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15.01.04 lcnf03p03aw.ppt - part 3 1
Part 3: Functional π-Systems
Outline
Ø Introduction
Ø Organic conducting molecules and polymers
Ø Fullerenes and nanotubes
Ø Flavins, DNA Photolyase
Ø Organic Light Emitting Diodes (OLED)
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Books and Articles
» J. Olmsted, III, G. M. Williams, Chemistry, 3rd ed., JohnWiley & Sons, New York, 2002.
» J.-M. Lehn, Supramolecular Chemistry Concepts andPerspectives, VCH, Weinheim, 1995.
» Der Weg zu einer neuen Materialklasse: Elektrischleitfähige Kunststoffe: M. Rehahn, Chemie in unserer Zeit2003, 37, 18-30.
» A. Hirsch The Chemistry of the Fullerenes; Thieme,Stuttgart, 1994.
» Elektrolumineszierende konjugierte Polymere - Polymereerstrahlen in neuem Licht: A. Kraft, A. C. Grimsdale, A.B. Holmes, Angew. Chem. 1998, 110, 416-443.
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The scaling of matter
» A. J. Bard, Integrated Chemical Systems - AChemical Approach to Nanotechnology, Wiley-Interscience, New York, 1994.
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Functional molecular and supramolecular devices
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Conductivity(S cm-1) of
organic andinorganicmaterials
pf
» A. G. MacDiarmid, Angew. Chem. 2001, 113, 2649-2659.
σσ/[S•cm-1] = n⋅⋅e⋅µ⋅µ σσ: conductivity
µ: mobilitye: electron charge
n: number of chargecarriers
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Band structure of lithium clusters Lin (Olmsted/Williams)
pf
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Conducting metals adjust their band structure to externalpotential – band bending (Olmsted/Williams)
pf
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pf
A semiconductor becomes a conductor by heating or byabsorption of light (Olmsted/Williams)
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Lead and diamond have different band gaps (Olmsted/Williams)
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Electrically conducting materials: molecularinteraction and band structure
Electronic energy level:top: a dimer formed of twomonomers
bottom: large assembly ofisolated molecular units(atoms) - band structure
» A. J. Bard, 'Integrated ChemicalSystems - A Chemical Approach toNanotechnology', Wiley-Interscience,1994.
pf_lcnf
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Charge-Transfer and Conductivity
pf/lcnf
CN
CNNC
NCS
S S
S S
S S
SS
S S
S
Tetracyanoquino-dimethane
(TCNQ)electron acceptor
Tetrathiafulvalene(TTF)
electron donor
BEDT-TTF
Ø BEDT-TTF: Bis(ethylenedithio)tetrathiafulvalene, beyond 4 Ksuperconductive on doping: (BEDT-TTF)2Cu(CF3)4 (J. Chem.Soc., Chem. Comm. 1994, 1599)
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Synthesis of TTF
pf/lcnf
EtO2C CO2EtS
SS
S
S S
S
(TTF)+
first step
Ø An Improved Synthesis of Tetrathiafulvalene, L. R.Melby, H. D. Hartzler, W. A. Sheppard, J. Org. Chem.1974, 36, 2456-2458.
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Synthesis of TCNQ
pf/lcnf
O
O
NC
NC
CN
CN
CH2(CN)2
TiCl4pyridineCH2Cl2
r.t.24 h
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Conducting charge-transfer systems
pf/lcnf
» F. Wudl, Acc. Chem. Res. 1984, 17, 227-232., 99, 1787-1799.
» M. Pope, C. E. Swenberg ElectronicProcesses in Organic Crystals andPolymers, Second Edition; Oxford UnivPress: Oxford, UK, 1999.
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About conducting polymers
pf
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π-Conjugated polymers: semiconducting materials
n
n
Polyacetylene (PA)» H. Shirakawa, Angew. Chem. , Int. Ed. 2001,
40, 2575.
Polyphenylene (PP)» A. J. Berresheim, M. Müller, and K. Müllen,
Chem. Rev., 1999, 99, 1747.
Hn
Polyphenylenevinylene (PPV)» A. Kraft, A. C. Grimsdale, and A. B. Holmes,
Angew. Chem., 1998, 110, 416.
pf
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π-Conjugated polymers: semiconducting materials
Polythiophene (PT)» J. Roncali, Chem. Rev. 1992, 92, 711-
738.
Sn
Polyazulene (PAZ)» F. X. Redl, O. Koethe, K. Roeckl, W.
Bauer, J. Daub, Macromol. Chem.Phys. 2000, 201, 2091-2100.
n
Polyaniline (PANI)
» A. G. MacDiarmid, Angew.Chem. 2001, 113, 2649-2659.
N
H
N
H
N
H
NH
pf
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Metathesis based ring-opening-polymerisation
. » Acc. Chem. Res. 1990, 23, 158-165.
CF3CF3CF3CF3
R1
R2
R3
R1
R2
R3
R2
R1R3
CF3CF3
cat
n n
∆∆
cat: (RO-)2W(=N-Ar)(=CHR)
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Ring-opening-polymerisation
.pf
» J. Am. Chem. Soc. 1989, 111, 7989.
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Ring-opening-polymerisation - References
.pf
» Olefin metathesis and beyond, A. Fürstner, Angew. Chem. Int. Ed.2000, 39, 3012-3043.
» K. J. Ivin, J. C. Mol, Olefin Metathesis and Metathesis Polymerization,Academic Press, San Diego, 2003.
» Die Olefinmetathese - neue Katalysatoren vergrößern dasAnwendungspotential, M. Schuster, S. Blechert, Chemie in unsererZeit 2001, 35, 24-29.
» Living ring-opening metathesis polymerization catalyzed by well-characterized transition-metal alkylidene complexes, R. R. Schrock,Acc. Chem. Res. 1990, 23, 158-165.
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Suzuki reaction - mechanism
1: oxidative addition2: transmetalation3: reductive elimination
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Synthesis of poly(p-phenylene) – Suzuki route
R
R
BrBr
R
R
* *n
R
R
B(OH)2Br
1. n-BuLi (1 mol)2. B(OCH3)3
3. HCl
Pd(OAc)2, PPh3
Na2CO3
» Coupling Method, see: A. Suzuki, Cross-coupling Reactions of OrganoboronCompounds with Organic Halides. In Metal-catalyzed Cross-coupling reactions;Diederich, F.; Stang, P. J. Eds.; Wiley-VCH: Weinheim, 1998.
pf
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Synthesis of poly(p-phenylene) – Bergman cyclization
R
* *n
R
RR
RR heat
n n
» Tetrahedron 1997, 53, 15515-15534.pf
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Calicheamicin - action based on Bergmancyclization
» Angew. Chem. 1991, 103, 1453-1481.
tbb
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Calicheamicin - chemistry of action
tbb
» Angew. Chem. 1991,103, 1453-1481.
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Synthetic route to polyphenylenevinylene (PPV)
CH2
CH2
R
R
SS
CH3
CH3CH3
CH3
CH
R
R
CH2S
CH3 CH3 n
R
R
**n
Cl Cl Cl
+ +
+
NaOH
H2O
300°C
-(CH3)2S, HCl
pf
» Electronic Materials: The Oligomer Approach; Muellen, K.; Wegner,G. Eds.; Wiley-VCH: Weinheim, 1998; 1.
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Synthesis of polyphenylenevinylene (PPV):Metathesis reaction
» Angew. Chem. 1997, 109, 2125; K. Müllen, G. Wegner, ‘ElectronicMaterials: The Oligomer Approach’, Wiley-VCH, Weinheim, 1998
pf
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Cyclic voltammetry
» Angew. Chem. 1984, 96, 823-840.mp
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Cyclic voltammetry under diffusion controlled conditions (left)and surface-immobilized conditions such as a conductingpolymer film (right)
mp
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Azulene/polyazulene: electrochemicalpolymerisation and dotation
» A. Mirlach. Dissertation, Universität Regensburg 1993» A. Mirlach, M. Feuerer, J. Daub, Adv. Mater. 1993, 5, 450-453. pap
HH n
dotated polyazuleneconducting material
radical cation/polaron
+
n
anodicoxidation
dotationby
electrochemicaloxidation
azulenemonomer
polyazulenenonconducting material
insulator
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Azulene/polyazulene-cyclic voltammetry
pap
left side: CV of the initial process of electropolymerisationright side: formation of a conducting film on the electrode
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Polyaniline – general formula
» A. G. MacDiarmid, Angew. Chem. 2001, 113, 2649-2659. pf
N
H
N
H
N N
X
( ) ( )y 1-y
y: 1 ⋅⋅⋅⋅⋅ 0.5 ⋅⋅⋅⋅⋅ 0
(1-y) = 0: leucoemeraldine(1-y) = 1: pernigraniline(1-y) = 0.5: emeraldine
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Polyaniline – conducting and nonconducting forms
pf
N
H
N
H
N
H
NH
N
H
N
H
N N
N N N N
N
H
N
H
N
H
NH
++
completely reduced form(leucoemeraldine)
semioxidized form(emeraldine)
oxidized form(pernigraniline)
conducting statemade by oxidationof leucoemeraldineor protonation of
emeraldine
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Properties and applications of conducting polymers
pf
Ø nonlinear optical responceØ semiconducting propertiesØ conducting transparent plasticsØ thin-film field-effect transistorsØ light-emitting diodesØ solid-state lasersØ photovoltaic devicesØ chemical sensors
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Allotropic forms of carbon
diamond graphite fullerene
l / cnf
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A high symmetric molecule – icosahedral symmetry (Ih)
C60 fullerene
l / cnf
Ø The Beauty of Symmetry: A. Müller, Science 2003, 300, 749-750.
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Platonic Symmetry
l / cnf
» Platonische Kohlenwasserstoffe: W. Grahn, Chemie in unserer Zeit1981, 15, 52-61.
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Nanotubes
» ChemPhysChem 2001, 2, 78-105; Chem. Rev. 1999, 99, 1787-1799. lcnf/sfg
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gff_lcnf
Isoalloxazine a heterocycle with great importance in Nature
∗ nomenclature of flavin: 7,8-dimethylbenzo[g]pteridine-2,4(3H,10H)-dione
∗ Riboflavin, Vitamin B2
∗ FMN: riboflavin-5‘-phosphate (D-ribityl unit)∗ major absorption bands of flavin in its oxidized form: (1)446,
(2)375, (3)265, 220 nm (polarization according to the right sideformula)
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gff_lcnf
Flavin: absorption and emission spectra
∗ color of flavin: yellow∗ color of fluorescence: bright
yellow, in aqueous solution,Φf 0.26, pH 7
∗ phosphorescence ( λ ~ 610nm, < 150K, orange-red, ΦP
0.0012)
P. F. Heelis, Chem. Soc. Rev. 1982, 11, 15-39;P. F. Heelis. The Photochemistry of Flavins. In Chemistry andBiochemistry of Flavoenzymes; Müller, F. Ed.; CRC: Boca Raton,1991; Vol. 1; pp. 171-193.
fluorescence
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Ribbon diagram of DNA photolyase of Eschericia colignl_lcnf
Science 1995, 268,1866-1872.
αα/ββ domain: whiteMTHF: light grayhelical domain: goldFAD: greenAMP: red
15.01.04 lcnf03p03aw.ppt - part 3 42
gnl_lcnf
Photolyase dependentrepair of DNA lesion
» Science 1999, 284, 760-765.» Eur. J. Org. Chem. 1998,
1245-1258.
antenna
excitation energy transfer
electron transfer:bond breaking upon reduction
15.01.04 lcnf03p03aw.ppt - part 3 43
fds_lcnf
Organic light emitting diodes: references
» Organic electroluminescent diodes: C. W. Tang, S. A. VanSlyke, Appl. Phys.Lett. 1987, 51, 913-915.
» Light-emitting diodes based on conjugated polymers: J. H. Burroughes, D. D.C. Bradley, A. R. Brown, R. N. Marks, K. MacKay, R. H. Friend, P. L. Burn, A.B. Holmes, Nature 1990, 347, 539-541.
» Efficient Two Layer LEDs on a Polymer Blend Basis: J. Pommerehne, H.Vestweber, W. Guss, R. F. Mahrt, H. Bässler, M. Porsch, J. Daub, Adv.Mater. 1995, 7, 551-554.
» Electroluminescence with Organic Compounds: J. Salbeck, Ber. Bunsenges.Phys. Chem. 1996, 100, 1667-1677.
» Elektrolumineszierende konjugierte Polymere - Polymere erstrahlen inneuem Licht: A. Kraft, A. C. Grimsdale, A. B. Holmes, Angew. Chem. 1998,110, 416-443.
» The electroluminescence of organic materials: U. Mitschke, P. Baeuerle, J.Mater. Chem. 2000, 10, 1471-1507.
15.01.04 lcnf03p03aw.ppt - part 3 44
fl_lcnf
Organic light emitting diodes (LED): basic processes
» Angew. Chem. 1998, 110,416-443.
a: photoluminescence
b: electroluminescence
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fds_lcnf
Organic light emitting diodes (LED): polymer blend basis
» Appl. Phys. Lett. 1987,51, 913
» Adv. Mater. 1995, 7,551-554.
» Bunsenges. Phys. Chem.1996, 100, 1667-1677.
Polymer- LED‘s use polymers suchas PPV as electroluminescentmaterials: Nature 1990, 347, 539-541.
15.01.04 lcnf03p03aw.ppt - part 3 46
fds_lcnf
Organic light emitting diodes (LED): polymer-LED
» Nature 1990, 347, 539-541; Angew. Chem. 1998, 110, 416-443.