Chemistry 328N
You don’t need DNA
to tell these apart!!
Chemistry 328N
Splitting of Signals
Nonequivalent protons split each other if they are on
adjacent carbons, i.e. separated by 3 sigma bonds
Chemistry 328N
BUT……………….
When using the Right-Hand Rules, it is important to remember
that the rules assume charges move in a conventional current
(the hypthetical flow of positive charges). In order to apply the
Right-Hand Rule to a moving negative charge, the direction of
charge flow must be reversed--….or use your LEFT hand.
The Right-Hand Rule #2
determines the direction of the
magnetic field aroud a current-
carrying wire and vice-versa
Chemistry 328N
“Tricks” for solving unknowns
Review….
Empirical formula is lowest common
denominator ratio of atomic composition
From Homework: unknown has an empirical
formula of C4H9….a single high field peak in
the 1H nmr and a molecular ion at M/Z = 114.
….propose a structure..and predict the M/Z of
the most intense fragment you expect to see in
the mass spectrum
Chemistry 328N
Index of Hydrogen Deficiency
I knew this as the unsaturation number
Valuable characteristic of structure
– Provides you with number of double bonds or rings
in a compound
– Easy with CHO formulas only…be careful with N
– Simplest, “saturated” normal alkanes have:
H –(CH2)n–H = CnH2n+2
Chemistry 328N
Index of H Deficiency
IHD: the sum of the number of rings and pi
bonds in a molecule….
Compare the number of hydrogens in an
unknown compound with the number in the
reference compound CnH2n+2
Chemistry 328N
CnH2n+2
C6H14
C6H12
2/2=1 => 1 ring or 1 double bond
Index of H Deficiency
IDH =2
(Hreference - Hmolecule )
C6H12 C5H10 C9H14
-
Chemistry 328N
Index of H Deficiency
No correction is necessary for the addition of
atoms of O
Subtract one H for each atom of halogen added
(halogens like Cl replace H one for one)
Add one hydrogen For each atom of N added to
the reference hydrocarbon
IDH =2
(Hreference - Hmolecule )
Chemistry 328N
“Unsaturation” Number or HDI
Should be CnH2n+2 +1-1 = C8H18
but it is… C8H14
Missing H4
So index is…. 4/2=2
Add one H for N and
subtract one for ClN
Cl H
CH3
C8H14ClN
Chemistry 328N
Calculate the Unsaturation Number
Should be CnH2n+2 +1 = C8H19
but it is… C8H9
Missing H10
So number is…. 10/2=5!
Add one H for NN
HH
H C8H9N
Chemistry 328N
0
Type of H d
1.6-2.6
2.0-3.0
0.9
1.2-1.4
1.4-1.7
2.1-2.3
0.5-6.0
2.2-2.6
3.3-4.0
2.2-2.5
0.5-5.0
RC CH
O
O
RCH2 OR
(C H3 ) 4 Si
ArC H3
RCH3
RCCH3
ROH
RCH2 R
R3 CH
R2 NH
RCCH2 R
R2 C=CRC HR2
Type of H d
Chemical Shift - 1H-NMR
Chemistry 328N
Chemical Shift - 1H-NMR
4.6-5.0
9.5-10.1
5.0-5.7
10-13
3.5-3.9
4.1-4.7
3.1-3.3
3.4-3.6
3.6-3.8
4.4-4.5
6.5-8.5
O
O
O
O
R2 C=C HR
RCH
RCOH
RCH2 Cl
RCH2 Br
RCH2 I
RCH2 F
ArH
R2 C=C H2RCOC H3
RCOC H2 R
Type of H d Type of H d
Chemistry 328N
Sample spectra
2.50 2.40 2.30 2.20 2.10 2.00 1.90 1.80 1.70 1.60 1.50 1.40 1.30 1.20 1.10 1.00 0.900
5
10
15
4
6
18
CH3
CH3
CH3CH3
O
C7H14O
Chemistry 328N
ClCH2CH2CH2Cl
3.5 3.0 2.50
1
2
3
4
5
6
7
8
9
2.30 2.20 2.100.0
0.5
1.0
1.5
2.0
2.5
3.0
Chemistry 328N
5.5 5.0 4.5 4.0 3.5 3.0 2.5 2.0 1.5 1.00
1
2
3
4
5
6
7
5.80 5.70 5.600.00
0.10
0.20
0.30
0.40
0.50
0.60
0.70
0.80
0.90
1.00
1.10
1.20
2.20 2.10 2.000.0
0.5
1.0
1.5
2.0
1.20 1.10 1.000.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5Cl2HCCH2CH3
Chemistry 328N
More Practice
4.5 4.0 3.5 3.0 2.5 2.0 1.5 1.00
5
10
15
1.50 1.40 1.30 1.20 1.10 1.000
1
2
3
4
5
6
7
8
9
10
4.5 4.0 3.50.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5 C6H14O2
Chemistry 328N
0
Type of H d
1.6-2.6
2.0-3.0
0.9
1.2-1.4
1.4-1.7
2.1-2.3
0.5-6.0
2.2-2.6
3.3-4.0
2.2-2.5
2.3-2.8
0.5-5.0
RC CH
O
O
RCH2 OR
(C H3 ) 4 Si
ArC H3
RCH3
RCCH3
ROH
ArC H2 R
RCH2 R
R3 CH
R2 NH
RCCH2 R
R2 C=CRC HR2
Type of H d
Chemical Shift - 1H-NMR
Chemistry 328N
4.6-5.0
9.5-10.1
5.0-5.7
10-13
3.5-3.9
4.1-4.7
3.1-3.3
3.4-3.6
3.6-3.8
4.4-4.5
6.5-8.5
O
O
O
O
R2 C=C HR
RCH
RCOH
RCH2 Cl
RCH2 Br
RCH2 I
RCH2 F
ArH
R2 C=C H2RCOC H3
RCOC H2 R
Type of H d Type of H d
Chemical Shift - 1H-NMR
Chemistry 328N
Deuterium Oxide
Heavy water is heavier than H2O (duh?), having a density of 1.108 g/cm3. Heavy water ice will actually sink in light liquid water. The freezing and boiling points are also elevated somewhat, with heavy water freezing at 3.81° C (38.86° F) and boiling at 101.42° C (214.56° F) at standard atmospheric pressure.
Heavy water toxicity manifests itself when about 50% of the water in the body has been replaced by D2O. Prolonged heavy water consumption can cause death. The price is about $300 per kilogram.
Chemistry 328N
Property D2O (Heavy water) H2O (Light water)
Freezing point (°C) 3.82 0.0
Boiling point (°C) 101.4 100.0
Density at STP
(g/mL)1.1056 0.9982
Dynamic viscosity (at
20°C, mPa·s)1.25 1.005
Heat of fusion
(cal/mol)1,515 1,436
pH (at 25°C) 7.41 (sometimes "pD") 7.00
Cost per kilogram ~$300~$0.002 for tap
~$5.00 for Fiji!!?
Deuterium Oxide vs Water
Chemistry 328N
http://www.imdb.com/
title/tt0059263/
Joachim Ronneberg
Heavy water plant in
Vemork, Norway
http://www.telegraph.co.uk/news/7664351/A-new-mission-
for-the-hero-of-Telemark.html