Chemistry - ORGANOMETALLIC COMPOUNDS Question with Solution | TestHub

Concept:

• Oxidative addition

• η²-ligand displacement

• Electron counting in Ni(0/II)

• Hapticity changes during reaction

Solution:

1. Ni(0) η²-C₂H₄ → 12e⁻ total? Ni(0) = 10? Wait, step by step:

○ Ni(0) = d¹⁰ → 10e⁻? Check: valence electrons of Ni(0) = 10e⁻

○ η²-C₂H₄ = 2e⁻, 2 PPh₃ = 4e⁻ → total = $10+2+4=16$e⁻

2. H₂ adds → oxidative addition → Ni(II) → adds 2 H → 2 more e⁻ → 16e⁻

3. C₂H₄ leaves → hapticity becomes irrelevant (no η²-ligand)

4. Oxidation state increases from 0 → +2