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

Syntese og oppdagelse av fosfonatbaserte MOF-er: En solvotermisk tilnærming

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.

Forfatter Spotlight: Akselererende oppdagelse i mikroporøs materialkjemi 

Oppdagelse og synteseoptimalisering av isoretikulære Al(III)fosfonatbaserte metallorganiske rammeforbindelser ved bruk av høykapasitetsmetoder

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  

Solvotermisk syntese og isolering av det krystallinske materialet Al-CAU-60

For å begynne, legg til linkeren H4PMP som et fast stoff til polytetrafluoretylen, eller PTFE, innsatser for Al-CAU-60. Bruk deretter en pipette for å tilsette aluminiumkloridoppløsningen, demineralisert vann og løsningen av tilsetningsstoffer til innsatsene. Sett platene inn i prøveplaten og plasser de fylte PTFE-innsatsene i prøveplaten.Merk jordplaten til reaktoren på en måte som gjør det mulig å identifisere PTFE-innsatsene og sett prøveplaten med de fylte PTFE-innsatsene inn i jordplaten. Forbered to PTFE-ark og legg dem på prøveplatene for å sikre full dekning. Forsikre deg om at PTFE-arket er riktig plassert og passer til hodeplaten ved hjelp av styrepinnene.Tilsett skruene og stram dem for hånd. Forsegl deretter den opprinnelig lukkede reaktoren ved hjelp av en mekanisk eller hydraulisk press og stram skruene for hånd igjen. Plasser multiklaven i en programmerbar tvungen konveksjonsovn.For Al-CAU-60, still inn temperaturtidsprogrammet som vises på skjermen. Start deretter temperaturtidsprogrammet. Fjern multiklaven fra ovnen.Når den er avkjølt til romtemperatur, legg den på en mekanisk eller hydraulisk presse og komprimer den forsiktig til skruene kan løsnes for hånd. Plasser multiklaven inne i en avtrekkshette og fjern reaktorens hodeplate. Fjern deretter PTFE-arkene og prøveplaten med PTFE-innsatsene fra jordplaten til reaktoren.Monter nå filtreringsblokken med høy gjennomstrømning ved å koble filterblokken til en vakuumpumpe via to vaskeflasker. Plasser to filterpapir mellom to silikonforseglingsmatter med tilsvarende utsparinger i filterblokken. Legg deretter PTFE-fylleblokken på toppen, og sørg for at de riktige utsparingene samsvarer med takmattene og filterblokken.Stram lagene ved hjelp av klemrammen, som holdes på plass av seks bolter. For å tette enheten ordentlig, bruk vingemuttere på piggboltene og stram dem for hånd. Lukk utsparingene på fylleblokken som ikke skal fylles med plugger.Slå på membranvakuumpumpen og sett den i en modus der den vil pumpe ned til best mulig vakuum. Overfør innholdet i PTFE-innsatsene til de angitte brønnene i fylleblokken med engangspipetter. Når alle innsatsene er tomme, ta en ekstra titt etter krystaller og isoler dem hvis de er til stede.Demonter filtreringsblokken forsiktig når alle brønnene er drenert. Et produktbibliotek er nå tilgjengelig på filterpapir. La den lufttørke inne i avtrekkshetten.Plasser produktbiblioteket mellom bunnplaten og dekselplaten for å karakterisere det oppnådde produktet ved pulverrøntgendiffraksjon senere. Forsikre deg om at utsparingene og platene samsvarer med produktplasseringene. Etter å ha justert platene, fest dem med to skruer.Sett produktbiblioteket inn i prøveholderen til diffraktometeret. Plasser den lastede prøveholderen forsiktig i XY-trinnet i diffraktometeret. Lukk instrumentet før du starter målingene.Parameterrommet er vist i denne figuren. Syntesen med natriumhydroksid som tilsetningsstoff er uthevet i blått, syntesen uten additiv er uthevet i grønt, og syntesen med additivet saltsyre er uthevet i oransje og rødt. Molforholdet mellom reagensene er vist på venstre side og på toppen.Den stablede plottet av alle de målte pulverrøntgendiffraksjonsmønstrene er vist i denne figuren. Her er tilsetningsstoffet natriumhydroksid uthevet i blått, ingen tilsetningsstoff er uthevet i grønt, og additivet saltsyre er uthevet i rødt. Prøvenavnene er vist her som korrelerer med molforholdet mellom utgangsmaterialene som brukes i synteseblandingen.Disse resultatene antyder at produktene med lav krystallinitet ble oppnådd fra syntesen hvor molforholdet mellom natriumhydroksid og aluminium var en-til-en, eller ingen natriumhydroksid eller saltsyre var tilstede. Produkter med høyere krystallinitet ble oppnådd fra syntese hvor saltsyre ble brukt som tilsetningsstoff.

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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 ...