ch3b isomers
TRANSCRIPT
Isomerism
• Molecules which have the same molecular formula, but differ in the arrangement of their atoms, are called isomers.
• Constitutional (or structural) isomers differ in their bonding sequence.
• Stereoisomers differ only in the arrangement of the atoms in space. =>
IsomersIsomers
StereoisomersStereoisomersconnectivity =connectivity =
orientationorientation≠≠
ConstitutionalConstitutionalstructural structural
connectivity connectivity ≠≠
DiastereomersDiastereomersnot mirror images
EnantiomersEnantiomersNon-superimposable mirror image
Structural Isomers
CH3 O CH3 and CH3 CH2 OH
CH3
CH3and
=>
ethane ethane
CC22HH6 6 oror CHCH33CHCH33
alkanes: propane (CHalkanes: propane (CH33CHCH22CHCH33))
H C
H
H
C H
H
H
C H
H
H
propane (Cpropane (C33HH88))
H C
H
H
C
H
H
C H
H
H
alkanes: CHalkanes: CH33CHCH22CHCH33
propane (Cpropane (C33HH88))
H C
H
H
C
H
H
C H
H
H
alkanes: CHalkanes: CH33CHCH22CHCH33
propane (Cpropane (C33HH88))
H C
H
H
C
H
H
C H
H
H
C H
H
H
C H
H
Horor
alkanes: propanealkanes: propane
butane (Cbutane (C44HH1010))H C
H
H
C
H
H
C H
H
H
propane propane (C(C33HH88))
H C
H
H
C
H
H
C C
H
H
H
H
H
H C
H
H
C
C
H
C H
H
H
H H
H
alkane isomers:alkane isomers: How many How many CC55HH1010 isomers? isomers?
butane (Cbutane (C44HH1010))
H C
H
H
C
H
H
C C
H
H
H
H
H
H C
H
H
C
C
H
C H
H
H
H H
H
alkane isomers:alkane isomers: How many How many CC55HH1010 isomers? isomers?
butane (Cbutane (C44HH1010))
H C
H
H
C
H
H
C C
H
H
H
H
H
H C
H
H
C
C
H
C H
H
H
H H
H
alkane isomers:alkane isomers: How many How many CC55HH1212 isomers? isomers?
C C C C C
H
H
H
H
H
H
H
H
H
H
H
H
How many CHow many C55HH12 12
isomers?isomers?
these two structures these two structures are identicalare identical
bond line bond line structures:structures:
alkane isomers:alkane isomers: How many CHow many C55HH12 12
isomers?isomers?
these two structures these two structures are identicalare identical
alkane isomers:alkane isomers: How many CHow many C55HH12 12
isomers?isomers?
these two structures these two structures are identicalare identical
alkane isomers:alkane isomers: How many CHow many C55HH12 12
isomers?isomers?
Butane = CButane = C44HH1010, CH, CH33CHCH22CHCH22CHCH33
HH
H H
H HH H
HH
C C
H
H
H
H
H
C
H
H
C
H
H
H
Butane, bond rotationsButane, bond rotations
rotations about single rotations about single bonds are very fast.bonds are very fast.
Butane, bond rotationsButane, bond rotations
= butane= butane
Butane, bond rotationsButane, bond rotations
==
Butane, bond rotationsButane, bond rotations
Isomers of CIsomers of C44HH1010..
==
==
Draw all of the isomers with the formula C4H9Cl.
Cl
Cl
Cl
Cl
Stereoisomers
Draw all of the isomers with the formula C4H9Cl.
ClH HCl
Are these two structures identical?
Draw all of the isomers with the formula C4H9Cl.
HCl
A 1:1 mixture of enantiomers is called a racemic mixture.
ClH+ H Cl +
HCl
HCl Are these two
structures identical?
mirror
Isomers ?
C CBr
CH3
Br
H3CC C
CH3
Br
Br
H3Cand
Cis - same side Trans - across
Cis-trans isomers are also called geometric isomers.There must be two different groups on the sp2 carbon.
C CH3C
H H
HNo cis-trans isomers possible