chemistry

Tris(triphenylphosphine)rhodium carbonyl hydride

Tris(triphenylphosphine)rhodium carbonyl hydride 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 Tris(triphenylphosphine)rhodium carbonyl hydride rather than just read about it. In short: Carbonyl hydrido tris(triphenylphosphine)rhodium(I) [Carbonyl(hydrido)tris(triphenylphosphane)rhodium(I)] is an organorhodium compound with the formula [RhH(CO)(PPh3)3] (Ph = C6H5). It is a yellow, benzene-soluble solid, which is used industrially for hydroformylation.

Key takeaways

Tris(triphenylphosphine)rhodium carbonyl hydride belongs to chemistry; place it in that map before memorising details.
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Connect Tris(triphenylphosphine)rhodium carbonyl hydride to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Tris(triphenylphosphine)rhodium carbonyl hydride from memory before moving on to harder problems.

Reference excerpt

Carbonyl hydrido tris(triphenylphosphine)rhodium(I) [Carbonyl(hydrido)tris(triphenylphosphane)rhodium(I)] is an organorhodium compound with the formula [RhH(CO)(PPh3)3] (Ph = C6H5). It is a yellow, benzene-soluble solid, which is used industrially for hydroformylation.

Preparation [RhH(CO)(PPh3)3] was first prepared by the reduction of [RhCl(CO)(PPh3)2], e.g. with sodium tetrahydroborate, or triethylamine and hydrogen, in ethanol in the presence of excess triphenylphosphine:

[RhCl(CO)(PPh3)2] + NaBH4 + PPh3 → [RhH(CO)(PPh3)3] + NaCl + BH3 It can also be prepared from an aldehyde, rhodium trichloride and triphenylphosphine in basic alcoholic media.

Structure The complex adopts a trigonal bipyramidal geometry with trans CO and hydrido ligands, resulting in pseudo-C3v symmetry. The Rh-P, Rh-C, and Rh-H distances are 2.32, 1.83, and 1.60 Å, respectively. This complex is one of a small number of stable pentacoordinate rhodium hydrides.

Use in hydroformylation This precatalyst was uncovered in attempts to use tris(triphenylphosphine)rhodium chloride as a hydroformylation catalyst. It was found that the complex would quickly carbonylate and that the catalytic activity of the resulting material was enhanced by a variety of additives but inhibited by halides. This inhibition did not occur in the presence of base, suggesting that the hydrido-complex represented the catalytic form of the complex.

Mechanistic considerations [RhH(CO)(PPh3)3] is a catalyst for the selective hydroformylation of 1-olefins to produce aldehydes at low pressures and mild temperatures. The selectivity for n-aldehydes increases in the presence of excess PPh3 and at low CO partial pressures. The first step in the hydroformylation process is the dissociative substitution of an alkene for a PPh3. The migratory insertion of this 18-electron complex can result in either a primary or secondary rhodium alkyl. This step sets the regiochemistry of the product, however it is rapidly reversible. The 16-electron alkyl complex undergoes migratory insertion of a CO to form the coordinately unsaturated acyl. This species once again gives an 18-electron acyl complex. The last step involves β-H elimination via hydrogenolysis which results in the cleavage of the aldehyde product and regeneration of the rhodium catalyst.

References

Illustrations

Worked examples

Example 1 — a first encounter with Tris(triphenylphosphine)rhodium carbonyl hydride

Start with the simplest possible case. Write down what Tris(triphenylphosphine)rhodium carbonyl hydride 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 Tris(triphenylphosphine)rhodium carbonyl hydride 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 Tris(triphenylphosphine)rhodium carbonyl hydride 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 Tris(triphenylphosphine)rhodium carbonyl hydride

In research: Tris(triphenylphosphine)rhodium carbonyl hydride 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 Tris(triphenylphosphine)rhodium carbonyl hydride 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: Tris(triphenylphosphine)rhodium carbonyl hydride is common in secondary-school and first-year university syllabi. It links to neighbouring topics Carbonyl complexes, Catalysts, Homogeneous catalysis, so understanding it makes those chapters shorter.
In everyday life: Look for Tris(triphenylphosphine)rhodium carbonyl hydride 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 Tris(triphenylphosphine)rhodium carbonyl hydride in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Tris(triphenylphosphine)rhodium carbonyl hydride 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.
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Frequently asked questions

What is Tris(triphenylphosphine)rhodium carbonyl hydride in simple terms?

Why does Tris(triphenylphosphine)rhodium carbonyl hydride 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 Tris(triphenylphosphine)rhodium carbonyl hydride?

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 Tris(triphenylphosphine)rhodium carbonyl hydride.