## CH3C=OCH2+, dehydro-2-propanone cation (see note)

 H5 H6 \ / C3 - H4 / O1 - C2 \ | C7 / | H9 H8
The ion charge is 1.

## Atomic Charges and Dipole Moment

O1 charge=-0.039
C2 charge= 0.526
C3 charge=-0.552
H4 charge= 0.259
H5 charge= 0.264
H6 charge= 0.259
C7 charge=-0.278
H8 charge= 0.280
H9 charge= 0.280
with a dipole moment of 7.75848 Debye

## Bond Lengths:

between O1 and C2: distance=1.272 ang___ between O1 and C7: distance=1.607 ang___
between C2 and C3: distance=1.442 ang___ between C2 and H5: distance=2.120 ang___
between C2 and C7: distance=1.448 ang___ between C3 and H4: distance=1.113 ang___
between C3 and H5: distance=1.102 ang___ between C3 and H6: distance=1.113 ang___
between C7 and H8: distance=1.097 ang___ between C7 and H9: distance=1.097 ang___

## Bond Angles:

for C3-C2-O1: angle=135.0 deg___ for H4-C3-C2: angle=108.6 deg___
for H5-C3-C2: angle=112.2 deg___ for H6-C3-C2: angle=108.5 deg___
for C7-C2-O1: angle=72.09 deg___ for H8-C7-C2: angle=119.7 deg___
for H9-C7-C2: angle=119.6 deg___

## Bond Orders (Mulliken):

between O1 and C2: order=1.363___ between O1 and C7: order=0.598___
between C2 and C3: order=0.774___ between C2 and H5: order=-0.053___
between C2 and C7: order=1.208___ between C3 and H4: order=0.933___
between C3 and H5: order=0.968___ between C3 and H6: order=0.932___
between C7 and H8: order=0.901___ between C7 and H9: order=0.901___

## Best Lewis Structure

The Lewis structure that is closest to your structure is determined. The hybridization of the atoms in this idealized Lewis structure is given in the table below.

### Hybridization in the Best Lewis Structure

1. A bonding orbital for O1-C2 with 1.9876 electrons
__has 66.78% O 1 character in a sp2.37 hybrid
__has 33.22% C 2 character in a s0.98 p3 hybrid

2. A bonding orbital for O1-C2 with 1.9771 electrons
__has 81.36% O 1 character in a p-pi orbital ( 99.82% p 0.18% d)
__has 18.64% C 2 character in a p-pi orbital ( 98.79% p 1.21% d)

3. A bonding orbital for O1-C7 with 1.9574 electrons
__has 73.50% O 1 character in a s0.26 p3 hybrid
__has 26.50% C 7 character in a s0.21 p3 hybrid

4. A bonding orbital for C2-C3 with 1.9953 electrons
__has 53.76% C 2 character in a sp1.21 hybrid
__has 46.24% C 3 character in a sp2.86 hybrid

5. A bonding orbital for C2-C7 with 1.9841 electrons
__has 50.67% C 2 character in a sp2.31 hybrid
__has 49.33% C 7 character in a sp2.57 hybrid

6. A bonding orbital for C3-H4 with 1.9507 electrons
__has 63.88% C 3 character in a s0.93 p3 hybrid
__has 36.12% H 4 character in a s orbital

7. A bonding orbital for C3-H5 with 1.9823 electrons
__has 63.95% C 3 character in a sp2.69 hybrid
__has 36.05% H 5 character in a s orbital

8. A bonding orbital for C3-H6 with 1.9505 electrons
__has 63.87% C 3 character in a s0.92 p3 hybrid
__has 36.13% H 6 character in a s orbital

9. A bonding orbital for C7-H8 with 1.9857 electrons
__has 63.01% C 7 character in a sp2.05 hybrid
__has 36.99% H 8 character in a s orbital

10. A bonding orbital for C7-H9 with 1.9857 electrons
__has 63.01% C 7 character in a sp2.05 hybrid
__has 36.99% H 9 character in a s orbital

15. A lone pair orbital for O1 with 1.9881 electrons

118. A antibonding orbital for O1-C2 with 0.1020 electrons
__has 18.64% O 1 character in a p-pi orbital ( 99.82% p 0.18% d)
__has 81.36% C 2 character in a p-pi orbital ( 98.79% p 1.21% d)

-With core pairs on: O 1 C 2 C 3 C 7 -

#### Donor Acceptor Interactions in the Best Lewis Structure

The localized orbitals in your best Lewis structure can interact strongly. A filled bonding or lone pair orbital can act as a donor and an empty or filled bonding, antibonding, or lone pair orbital can act as an acceptor. These interactions can strengthen and weaken bonds. For example, a lone pair donor->antibonding acceptor orbital interaction will weaken the bond associated with the antibonding orbital. Conversly, an interaction with a bonding pair as the acceptor will strengthen the bond. Strong electron delocalization in your best Lewis structure will also show up as donor-acceptor interactions.
Interactions greater than 20 kJ/mol for bonding and lone pair orbitals are listed below.

The interaction of bonding donor orbital, 1, for O1-C2 with the antibonding acceptor orbital, 119, for O1-C7 is 25.3 kJ/mol.

The interaction of the second bonding donor orbital, 2, for O1-C2 with the antibonding acceptor orbital, 125, for C7-H8 is 26.8 kJ/mol.

The interaction of the second bonding donor orbital, 2, for O1-C2 with the antibonding acceptor orbital, 126, for C7-H9 is 26.8 kJ/mol.

The interaction of bonding donor orbital, 3, for O1-C7 with the antibonding acceptor orbital, 117, for O1-C2 is 48.8 kJ/mol.

The interaction of bonding donor orbital, 3, for O1-C7 with the antibonding acceptor orbital, 120, for C2-C3 is 100. kJ/mol.

The interaction of bonding donor orbital, 6, for C3-H4 with the second antibonding acceptor orbital, 118, for O1-C2 is 58.4 kJ/mol.

The interaction of bonding donor orbital, 7, for C3-H5 with the antibonding acceptor orbital, 121, for C2-C7 is 38.0 kJ/mol.

The interaction of bonding donor orbital, 8, for C3-H6 with the second antibonding acceptor orbital, 118, for O1-C2 is 58.8 kJ/mol.

## Molecular Orbital Energies

The orbital energies are given in eV, where 1 eV=96.49 kJ/mol. Orbitals with very low energy are core 1s orbitals. More antibonding orbitals than you might expect are sometimes listed, because d orbitals are always included for heavy atoms and p orbitals are included for H atoms. Up spins are shown with a ^ and down spins are shown as v.

19 ----- -3.819

18 ----- -4.085

17 ----- -7.918

16 ----- -9.765

15 -^-v- -15.09

14 -^-v- -15.42

13 -^-v- -16.26

12 -^-v- -16.57

11 -^-v- -17.94

10 -^-v- -18.94

9 -^-v- -19.42

8 -^-v- -20.69

7 -^-v- -24.25

6 -^-v- -25.60

5 -^-v- -35.60

4 -^-v- -273.0

3 -^-v- -275.1

2 -^-v- -276.8

1 -^-v- -515.7

## Total Electronic Energy

The total electronic energy is a very large number, so by convention the units are given in atomic units, that is Hartrees (H). One Hartree is 2625.5 kJ/mol. The energy reference is for totally dissociated atoms. In other words, the reference state is a gas consisting of nuclei and electrons all at infinite distance from each other. The electronic energy includes all electric interactions and the kinetic energy of the electrons. This energy does not include translation, rotation, or vibration of the the molecule.

Total electronic energy = -192.2603841669 Hartrees

* The ketone isomer of this cation rearranges to give this cyclic isomer. This ion is the product of the decomposition of a methyl ketone radical cation, or heterolytic bond breaking of the stable neutral methyl ketone. The acyclic isomer is much higher in energy.