cwiwPwZ
‡gv: gvmyg web InvecÖfvlK, imvqb wefvMXvKv †iwm‡Wbwmqvj g‡Wj K‡jR
AvR‡Ki cvV
mgvYyZv
Øv`k †kÖwY
wkLbdj
GB cvV †k‡l wkÿv_©xiv Rvb‡Z cvi‡e-mgvYyZv KxMvVwbK mgvYZv Kx I Zvi kZ© wÎgvwÎK mgvbyZv I Zvi kZ© - Rvb‡Z cvi‡e|
Isomerism/mgvYyZv
‡h mKj †hŠ‡Mi AvbweK ms‡KZ GKB wKš‘ MvVwbK ms‡KZ wfbœ nevi Kvi‡Y Kgc‡ÿ GKwU †fŠZ ev ivmvqwbK a‡g©i cv_©K¨ †`Lvq Zv‡`i †K ci¯ú‡ii Zv‡`i‡K ci¯ú‡ii mgvby e‡j |‡hmKj †hŠ‡Mi AvbweK I MvVwbK ms‡KZ GKB wKš‘ wÎgvwÎK web¨vm wfbœ nevi Kvi‡Y Kgc‡ÿ GKwU †fŠZ ev ivmvqwbK a‡g©i cv_©K¨ †`Lvq Zv‡`i †K ci¯ú‡ii mgvby e‡j |
‡hŠ‡Mi Giæc ag©‡K mgvYyZv(Isomerism) e‡j |
mgvYyZv
StereoisomersStereoisomers// wÎgvwÎK mgvYyZv wÎgvwÎK mgvYyZv
Structural isomerismStructural isomerism/MvVwbK mgvYyZv/MvVwbK mgvYyZv
DiastereomersDiastereomersnot mirror images
EnantiomersEnantiomersNon-superimposable mirror image
MvVwbK mgvYyZv
‡hŠ‡Mi Abyw¯’Z wewfbœ cigvYy ev g~j‡Ki m¤¢ve¨ GKvwaK Ae¯’vb web¨v‡mi cv_©K¨ †nZz‡h mgvYyZvi D™¢e nq Zv‡K MvVwbK mgvYyZv e‡j |
8
1. wkKj mgvYyZv1. wkKj mgvYyZvKve©b wkK‡ji wfbœZv‡nZz G mgvYyZvi D™¢e nq|
9
1. Chain isomerism1. Chain isomerism
C6H14p.2, Q.2
10
2. Ae¯’vb mgvYyZv2. Ae¯’vb mgvYyZv
GKB Kve©b KvVv‡gv Dcw¯’Z wKš‘ Kvh©Kix g~j‡Ki Ae¯’v‡bi wfbœZvi Kvi‡Y G ai‡bi mgvYyZvi D™¢e N‡U|
11
2. Ae¯’vb mgvYyZv2. Ae¯’vb mgvYyZve.g. Butan-1-ol and butan-2-ol
(molecular formula: C4H10O)
12
Wrong !
Q.15
Are they position isomers ?
Giv ci¯ú‡ii wkKj mgvYy
13
3.Kvh©Kix g~jK mgvYyZv3.Kvh©Kix g~jK mgvYyZv
wfbœ wfbœ Kvh©Kix g~j‡Ki &&&&&&&&&&&&&&Dcw¯’wZi Kvi‡Y &&G ai‡bi mgvYyZvi D™¢e nq|
14
Functional Group IsomerismFunctional Group Isomerism
C
H
H
H
C
H
H
O H C O C HH
H
H
H
H
Alcohol EtherVs
C2H6O
New Way Chemistry for Hong Kong A-Level Book 3A1515
Functional Group IsomerismFunctional Group Isomerism
H C
H
H
C
H
H
C
H
O
H C C C H
O H
H
H
H
Aldehyde KetoneVs
C3H6O
New Way Chemistry for Hong Kong A-Level Book 3A1616
4.
‡gUvgvwiRg
4.
‡gUvgvwiRg
Kvh©Kix g~j‡Ki &&&&&&&&&&&Dfq cv‡k Kve©b cigvYyi msLvi wfbœZvi Kvi‡b G ai‡bi mgvYyZvi &&&&D™¢e nq|
New Way Chemistry for Hong Kong A-Level Book 3A1717
4.
‡gUvgvwiRg
4.
‡gUvgvwiRge.g. Methoxypropane and ethoxyethane
(molecular formula: C4H10O)
New Way Chemistry for Hong Kong A-Level Book 3A1818
4.
‡gUvgvwiRg
4.
‡gUvgvwiRge.g. Pentan-2-one and pentan-3-one
(molecular formula: C5H10O)
can also be considered as position isomers
New Way Chemistry for Hong Kong A-Level Book 3A1919
OH
OHAe¯’vb mgvYyZv
OH
OHAe¯’vb mgvYyZv
wkKj mgvYyZv
C4H10O
New Way Chemistry for Hong Kong A-Level Book 3A2020
5. U‡UvgvwiRg
5. U‡UvgvwiRg
`ywU wfbœ Kvh©Kix g~j‡Ki g‡a¨ GKwU MwZkxj mvg¨ve¯’v eRvq ZvK‡j G ai‡Yi mgvYyZvi m„wó nq|
New Way Chemistry for Hong Kong A-Level Book 3A2121
5. U‡UvgvwiRg
5. U‡UvgvwiRg
ethenol ethanal
Bbj – wK‡Uv
U‡UvgvwiR
g
C C
H
H
H
OH
C C
H
H
H
H
O
New Way Chemistry for Hong Kong A-Level Book 3A2222
5. U‡UvgvwiRg
5. U‡UvgvwiRg
ethenol ethanal
B‡bvj KvVv‡gv‡Z -OH MÖæcwU mivmwi wØeÜb hy³ Kve©‡bi mv‡_ hy³ _v‡K
C C
H
H
H
OH
C C
H
H
H
H
O
New Way Chemistry for Hong Kong A-Level Book 3A2323
StereoisomerismStereoisomerism
wÎgvwÎK mgvYyZvwÎgvwÎK mgvYyZv
New Way Chemistry for Hong Kong A-Level Book 3A2424
StereoisomerisStereoisomerismm†hŠ‡Mi AvbweK I MvVwbK ms‡KZ GKB wKš‘ wÎgvwÎK web¨vm wfbœ nevi Kvi‡Y G ai‡bi mgvYyZvi m„wó nq|
New Way Chemistry for Hong Kong A-Level Book 3A2525
StereoisomerisStereoisomerismm
wÎgvwÎK mgvYyZv `yB ai‡bi :
1. Geometrical isomerism
2. Optical isomerism
New Way Chemistry for Hong Kong A-Level Book 3A2626
Geometrical IsomerismGeometrical IsomerismC=C double bond.N~Y©b cÖwZeÜKZvB G mgvYyZvi KviY............................
StereoisomerisStereoisomerismm
New Way Chemistry for Hong Kong A-Level Book 3A2727
Rotation about the axis of a double bond through an angle of 90o results in the breaking of the π
bond
maximum overlap of pz orbitals
minimum overlap of pz orbitals
New Way Chemistry for Hong Kong A-Level Book 3A2828
Geometrical Isomerism - CriteriaGeometrical Isomerism - Criteria
d
c
b
a
where a b and c d
New Way Chemistry for Hong Kong A-Level Book 3A2929
wmm- UªvÝ mgvYyZv
C=C double bond Gi mv‡_ hy³ GKB ai‡bi MÖæc ¸‡jv GKB w`‡K _vK‡j Zv‡K wmm/cis mgvYy e‡j|
C=C double bond Gi mv‡_ hy³ GKB ai‡bi MÖæc ¸‡jv wfbœ w`‡K _vK‡j Zv‡K UªvÝ/trans mgvYy e‡j|
New Way Chemistry for Hong Kong A-Level Book 3A3030
Geometrical Isomers Geometrical Isomers
H
Cl
H
Cl
H
H
Cl
Cl
1,2 dichloro 1,2 dichloro
cis-butene-2 trans-butene-2
m.p. 80C 50C
b.p. 60C 48C
1.
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
New Way Chemistry for Hong Kong A-Level Book 3A3232
wKQz geometric isomers mg~‡ni ¸iyZ¡c~Y© chemical properties Gi difference _v‡K1. H COOH
H COOH
H COOH
HOOC H
K1 1.4102 mol dm3 >> 9.3105 mol dm3
K2 8.0107 mol dm3 < 3.6105 mol dm3
New Way Chemistry for Hong Kong A-Level Book 3A3333
O
O
H
OH
O
Formation of intra-molecular hydrogen bond helps to draw electrons from the –OH Weakening O – H
Ease of release of H+
H+
K1 : cis > trans
Geometric Isomers in Cycloalkanes Ring structures like C=C restrict
rotation and therefore can result in cis and trans isomers
34
New Way Chemistry for Hong Kong A-Level Book 3A35
Optical Isomerism/Av‡jvK mgvYyZv
35
New Way Chemistry for Hong Kong A-Level Book 3A36
Av‡jvK mgvYyZv
‡h mKj †hŠ‡Mi AvbweK I MvVwbK ms‡KZ GKB wKš‘ wÎgvwÎK web¨vm wfbœ nevi Kvi‡Y GK mgZjxq Av‡jvi cÖwZ wfbœ iæc AvPib K‡i Zv‡`i‡K ci¯ú‡ii Av‡jvK mwµq mgvYy e‡j|
36
New Way Chemistry for Hong Kong A-Level Book 3A3737
Av‡jv mwµq mgvYyZvi kZ©
AcÖwZmg Kve©b cigvYy _vK‡Z n‡e A_©vr KvBivj Kve©b _vK‡Z n‡e |
‡Kvb Sp3 carbon atom Gi mv‡_ PviwU wfbœ wfbœ cigvYy ev MÖæc hy³ _vK‡j H Kve©b cigvYywU AcÖwZmg nq|
New Way Chemistry for Hong Kong A-Level Book 3A3838
KvBivj Kve©b
New Way Chemistry for Hong Kong A-Level Book 3A3939
It is not superimposable with its mirror image
A_©vr cimec‡ii Dci AmgcvwZZ n‡Z n‡e
mirror
New Way Chemistry for Hong Kong A-Level Book 3A4040
New Way Chemistry for Hong Kong A-Level Book 3A4141
plane-polarized light
Light vibrating in ALL possible planes Light vibrating in
only ONE plane
New Way Chemistry for Hong Kong A-Level Book 3A4242
Optically active
Optically active substance can rotate the plane of polarization of plane-polarized light
Measured by a polarimeter.
New Way Chemistry for Hong Kong A-Level Book 3A4343
Optically active
Dextrorotatory(+) : Nwoi KuvUvi w`‡K N~Y©Y (to the right)
Laevorotatory(-): Nwoi KuvUvi wecixZ w`‡K N~Y©Y (to the left)
Dc‡ii bg~bvwU Kx Dextrorotatory ?
No. It is laevorotatory
New Way Chemistry for Hong Kong A-Level Book 3A4444
C
OH
H CH3
C2H5 C
OH
HH3C
C2H5
Enantiomers (對映異構體 )
Giv G‡K Ac‡ii `c©Y cÖwZwe¤^
Giv G‡K Ac‡ii Dci Dc¯’vbxq bq
Giv GK mgZjxq Av‡jvi Zj‡K GKB cwigv‡Y wKš‘ wecixZ w`‡K †Nvivq
New Way Chemistry for Hong Kong A-Level Book 3A45
g~j¨vqY
UviUvwiK Gwm‡Wi KqwU Av‡jvK mwK&ªq mgvYy m¤¢e?
Maleic acid I Fumaric acidGi g‡a¨ †KvbwUi MjYvsK I ùzUYvsK †ewk
v‡es †Kb?
45
New Way Chemistry for Hong Kong A-Level Book 3A46
THANKYOU
46