chemistry

UiO MOFs

UiO MOFs is a chemistry topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand UiO MOFs rather than just read about it. In short: The UiO (University of Oslo) series frameworks are a group of metal-organic frameworks (MOFs) that were first discovered in 2008 with the general formula Zr6O4(OH)4(L)6, where L is an organic ligand. UiO series MOFs contain zirconium oxo clusters that adopt an octahedral geometry with zirconium present in each of its vertices.

Key takeaways

UiO MOFs belongs to chemistry; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect UiO MOFs to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of UiO MOFs from memory before moving on to harder problems.

Reference excerpt

The UiO (University of Oslo) series frameworks are a group of metal-organic frameworks (MOFs) that were first discovered in 2008 with the general formula Zr6O4(OH)4(L)6, where L is an organic ligand. UiO series MOFs contain zirconium oxo clusters that adopt an octahedral geometry with zirconium present in each of its vertices. In pristine UiO MOFs, each cluster binds to twelve organic ligands, but these MOFs are also stable with missing organic linkers, or defect sites. Non-modified UiO MOFs have a Fm3m space group. The zirconium oxo clusters with the bridging μ3-OH, has D3d symmetry. UiO MOFs have seen great interest in materials science for various applications including gas storage, radionuclide adsorption, catalysis, and sensing. The series is made up of 4 members that differ in the number of phenyl rings in their organic linkers. The organic linkers are terepthalic acid, biphenyl-4,4′-dicarboxylic acid, terphenyl-4,4''-dicarboxylic acid, and quaterphenyl-4,4'-dicarboxylic acid for UiO-66, UiO-67, Ui-68, and UiO-69, respectively. UiO MOFs have seen significant research interest because of their high thermal stability (450-500°C), chemical stability, tunable pore size, and high accessible surface area. The high thermal and chemical stability of this class is due to, in part, the high oxophilicity of the zirconium making the Zr-O bond robust and the hardness of both the ligand's carboxylate group and the zirconium(IV) in the nodes. The decomposition observed around 500°C is caused by the break down of the phenyl groups of the organic ligands. The stability of the class is inversely proportional to the length of the organic ligand, so the UiO-69 structure is the least structurally robust. Defective sites in the MOFs tend to decrease the thermal and chemical stability of the structure, but allow for post-synthetic addition of new functional organic ligands.

Synthesis

UiO MOFs are commonly produced via solvothermal methods, which are able to produce bulk crystalline powders. Solvothermal reactions of UiO MOFs are often done in dimethylformamide (DMF) and require elevated temperatures. When heated, DMF can break down to form dimethylamine and formic acid, which can act as a modulator in the synthesis. Modulators compete with the binding of the typical organic ligands and slow the growth of crystals, which improves the crystallinity and size of MOF particles. Single crystals of UiO MOFs have been grown and analyzed by single-crystal X-ray diffraction (SCXRD) using the modulator growth method. Modulators act to slow down the growth and reduce the seeding of crystals, which allows for small single crystals to nucleate. SCXRD has allowed for detailed understanding of the structure of these MOFs and their defect sites. Where carboxylate ligands are typically located, defective sites are stabilized by hydroxide ions or solvent molecules like DMF or water. A variety of other methods have been explored for the synthesis of UiO MOFs, including microwave, electrochemical, and ultrasonic methods.

UiO analogs Isoreticular structures of UiO MOFs have been made with other tetravalent metals including hafnium, cerium, thorium, and plutonium. A variety of other structures have been produced that use organic ligands that have been modified before the synthesis of the structure. One commonly used example is NH2-UiO-66, which uses aminoterephthalic acid as the organic ligand, which can be modified post-synthetically to further functionalize the material.

References

Illustrations

Worked examples

Example 1 — a first encounter with UiO MOFs

Start with the simplest possible case. Write down what UiO MOFs claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In chemistry, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to UiO MOFs before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about UiO MOFs ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of UiO MOFs

In research: UiO MOFs appears in chemistry research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses UiO MOFs in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: UiO MOFs is common in secondary-school and first-year university syllabi. It links to neighbouring topics Metal-organic frameworks, Zirconium(IV) compounds, so understanding it makes those chapters shorter.
In everyday life: Look for UiO MOFs outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study UiO MOFs in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what UiO MOFs means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain UiO MOFs out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is UiO MOFs in simple terms?

Why does UiO MOFs matter?

Because it connects several chemistry ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study UiO MOFs?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on UiO MOFs.