synthesis of a fluoreno[2,3- b]fluorene derivative to experimentally verify extraordinary optical...
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Synthesis of a Fluoreno[2,3-b]fluorene Derivative to
Experimentally Verify Extraordinary Optical Properties of
Indenofluorenes
Tobe Lab.Masahito Miki
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Contents
• Introduction Singlet biradicals
Resonance structures
Quinodimethanes
• Previous work Comparision of UV-vis-NIR spectra
p-conjugation space and absorption wave length
New Principle for Low Energy Absorption
Nonalternant hydrocarbons
Excitation energy of biradical compounds
• My work2
Singlet BiradicalsHOMO and LUMO of biradicaloids
y = 0Fabian, J. et al. Angew. Chem. Int. Ed. 1989, 28, 677.
closed shell singlet biradical open shell
y = 1
0 < y < 1
一重項ビラジカル 閉殻 開殻
HOMO
LUMO
UHF/6-31G*//UB3LYP/6-31G* and Yamaguchi schemeYamaguchi, K. Chem. Phys. Lett. 1975, 33,
330.
nHOMO, nLUMO; occupation numbers of HOMO or LUMO
21
21
T
Ty
2
LUMOHOMO nnTbiradical character :
3
Resonance Structures
Closed shell閉殻構造
Open shell開殻構造
・ All electrons are used to bonds.・ closed-shell
・ A bond is broken・ open-shell
Energy loss for breaking pbond (272 kJ / mol)
Aromatic stabilization energy芳香族安定化エネルギー(about 90 kJ / mol)
benzene
Unimportant contributor
Important contributor
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Quinodimethanes (QDM)
R
RR = Si
Mes Mes
Mes =
Chase, D. T. et al. Angew. Chem. Int. Ed. 2011, 50, 11103.
Shimizu, A.; Tobe, Y. Angew. Chem. Int. Ed. 2011, 50, 6906.
o-quinodimethanep-quinodimethane
Ph
Ph
Kubo, T. et al. Angew. Chem. Int. Ed. 2005, 44, 6564.
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Ph =
速度論的安定化
熱力学的安定化thermodynamical stabilization
Kinetic stabilization
Previous WorkR R
1
Tobe, Y. et al. Angew. Chem. Int. Ed. 2013, 52, 6076.
UV-vis-NIR absorption spectra of 1b in CH2Cl2.
m-quinodimethane
1700nm
1a : R = H
1b : R = Mes =
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Mes Mes Mes Mes
singlet tripletDES-T = -17.6 kJ/mol
Comparision of UV-vis-NIR Spectra
Mes Mes
Mes =Mes =
Mes Mes
1b7
A derivertive of Indeno[2,1-a]fluorene
UV-vis-NIR absorption spectra of 1b in CH2Cl2.UV-vis-NIR absorption spectra of a below compound in CH2Cl2. Tobe, Y. et al. Angew. Chem. Int.
Ed. 2013, 52, 6076.Tobe, Y. et al. Angew. Chem. Int. Ed.
2011, 50, 6906.
Larger p-conjugation space Lower absorption energy
n
acenes
Anthony, J. E. et al. Angew. Chem. Int. Ed. 2008, 47, 452.
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p-Conjugation Space and Absorption Wave Length
New Principle for Low Energy Absorption
1. Moderate singlet biradical character2. Nonalternant hydrocarbon3. Smaller p-conjugation space Lower absorption energy
Nakano.M (unpublished)
1a 2a
HOMO−LUMO Energy Gap : 1a > 2a
Singlet Biradical Character : 1a < 2a
Transition Energy (Prediction) : 1a < 2a9
Nonalternant Hydrocarbons
10Michl, J. et al. Tetrahedron 1976, 32, 205.
HOMO
LUMO
**
* ** ** **
**
azulenenaphthalene
Nonalternant hydrocarbonAlternant hydrocarbon
U Effective Coulombic Repulsion Energy ↘ • Smaller HOMO-LUMO overlap
fE(y) Function of Biradical Factor (y) ↘
• Larger Biradical Factor (y)
Kab Exchange Integral ↗ • Larger Space Separation between HOMO-LUMO• Smaller pi-System
y Biradical Factor ↗ • Increasing U (larger HOMO-LUMO overlap)• Decreasing ɛHL
y=1−1
√1+( 𝑈2𝜀𝐻𝐿
)2𝑓 𝐸 (𝑦 )=1+ 1
√1− (1− 𝑦 )2
𝛥𝐸𝑎𝑏=¿¿Transition Energy :
1
2
3
4
5
6
7
0 0.2 0.4 0.6 0.8 1
f E(y
)
y
𝛥𝐸𝑎𝑏=¿¿
• Moderate biradical character
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Excitation Energy of Biradical Compounds
First Transition Energy :
Kab Exchange Integral ↗ • Nonalternant hydrocarbon• Smaller pi-System
JHHM,
JLLM
Coulombic Integral in HOMO or LUMO ↗
• Smaller pi-System
JHL
Coulombic Integral between HOMO and LUMO
↘• Nonalternant hydrocarbon• Larger Space Separation between HOMO-LUMO
JHHM, JLL
M: Coulombic Integral in HOMO or LUMO
JHL: Coulombic Integral between HOMO and LUMO
K ab=14
( 𝐽 𝐻𝐻𝑀+ 𝐽 𝐿𝐿𝑀−2 𝐽 𝐻𝐿𝑀 )
𝛥𝐸𝑎𝑏=¿¿
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Excitation Energy of Biradical Compounds
Nonalternant Hydrocarbons
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Michl, J. et al. Tetrahedron 1976, 32, 205.
HOMO
LUMO
**
* ** ** **
**
azulenenaphthalene
Nonalternant hydrocarbonAlternant hydrocarbon
First Transition Energy :
Kab Exchange Integral ↗ • Nonalternant hydrocarbon• Smaller pi-System
JHHM,
JLLM
Coulombic Integral in HOMO or LUMO ↗
• Smaller pi-System
JHL
Coulombic Integral between HOMO and LUMO
↘• Nonalternant hydrocarbon• Larger Space Separation between HOMO-LUMO
JHHM, JLL
M: Coulombic Integral in HOMO or LUMO
JHL: Coulombic Integral between HOMO and LUMO
K ab=14
( 𝐽 𝐻𝐻𝑀+ 𝐽 𝐿𝐿𝑀−2 𝐽 𝐻𝐿𝑀 )
𝛥𝐸𝑎𝑏=¿¿Excitation Energy of Biradical Compounds
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New Principle for Low Energy Absorption
1. Moderate singlet biradical character2. Nonalternant hydrocarbon3. Smaller p-conjugation space Lower absorption energy
Nakano.M (unpublished)
1a 2a
HOMO−LUMO Energy Gap : 1a > 2a
Singlet Biradical Character : 1a < 2a
Transition Energy (Prediction) : 1a < 2a15
Mes Mes
Mes =2b
Synthetic Scheme of 2b
OTfTfO
H2SO4
r.t.OHHO
O O
4†
6
Pd2(dba)3CHCl3
CH3CN, 50 °C
KCN
NaOH
ethylene glycol
170 °C
CNNC
587%
79% (2 steps)
OHHO
3
(5 steps) DPPF
O O
7
RLiHO R R R R
THF toluene
OHSnCl2
R =
† 平野慎太朗、大阪大学基礎工学部化学応用科学科、学士学位論文 (2013).
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O O
7
MesMgBrHO Mes Mes Mes Mes
Et2O, r.t. toluene8 2b
OH
37% r.t.
SnCl2
Mes =
conclusion
• Biradicaloids have intermediate nature between the nature of two structure which are a closed-shell and open-shell.
• Indeno[2,1-b]fluorene has a extraordinary optical property.
• Nonalternant hydrocarbons which have moderate singlet biradical character can have the extraordinary optical property.
• Synthesis of fluoreno[2,3-b]fluorene is undergone.
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