Which is not a `pi`-bonded complex ?

Options

A. Zeise.s salt
B. ferrocene
C. dibenzene chromium
D. Tetraethyl lead

Explanation

To determine which complex is not a π-bonded complex, we need to analyze the bonding in each of the given options. Let's go through the options step by step.

### Step 1: Identify the complexes
We have four complexes to evaluate:
1. Zasis salt (platinum complex with ethylene)
2. Ferrocene (iron complex with cyclopentadiene)
3. Dibenzene chromium (chromium complex with two benzene rings)
4. Tetraethyl lead (lead complex with four ethyl groups)

### Step 2: Analyze each complex

**1. Zasis Salt:**
- The structure consists of platinum (Pt) bonded to chlorine and ethylene (C=C).
- Ethylene has a double bond, which means it contributes a π-bond.
- Therefore, Zasis salt is a π-bonded complex.

**2. Ferrocene:**
- Ferrocene consists of an iron (Fe) atom sandwiched between two cyclopentadiene rings.
- Cyclopentadiene is an aromatic compound, which has delocalized π-electrons.
- Thus, ferrocene is also a π-bonded complex.

**3. Dibenzene Chromium:**
- This complex has chromium (Cr) bonded to two benzene rings.
- Each benzene ring has delocalized π-electrons, contributing to π-bonding.
- Therefore, dibenzene chromium is a π-bonded complex.

**4. Tetraethyl Lead:**
- Tetraethyl lead consists of lead (Pb) bonded to four ethyl groups (C2H5).
- The bonding here is through single bonds (sigma bonds) between lead and the ethyl groups.
- There are no double or triple bonds present, indicating that there are no π-bonds.
- Thus, tetraethyl lead is not a π-bonded complex.

### Conclusion:
The complex that is not a π-bonded complex is **tetraethyl lead**.

### Final Answer:
**Tetraethyl lead is not a π-bonded complex.**

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