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time dependent phenomena

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Dynamic Properties: time dependent phenomena Static Properties: time independent phenomena – PowerPoint PPT presentation

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Title: time dependent phenomena


1
??????????????????
Dynamic Properties
time dependent phenomena
Static Properties
time independent phenomena
2
Static Properties
time independent phenomena
Geometry of Excited State
Acid-Base Properties
Dipole Moment
Solvent Effect
3
Geometry of Excited State
Acetylene
HC ? CH
transoid trigonal planar
(linear)
ground state
excited state
4
2 sC-H
1 sC-C
2 pC-C
??? excited state ?????????? orbital ????
p ? p transition (250-210 nm)
sp2 hybridization
5
Ethylene
H2C CH2
???????????? p ???porbitals ????????????
P-orbitals ??? C ???????????? ???????????????????
??????????????? s-bond ???CH2-plane ?????????
s-bond
p ? p
6
?????????? CH2 ????????? ?????????????????????????
???????????????????????????????? cis-trans
Photoisomerization
900
7
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8
Formaldehyde
p ? p Transition
n ? p Transition
???????????
????????????? p-bond ????????????????????????????
C-O atoms ?????????
9
???????????? p-orbital ???????????????????? ????
??????????????? C-atom ??????????????? ???????
hybridization ???? (? SP3) ???????????????????????
?????????
10
H
o
122 A
o
o
132 A
O
C
131 A
o
O
C
120
C
O
H
H
o
120
o
120
H
o
120
o
35
Planar
Bent
Bent
H
H
(n,
p
)
S
S
T
(n,
p
)
0
1
1
11
Acid-Base Properties
(5)
(1) 0.02 M NaOH (2) 0.02 M Acetic acid
0.02 M sodium acetate (3) pH 5-6 (4) 0.004 M
HClO4 (5) 0.15 M HClO4
(1)
(2)
??? 2-Naphthol ??? pH ???? ?
Fluorescence Spectra
12
(No Transcript)
13
Spectra 2,3 ??? 4 ?????????????? ????????????
?? anion ??? 2-naphthoxide (??????????? ?????????
??? 2-naphthol) ????????
14
..
Froster-Weller Cycle
????????????? pKa ????????????
15
A- (S1)
A- (S0)
D H
?????? 5.8
Froster - Weller cycle for deriving


K
values
for excited states.
p
16
hn
DH
HA
HA
H A-
DEHA
hn
DH
HA
H A-
H A-
DEA-
DEHA DH DH DEA-
17
Solvent Effect
???????????? ??????????? ??????????????????? (????
??????????????)
18
p
p
DE hn
???????
DE hn
DE gt DE
p
p
????????????????? ???????????
????????????????? ???????????
19
???????????????????????????????????????????
??????????? Bathochromic shift ???? red
shift
???????????????? ?????????????????
20
???? Polar solvent ?? stabilized p?
ptransition
21
Blue shift ?
Hypsochromic shift
lmax ???? (????????????????)
22
???????????? ?????????????????? ????
?????????????? n? p transition ??? Pyridinium
Iodide ???????????? ????????????? iodide ion
????? aromatic ring
? p

.
n
Et
Et
N
CO
Et
N
CO
Et
2
2
.
-
I

I

excited state
ground state
23
p
p
DE hn
???????
DE hn
DE lt DE
n
????????????????? ???????????
n
????????????????? ???????????
24
???? Polar solvent ?? destabilized n?
ptransition
25
Non - polar solvents
Polar solvents
S2 (n,p)
S2 (p,p)
???????
S1 (n,p)
S1 (p,p)
S0
S0
Solvent Polarity
26
Polar solvent
stabilized p? p transition destabilized n?
p transition
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