IR and MS

ir

• provided information about what function groups are present or absent

• measures the amount of light absorbed or transmitted as a function of wavenumber

nmr

• provides information on the number, connectivity, and functional-group environment of carbons and hydrogens

UV-vis

• provides information about the types of pie electron systems present

mass spectrometry

• gives information about molar mass, and composition by analyzing the fragments of radical ions

wavenumber

• 1/lambda

2.1-2.6

2.3-2.9

4.5-6.0

aldehydic

9.0-10.0

6.5-8.0

0.7-1.7

halogens O~Cl>Br>I

3.5-4.5

cis coupling constant

J = 6-14

trans coupling constant

J = 11-18

geminal

J = 0-3.5

primary and secondary alcohols chem shift

• 3.2-4.2

pure ethanol chem shift

• 5.3

• much H-bonding

ethanol in CCl4

• 2-3

• little H-bonding

gas-phase ethanol

• 0.8

• essentially no H-bonding

25-52

10-45

100-145

10-50

20-60

40-80

35-60

190-220 (aldehyde/ketone)