Which of the folowing is an example of `pi` boneded organometallic complex ?

Options

A. Ferrocene
B. Dibenzenechromium
C. `Zn(C_(2)H_(5))_(2)`
D. `Pb(C_(2)H_(5))_(4)`

Answer

To determine which of the following is an example of a π-bonded organometallic complex, we need to analyze the given options based on the presence of carbon-metal (C-M) bonds and π-bonding characteristics.

### Step-by-Step Solution:

1. **Understanding Organometallic Complexes**:
- An organometallic complex is defined as a compound that contains at least one carbon-metal bond. In addition, we are specifically looking for complexes that exhibit π-bonding.

**Hint**: Recall that π-bonding involves the overlap of p-orbitals, which can occur in certain types of organometallic complexes.

2. **Analyzing the First Option: Ferrocene (Fe(C5H5)2)**:
- Ferrocene consists of an iron (Fe) atom sandwiched between two cyclopentadienyl (C5H5) anions. The cyclopentadienyl ligands are π-acceptors, and they form π-bonds with the iron center.
- Therefore, ferrocene is indeed a π-bonded organometallic complex.

**Hint**: Look for structures where cyclic ligands can donate π-electrons to a metal center.

3. **Analyzing the Second Option: Dibenzene Chromium (Cr(C6H6)2)**:
- In dibenzene chromium, the chromium atom is coordinated to two benzene rings. Each benzene ring can donate π-electrons to the chromium, forming π-bonds.
- Thus, dibenzene chromium is also a π-bonded organometallic complex.

**Hint**: Consider how aromatic compounds can participate in π-bonding with metals.

4. **Analyzing the Third Option: Zinc Ethyl (Zn(C2H5)2)**:
- Zinc ethyl consists of a zinc atom bonded to two ethyl groups (C2H5). However, the bonding here is primarily σ-bonding, and there are no π-bonds formed between the zinc and the ethyl groups.
- Therefore, this option does not represent a π-bonded organometallic complex.

**Hint**: Identify if there are any double bonds or aromatic systems that can contribute to π-bonding.

5. **Conclusion**:
- The correct answers are the first option (Ferrocene) and the second option (Dibenzene Chromium) as both are examples of π-bonded organometallic complexes.

### Final Answer:
- The examples of π-bonded organometallic complexes are:
1. Ferrocene (Fe(C5H5)2)
2. Dibenzene Chromium (Cr(C6H6)2)