Advanced Organometallic Chemistry

Back to: Organic Chemistry 400 Level

Welcome to class!

Hello brilliant learner, I’m really happy to see you again today. I hope you’re feeling inspired and ready, because this topic — Advanced Organometallic Chemistry — takes us deeper into the world of chemistry where metals and organic molecules work together in very interesting and powerful ways. At this advanced level, you will understand how organometallic compounds are designed, how they react and how they are used in sophisticated catalytic processes, especially in modern drug and material synthesis.

Advanced Organometallic Chemistry

We use metals in everyday life — from cooking pots to electrical cables — but in chemistry, metals can also form special bonds with carbon to make reactions more efficient and selective. That is the beauty of organometallic chemistry.

Nature of Metal–Carbon Bonds

In organometallic compounds, the metal–carbon bond can be:

Ionic, where the carbon carries a negative charge (as in organolithium reagents)

Covalent, where electrons are shared more equally (as in most transition metal complexes)

Dative (co-ordinate), where the carbon donates an electron pair to the metal (e.g. metal–alkene bonds in catalysts)

The character of this bond influences the reactivity and stability of the compound.

Ligands in Organometallic Complexes

Ligands are atoms or groups that donate electrons to the metal centre. Common ligands include:

Alkenes and alkynes (π-ligands)

Carbon monoxide (CO)

Cyclopentadienyl (Cp) rings

Phosphines (PR₃)

For example, the well-known ferrocene contains two cyclopentadienyl ligands bound to an iron atom in a sandwich structure. This compound is extremely stable and is often used as a model organometallic system.

Important Organometallic Reactions

Oxidative Addition – The metal inserts into a chemical bond (e.g. H–H, C–X), increasing its oxidation state. This step is common in catalytic cycles.

Reductive Elimination – Two ligands on the metal combine and leave, reducing the metal back to a lower oxidation state.

Migratory Insertion – A ligand migrates from the metal to another ligand, helping form new C–C or C–X bonds.

β-Hydride Elimination – An alkyl ligand gives up a hydrogen atom to the metal and forms an alkene.

These steps often occur as part of catalytic cycles such as the Heck, Suzuki or Olefin Metathesis reactions, which are vital in pharmaceutical and polymer industries.

Applications of Advanced Organometallic Chemistry

Homogeneous Catalysis – Palladium and nickel complexes catalyse carbon–carbon coupling reactions that are used for drug and agrochemical synthesis.

Polymerisation Catalysts – Ziegler–Natta catalysts (Ti and Al compounds) produce polyethylene and polypropylene plastics.

Asymmetric Catalysis – Chiral organometallic complexes are used to produce enantiomerically pure drugs.

Summary

• Metal–carbon bonds in organometallic chemistry can be ionic, covalent or dative.
• Organometallic complexes often contain ligands such as alkenes, phosphines, CO and cyclopentadienyl rings.
• Important reaction steps include oxidative addition, reductive elimination, migratory insertion and β-hydride elimination.
• These steps form catalytic cycles used in cross-coupling and metathesis reactions.
• Organometallic chemistry has major applications in homogeneous catalysis, polymerisation and asymmetric synthesis.

Evaluation

1. Differentiate between oxidative addition and reductive elimination.
2. What is a ligand and give one example of a ligand used in organometallic chemistry.
3. Mention one industrial application of advanced organometallic chemistry.
4. Explain the meaning of migratory insertion.

You’re doing excellently well and Afrilearn is very proud of your steady progress. Keep going — your passion and dedication are building a strong future for you!