我们承认来自情报局 (ANR-15-CE29-0020-01, 活动), CNRS, ICMR, 大学 de 兰斯香槟住宿, ENSCM 和 ICGM 的财政支持。我们感谢卡琳马查多和安东尼. 罗伯特的帮助与磁共振和核磁共振分析。

1. Glovebox 外的起始材料的制备
<ol><li>准备必要的设备: 用磁力搅拌棒、真空/惰性气体线 (氩或氮气) 和磁力搅拌器的烘箱干 Schlenk 管。</li>
	<li>根据文献13准备 trifluoromethylated benzofulvene。</li>
	<li>称量出 trifluoromethylated benzofulvene (177 毫克, 0.65 毫摩尔), 并加入一个烤箱干燥 Schlenk 管配备了磁力搅拌棒。</li>
	<li>用带有聚四氟乙烯衬垫的塑料螺钉盖关闭 Schlenk 管, 并连接至真空线。</li>
	<li>开始搅拌和应用真空干燥 benzofulvene 10 分钟。然后, 用氩/氮气释放真空, 再应用真空。重复此过程3次。最后, 用氩/氮气填充 Schlenk 管, 并紧密地关闭。</li>
	<li>把 Schlenk 管放在氩/氮气的手套盒里。</li>
</ol>2. Glovebox 内新提交的镝金属的制备
<ol><li>准备必要的设备: 用称量天平、金属锉、钳子、铝箔、镊子、刮刀、试管和2橡胶隔膜在氩/氮气下的手套箱。</li>
	<li>制备化学品: 金属镝和无水 AlCl3
</li>
	<li>插入 Schlenk 管与 benzofulvene, 试管和2橡胶隔膜进入 glovebox 根据您的小组的一般做法为处理 glovebox,例如,为一个小房间应用真空1分钟然后释放与氩/氮气三次。</li>
	<li>把一块铝箔放在天平上, 一张放到 glovebox 地板上的盘子上, 以便归档。</li>
	<li>在钳子的帮助下紧紧地握住镝金属, 并通过用金属锉锉来获得光亮的金属表面, 从而去除上面不活跃的层。扔掉这个金属。 注: (1) 使用大型金属件进行归档, 避免钳和文件之间的接触, 以免污染镝金属与其他金属。(2) 对每种镧系金属使用不同的金属文件, 以避免交叉污染。(3) 废弃金属粉末应在手套箱外单独淬火, 使用 dil. HCl 溶液。 注意: 镝与蒽醌的反应是放热的, 产生氢气, 因此在被冰浴包围的开瓶中淬火镝。</li>
	<li>准备新提交的镝金属 (82 毫克, 0.50 毫摩尔), 添加到 Schlenk 管, 并关闭管与橡胶隔膜。</li>
	<li>将无水 AlCl3 (200 毫克, 1.5 毫摩尔) 称量成试管, 用橡胶隔膜关闭管。</li>
	<li>从手套箱中取出 Schlenk 管和试管。</li>
</ol>3. 在 Glovebox 外启动 C F 活化反应
<ol><li>准备必要的设备: 真空/惰性气体线 (氩或氮气), 磁性搅拌器和干2毫升注射器与针。</li>
	<li>准备化学品: 新鲜蒸馏干 THF 和碘。</li>
	<li>将 Schlenk 管夹在磁搅拌器上方的通风罩内, 并连接至真空线。在氩/氮气的正流动下打开 Schlenk 管前, 执行三次真空/惰性气体循环。启动磁力搅拌器。</li>
	<li>用 AlCl3在通风罩中夹住试管, 在氩/氮气的正流动下通过针连接到惰性气体线。</li>
	<li>在正氩/氮气流下加入催化量的碘 (10-12 毫克) 到 Schlenk 管。</li>
	<li>用针在氩/氮气下清除干2毫升注射器</li>
	<li>服用1.5 毫升新鲜蒸馏干 THF 使用清除注射器和增加0.5 毫升到 Schlenk 管获得一个深褐色溶液 (碘的颜色在 THF)。</li>
	<li>将剩余的1.0 毫升 THF 滴到试管中, AlCl3, 这将导致轻微的黄色溶液。 注: 根据 AlCl3的质量, 添加 THF 可以或多或少放热。</li>
	<li>虽然仍然温暖, 转移这个 AlCl3解决方案从试管到 Schlenk 管使用注射器。</li>
	<li>允许反应搅拌, 直到充分消耗 benzofulvene。最初, 深褐色的颜色将消失, 给一个黄色的解决方案, 随着时间的推移将变成一个深绿色混浊的解决方案。</li>
	<li>在氩/氮的正流动下, 用毛细管将反应混合物的样品取样, 检查1小时后薄层层析 (TLC) 的反应。以石油醚为淋洗。 注: 在薄层色板上的起始 benzofulvene 为亮黄色, 可轻易观察到其消失。</li>
</ol>4. 添加 Nitroalkene
<ol><li>根据文献16准备 4-methoxyphenylnitroalkene。</li>
	<li>在试管中称 4-methoxyphenylnitroalkene (90 毫克, 0.50 毫摩尔), 用橡胶塞子关闭管子, 通过针连接将其干燥在真空线上。</li>
	<li>在反应混合物中 benzofulvene 消失后 (经薄层分析证实), 在氩/氮正流动下加入干 nitroalkene Schlenk 管。反应混合物会改变颜色为黄绿色。</li>
	<li>监测反应的薄层色谱分析, 直到充分消耗的 nitroalkene (通常1小时)。以石油醚/乙酸乙酯95/5 为淋洗。</li>
</ol>5. 检查和纯化
<ol><li>用20毫升乙醚稀释反应混合物, 在开 Schlenk 管中用5毫升1摩尔水溶液将其淬火。 注意: 残余镝与蒽醌的反应是放热的, 产生氢气, 这可能会导致 Schlenk 中的压力积聚。因此, 在良好的油烟罩下, 在开 Schlenk 中淬火反应。</li>
	<li>淬火后的反应, 转移到一个部位漏斗。</li>
	<li>在锥形瓶中收集有机相。用10毫升乙醚洗涤水相2次, 在锥形瓶中收集有机相。</li>
	<li>干燥的有机相超过 MgSO4, 过滤成一个预称量瓶, 并集中在减少压力的旋转蒸发器, 以获得原油产品作为一个橙色棕油。</li>
	<li>以石油醚为淋洗, 用硅凝胶柱层析法提纯粗品, 去除非极性水解产物。增加极性高达10/1 石油醚/乙酸乙酯给新的含硝基的 difluoroalkenes。 注意: 在长柱上执行柱层析和缓慢增加极性时, 可以将 diastereoisomers 分离, 以供分析之用。</li>
</ol>

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作者没有什么可透露的。

该协议涉及高反应性, 空气和湿度敏感的镧系金属的工作。因此, 整个反应过程必须在干惰性气体下进行, 所有起动材料, 包括溶剂, 在使用前必须非常干净和干燥。
在购买已提交的金属方面有两个好处: (一) 采购件或锭的经济大大增加, (二) 新提交的金属由于表面钝化造成的减少而更具反应性。由储存的金属。
所述过程有两个主要的关键步骤: (i) 通过提交?...

自二十世纪七十年代代末以来, 稀土金属在有机合成中已被零星使用。最初, 这些强还原剂, 其氧化还原电位在约-2.3 V 的3 +/里, 主要用于桦木型的芳香化合物的减少和频哪醇偶联反应。二十世纪八十年代对稀土金属的可用性和纯度的提高, 以及开发处理空气和湿气敏感化合物的方法和设备, 导致了稀土金属的新应用。直接从 Sm 金属和 diiodoethane 或碘中广泛使用的 SmI2的制备是镧系化学2的突破。近年来, 对镧系金属的新的反应性模式进行了描述, 例如, 烯卤化物与羰基化合物的 Barbier 型反应,包括二芳基酮4或酰的还原偶联反应。氯化物5, 选择性环丙烷化反应6, 和镧系金属的组合4茂金属7,8。这些研究表明, 镧系金属具有很好的功能基团耐受性, 它们的反应能力会随稀土系列的不同而变化, 使它们成为有机转化过程中微调反应条件的合适试剂。
在40年9、10、11的芳香和脂肪族碳氟键的活化反应中, 研究了 Organolanthanide 配合物和无机镧系盐。在 2014年, 第一次报告的 C F 活化使用元素镱金属出现12。它显示了 Yb 与 pentafluorobenzene 的选择性反应, 以支付 tetrafluorobenzene 和 YbF2。最近, 我们已经表明, 各种镧系金属可以与 trifluoromethylated benzofulvenes 在氯化铝的存在, 以获得ε, difluoropentadienylmetal 络合物, 有选择地反应与广泛的醛, 以新的difluoroalkenes (图 1)13。结果表明, 金属镝和氯化铝的结合给出了最高的产量和最佳的选择性。我们在这里提出了这项工作的扩展使用 nitroalkenes 作为 electrophiles14, 导致 regioselectively 到一个新的类 difluoroalkenes15。

<table border="0" cellpadding="0" cellspacing="0" width="626">
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Dysprosium ingot</td>
			<td style="width:124px;">Strem</td>
			<td style="width:119px;">93-6637</td>
			<td style="width:167px;">Store under nitrogen/argon</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Anhydrous aluminum chloride</td>
			<td style="width:124px;">Alfa Aesar</td>
			<td style="width:119px;">88488</td>
			<td>Store under nitrogen/argon</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Iodine 99.5% for analysis</td>
			<td style="width:124px;">Across Organics</td>
			<td>212491000</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">THF GPR Rectapur</td>
			<td style="width:124px;">VWR Chemicals</td>
			<td style="width:119px;">28552.324</td>
			<td>Dried and distilled over Na/benzophenone before use</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Glovebox</td>
			<td style="width:124px;">MBraun</td>
			<td style="width:119px;"></td>
			<td>Under nitrogen atmosphere</td>
		</tr>
	</tbody>
</table>

application of elemental lanthanides in the selective c-f activation of trifluoromethylated benzofulvenes providing access to various difluoroalkenes

在 polyfluorinated 芳香分子中或在含三氟甲基基板上选择性活化一碳-氟键, 可获得具有独特含氟分子的可能性, 而其他合成通路。在各种金属中, 可以通过 C f 活化, 镧 (ln) 是良好的候选, 因为它们形成了强大的 F 型债券。镧系金属是具有氧化还原电位的强还原剂, 在约-2.3 V 的3 +/中, 可与镁2 +/毫克氧化还原偶的值相媲美。此外, 镧系金属具有很好的功能基团耐受性, 它们的活性可以随稀土系列的不同而变化, 使它们适合于有机和金属化转化过程中微调反应条件的合适试剂。然而, 由于他们的 oxophilicity, 镧反应容易与氧气和水, 因此需要特殊条件的储存, 处理, 准备和活化。这些因素限制了在有机合成中的广泛应用。在这里, 我们介绍了金属镝是如何使用 glovebox 和 Schlenk 技术在无水条件下进行新鲜制备的。新提交的金属与氯化铝结合, 在 trifluoromethylated benzofulvenes 启动选择性的 C F 活化。由此产生的反应中间体与 nitroalkenes 反应, 以获得一个新的 difluoroalkenes 家族。

这种镧系介导的 C F 活化过程随后与 nitroalkenes 的反应, 可以方便地进入含有硝基基团的新 difluoroalkenes。图 2描述了一个看似合理的反应机制。与我们以前的工作使用醛作为 electrophiles (图 1)13, nitroalkenes 支付 13-disubstituted 茚产品 regioselectively。这可能是由 nitroalkene 组的较大空间体积来解释的。
<p class="jove_conte...

Watch this Scientific Journal Video about Application of Elemental Lanthanides in the Selective C-F Activation of Trifluoromethylated Benzofulvenes Providing Access to Various Difluoroalkenes at JoVE.

Application of Elemental Lanthanides in the Selective C-F Activation of Trifluoromethylated Benzofulvenes Providing Access to Various Difluoroalkenes

本协议描述了惰性气氛下元素镧的制备及其在含有 trifluoromethylated benzofulvenes 的选择性 C F 活化过程中的应用。

元素镧在选择性 c-F 活化 Trifluoromethylated Benzofulvenes 中的应用提供各种 Difluoroalkenes 的访问

The selective activation of one carbon-fluorine bond in polyfluorinated aromatic molecules or in trifluoromethyl-containing substrates offers the ...

application-elemental-lanthanides-selective-c-f-activation

Universidad de Cartagena UDEC

Research

JoVE Journal

Chemistry

6.4K 次观看.  Université de Reims Champagne Ardenne. 本协议描述了惰性气氛下元素镧的制备及其在含有 trifluoromethylated benzofulvenes 的选择性 C F 活化过程中的应用。

视频: Application of Elemental Lanthanides in the Selective C-F Activation of Trifluoromethylated Benzofulvenes Providing Access to Various Difluoroalkenes

Synthesis of Hypervalent Iodonium Alkynyl Triflates for the Application of Generating Cyanocarbenes

The procedures described in this article involve the synthesis and isolation of hypervalent iodonium alkynyl triflates (HIATs) and their subsequent reactions with azides to form cyanocarbene intermediates. The synthesis of hypervalent iodonium alkynyl triflates can be facile, but difficulties stem from their isolation and reactivity. In particular, the necessity to use filtration under inert atmosphere at -45 &deg;C for some HIATs requires special care and equipment. Once isolated, the compounds can be stored and used in reactions with azides to form cyanocarbene intermediates. 
The evidence for cyanocarbene generation is shown by visible extrusion of dinitrogen as well as the characterization of products that occur from O-H insertion, sulfoxide complexation, and cyclopropanation. A side reaction of the cyanocarbene formation is the generation of a vinylidene-carbene and the conditions to control this process are discussed. There is also potential to form a hypervalent iodonium alkenyl triflate and the means of isolation and control of its generation are provided. The O-H insertion reaction involves using a HIAT, sodium azide or tetrabutylammonium azide, and methanol as solvent/substrate. The sulfoxide complexation reaction uses a HIAT, sodium azide or tetrabutylammonium azide, and dimethyl sulfoxide as solvent. The cyclopropanations can be performed with or without the use of solvent. The azide source must be tetrabutylammonium azide and the substrate shown is styrene.

Herein is described the synthesis, isolation, and reactions of hypervalent iodonium alkynyl triflates (HIATs) with azides to generate cyanocarbenes. The procedures will involve air-sensitive and cryogen techniques, including cold filtration under an inert atmosphere. Handling and safety of the synthesized compounds will also be discussed.

高价碘鎓炔基三氟甲磺酸酯的生成Cyanocarbenes的合成应用

The procedures described in this article involve the synthesis and isolation of hypervalent iodonium alkynyl triflates (HIATs) and their subsequent ...

科研

化学

Retropinacol/Cross-pinacol Coupling Reactions - A Catalytic Access to 1,2-Unsymmetrical Diols

Unsymmetrical 1,2-diols are hardly accessible by reductive pinacol coupling processes. A successful execution of such a transformation is bound to a clear recognition and strict differentiation of two similar carbonyl compounds (aldehydes &#8594; secondary 1,2-diols or ketones &#8594; tertiary 1,2-diols). This fine-tuning is still a challenge and an unsolved problem for an organic chemist. There exist several reports on successful execution of this transformation but they cannot be generalized. Herein we describe a catalytic direct pinacol coupling process which proceeds via a retropinacol/cross-pinacol coupling sequence. Thus, unsymmetrical substituted 1,2-diols can be accessed with almost quantitative yields by means of an&#160;operationally simple performance under very mild conditions. Artificial techniques, such as syringe-pump techniques or delayed additions of reactants are not necessary. The procedure we describe provides a very rapid access to cross-pinacol products (1,2-diols, vicinal diols). A further extension of this new process, e.g. an enantioselective performance could provide a very useful tool for the synthesis of unsymmetrical chiral 1,2-diols.

A novel account for the synthesis of unsymmetrical 1,2-diols based on a retropinacol/cross-pinacol coupling mechanism is described. Due to the catalytic execution of this reaction a considerable improvement compared to conventional cross-pinacol couplings is achieved.

Retropinacol /跨频哪醇偶联反应 - 催化访问1,2  - 非对称二醇

Unsymmetrical 1,2-diols are hardly accessible by reductive pinacol coupling processes. A successful execution of such a transformation is bound to a clear ...

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 ...

Assessment of Boron Doped Diamond Electrode Quality and Application to In Situ Modification of Local pH by Water Electrolysis

Boron doped diamond (BDD) electrodes have shown considerable promise as an electrode material where many of their reported properties such as extended solvent window, low background currents, corrosion resistance, etc., arise from the catalytically inert nature of the surface. However, if during the growth process, non-diamond-carbon (NDC) becomes incorporated into the electrode matrix, the electrochemical properties will change as the surface becomes more catalytically active. As such it is important that the electrochemist is aware of the quality and resulting key electrochemical properties of the BDD electrode prior to use. This paper describes a series of characterization steps, including Raman microscopy, capacitance, solvent window and redox electrochemistry, to ascertain whether the BDD electrode contains negligible NDC i.e. negligible sp2 carbon. One application is highlighted which takes advantage of the catalytically inert and corrosion resistant nature of an NDC-free surface i.e. stable and quantifiable local proton and hydroxide production due to water electrolysis at a BDD electrode. An approach to measuring the local pH change induced by water electrolysis using iridium oxide coated BDD electrodes is also described in detail.

Assessment of Boron Doped Diamond Electrode Quality and Application to In Situ Modification of Local pH by Water Electrolysis

A protocol is described for the characterization of the key electrochemical parameters of a boron doped diamond (BDD) electrode and subsequent application for in situ pH generation experiments.

掺硼金刚石电极质量和应用，以评估<em&gt;原位</em&gt;本地pH值通过水电改造

Boron doped diamond (BDD) electrodes have shown considerable promise as an electrode material where many of their reported properties such as extended ...

Synthesis of Protein Bioconjugates via Cysteine-maleimide Chemistry

The chemical linking or bioconjugation of proteins to fluorescent dyes, drugs, polymers and other proteins has a broad range of applications, such as the development of antibody drug conjugates (ADCs) and nanomedicine, fluorescent microscopy and systems chemistry. For many of these applications, specificity of the bioconjugation method used is of prime concern. The Michael addition of maleimides with cysteine(s) on the target proteins is highly selective and proceeds rapidly under mild conditions, making it one of the most popular methods for protein bioconjugation.
We demonstrate here the modification of the only surface-accessible cysteine residue on yeast cytochrome c with a ruthenium(II) bisterpyridine maleimide. The protein bioconjugation is verified by gel electrophoresis and purified by aqueous-based fast protein liquid chromatography in 27% yield of isolated protein material. Structural characterization with MALDI-TOF MS and UV-Vis is then used to verify that the bioconjugation is successful. The protocol shown here is easily applicable to other cysteine - maleimide coupling of proteins to other proteins, dyes, drugs or polymers.

Synthesis of Protein Bioconjugates via Cysteine-maleimide Chemistry

This protocol details the important steps required for the bioconjugation of a cysteine containing protein to a maleimide, including reagent purification, reaction conditions, bioconjugate purification and bioconjugate characterization.

蛋白质生物缀合物的合成<em&gt;通过</em&gt;半胱氨酸马来酰亚胺化学

The chemical linking or bioconjugation of proteins to fluorescent dyes, drugs, polymers and other proteins has a broad range of applications, such as the ...

Sulfate Separation by Selective Crystallization with a Bis-iminoguanidinium Ligand

A simple and effective method for selective sulfate separation from aqueous solutions by crystallization with a bis-guanidinium ligand, 1,4-benzene-bis(iminoguanidinium) (BBIG), is demonstrated. The ligand is synthesized as the chloride salt (BBIG-Cl) by in situ imine condensation of terephthalaldehyde with aminoguanidinium chloride in water, followed by crystallization as the sulfate salt (BBIG-SO4). Alternatively, BBIG-Cl is synthesized ex situ in larger scale from ethanol. The sulfate separation ability of the BBIG ligand is demonstrated by selective and quantitative crystallization of sulfate from seawater. The ligand can be recycled by neutralization of BBIG-SO4 with aqueous NaOH and crystallization of the neutral bis-iminoguanidine, which can be converted back into BBIG-Cl with aqueous HCl and reused in another separation cycle. Finally, 35S-labeled sulfate and &#946; liquid scintillation counting are employed for monitoring the sulfate concentration in solution. Overall, this protocol will instruct the user in the necessary skills to synthesize a ligand, employ it in the selective crystallization of sulfate from aqueous solutions, and quantify the separation efficiency.

A protocol for in situ aqueous synthesis of a bis(iminoguanidinium) ligand and its utilization in selective separation of sulfate is presented.

分离硫酸选择性结晶用双 -  iminoguanidinium配体

A simple and effective method for selective sulfate separation from aqueous solutions by crystallization with a bis-guanidinium ligand, ...

Application and Methodology of the Non-destructive 19F Time-domain NMR Technique to Measure the Content in Fluorine-containing Drug Products

Here, we describe a protocol developed by our group that uses low-field fluorine-19 (19F) time-domain (TD) nuclear magnetic resonance (NMR) to measure the average content of fluorinated drugs in their formulated drug product forms: tablets or capsules. This method is specific to fluorinated drugs because it detects only the content of fluorine, avoiding interference from the excipients that lack fluorine. The advantages of measuring the active content of fluorinated drugs using low-field 19F TD-NMR versus high-field 19F solid-state (SS) NMR are the simplicity of the method; the low cost; and the non-destructive nature of the technique, with all samples recoverable in intact forms (e.g., powders, tablets, and capsules), making this technique affordable for any laboratory.
We have tested the method with three fluorinated drug products available on the market - cinacalcet, lansoprazole, and ciprofloxacin - with doses ranging from 15 to 500 mg. The results of the analyses, measured by low-field 19F TD-NMR, supported the reported label claims for the average drug content.
Based on the simplicity and reproducibility of the analysis, we envision this methodology being implemented in any laboratory, including manufacturing plants, as a process analytical technology (PAT) tool in the pharmaceutical industry.

Application and Methodology of the Non-destructive 19F Time-domain NMR Technique to Measure the Content in Fluorine-containing Drug Products

A simple and non-destructive technique that measures the average content of drug substances in formulated drug products containing fluorine using low-field fluorine-19 (19F) time-domain (TD) nuclear magnetic resonance (NMR) is presented here. The technique can be applied to the development and manufacturing of drugs in the pharmaceutical industry.

应用程序和非破坏性19F 时间域核磁共振技术的方法来衡量中含氟药物产品的内容

Here, we describe a protocol developed by our group that uses low-field fluorine-19 (19F) time-domain (TD) nuclear magnetic resonance (NMR) to measure the ...

Preparation of Chitosan-based Injectable Hydrogels and Its Application in 3D Cell Culture

The protocol presents a facile, efficient, and versatile method to prepare chitosan-based hydrogels using dynamic imine chemistry. The hydrogel is prepared by mixing solutions of glycol chitosan with a synthesized benzaldehyde terminated polymer gelator, and hydrogels are efficiently obtained in several minutes at room temperature. By varying ratios between glycol chitosan, polymer gelator, and water contents, versatile hydrogels with different gelation times and stiffness are obtained. When damaged, the hydrogel can recover its appearances and modulus, due to the reversibility of the dynamic imine bonds as crosslinkages. This self-healable property enables the hydrogel to be injectable since it can be self-healed from squeezed pieces to an integral bulk hydrogel after the injection process. The hydrogel is also multi-responsive to many bio-active stimuli due to different equilibration statuses of the dynamic imine bonds. This hydrogel was confirmed as bio-compatible, and L929 mouse fibroblast cells were embedded following standard procedures and the cell proliferation was easily assessed by a 3D cell cultivation process. The hydrogel can offer an adjustable platform for different research where a physiological mimic of a 3D environment for cells is profited. Along with its multi-responsive, self-healable, and injectable properties, the hydrogels can potentially be applied as multiple carriers for drugs and cells in future bio-medical applications.

Here we describe a facile preparation of chitosan-based injectable hydrogels using dynamic imine chemistry. Methods to adjust the hydrogel&#8217;s mechanical strength and its application in 3D cell culture are presented.

糖注射水凝胶的制备及其在3D 细胞培养中的应用

The protocol presents a facile, efficient, and versatile method to prepare chitosan-based hydrogels using dynamic imine chemistry. The hydrogel is ...

Elemental-sensitive Detection of the Chemistry in Batteries through Soft X-ray Absorption Spectroscopy and Resonant Inelastic X-ray Scattering

Energy storage has become more and more a limiting factor of today's sustainable energy applications, including electric vehicles and green electric grid based on volatile solar and wind sources. The pressing demand of developing high-performance electrochemical energy storage solutions, i.e., batteries, relies on both fundamental understanding and practical developments from both the academy and industry. The formidable challenge of developing successful battery technology stems from the different requirements for different energy-storage applications. Energy density, power, stability, safety, and cost parameters all have to be balanced in batteries to meet the requirements of different applications. Therefore, multiple battery technologies based on different materials and mechanisms need to be developed and optimized. Incisive tools that could directly probe the chemical reactions in various battery materials are becoming critical to advance the field beyond its conventional trial-and-error approach. Here, we present detailed protocols for soft X-ray absorption spectroscopy (sXAS), soft X-ray emission spectroscopy (sXES), and resonant inelastic X-ray scattering (RIXS) experiments, which are inherently elemental-sensitive probes of the transition-metal 3d and anion 2p states in battery compounds. We provide the details on the experimental techniques and demonstrations revealing the key chemical states in battery materials through these soft X-ray spectroscopy techniques.

Here, we present a protocol for typical experiments of soft X-ray absorption spectroscopy (sXAS) and resonant inelastic X-ray scattering (RIXS) with applications in battery material studies.

软 x 射线吸收光谱和共振非弹性 x 射线散射法检测电池化学成分的元素敏感度

Energy storage has become more and more a limiting factor of today's sustainable energy applications, including electric vehicles and green electric grid ...

Preparation of Polyoxometalate-based Photo-responsive Membranes for the Photo-activation of Manganese Oxide Catalysts

This paper presents a method to prepare charge-transfer chromophores using polyoxotungstate (PW12O403-), transition metal ions (Ce3+ or Co2+), and organic polymers, with the aim of photo-activating oxygen-evolving manganese oxide catalysts, which are important components in artificial photosynthesis. The cross-linking technique was applied to obtain a self-standing membrane with a high PW12O403- content. Incorporation and structure retention of PW12O403- within the polymer matrix were confirmed by FT-IR and micro-Raman spectroscopy, and optical characteristics were investigated by UV-Vis spectroscopy, which revealed successful construction of the metal-to-metal charge transfer (MMCT) unit. After deposition of MnOx oxygen evolving catalysts, photocurrent measurements under visible light irradiation verified the sequential charge transfer, Mn &#8594; MMCT unit &#8594; electrode, and&#160;the photocurrent intensity was consistent with the redox potential of the donor metal (Ce or Co). This method provides a new strategy for preparing integrated systems involving catalysts and photon-absorption parts for use with photo-functional materials.

Here, we present a protocol to prepare charge transfer chromophores based on a polyoxometalate/polymer composite membrane.

氧化锰催化剂光活化 Polyoxometalate 基光响应膜的制备

This paper presents a method to prepare charge-transfer chromophores using polyoxotungstate (PW12O403-), transition metal ions (Ce3+ or Co2+), and organic ...

元素镧在选择性 c-F 活化 Trifluoromethylated Benzofulvenes 中的应用提供各种 Difluoroalkenes 的访问

摘要

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此视频中的章节

高价碘鎓炔基三氟甲磺酸酯的生成Cyanocarbenes的合成应用

Retropinacol /跨频哪醇偶联反应 - 催化访问1,2 - 非对称二醇

羰基饰卡宾的白色磷的活化制备方法和用途

掺硼金刚石电极质量和应用，以评估

蛋白质生物缀合物的合成

分离硫酸选择性结晶用双 - iminoguanidinium配体

应用程序和非破坏性¹⁹F 时间域核磁共振技术的方法来衡量中含氟药物产品的内容

糖注射水凝胶的制备及其在3D 细胞培养中的应用

软 x 射线吸收光谱和共振非弹性 x 射线散射法检测电池化学成分的元素敏感度

氧化锰催化剂光活化 Polyoxometalate 基光响应膜的制备