Chapter 17- Aromatics Flashcards
What is the product of Benzene and Br2?
No reaction!
How does aromaticity affect stabilization?
Enhanced stability
What is the criteria to be classified as an aromatic?
- cyclic
- continuous conjugation across atoms in cycle
- Planar
- Delocalized pi electrons (enhances stability)
- # of pi electrons equation
What is the equation (Huckel’s rule) for determining aromaticity?
pi electrons = 4N + 2
What is the criteria to be classified as an anti-aromatic?
- cyclic
- continuous conjugation across atoms in cycle
- Planar
- Delocalized pi electrons (Destabilized)
- # of pi electrons equation
What is the equation (Huckel’s rule) for determining antiaromaticity?
pi electrons = 4N
What is the criteria to be classified as Non Aromatic?
- not cyclic
- not planar
- no continuous conjugation
Rank the stability of aromatic, antiaromatic and nonaromatic molecules
aromatic > nonaromatic > antiaromatic
What is the rule dealing with lone pairs of a heteroatom?
If the heteroatom’s lone pair is necessary for aromaticity, it will be counted in the Huckel number of pi electrons.
(only count 1 LP, not the other one, if there is one)
What is the general rule for Basicity?
If the lone pair is necessary for aromaticity, then the lone pair will not be basic
What is the general rule for Acidity?
If the loss of the proton provides an aromatic stabilized conjugate base, it is favorable.
What is important to remember when drawing MO diagrams
- vertex down
- cut shape in half
-label bonding, n , and antibonding
-lowest orbitals get filled first
Name this molecule.
chlorobenzene
Name this molecule.
nitrobenzene
Name this molecule.
Ethylbenzene
Name this molecule.
tetraphenylcyclopentadienone
Name this molecule.
Toluene
Name this molecule.
phenol
Name this molecule.
Anisole
Name this molecule.
Aniline
Name this molecule.
Benzoic acid
Name this molecule.
benzaldehyde
Name this molecule.
Acetophenone
Name this molecule.
styrene
What is this location name?
1,2 or ortho
What is this location name?
1, 3 or meta
What is this location name?
1,4 or para
Name this molecule.
ortho-Nitroanisole
(2-Nitroanisole)
Name this molecule.
meta-Bromotoluene
(3-Bromotoluene)
Name this molecule.
para-Chlorobenzaldehyde
Name this molecule.
1,3,5-trinitrobenzene
Name this molecule.
2,4-dinitrophenol
Name this molecule.
3,5-dihyroxybenzoic acid
What word is used when benzene is not the priority functional group/root
phenyl
What is the word for the group when the aromatic is substituted?
aryl group
What word is used when there is an additional methylene linked to a phenyl
a benzyl group
Where do ring vibrations show up on IR spectroscopy?
1450-1650cm-1
Where do aromatic protons appear in 1H NMR?
6.5 to 8 ppm
How does the integration of the 1H NMR help with determining structures?
Can determine symmetry and if there are multiple substituents off of the molecule
Where do signals appear that typically indicate a benzene ring in a 13C NMR?
100 to 150ppm
How can the number of signals from a 13C NMR help determine structure
The number of signals help determine the substitution pattern
