Outer sphere refers to an electron transfer (ET) event that occurs between chemical species that remain separate and intact before, during, and after the ET event. In contrast, for inner sphere electron transfer the participating redox sites undergoing ET become connected by a chemical bridge.
What are the important factors for outer sphere electron transfer reactions?
Formation of (a) internal reorganization and (b) corresponding ligand field splitting. The main factors affecting the outer sphere electron transfer are: 1. Orbital Symmetry: Electron transfer outer-sphere mechanism requires orbital overlap and occurs between orbitals of the same symmetry.
How do you know if a reaction is inner or outer sphere?
The key difference between inner sphere and outer sphere mechanism is that inner sphere mechanism occurs between complexes via a binding ligand whereas outer sphere mechanism occurs between complexes that do not undergo substitution.
What are the 3 types of electron transfer?
Classes of electron transfer
- Inner-sphere electron transfer.
- Outer-sphere electron transfer.
- Heterogeneous electron transfer.
Why do proteins use outer sphere electron transfer?
Often, when the transfer occurs between two metals, the metal ions may be constrained in particular binding sites within a protein, or even in two different proteins. That means the electron must travel through space to reach its destination. This long distance hop is called an outer sphere electron transfer.
Is inner sphere electron transfer faster than outer sphere?
Outer sphere electron transfer occurs between two species that do not undergo substitution and do not involve the incursion of significant covalent bond formation. It occurs when none of the ligands can function as a bridge. It is faster than inner sphere because the energetic demands are less.
What is an outer sphere electron transfer?
This long distance hop is called an outer sphere electron transfer. The two metals react without ever contacting each other, without getting into each others’ coordination spheres. Of course, there are limitations to the distance involved, and the further away the metals, the less likely the reaction.
What is the barrier to electron transfer?
The barrier to electron transfer has to do with reorganizations of all those big atoms before the electron makes the jump. In terms of the coordination sphere, those reorganizations involve bond vibrations, and bond vibrations cost energy. Outside the coordination sphere, solvent molecules have to reorganize, too.
What is an outer sphere?
Outer sphere refers to an electron transfer (ET) event that occurs between chemical species that remain separate and intact before, during, and after the ET event.
What changes are needed for electron transfer to occur?
Thus, the energetic changes needed before electron transfer can occur involve a variety of changes, including bond lengths of several ligands, bond angles, solvent molecules, and so on. The whole system, involving both metals, has some optimum set of positions of minimum energy.
