ir/mass spec quiz

rule of 13

#c=x=MW/13

#h=y=MW-(X(12))

#nitrogens in DOU also includes…

P

#carbons in DOU also includes..

Si

max hydrogen rule

max hydrogens=2c+2

if M+2 is as tall as main peak, there is a __ in the compound

Br

is main peak is x3 taller than M+2 peak, there is a __ in the compound

Cl

carboxylic acids are ____(broader/sharper) than alcohol peaks

broader

saturated (sp3) C-H peaks

below 3000 (s)

unsaturated C-H peaks

above 3000 (sh)

critical reference value for CC/CN zone

2250 (m-w)

carboxylic amide

-30cm (1685)

carboxylic ester

+30 cm (1745)

carboxylic halides

+90 cm (1805)

ring strain effects

decreasing ring size→ increases by 30cm each time

order of zones IR

1) OH, N-H

2) C-H

3) Ctriple bondC, nitrile

4) C=O

5) C=C

6) Fingerprint region (<1500cm)

aromatic c=c

1600 and 1500

unsaturated c=c

above 1600

NO2 ir frequencies

1550, 1350

aldehyde c-h peaks

2850, 2750