chemistry

Metal nitrido complex

Metal nitrido complex 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 Metal nitrido complex rather than just read about it. In short: Metal nitrido complexes are coordination compounds and metal clusters that contain an atom of nitrogen bound only to transition metals. These compounds are molecular, i.e. discrete, in contrast to the polymeric, dense nitride materials that are useful in materials science.

Key takeaways

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

Reference excerpt

Metal nitrido complexes are coordination compounds and metal clusters that contain an atom of nitrogen bound only to transition metals. These compounds are molecular, i.e. discrete, in contrast to the polymeric, dense nitride materials that are useful in materials science. The distinction between the molecular and solid-state polymers is not always very clear as illustrated by the materials Li6MoN4 and more condensed derivatives such as Na3MoN3. Transition metal nitrido complexes have attracted interest in part because it is assumed that nitrogen fixation proceeds via nitrido intermediates. Nitrido complexes have long been known, the first example being salts of [OsO3N]−, described in the 19th century.

Structural trends Mononuclear complexes feature terminal nitride ligands, typically with short M-N distances consistent with metal ligand multiple bonds. For example, in the anion in PPh4[MoNCl4], the Mo-N distance is 163.7 pm. The occurrence of terminal nitrido ligands follow the patterns seen for oxo complexes: they are more common for early and heavier metals. Many bi- and polynuclear complexes are known with bridging nitrido ligands. More exotic metal nitrido complexes are also possible, such as a recently reported compound containing a terminal uranium nitride (-U≡N) bond.

Preparative routes Metal nitrido complexes are produced using a variety of nitrogen sources. The first example above is prepared from amide (NH2−) as the N3− source:

OsO4 + KNH2 → KOsO3N + H2O Most commonly however, nitrido complexes are produced by decomposition of azido complexes. The driving force for these reactions is the great stability of the N2 leaving group. Alternatively, chlorothiazido ligands (M-N-S-Cl; see also metal thionitrosyl complexes) react with bases to give nitrido complexes. Nitrogen trichloride is an effective reagent to give chloro-nitrido complexes. Some three-coordinated Mo(III) complexes cleave N2 to give nitrides. These complexes are so bulky that they cannot readily form Mo≡Mo bonds. In such cases, an intermediate bridging dinitrogen can be observed.

2 Mo(NR2)3 + N2 → (R2N)3Mo-N2-Mo(NR2)3 (R2N)3Mo-N2-Mo(NR2)3 → 2 N≡Mo(NR2)3

Reactions of nitrido ligands The nitride ligand can be electrophilic and nucleophilic, depending on the metal and other ligands. Terminal nitrides of early metals tend to be basic and oxidizable, whereas nitrides of the later metals tend to be oxidizing and electrophilic. The former behavior is illustrated by their N-protonation and N-alkylation. Ru and Os nitrido complexes often add organophosphines to give iminophosphine derivatives containing the R3PN− ligand. Some metal nitrido complexes have been used to make nitriles.

Interstitial nitrides Owing to the ability of nitrido ligands to serve as a bridging ligand, several metal clusters are known to contain nitride ligands at their center. Such nitrido ligands are termed interstitial. In some cases, the nitride is completely encased in the center of six or more metals and cannot undergo reactions, although it contributes to the intermetallic bonding.

See also Abiological nitrogen fixation Transition metal dinitrogen complex

General references

Illustrations

Worked examples

Example 1 — a first encounter with Metal nitrido complex

Start with the simplest possible case. Write down what Metal nitrido complex 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 Metal nitrido complex 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 Metal nitrido complex 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 Metal nitrido complex

In research: Metal nitrido complex 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 Metal nitrido complex 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: Metal nitrido complex is common in secondary-school and first-year university syllabi. It links to neighbouring topics Coordination complexes, Inorganic chemistry, so understanding it makes those chapters shorter.
In everyday life: Look for Metal nitrido complex 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 Metal nitrido complex in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Metal nitrido complex 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 Metal nitrido complex in simple terms?

Why does Metal nitrido complex 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 Metal nitrido complex?

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 Metal nitrido complex.