Which of the following molecules involves the formation of `dpi - p pi` bonding ?

Options

A. Trimethyl amine
B. Carbon monoxide
C. Trisilyl amine
D. `C_3O_2`

Answer

To determine which molecule involves the formation of `dπ - pπ` bonding, we need to analyze the presence of d orbitals and p orbitals in the given options.

### Step-by-Step Solution:

1. **Understand the Requirement for dπ - pπ Bonding**:
- For `dπ - pπ` bonding to occur, there must be the presence of d orbitals (from a transition metal) and p orbitals (from a non-metal or another atom).

2. **Analyze Each Option**:
- **Option A: Trimethylamine (N(CH₃)₃)**:
- Nitrogen (N) has the electronic configuration of 1s² 2s² 2p³. It has no d orbitals.
- Carbon (C) has the electronic configuration of 1s² 2s² 2p². It also has no d orbitals.
- Conclusion: No dπ - pπ bonding.

- **Option B: Carbon Monoxide (CO)**:
- Carbon (C) has no d orbitals (1s² 2s² 2p²).
- Oxygen (O) also has no d orbitals (1s² 2s² 2p⁴).
- Conclusion: No dπ - pπ bonding.

- **Option C: C₂O (Carbon Dioxide)**:
- The structure is O=C=O, where both carbon and oxygen only have p orbitals.
- Conclusion: No dπ - pπ bonding.

- **Option D: Tri-silicon Amine (N(SiH₃)₃)**:
- Nitrogen has p orbitals (1s² 2s² 2p³).
- Silicon (Si) has the electronic configuration of 1s² 2s² 2p⁶ 3s² 3p², and importantly, it has empty 3d orbitals.
- This allows nitrogen to form `pπ` bonds with silicon's empty `d` orbitals, leading to `dπ - pπ` bonding.

3. **Conclusion**:
- The molecule that involves the formation of `dπ - pπ` bonding is **Tri-silicon Amine (N(SiH₃)₃)**.

### Final Answer:
**Option D: Tri-silicon Amine (N(SiH₃)₃)** involves the formation of `dπ - pπ` bonding.