IR Stretching Frequencies

TRICK!!!!!!!!!!!!!!!

***"CARBOXYLIC ACID" group is in same range as O-H but even BROADER!! (3500-2500)

Trends:

3600 - 2700 cm-1	X-H
2700 - 1900 cm-1	X=Y
1900 - 1500 cm-1	X=Y
1500 - 500 cm-1	X-Y

**Add AROMATIC ranges:

Aromatic C-H Stretch Aromatic C-H Bending Aromatic C=C Bending

~3030 (v) 860 - 680 (s) 1700 - 1500 (m,m)

1) More thorough TABLE: http://www.chem.ucla.edu/~webspectra/irtable.html

2) Explanation: http://www.chem.ucla.edu/~webspectra/irintro.html

3) Practice Problems: http://www.chem.ucla.edu/~webspectra/

Acidity/Basicity of Functional Groups

Acidity

Basicity

Ortho/Meta/Para Directors

Electron Donating = Activating (Ortho, Para) (HAS LONE PAIR OF ELECTRONS, FORMS RESONANCE STRUCTURES!)

- participates in electrophilic substitution reactions

EX: -NH2, -OH, -OR (there's lone pair on the nitrogen/oxygen)
Strong: Anything that has lone pair w/o a group of carbonyl.
EX: -OR
Moderate: They have a C=O (carbonyl)
EX: -NHCOR
Weak: All alkyl group because they donate in electron density.

Electron Withdrawing = Deactivating (Meta, Halogens) (USUALLY POSITIVE, NO LONE PAIR ELECTRONS)

- removes electron density from the benzene ring, making electrophilic aromatic substitution reactions slower and more complex relative to benzene

-NO2, -NH3+ (there's no lone pair on the nitrogen)
STRONG: there's no lone pair, no carbonyl group
EX: -CN, -NO2
MODERATE: carbonyl, but no lone pair
Ex: -COH, -CO2H
WEAK:
Deactivating: o,p directors
These are all HALOGENS.

ATOMIC TRENDS

(atomic radius)

(attract electrons to itself)