Which of the following complexes can exists as enantiomers ? Draw their structures
`(a) cis-[Co(NH_(3))_(4)Br_(2)]^(+) " " (b) cis-[Cr(H_(2)O)_(2)(en)_(2)]^(3+)" " (c )[Cr(gly)_(3)]`
`(d) [Cr(en)_(3)]^(3+) " " ( e) cis-[Co(NH_(3))Cl(en)_(2)]^(2+) " " (f) trans-[Co(NH_(3))_(2)(en)_(2)]^(2+)`

Answer

To determine which of the given complexes can exist as enantiomers, we will analyze each complex one by one and draw their structures. Enantiomers are non-superimposable mirror images, similar to left and right hands.

### Step 1: Analyze each complex

**(a) cis-[Co(NH₃)₄Br₂]⁺**

1. **Structure**: The complex has a cobalt ion surrounded by four ammonia (NH₃) ligands and two bromide (Br) ligands in a cis configuration.
2. **Drawing**: The bromide ions are adjacent to each other, and the ammonia ligands are positioned around the cobalt.
3. **Mirror Image**: When we take the mirror image, we can see that rotating the structure will bring the bromides back to their original positions, meaning they are superimposable.
4. **Conclusion**: This complex does not exist as enantiomers.

**(b) cis-[Cr(H₂O)₂(en)₂]³⁺**

1. **Structure**: The complex has a chromium ion with two water (H₂O) ligands and two ethylenediamine (en) ligands in a cis configuration.
2. **Drawing**: The two water molecules are adjacent, and the ethylenediamine ligands are positioned around the chromium.
3. **Mirror Image**: The mirror image cannot be superimposed on the original structure due to the arrangement of the ligands.
4. **Conclusion**: This complex can exist as enantiomers.

**(c) [Cr(gly)₃]**

1. **Structure**: Glycine (gly) can coordinate through both nitrogen and oxygen, leading to a chiral arrangement.
2. **Drawing**: The structure will have three glycine ligands arranged around the chromium.
3. **Mirror Image**: The mirror image will not be superimposable due to the arrangement of glycine ligands.
4. **Conclusion**: This complex can exist as enantiomers.

**(d) [Cr(en)₃]³⁺**

1. **Structure**: The complex has a chromium ion surrounded by three ethylenediamine ligands.
2. **Drawing**: The ethylenediamine ligands are arranged in a way that creates chirality.
3. **Mirror Image**: The mirror image cannot be superimposed on the original structure.
4. **Conclusion**: This complex can exist as enantiomers.

**(e) cis-[Co(NH₃)Cl(en)₂]²⁺**

1. **Structure**: The complex has a cobalt ion with one chloride (Cl) and two ethylenediamine ligands in a cis configuration.
2. **Drawing**: The chloride and ammonia are adjacent, while the ethylenediamine ligands are positioned around the cobalt.
3. **Mirror Image**: The mirror image will not be superimposable due to the arrangement of ligands.
4. **Conclusion**: This complex can exist as enantiomers.

**(f) trans-[Co(NH₃)₂(en)₂]²⁺**

1. **Structure**: The complex has a cobalt ion with two ammonia ligands and two ethylenediamine ligands in a trans configuration.
2. **Drawing**: The ligands are arranged in a way that they are opposite each other.
3. **Mirror Image**: The mirror image will be superimposable on the original structure.
4. **Conclusion**: This complex does not exist as enantiomers.

### Summary of Results
- **Enantiomers**: (b), (c), (d), (e)
- **Not Enantiomers**: (a), (f)