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Guest Inclusion in Butadiyne-Bridged Macrocycles
(ブタジイン架橋マクロサイクルのゲスト分子包摂)
Tobe Lab. M1Hiroshi Takeda
1
Contents
• Host–Guest Chemistry
• About Macrocycle
• Complexation of Butadiyne-Bridged Pyridinophane and Tropylium Cation
• STM & Guest Inclusion Ability
• My Work
• Summary
2
Contents
• Host–Guest Chemistry
• About Macrocycle
• Complexation of Butadiyne-Bridged Pyridinophane and Tropylium Cation
• STM & Guest Inclusion Ability
• My Work
• Summary
3
Host–Guest Chemistry
Like the relation between “a key and a keyhole”, an enzyme reaction may show high selectivity. The molecules called host have spaces where they can selectively recognize a specific molecule. The molecules called guest are accepted in a host molecules. We create the substances which show new recog-nition ability, and study about their interaction .
+
hostguest4
Contents
• Host–Guest Chemistry
• About Macrocycle
• Complexation of Butadiyne-Bridged Pyridinophane and Tropylium Cation
• STM & Guest Inclusion Ability
• My Work
• Summary
5
About Macrocycle
pyridinebutadiyne
Butadiyne-bridged pyridinophane
N
HC C C CH
( )
macrocycle
6
Mechanism of Complexation
δ -δ -
δ -δ - δ+
Ion Dipole Interaction The ion-dipole interaction refers to weak noncovalent bonds. It is due to interactions between ions and polar groups of molecules (or induced dipoles).
7
Titration of Pyridinophan
8
1
R=
H
H2CCH2
H2C
CH2
H2C
CH2
H2C
CH3
H
Titration of Pyridinophan
H
9
1R=C8H17Addition
of guest
Shiftch
emic
al s
hift
concentration
KK is complex formation constant :錯形成定数
Contents
• Host–Guest Chemistry
• About Macrocycle
• Complexation of Butadiyne-Bridged Pyridinophane and Tropylium Cation
• STM & Guest Inclusion Ability
• My Work
• Summary
10
Complexation of Butadiyne-Bridged Pyridinophane and T ropylium Cation in Solution
R=C8H17
R=C8H17
To examine the binding ability of pyridinophanes 1 and 2, we choose tropylium ion as a guest
⇒the cation size is slightly larger than the cavity of 1 but it is too small to fit the cavity of 2.
tropylium ion
1 2
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Complexation of Butadiyne-Bridged Pyridinophane and Tropylium Cation in Solution
R=C8H17R=C8H17
The nonlinear least-squares regression analysis gave K11(1:1) and K21(2:1) → For 1, K11 = 3×103 M-1 and K21 = 3×104 M-1 For 2, K11 = 1×102 M-1 and K21 = 4×102 M-1
The larger binding constants of 1 than those of 2 → The size of the cavity of 1 which fits better than that of 2.
> K11(1:1) K21(2:1)
1 3 ×103 3 ×104
2 1 ×102 4 ×102
K is complex formation constant : 錯形成定数 12
1 2
Contents
• Host–Guest Chemistry
• About Macrocycle
• Complexation of Butadiyne-Bridged Pyridinophane and Tropylium Cation
• STM & Guest Inclusion Ability
• My Work
• Summary
13
Until the former half of the 1980s, It was the dream for researchers to study a substance with an atomic level by using the atomic resolution microscope.
Binnig Rohrer
A scanning tunneling microscope (STM) is an instrument for imaging surfaces at the atomic level. Its development in 1981 ear-ned its inventors, Gerd Binnig and Heinrich Rohrer (at IBM Zürich), the Nobel Prize in Physics in 1986.
Invention of STM (Scanning Tunneling Microscopy)
Scanning Tunneling Microscopy(STM)
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Scanning Tunneling Microscopy (STM)
Tunneling current
electron
Tunneling current
Tip
Sample
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Scanning Tunneling Microscope (STM)
Small change
d (distance)
Ji (tunneling current)
Large change
Ji = Aexp(-Bd)
Ji : tunneling currentA, B : constantd : distance
Tip
Sample
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Self-Assembly of Butadiyne-Bridged Pyridinophane
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R = COOC8H171
Guest Inclusion Ability of Butadiyne-Bridged Pyridinophane on Solid Surfaces
The brighter spots within the cavity of 1 are trapped tropylium cations.
An empty macrocycle 1
+
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R = COOC8H171
Guest Inclusion Ability of Butadiyne-Bridged Pyridinophane on Solid Surfaces
・ Squares filled with a bright spot are 1+ tropylium cation complex
・ Darker square features are 3
・ They appear randomly in the domains
+
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R = COOC8H17R = COOC8H17
1 3
Guest Inclusion Ability of Butadiyne-Bridged Pyridinophane on Solid Surfaces
・ Squares filled with a bright spot are 1+ tropylium cation complex
・ Darker square features are 3
・ They appear randomly in the domains 20
R = COOC8H17R = COOC8H17
1 3
Only 1 formed the complex with tropylium cation !
Contents
• Host–Guest Chemistry
• About Macrocycle
• Complexation of Butadiyne-Bridged Pyridinophane and Tropylium Cation
• STM & Guest Inclusion Ability
• My Work
• Summary
21
Purpose of My Work
・ Synthesis of butadiyne-bridged pyridino phane which possesses a larger cavity
・ Evaluation of its guest inclusion
N
N
N
N
N
N
C10H21
C10H21
C10H21
C10H21
C10H21
C10H21
・ Formation of two-dimensional (2D) molecular networks on the solid surface.
・ guest inclusion ability
O
O
N
OFeCl4
-
+
22
O
O OPF6
Contents
• Host–Guest Chemistry
• About Macrocycle
• Complexation of Butadiyne-Bridged Pyridinophane and Tropylium Cation
• STM & Guest Inclusion Ability
• My Work
• Summary
23
Summary• The tetragonal butadiyne-bridged pyridinophane and
tropylium cation form the complex in solution.
• The binding constants of tetragonal butadiyne-bridged pyridinophane are larger than those of hexagonal.
• The tetragonal butadiyne-bridged pyridinophane also forms complex with tropylium cation on solid surfaces.
• A purpose of my work is to synthesize butadiyne-bridged pyridinophane which possesses a larger cavity and evaluate its guest inclusion.
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Thank you for listening.
25