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

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Contents

• Host–Guest Chemistry

• About Macrocycle

• Complexation of Butadiyne-Bridged Pyridinophane and Tropylium Cation

• STM & Guest Inclusion Ability

• My Work

• Summary

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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

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About Macrocycle

pyridinebutadiyne

Butadiyne-bridged pyridinophane

N

HC C C CH

（　　　　　　　　　　　　）

macrocycle

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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).

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Titration of Pyridinophan

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1

R=

H

H2CCH2

H2C

CH2

H2C

CH2

H2C

CH3

H

Titration of Pyridinophan

H

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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

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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

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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

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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

-

＋

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O

O OPF6

Contents

• Host–Guest Chemistry

• About Macrocycle

• Complexation of Butadiyne-Bridged Pyridinophane and Tropylium Cation

• STM & Guest Inclusion Ability

• My Work

• Summary

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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.

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