Name: Solvothermal Synthesis and Isolation of the Crystalline Material Al-CAU-60
Uploaded: 2023-10-06T14:20:00
Description: Watch this Scientific Journal Video about Solvothermal Synthesis and Isolation of the Crystalline Material Al-CAU-60 at JoVE.com

solvothermal synthesis and isolation of the crystalline material al-cau-60

ホスホネート基幹細胞の合成と発見:ソルボサーマルアプローチ

Metal-organic frameworks (MOFs) are porous, crystalline compounds whose structures consist of metal-containing nodes, like metal ions or metal-oxygen clusters, which are connected by organic molecules (linkers)1. By varying the metal-containing nodes as well as the linker, a variety of compounds can be obtained that exhibit a wide range of properties and therefore have potential applications in different fields1.
The stability of a material is important for its application1,2,3. Therefore, MOFs containing tri- or tetravalent metal ions, such as Al3+, Cr3+, Ti4+, or Zr4+, with carboxylate2 or phosphonate4 linker molecules have been the focus of many investigations5,6,7. In addition to the direct synthesis of stable MOFs, the enhancement of stability through post-synthetic modifications as well as the formation of composites is a field of interest2. Phosphonate-based MOFs have been less often reported compared to carboxylate-based MOFs8. One reason is the higher coordination flexibility of the CPO32- group compared to the -CO2- group, which often leads to the formation of dense structures and greater structural diversity8,9,10,11. In addition, phosphonic acids often must be synthesized, as they are rarely available on the market. While some metal phosphonates exhibit exceptional chemical stability10, systematic access to isoreticular metal phosphonate MOFs, which allows the tuning of properties, is still a topic of high relevance12,13. Different strategies for the synthesis of porous metal phosphonates have been investigated, such as incorporating defects into otherwise dense layers, for example, by partially replacing phosphonate with phosphate ligands4,14. However, as defective structures are poorly reproducible, and the pores are not uniform, other strategies have been developed. In recent years, the use of sterically demanding or orthogonalized phosphonic acids as linker molecules have emerged as a suitable strategy for the preparation of porous metal phosphonates4,8,10,11,13,15,16,17,18. However, a universal synthesis route for porous metal phosphonates has not yet been discovered. As a result, the synthesis of metal phosphonates is often a process of trial and error, requiring the investigation of many synthesis parameters.
The parameter space of a reaction system includes chemical and process parameters and can be vast19. It consists of parameters such as the type of starting material (metal salt), molar ratios of starting materials, additives for pH adjustment, modulators, type of solvent, solvent mixtures, volumes, reaction temperatures, times, etc.19,20. A moderate number of parameter variations can easily result in several hundred individual reactions, making a carefully considered synthesis plan and well-chosen parameter space necessary. For example, a simple study using six molar ratios of the linker to the metal (e.g., M:L = 1:1, 1:2, ... to 1:6) and four different concentrations of an additive and keeping the other parameter constant, leads already to 6 x 4 = 24 experiments. Using four concentrations, five solvents, and three reaction temperatures would necessitate carrying out the 24 experiments 60 times, resulting in 1,440 individual reactions.
High-throughput (HT) methods are based on the concepts of miniaturization, parallelization, and automation, to varying degrees depending on the scientific question being addressed19,20. As such, they can be used to accelerate the investigation of multi-parameter systems and are an ideal tool for the discovery of new compounds, as well as synthesis optimization19,20. HT methods have been used successfully in different fields, ranging from drug discovery to materials science20. They have also been used for the investigation of porous materials such as zeolites and MOFs in solvothermal reactions, as recently summarized20. A typical HT workflow for solvothermal synthesis consists of six steps (Figure 1)19,20,21: a) selection of the parameter space of interest (i.e., the design of experiment [DOE]), which can be done manually or by using software; b) dosing of the reagents into the vessels; c) solvothermal synthesis; d) isolation and workup; e) characterization, which is typically done with powder X-ray diffraction (PXRD); and f) data evaluation, which is followed by step one again.
Parallelization and miniaturization are achieved in solvothermal reactions through the use of multiclaves, often based on the well-established 96-well plate format most commonly used in biochemistry and pharmacy19,20,22,23. Various reactor designs have been reported and several groups have constructed their own reactors19,20. Reactor choice depends on the chemical system of interest, especially the reaction temperature, (autogenous) pressure, and reactor stability19,20. For example, in a systematic study of zeolitic imidazolate frameworks (ZIFs), Banerjee et al.25 used the 96-well glass plate format to perform over 9600 reactions24. For reactions under solvothermal conditions, customized polytetrafluoroethylene (PTFE) blocks, or multiclaves with 24 or 48 individual PTFE inserts, have been described among others by the Stock group19,20.&#160;They are routinely employed, for example, in the synthesis of metal carboxylates and phosphonates. As such, Reinsch et al.25 reported the advantages of the methodology in the field of porous aluminum MOFs25. The in-house made HT reactor systems (Figure 2), which allow 24 or 48 reactions to be studied simultaneously, contain PTFE inserts with a total volume of 2.655 mL and 0.404 mL, respectively (Figure 2A,B). Usually, no more than 1 mL or 0.1 mL, respectively, is used. While these reactors are used in conventional ovens, microwave-assisted heating using SiC blocks and small glass vessels has also been reported26.
The automation of studies leads to time savings and improved reproducibility, as influence of the human factor is minimized20. The degree to which automation has been used varies strongly19,20. Fully automated commercial systems, including pipetting20 or weighting capabilities20, are known. A recent example is the use of a liquid-handling robot to study ZrMOFs, reported by the group of Rosseinsky27. Automated analysis can be performed by PXRD using a diffractometer equipped with an xy stage. In another example, a plate reader was used to screen solid-state catalysts, mainly MOFs, for HT screening of nerve agent degradation28. Samples can be characterized in a single run without the need for manual sample or position changes. Automation does not eliminate human error, but it reduces the possibility of its occurring19,20.
Ideally, all steps in a HT workflow should be adapted in terms of parallelization, miniaturization, and automation to eliminate possible bottlenecks and maximize efficiency. However, if it is not possible to establish a HT workflow in its entirety, it may be helpful to adopt selected steps/tools for one&#39;s own research. The use of multiclaves for 24 reactions is particularly useful here. The technical drawings of the in-house made equipment used in this study (as well as others) are published for the first time and can be found in Supplementary File 1, Supplementary File 2, Supplementary File 3, and Supplementary File 4.

著者スポットライト:微多孔質材料化学における発見の加速 

ハイスループット法を用いた等網状Al(III)ホスホネート系金属有機骨格化合物の発見と合成最適化

I see the periodic table as a huge playground, and in our research, we focus on the synthesis of new materials, porous materials, such as this here. That's a structural model, and we see holes in the framework. and that can be used to store molecules or also to separate molecules based on the size of these.And in addition to that kind of studies, we also develop new reactor systems in order to accelerate the discovery process. The current experimental challenges are to further accelerate the synthesis and characterization process with additional high throughput instrumentation, such as high throughput absorption characterization device. The lack of detail in publications regarding the synthesis and characterization procedure affecting reproducibility is a well-known problem in chemistry.By providing a thorough description of our method and setup, we aim to encourage other groups to adopt the described methodology, thereby increasing the reproducibility of experimental studies. We do not know what the future will bring since we work on the discovery of new materials, and we never know what kind of properties these materials will have. Nevertheless, I think that the use of linker molecules from renewable feedstocks will play a major role.And regarding the application, the use in sensing and the separation of gas molecules will be very important.

Watch this Scientific Journal Video about Solvothermal Synthesis and Isolation of the Crystalline Material Al-CAU-60 at JoVE.com

Solvothermal Synthesis and Isolation of the Crystalline Material Al-CAU-60  

結晶性物質Al-CAU-60のソルボサーマル合成と単離

まず、リンカーH4PMPを固体としてAl-CAU-60のポリテトラフルオロエチレン(PTFE)インサートに追加します。次に、ピペットを使用して、塩化アルミニウム溶液、脱塩水、および添加剤の溶液をインサートに追加します。ディスクをサンプルプレートに挿入し、充填されたPTFEインサートをサンプルプレートに配置します。PTFEインサートを識別できるようにリアクターのアースプレートにマークを付け、充填されたPTFEインサートを備えたサンプルプレートをアースプレートに挿入します。2枚のPTFEシートを準備し、サンプルプレートに置き、完全にカバーするようにします。ガイドピンを使用して、PTFEシートが正しく配置され、ヘッドプレートにフィットしていることを確認します。ネジを追加し、手で締めます。次に、機械的または油圧プレスを使用して最初に閉じた反応器を密閉し、再び手でネジを締めます。マルチクレーブをプログラム可能な強制対流式オーブンに入れます。Al-CAU-60の場合、画面に表示される温度時間プログラムを設定します。次に、温度時間プログラムを開始します。マルチクレーブをオーブンから取り出します。室温まで冷めたら、機械式または油圧式のプレス機の上に置き、ネジが手で緩めるまでゆっくりと圧縮します。マルチクレーブをヒュームフード内に置き、反応器のヘッドプレートを取り外します。次に、PTFEシートとPTFEインサート付きのサンプルプレートを反応器のアースプレートから取り外します。次に、2つの洗浄ボトルを介してフィルターブロックを真空ポンプに接続することにより、高スループットろ過ブロックを組み立てます。フィルターブロックの対応するくぼみがある2つのシリコンシーリングマットの間に2つのろ紙を置きます。次に、PTFE充填ブロックを上に置き、適切なくぼみが天井マットとフィルターブロックと一致することを確認します。6本のスタッドボルトで固定されているクランプフレームを使用して層を締めます。ユニットを適切に密閉するには、スタッドボルトに蝶ナットを使用し、手で締めます。プラグを充填しない充填ブロックのくぼみを閉じます。メンブレン真空ポンプをオンにして、可能な限り最高の真空までポンプダウンするモードに設定します。PTFEインサートの内容物を使い捨てピペットで充填ブロックの指定されたウェルに移します。すべてのインサートが空になったら、結晶をもう一度探し、存在する場合はそれらを分離します。すべてのウェルが排出されたら、ろ過ブロックを慎重に分解します。製品ライブラリがろ紙で利用できるようになりました。ドラフト内で風乾させます。ベースプレートとカバープレートの間にプロダクトライブラリを配置し、得られたプロダクトを粉末X線回折により後から特徴付けた。くぼみとプレートが製品の位置と一致していることを確認してください。プレートを合わせたら、2本のネジで固定します。製品ライブラリを回折計のサンプルホルダーに挿入します。ロードしたサンプルホルダーを回折計のXYステージに慎重に配置します。測定を開始する前に、機器を閉じてください。パラメーター・スペースをこの図に示します。水酸化ナトリウムを添加剤とした合成は青色で強調表示され、無添加の合成は緑色で強調表示され、塩酸を添加剤とした合成はオレンジと赤で強調表示されます。試薬のモル比を左側と上部に示します。測定されたすべての粉末X線回折パターンの積み上げプロットをこの図に示します。ここでは、添加剤水酸化ナトリウムは青色で強調表示され、添加剤なしは緑色で強調表示され、添加剤塩酸は赤色で強調表示されます。合成混合物に使用される出発物質のモル比に相関するサンプル名をここに示します。これらの結果から,水酸化ナトリウムとアルミニウムのモル比が1対1であったり,水酸化ナトリウムや塩酸が存在しない合成から結晶性の低い生成物が得られたことが示唆された。より高い結晶性の生成物は、塩酸が添加剤として使用された合成から得られた。

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Chemistry

Solvothermal Synthesis and Isolation of the Crystalline Material Al-CAU-60

Discovery and Synthesis Optimization of Isoreticular Al(III) Phosphonate-Based Metal-Organic Framework Compounds Using High-Throughput Methods

High-throughput (HT) methods are an important tool for the fast and efficient screening of synthesis parameters and the discovery of new materials. This ...