Which of the following compound will not undergo amine inversion?

Options

A.
B. `CH_(3)-NH-CH_(3)`
C. `NH_(3)`
D.

Answer

To determine which compound will not undergo amine inversion, we need to understand the concept of amine inversion and the conditions under which it occurs.

### Step-by-Step Solution:

1. **Understanding Amine Inversion**:
- Amine inversion refers to the process where the lone pair of electrons on a tetrahedral nitrogen atom moves from one side to the opposite side, effectively changing the spatial arrangement of the substituents attached to the nitrogen. This is common in amines with sp³ hybridized nitrogen.

2. **Identifying Tetrahedral Nitrogen**:
- For amine inversion to occur, the nitrogen atom must be tetrahedral (sp³ hybridized) and have at least one lone pair of electrons. The presence of three different substituents can facilitate this inversion.

3. **Analyzing the Options**:
- We need to evaluate the given compounds (not specified in the question) to see which one has a nitrogen atom that is unable to undergo inversion due to steric hindrance or fixed substituents.

4. **Condition for Non-Inversion**:
- If all three substituents on the nitrogen are bulky or fixed in a way that prevents the lone pair from moving to the opposite side, then amine inversion cannot occur. This typically happens in cases where nitrogen is part of a cyclic structure or when it is bonded to large groups that restrict rotation.

5. **Conclusion**:
- Based on the analysis, the compound where all three substituents are not free to rotate or are bulky will not undergo amine inversion. Therefore, the answer is the compound represented by option D.

### Final Answer:
- The compound that will not undergo amine inversion is **option D**.