1. FTIR -- InfraRed IR 1. Bet vis & microwave 2. Organic chemists use 4000 - 400 cm -1 3. cm -1  E of vibration No 2 cmpds give exact sample IR (enantimoers) 2 types of molecular vibration stretching bending 3 vibrations symmetrical asymmetrical scissoring

2. Stretching Frequencies ( ) C-C C-O C-N 1300 - 1500 cm -1 C=C C=O C=N N=O 1900 - 1500 C C C N 2300 - 2000 C-H O-H N-H 3800 - 2700 2 imprt areas for prelim exam of spectra 4000 - 1300 900 - 650 1300 - 900 fct group region fingerprint complex Imprt for -OH NH C=O strong bands 1600 - 1310 aromatics (benzene ring) 900 - 650 strong out-of-plane bending & ring bending

3. C - H Stretch Alkanes 3000 - 2840 (s) other: near 1375 & 1450 Cycloalkanes 3100 - 2990 (m) other: near 1450 (m) Alkenes above 3000 (s) other: near 1416 (m) ; 1000-650 (w) ; near 850 (s) Alkynes 3333 - 3267 (n,s) stronger-narrower than OH & NH other: 700-610 (b,s) ; 1370-1220 (w,o) Aromatics 3100 - 3000 & 2000 - 1650 (w,o) other: 900-675 (s) ; 1300-1000 (m) Aldehydes 2830 - 2695 (2:s) w / near 1390 other: near 2720 (m)

4. C to C Alkanes below 500; 1200 - 800 (w) are of little value best is C-H CH 3 2962 & 2872 CH 2 near 2926 & near 2853 (+ / -10) CH near 1375 & near 1450 Alkenes 1667 - 1640 (m) Alkynes 2260 - 2100 (w)

5. ALCOHOLS -- PHENOLS Alkenes - Phenols -OH & C-O OH 3650 - 3584 (b,s) ; 1420 - 1330 (m) CO 1260 - 1000 (s) ETHERS Ethers C-O-C similar to C-C-C but more intense 1150 - 1085 (s)

6. CARBONYL C=O containing Carbonyls (ketones, aldehydes, carboxylic acids, esters, anhydrides, amides) C=O 1870 - 1540 (s) Ketones 1300 - 1100 (m) Aldehydes 1740 - 1720 C-H 2830-2695 (2:m) & near 2720 (m) Carboxylic Acids O-H 3300 - 2500 (b,s) C=O near 1766 (s) C-O & O-H near 1320-1210 (m) & near 1440-1395 (m) Esters C=O 1750 - 1715 (s) higher freq than ketones C-O 1210- 1163 (2:s)

7. NITROGEN CONTAINING Amides NH 2 or NH 1650 - 1515 other: near 3520 (m) & near 3400 (m) C=O 1694 & 1650 (s) C-N near 1400 (m) Amine N-H near 3500 (w) & near 3400 (w) other: NH 1650-1580 (m) C-N 1250 - 1020 (m) aromatic C-N 1342-1266 (s) Nitriles C=N 2260 - 2222 (m)