Which of the following coordination compounds has maximum number of isomers ?

Options

A. `[Pt(NH_(3))_(4)Cl_(2)]^(2+)`
B. `[Pt(gly)_(3)]^(2-)`
C. `[Pt(en)_(3)]^(4+)`
D. `[Pt(NH_(3))_(2)Cl_(2)]`

Answer

To determine which coordination compound has the maximum number of isomers, we will analyze each option step by step.

### Step 1: Analyze the first compound - [Pt(NH3)2Cl2]²⁺
- **Structure**: This compound has an octahedral geometry.
- **Isomers**:
- **Cis Isomer**: Both Cl atoms are adjacent (90° apart).
- **Trans Isomer**: Both Cl atoms are opposite each other (180° apart).
- **Total Isomers**: 2 (Cis and Trans).

### Step 2: Analyze the second compound - [Pt(gly)(gly)]²⁻
- **Structure**: Glycine (gly) is a bidentate ligand that can coordinate through both nitrogen and oxygen.
- **Isomers**:
- **Cis Isomer**: Both glycine ligands are adjacent.
- **Trans Isomer**: Both glycine ligands are opposite.
- **Optical Isomers**: Since there is no plane of symmetry, each of the cis and trans forms can have optical isomers (D and L forms).
- **Total Isomers**: 4 (2 from cis and 2 from trans).

### Step 3: Analyze the third compound - [Pt(en)2]²⁺
- **Structure**: Ethylene diamine (en) is also a bidentate ligand.
- **Isomers**:
- **Geometrical Isomers**: There are no geometrical isomers (cis/trans) because the ligands are identical.
- **Optical Isomers**: There are optical isomers due to the lack of a plane of symmetry.
- **Total Isomers**: 2 (D and L forms).

### Step 4: Analyze the fourth compound - [Pt(NH3)2Cl2]
- **Structure**: Similar to the first compound, it has an octahedral geometry.
- **Isomers**:
- **Cis Isomer**: Both Cl atoms are adjacent.
- **Trans Isomer**: Both Cl atoms are opposite.
- **Optical Isomers**: There is a plane of symmetry, so no optical isomers exist.
- **Total Isomers**: 2 (Cis and Trans).

### Conclusion:
After analyzing all the options:
- Option 1: 2 isomers
- Option 2: 4 isomers
- Option 3: 2 isomers
- Option 4: 2 isomers

**The coordination compound with the maximum number of isomers is option 2, [Pt(gly)(gly)]²⁻, with a total of 4 isomers.**