chemistry

Hexakis(trimethylphosphine)tungsten

Hexakis(trimethylphosphine)tungsten 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 Hexakis(trimethylphosphine)tungsten rather than just read about it. In short: Hexakis(trimethylphosphine)tungsten is a tungsten(0) organometallic compound with the formula W(P(CH3)3)6. It is a yellow crystalline solid, soluble in organic solvents.

Key takeaways

Hexakis(trimethylphosphine)tungsten belongs to chemistry; place it in that map before memorising details.
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Reproduce the core statement of Hexakis(trimethylphosphine)tungsten from memory before moving on to harder problems.

Reference excerpt

Hexakis(trimethylphosphine)tungsten is a tungsten(0) organometallic compound with the formula W(P(CH3)3)6. It is a yellow crystalline solid, soluble in organic solvents. Much of the most interesting and varied chemistry occurs from its dissociated variants, such as W(PMe3)5.

Synthesis and equilibrium W(PMe3)6 is a relatively difficult zero-valent, homoleptic trimethylphosphine complex to synthesize and isolate. It equilibrates with PMe3 and the metallacycle W(PMe3)4(η2-CH2PMe2)H:

The equilibrium constant at 30 °C is about 17.8 M, and the rightwards reaction has ΔH° = 9.3 kcal/mol (39 kJ/mol) and ΔS° = 37 eu (150 J K−1 mol−1). Thus W(PMe3)6 solutions decompose in about 2 hours, unless the equilibrium is driven to the left by an excess of PMe3. Naive attempts to prepare W(PMe3)6 by co-condensation of tungsten with PMe3, or reduction of WCl6 with alkali metals, only form W(PMe3)4(η2-CH2PMe2)H. Parkin and Rabinovich first recognized in 1990 that these attempts, using only stoichiometric PMe3 and slow extraction procedures, must necessarily fight the equilibrium. Simple room-temperature reduction with Na-K alloy gives the homoleptic complex when excess PMe3 is the solvent:

Crystal properties In the solid state, W(PMe3)6 is stable at room temperature for at least two weeks. The complex was crystallographically characterized, demonstrating W-P bond lengths of 2.455 ± 0.01 Å (245.5 ± 1.0 pm) and P-W-P bond angles of 90° and 180°.

Reactivity Metal complexes of the form M(PMe3)n contain very electron-rich and highly-reactive metal centers as a result of the combination of the strong σ-donating and π-accepting nature of the PMe3 ligand. These complexes have been shown to be capable of activating C-H and other otherwise unreactive σ bonds via oxidative addition, often forming cyclometalated products. W(PMe3)6 possesses an 18-electron valence count, and as such demonstrates somewhat limited reactivity.

Diphosphene metathesis W(PMe3)6 can catalyze the metathesis of phosphorus-phosphorus double-bonds. Interaction of the appropriate dichlorophosphane with W(PMe3)6 leads to dechlorination and formation of symmetrical and unsymmetrical diphosphenes:

The resultant phosphorus-tungsten species can also catalyze the exchange of diphosphene end-groups.

Metal-germanium triple bonds The W(PMe3)4(η2-CH2PMe2)H species formed upon the dissolution of W(PMe3)6 can participate in a Ge-Cl bond heterolysis and form a metal-germanium triple bond:

References

Illustrations

Worked examples

Example 1 — a first encounter with Hexakis(trimethylphosphine)tungsten

Start with the simplest possible case. Write down what Hexakis(trimethylphosphine)tungsten 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 Hexakis(trimethylphosphine)tungsten 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 Hexakis(trimethylphosphine)tungsten 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 Hexakis(trimethylphosphine)tungsten

In research: Hexakis(trimethylphosphine)tungsten 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 Hexakis(trimethylphosphine)tungsten 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: Hexakis(trimethylphosphine)tungsten is common in secondary-school and first-year university syllabi. It links to neighbouring topics Phosphine complexes, Tertiary phosphines, Tungsten(0) compounds, so understanding it makes those chapters shorter.
In everyday life: Look for Hexakis(trimethylphosphine)tungsten 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 Hexakis(trimethylphosphine)tungsten in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Hexakis(trimethylphosphine)tungsten means in your own words.
Compare your version with the excerpt and mark what you missed.
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Frequently asked questions

What is Hexakis(trimethylphosphine)tungsten in simple terms?

Hexakis(trimethylphosphine)tungsten is a tungsten(0) organometallic compound with the formula W(P(CH3)3)6. It is a yellow crystalline solid, soluble in organic solvents.

Why does Hexakis(trimethylphosphine)tungsten 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 Hexakis(trimethylphosphine)tungsten?

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 Hexakis(trimethylphosphine)tungsten.