Chelate Effect in [Ag(en)]+
The chelate effect refers to the enhanced stability of a complex formed when a metal ion is bound by a multidentate ligand compared to several monodentate ligands binding to the metal ion separately. However, in the case of [Ag(en)]+, the chelate effect is denied due to certain reasons.

Reasons why Chelate Effect is Denied in [Ag(en)]+
- Size of the Metal Ion: Silver ion (Ag+) is relatively large in size compared to other transition metal ions. This leads to a decrease in the steric hindrance and an increase in the coordination number of the metal ion, making the chelate effect less significant.
- Ligand Flexibility: The ligand ethylenediamine (en) is relatively flexible and can adopt various conformations, leading to a less rigid chelate structure. This flexibility reduces the chelate effect as compared to more rigid ligands.
- Charge of the Complex: The [Ag(en)]+ complex has a net positive charge, which can affect the distribution of electron density within the complex. This altered electron distribution can weaken the chelate effect.
- Coordination Geometry: The coordination geometry of the [Ag(en)]+ complex may not favor the formation of a stable chelate structure. The geometry of the complex can influence the strength of the chelate effect.
In conclusion, the denial of the chelate effect in [Ag(en)]+ is due to factors such as the size of the metal ion, ligand flexibility, charge of the complex, and coordination geometry. These factors collectively weaken the chelate effect in this particular complex.