2d. State, with justification, whether you expect nitric oxide (NO) to be a stronger or weaker pi-acceptor ligand than CO? The ability of ligands to accept л-electron density from the metal into their low-lying empty orbitals increase with increase in the electronegativity of their atoms because it decreases the energy of vacant * molecular orbitals and make them more suitable to accept í electron density from metal d orbital. NO is strictly an organometallic ligand and is a radical with 1 valence electrons. When bound, NO is referred to as the nitrosyl ligand and can bond in one of two modes to d-metal atoms, in either a bent or a linear, In the linear, the ligand is considered to be the NO+ cation which is isoelectronic with CO and the bonding can be considered in a similar. In bent, NO is considered to behave as NO- that donate 2 electrons. In the case of NO and CO, NO is a weaker pi-acceptor ligand than CO. Even nitrogen is mor electronegative than carbon, the electronic structure of the ligand's π* orbital is a more significant factor in determining its strength. [5] The T* orbital of NO is partially filled with an unpaired electron, which makes it less efficient in accepting electron density from the metal's d orbitals. On the other hand, the fully empty pi*orbital of CO can strongly overlap with the metal's d orbitals, resulting in a stronger π-back bonding interaction and a stronger metal-ligand bond.
Is this correct? Could you please correct me if I'm wrong?
Step by step
Solved in 3 steps
what about this answer ? Is this also correct? Isn't it contradict? "
However, the back-donation from the metal center to CO's empty 2π* orbital is less extensive than with NO. This is because CO's 2π* orbital is higher in energy compared to NO's 2π* orbital.
In summary, both NO and CO are pi-acceptor ligands due to their empty 2π* orbitals. However, NO is expected to be a stronger pi-acceptor ligand than CO because of the presence of the unpaired electron in its 2π* orbital and the lower energy of this orbital. The stronger pi-acceptor ability of NO can lead to a more stable metal-ligand bond, as well as greater electron density redistribution between the metal center and the ligand."
I'm so confused NO is weaker or stronger pi-acceptor ligands