Wilkinson catalyst is
(a) [(Et3P)3RhCl]
(b) [(Et3P)3IrCl] (Et = C2H5)
(c) [(Ph3P)3RhCl]
(d) [(Ph3P)3

Q: What is the oxidation state of Rh in Wilkinson's catalyst?

The oxidation state of Rhodium in Wilkinson's catalyst is $+1$. The chloride ligand contributes a $-1$ charge, and the triphenylphosphine ligands are neutral, balancing the overall neutral complex.

Q: Why is it called a homogeneous catalyst?

It is called a homogeneous catalyst because it dissolves in the reaction medium (usually an organic solvent like benzene or dichloromethane), meaning it is in the same phase as the reactants.

Q: What is the geometry of Wilkinson's catalyst?

Wilkinson's catalyst has a square planar geometry. This is typical for $d^8$ transition metal complexes like $Rh(I)$.

Q: Does it hydrogenate alkynes as well?

Yes, it can hydrogenate alkynes to alkenes, and then further to alkanes. However, it is most famous for its highly selective hydrogenation of unhindered alkenes.

Q: Why are triphenylphosphine ligands used instead of simpler ligands?

The bulky triphenylphosphine ligands provide steric hindrance, which prevents the catalyst from clumping together (dimerizing) and helps tune the electronic properties of the Rhodium center to perfectly facilitate the catalytic cycle.

Question

Wilkinson catalyst is

Options:

(A) $[(Et_3P)_3RhCl]$

(B) $[(Et_3P)_3IrCl] (Et = C_2H_5)$

(C) $[(Ph_3P)_3RhCl]$

(D) $[(Ph_3P)_3IrCl]$

Sigma Percentile · Accepted Answer

### The Magic of Wilkinson's Catalyst

Imagine you have a complex organic molecule with a double bond that you desperately need to convert into a single bond, but you don't want to destroy the rest of the delicate functional groups in the molecule. Enter **Wilkinson's catalyst**, a true hero in the world of organic synthesis.

Wilkinson's catalyst is a highly famous coordination compound that acts as a **homogeneous catalyst**. This means it dissolves in the same solvent as your reactants, allowing for smooth, uniform, and highly selective reactions. Its primary job? The hydrogenation of alkenes and unsaturated vegetable oils.

### Breaking Down the Structure

Let's look at what makes this catalyst tick. The chemical formula is **$[(Ph_3P)_3RhCl]$**.

At the heart of this complex is a **Rhodium ($Rh$)** atom sitting in a $+1$ oxidation state. Rhodium is a transition metal that is perfect for shuffling electrons around during a catalytic cycle.

Surrounding the Rhodium are four ligands:
1. One simple **chloride ion ($Cl^-$)**.
2. Three bulky **triphenylphosphine ($PPh_3$)** groups.

Because Rhodium(I) has a $d^8$ electron configuration, it prefers to adopt a **square planar geometry**. The bulky triphenylphosphine groups provide just the right amount of steric crowding to make the catalyst stable yet reactive enough to temporarily bind hydrogen gas and an alkene.

### The Official Name

If you want to be formal, the IUPAC name for this complex is **Chloridotris(triphenylphosphine)rhodium(I)**. It is classified as a $\sigma$-bonded organometallic compound.

So, the next time you see a question asking about Wilkinson's catalyst, just remember the Rhodium atom surrounded by its three bulky phosphine bodyguards and one chloride sidekick!

Animated Solution for Chemistry - Coordination Compounds: Wilkinson catalyst is

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Visualized Solution

$Identifying Wilkinson’s Catalyst$

$Structure of the Catalyst$

$IUPAC Name and Application$

The Sigma Insight: Nomenclature, Isomerism, Importance and Werner's Theory

The Magic of Wilkinson's Catalyst

Breaking Down the Structure

The Official Name

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