The latter effect is due to charge depletion of the CO 5? bonding and charge increase of the CO 2? * antibonding orbital.
12.
Do those nucleophile electrons in fact, contribute to an antibonding orbital, that somehow negates the bonding between the LG and the carbon?
13.
But ? *, the antibonding orbital of a single bond, does look like you describe in the area between the two atoms.
14.
In the staggered conformation, one C-H sigma bonding orbital donates electron density to the antibonding orbital of the other C-H bond.
15.
If so, how does an antibonding orbital convert into a bonding orbital ( presumably that as the LG leaves a bond must be formed simultaneously )?
16.
The donor is usually a higher bonding or nonbonding orbital and the acceptor is often a low-lying antibonding orbital as shown in the scheme below.
17.
Thus the two electrons in the ground-state ? 2 orbital are transferred to an excited antibonding orbital, creating a doubly excited electronic state of the cyclobutene.
18.
The symmetric combination ( called a bonding orbital ) is lower in energy than the basis orbitals, and the antisymmetric combination ( called an antibonding orbital ) is higher.
19.
Because ? bonds feature greater overlap than ? bonds, ? and ? * bonding and antibonding orbitals feature greater energy splitting ( separation ) than ? and ? * orbitals.
20.
The energy level of a non-bonding orbital is typically in between the lower energy of a valence shell bonding orbital and the higher energy of a corresponding antibonding orbital.
