chemistry

Resorcinarene

Resorcinarene 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 Resorcinarene rather than just read about it. In short: In chemistry, a resorcinarene (also resorcarene or calix[4]resorcinarene) is a macrocycle, or a cyclic oligomer, based on the condensation of resorcinol (1,3-dihydroxybenzene) and an aldehyde. Resorcinarenes are a type of calixarene.

Key takeaways

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

Reference excerpt

In chemistry, a resorcinarene (also resorcarene or calix[4]resorcinarene) is a macrocycle, or a cyclic oligomer, based on the condensation of resorcinol (1,3-dihydroxybenzene) and an aldehyde. Resorcinarenes are a type of calixarene. Other types of resorcinarenes include the related pyrogallolarenes and octahydroxypyridines, derived from pyrogallol and 2,6-dihydroxypyridine, respectively. Resorcinarenes interact with other molecules forming a host–guest complex. Resorcinarenes and pyrogallolarenes self-assemble into larger supramolecular structures. Both in the crystalline state and in organic solvents, six resorcinarene molecules are known to form hexamers with an internal volume of around one cubic nanometer (nanocapsules) and shapes similar to the Archimedean solids. Hydrogen bonds appear to hold the assembly together. A number of solvent or other molecules reside inside. The resorcinarene is also the basic structural unit for other molecular recognition scaffolds, typically formed by bridging the phenolic oxygens with alkyl or aromatic spacers. A number of molecular structures are based on this macrocycle, namely cavitands and carcerands.

Synthesis The resorcinarenes are typically prepared by condensation of resorcinol and an aldehyde in acid solution. This reaction was first described by Adolf von Baeyer who described the condensation of resorcinol and benzaldehyde but was unable to elucidate the nature of the product(s). The methods have since been refined. Recrystallization typically gives the desired isomer in quite pure form. However, for certain aldehydes, the reaction conditions lead to significant by-products. Alternative condensation conditions have been developed, including the use of Lewis acid catalysts.

A green chemistry procedure uses solvent-free conditions: resorcinol, an aldehyde, and p-toluenesulfonic acid are ground together in a mortar and pestle at low temperature.

Structure Resorcinarenes can be characterized by a wide upper rim and a narrow lower rim. The upper rim includes eight hydroxyl groups that can participate in hydrogen bonding interactions. Depending on the aldehyde starting material, the lower rim includes four appending groups, usually chosen to give optimal solubility. The resorcin[n]arene nomenclature is analogous to that of calix[n]arenes, in which 'n' represents the number of repeating units in the ring. Pyrogallolarenes are related macrocycles derived from the condensation of pyrogallol (1,2,3-trihydroxybenzene) with an aldehyde. Resorcinarenes and pyrogallolarenes self-assemble to give supramolecular assemblies. Both in the crystalline state and in solution, they are known to form hexamers that are akin to certain Archimedean solids with an internal volume of around one cubic nanometer (nanocapsules). (Isobutylpyrogallol[4]arene)6 is held together by 48 intermolecular hydrogen bonds. The remaining 24 hydrogen bonds are intramolecular. The cavity is filled by solvent.

Catalysis The resorcinarene hexamer has been described as a yoctolitre reaction vessel. Within the confines of the container, terpene cyclizations and iminium catalyzed reactions have been observed.

References

Palmer LC, Shivanyuk A, Yamanaka M, Rebek J (2005). "Resorcinarene assemblies as synthetic receptors". Chemical Communications. 2005 (7): 857–858. doi:10.1039/b414252g. PMID 15700060.{{cite journal}}: CS1 maint: multiple names: authors list (link)

Worked examples

Example 1 — a first encounter with Resorcinarene

Start with the simplest possible case. Write down what Resorcinarene 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 Resorcinarene 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 Resorcinarene 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 Resorcinarene

In research: Resorcinarene 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 Resorcinarene 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: Resorcinarene is common in secondary-school and first-year university syllabi. It links to neighbouring topics Cyclophanes, Macrocycles, Supramolecular chemistry, so understanding it makes those chapters shorter.
In everyday life: Look for Resorcinarene 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 Resorcinarene in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Resorcinarene 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 Resorcinarene out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Resorcinarene in simple terms?

Why does Resorcinarene 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 Resorcinarene?

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 Resorcinarene.