样品的结晶度。例如，图2显示了晶体Sn1-Pd的PXRD图谱。验证样品是否结晶的关键特征是反射峰相对尖锐且基线平坦。峰展宽通常表示无定形材料。为了说明这一点，图3显示了Sn1-Pd</stro...

Watch this Scientific Journal Video about Experimental Approaches for the Synthesis of Low-Valent Metal-Organic Frameworks from Multitopic Phosphine Linkers at JoVE.com

在这里，我们描述了在无空气条件下从低价金属和多主题磷化氢接头合成低价金属有机框架（LVMOF）的方案。所得材料作为模拟低价金属基均相催化剂的多相催化剂具有潜在的应用前景。

Metal-organic frameworks (MOFs) are the subject of intense research focus due to their potential applications in gas storage and separation, biomedicine, ...

我们的研究旨在探索由低价金属离子构建的金属有机骨架的合成和性质。如何制备这些材料及其特性尚未得到广泛了解，但它们可能为固态催化和其他应用提供了巨大的机会。除了我们自己的工作之外，只有少数关于由低价金属离子制备的MOF的报告。也许最值得注意的是加州大学圣地亚哥分校的Joshua Figueroa教授的那些，他描述了由笨重的异氰酸酯配体和零价或一价金属制备的MOF。由于对低价MOF的描述很少，我们的协议提供了用于制造这些材料的第一个基线协议。也就是说，我们的方案是专门为磷化氢配体设计的，可能不容易转化为不同的配体系统，如异氰酸酯。我们的发现为探索具有与迄今为止描述的大多数MOF不同特征的MOF材料提供了机会。例如，我们有一篇新论文报道了Vaska复合物的固态类似物，与其他少数这样做的MOF相比，它以独特的方式可逆地结合氧气。我们有兴趣为制造低价MOFs开辟新的机会，特别是作为新的固态催化剂。我们想回答这样的问题：还有哪些低价金属离子可以用来制造LV MOF，我们是否可以使用这些固态材料模拟低价化合物的反应性？

experimental-approaches-for-synthesis-low-valent-metal-organic

Research

JoVE Journal

Chemistry

Experimental Approaches for the Synthesis of Low-Valent Metal-Organic Frameworks from Multitopic Phosphine Linkers

1.4K 次观看.  University of California, San Diego. 我们的研究旨在探索由低价金属离子构建的金属有机骨架的合成和性质。如何制备这些材料及其特性尚未得到广泛了解，但它们可能为固态催化和其他应用提供了巨大的机会。除了我们自己的工作之外，只有少数关于由低价金属离子制备的MOF的报告。也许最值得注意的是加州大学圣地亚哥分校的Joshua Figueroa教授的那些，他描述了由笨重的异氰酸酯配体和零价或一价金属?...