Orgo Chem 2 Exam 1

What’s is the approximate absorption on and IR graph?

sp3 C-H

3000--2850

What’s is the approximate absorption on and IR graph?

sp2 C-H

just above 3000

What’s is the approximate absorption on and IR graph?

sp C-H

about 3300 sharp

What’s is the approximate absorption on and IR graph?

O-H (alchol)

BIG broad swoop- 3200-3600

What’s is the approximate absorption on and IR graph?

N-H

3300-3500

Amides rules regarding a primary NH, secondary NH, and tertiary NH

primary- 2 small swoops around 3300-3500

Secondary- small peak (swoop) around 3300-3500

Tertiary- N/A

Aldehyde

O double bond C with only ONE functional group

Ketones

O double bond with TWO functional groups

What’s is the approximate absorption on and IR graph?

C (double bond) C

2100-2260

What’s is the approximate absorption on and IR graph?

C (triple bond)

2200-2300

What’s is the approximate absorption on and IR graph?

C (double bond) O

1700 (LOW NUMBER)

What’s is the approximate absorption on and IR graph?

C (double bond) C

1650 (LOW)

What’s is the approximate absorption on and IR graph?

C-O

1000-1300 (LOWEST)

Key difference between alchol and ether

alcohol has OH and C-O

Ether only has a C-O

Key characteristic of an Aldehyde absorptions

C (double) O around 1700

and

C-H absorption at 2800 and 2900

IR difference in broad swoop Alcohol vs Carboxylic acid

Alcohol→ borad O-H around 3200-2600

Carboxy → 3300-2500 and a C (double) O 1700

stronger the bond the HIGHER/LOWER the wavenumber

HIGHER

lighter the atoms the HIGHER/LOWER the wavenumber

HIGHER

What 2 things does for s-characters mean

stronger bond

high wave number

What does resonance mean for strength of bond and wave number

weak effective double bond

low wave number

5 key parts of Electron Impact (EI) Mass spectrometry

1. Molecule is vaporized

2. 2. High energy electrons interact with the molecule

3. Electron is removed, producing molecular ion/radical cation (M+.)

4. Molecular ion can break apart into smaller fragments ions

5. Ions are detected according to their mass-to-charge ratio

What is a Molecular Ion (M+ . )

It corresponds to the molecular mass of the compound

what is a base peak?

Tallest peak in spectrum, not always the molecular ion

What are fragment peaks?

Produced when ions break apart

They provide info about structure

Odd molecular ion means…. What number of N atoms

Uneven N

Isotope pattern- 3:1 Cl or Br

Cl

isotope patterns 1:1… Br or Cl?

Br

what is the M + 1 peak ?

Most carbon is the usual 12 C, but there is still some 13 C that naturally occurs. Its molecular weight plus 1

what type of fragmentation does aldehydes and ketones use?

alpha cleavage (next to a carboxyl group)

What type of fragmentation does alcohol use?

Alpha cleavage

M- 18 (dehydration effect)

What fragmentation does Amines use?

basic fragmentation patterns involving Carbon adjacent to Nitrogen (alpha and beta carbons)