chemistry

Tetramesityl compounds

Tetramesityl compounds 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 Tetramesityl compounds rather than just read about it. In short: Homoleptic tetra-mesityl complexes of transition metals in the +4 oxidation state, (IV), denoted as M(mes)4, constitute a category of organometallic substances that remain relatively unexplored. Characterized by tetrahedral coordination geometry, these compounds exhibit distinctive electrochemical, magnetic, and optical properties.

Key takeaways

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

Reference excerpt

Homoleptic tetra-mesityl complexes of transition metals in the +4 oxidation state, (IV), denoted as M(mes)4, constitute a category of organometallic substances that remain relatively unexplored. Characterized by tetrahedral coordination geometry, these compounds exhibit distinctive electrochemical, magnetic, and optical properties. Their unique attributes surpass those of their isostructural counterparts in group 14, commonly employed as fundamental components in advanced molecular materials like covalent- and metal–organic frameworks, polymers, self-assembled monolayers, and single-molecule electronic devices. Recent advancements, showcase the potential of modular, isostructural M(aryl) units in providing novel avenues for adjusting the electrochemical energy storage capacity, electrocatalytic functionality, and electrical conductivity/conductance of such materials, opening up various applications. The synthesis and reaction chemistry of several homoleptic transition metal tetramesityl complexes has been reported, and conclusive identification has been provided through X-ray structural studies. Among the various M(aryl)4 materials, Os(IV) and Ru(IV) are particularly noteworthy, especially when they feature ortho-methylated sigma-aryl ligands. This is because these compounds exhibit remarkable robustness, as their stability can be attributed to a d4 low-spin electronic configuration, with the ligand methyl groups effectively inhibiting decomposition pathways such as reductive elimination and ortho-hydrogen abstraction. These compounds can be purified through air chromatography and their aryl ligands can be subjected to chemical functionalization using various methods such as bromination, Suzuki coupling, and Friedel-Crafts acylation. Os(aryl)4 compounds have rich redox chemistry, which allows for the early isolation of a stable paramagnetic Os(V) complex.

Synthesis

Tetramesityl vanadium Trimesitylvanadium was first reported by Seidel and Kreisel in 1974 with the formula V(C9H11)3(THF)n. They then moved on to explore the synthesis tetramesityl vanadium compounds. Tetramesityl vanadium was prepared by adding one equivalent of mesLi to V(mes) in THF-Et2O to form this intermidate, V(mes)4Li. Air oxidation of the intermediate formed V(mes)4. An X-ray study shows V(mes)4, to have a slightly distorted tetrahedral structure.

V(mes)3THF + mesLi → [V(mes)4]Li [V(mes)4]− + O2 → V(mes)4

Tetramesityl iridium

The synthesis, X-ray structure and reactions of tretra-(mesityl)rhodium(IV) (mesityl = 2,4,6-trimethylphenyl, mes) was described. Hursthouse et al. reported the synthesis of Ir(mes)4, along with the X-ray crystal structure. The reaction of partially dehydraterd IrCl3(nH2O) with 2,4,6-trimethylphenyllithium at -20 °C, resulted in the tetrakis(mesityl)ruthenium complex.

Ir(Cl)3·nH2O + mesLi → [Ir(mes)4] No product was obtained when tetrahydrofuran was used as a solvent although Ir(mes)4, is stable in tetrahydrofuran. The yield, which never exceed about 20%, was dependent on the IrCl3(nH2O) batch and on the drying process. The results showcased that the reaction of IrCl3 results in the generation of an iridium(IV) compound. One possible explanation had to do with a disproportionation reaction, as no other product could be isolated.

2Ir^−3> Ir^2 + Ir^2 A possible intermediate could have been Li[Ir(mes)4] but, Ir(mes)3 , does not react with Li(mes) in Et2O and careful air-oxidation of the ether solution gives no Ir(mes)4. The product was obtained by evaporation, extraction of the residue with hexane, and crystallization at -20 °C. The resulting brown crystals had a melting point of 138-139 °C and were obtained in a yield of about 15%. The remaining substance after hexane extraction is black in color and is insoluble in organic solvents. The tetramesityl compound is stable in both solid and hexane solution states even when exposed to air. However, if it is heated in an air environment, it undergoes decomposition, leading to the formation of a green, diamagnetic substance. The tetramesityl compound's structure has been determined through X-ray crystallography. The geometry of the compound is best described as distorted tetrahedral, with C-Ir-C angles ranging from 89.0 to 123.9 degrees. The Ir-C bond lengths range from 1.99 to 2.02 A. The distortion in the low-spin iridium(IV) system is likely due to steric factors, which result from the distribution and orientation of the ligands in a way that minimizes non-bonding interactions between them. The electronic properties of the system are not likely to be the origin of the distortion.

Homoleptic tetramesityl ruthenium(IV) complex

Previously, Wilkinson and his colleagues reported a series of tetra-arylruthenium(IV) complexes. The procedure follows RuCl3(tht), tht = tetrahydrothiophene, in Et2O at -78 °C was added a solution of Mg(mes)2(thf), thf = tetrahydrofuran with vigorous stirring. After warming and stirring at room temperature the solution was evaporated under vacuum and the residue extracted with light petroleum. The extracts were reduced, filtered and cooled to give feathery crystals with 18% yield.

RuCl3(tht) + Mg(mes)2(thf) → [Ru(mes)4] In order to improve the yield of tetra-mes ruthenium(IV), complexes recent advances have synthesized homoleptic tetraarylruthenium(IV) complex Ru(2,4,5-Me3C6H2)4with a moderate yield of 37%. The procedure follows [Ru(acac)3] in THF at -78 °C was added to a 7 equiv. of (2,4,5-Me3C6H2)MgBr in THF.

[Ru(acac)3] + 2,4,−5Me3C6H2MgBr → [Ru(mes)4] The resulting brown mixture was stirred at room temperature overnight and followed by column chromatography in air, afforded the homoleptic tetra-mes ruthenium(IV) complex [Ru(2,4,5-Me3C6H2)4] as a purple crystalline solid in 37% isolated yield. The geometry around the central ruthenium atom is a slightly distorted tetrahedral. The C-Ru-C bond angles in the complex [Ru(2,4,5-Me3C6H2)4] are 98.9(6)–117.4(6)°. This is possibly as a result of the steric effect of two ortho-methyl moieties in mesityl groups.

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Illustrations

Worked examples

Example 1 — a first encounter with Tetramesityl compounds

Start with the simplest possible case. Write down what Tetramesityl compounds 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 Tetramesityl compounds 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 Tetramesityl compounds 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 Tetramesityl compounds

In research: Tetramesityl compounds 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 Tetramesityl compounds 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: Tetramesityl compounds is common in secondary-school and first-year university syllabi. It links to neighbouring topics Organometallic compounds, Transition metal compounds, so understanding it makes those chapters shorter.
In everyday life: Look for Tetramesityl compounds 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 Tetramesityl compounds in 20 minutes

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

Frequently asked questions

What is Tetramesityl compounds in simple terms?

Why does Tetramesityl compounds 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 Tetramesityl compounds?

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 Tetramesityl compounds.