01.02.05 ws 04/05-functional π-systems: part 3 1

Outline

Ø Introduction

Ø Organic conducting molecules and polymers

Ø Fullerenes and nanotubes

Ø Flavins, DNA Photolyase

Ø Organic Light Emitting Diodes (OLED)

Part 3: Functional ππ-systems

01.02.05 ws 04/05-functional π-systems: part 3 2

» 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.

Books and articles

01.02.05 ws 04/05-functional π-systems: part 3 3

The scaling of matter

» A. J. Bard, Integrated Chemical Systems - AChemical Approach to Nanotechnology, Wiley-Interscience, New York, 1994.

01.02.05 ws 04/05-functional π-systems: part 3 4

Functional molecular and supramolecular devices

» J.-M. Lehn, Supramolecular Chemistry Concepts andPerspectives, VCH, Weinheim, 1995.

01.02.05 ws 04/05-functional π-systems: part 3 5

Conductivity of organic and inorganic materials

» A. G. MacDiarmid, Angew.Chem. 2001, 113, 2649.

σσ= n⋅⋅e⋅µ⋅µ [S•cm-1]  σσ: conductivity

µ: mobilitye: electron charge

n: number of chargecarriers

σσ

conductivity

01.02.05 ws 04/05-functional π-systems: part 3 6

Band structure of lithium clusters Lin

J. Olmsted, III, G. M. Williams, Chemistry, 3rd

ed., John Wiley & Sons, New York, 2002.

01.02.05 ws 04/05-functional π-systems: part 3 7

pf

From a semiconductor to a conductor

01.02.05 ws 04/05-functional π-systems: part 3 8

Energetic diagram showing dotation

valence band

conducting band

» Angew. Chem. 2001, 113, 2660-2682.

Ø hole polaron (model owes to thedeformation of the lattice ondotation)

Ø singly occupied mid-band state

01.02.05 ws 04/05-functional π-systems: part 3 9

Interesting articles to read

» "Organic metals" - the intermolecular migration ofaromaticity, J. H. Perlstein, Angew. Chem. 1977,89, 534-549.

» Polarons, bipolarons, and solitons in conductingpolymers, J. L. Brédas, G. B. Street, Acc. Chem.Res. 1985, 18, 309-315.

» Der Weg zu einer neuen Materialklasse: Elektrischleitfähige Kunststoffe, M. Rehahn, Chemie inunserer Zeit 2003, 37, 18-30.

01.02.05 ws 04/05-functional π-systems: part 3 10

The charge-transfer effect 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)

01.02.05 ws 04/05-functional π-systems: part 3 11

Synthesis of tetrathiafulvalene

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.

01.02.05 ws 04/05-functional π-systems: part 3 12

Synthesis of tetracyanoquinodimethane

pf/lcnf

O

O

NC

NC

CN

CN

CH2(CN)2

TiCl4pyridineCH2Cl2

r.t.24 h

01.02.05 ws 04/05-functional π-systems: part 3 13

A conducting material

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.

01.02.05 ws 04/05-functional π-systems: part 3 14

Ø Elektrisch leitfähige Materialien: Elektrisch leitende

Polymere

Ø Bandstruktur

Ø Verbindungsklassen - Synthese

Ø Leitfähigkeit - Dotierung: Vom Halbleiter zum Leiter

Ø Fullerene - Nanotubes

Vorlesung: 21. 01. 2005

01.02.05 ws 04/05-functional π-systems: part 3 15

About conducting polymers

pf

01.02.05 ws 04/05-functional π-systems: part 3 16

pf

Linear combination of atomic orbitals (p-orbitals):From atomic orbitals to the band structure

» Der Weg zu einer neuen Materialklasse: Elektrisch leitfähigeKunststoffe, M. Rehahn, Chemie in unserer Zeit 2003, 37, 18.

01.02.05 ws 04/05-functional π-systems: part 3 17

ππ-Conjugated polymers: semiconducting materials - 1

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

01.02.05 ws 04/05-functional π-systems: part 3 18

ππ-Conjugated polymers: semiconducting materials - 2

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

01.02.05 ws 04/05-functional π-systems: part 3 19

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)

01.02.05 ws 04/05-functional π-systems: part 3 20

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.

01.02.05 ws 04/05-functional π-systems: part 3 21

Suzuki reaction - mechanism

1: oxidative addition2: transmetalation3: reductive elimination

01.02.05 ws 04/05-functional π-systems: part 3 22

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

01.02.05 ws 04/05-functional π-systems: part 3 23

Poly(p-phenylene) – Bergman cyclization

R

* *n

R

RR

RR heat

n n

» Tetrahedron 1997, 53, 15515-15534.pf

01.02.05 ws 04/05-functional π-systems: part 3 24

Calicheamicin - Bergman cyclization in Nature

» Angew. Chem. 1991, 103, 1453-1481.

tbb

01.02.05 ws 04/05-functional π-systems: part 3 25

Calicheamicin - biological function

tbb

» Angew. Chem. 1991,103, 1453-1481.

01.02.05 ws 04/05-functional π-systems: part 3 26

Methodology of PPV synthesis

pf

∗ Dehydrohalogenation∗ Elimination of sulfonium salts∗ Knoevenagel condensation∗ Horner condensation∗ Wittig condensation∗ Heck reaction∗ Suzuki reaction

R

R

**n

Polyvinylenephenylene(PPV)

01.02.05 ws 04/05-functional π-systems: part 3 27

Synthetic route towards 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.

01.02.05 ws 04/05-functional π-systems: part 3 28

Synthesis of PPV: Metathesis reaction

» Bull. Chem. Soc. Jpn. 1992, 65, 853-857

MMA

Ø Acyclic diene metathesis (ADMET): only oligo(phenylenevinylene)sare formed

01.02.05 ws 04/05-functional π-systems: part 3 29

Cyclic voltammetry

» Angew. Chem. 1984, 96, 823-840.mp

01.02.05 ws 04/05-functional π-systems: part 3 30

mp

Cyclic voltammetry (CV)

diffusion controlledconditions

conductingpolymer film

01.02.05 ws 04/05-functional π-systems: part 3 31

Ø Elektrische Leitfähigkeit: Dotierung

Ø Elektrisch leitende Polymere

- Polyazulen

- Polyanilin

Ø Fullerene

- Struktur

- Funktionalisierung und Einschlussverbindungen

Ø Nanotubes

Vorlesung: 28. 01. 2005

01.02.05 ws 04/05-functional π-systems: part 3 32

Polyazulene

n

oxidation

azulene polyazulene

non-conducting form(isolator)

conducting form(semiconductor)

oxidation

"radical cations"

01.02.05 ws 04/05-functional π-systems: part 3 33

Cyclic voltammetry (CV) of film formation of polyazulene

Ø Adv. Mater. 1993, 5, 450-453.

CV of monomer (irreversible)

CV of polymeric film

01.02.05 ws 04/05-functional π-systems: part 3 34

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

01.02.05 ws 04/05-functional π-systems: part 3 35

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

01.02.05 ws 04/05-functional π-systems: part 3 36

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

01.02.05 ws 04/05-functional π-systems: part 3 37

Platonic Symmetry

l / cnf

» Platonische Kohlenwasserstoffe: W. Grahn, Chemie in unserer Zeit1981, 15, 52-61.

01.02.05 ws 04/05-functional π-systems: part 3 38

Allotropic forms of carbon

diamond graphite Fullerene„truncatedicosahedran“ l / cnf

01.02.05 ws 04/05-functional π-systems: part 3 39

References on fullerene chemistry

» A. Hirsch, Chemie in unserer Zeit 1994, 28, 79-87.

» A. Hirsch, The Chemistry of the Fullerenes, GeorgThieme Verlag, Stuttgart, 1994.

» M. S. Dresselhaus, G. Dresselhaus, P. C. Eklund,Science of Fullerenes and Carbon Nanotubes, AcademicPress, San Diego, 1996.

01.02.05 ws 04/05-functional π-systems: part 3 40

Icosahedral symmetry (Ih)

C60 fullerene:A truncated icosaeder

l / cnfØ The Beauty of Symmetry: A. Müller, Science 2003, 300, 749-750.

icosaeder

01.02.05 ws 04/05-functional π-systems: part 3 41

Some properties of C60

Ø discovered 1985 (Nature 1985, 318, 162)Ø truncated icosahedral structure, Ih symmetryØ 12 pentagonale rings (Euler‘s rule), 20 hexagonale ringsØ substructures: radialene, benzene, corannulene,

pyracyclene; „isolated pentagon rule“Ø strained hydrocarbon, diameter around 7.1 DØ 13C-NMR: one signal, δ = 143 ppm (benzene, 128 ppm)Ø ionization energy around 7.6 eV, electron affinity around

2,7 eV

01.02.05 ws 04/05-functional π-systems: part 3 42

Electronic structure of C60 fullerene

C60 fullerene:A truncated icosaeder

01.02.05 ws 04/05-functional π-systems: part 3 43

1,3-Dipoles

C NR

CH2 CN

C

R

H

H+ azomethine ylide

01.02.05 ws 04/05-functional π-systems: part 3 44

1,3-Dipolar cycloaddition: HOMO-LUMO interaction

» R. Sustmann, Pure and Applied Chemistry 1974, 40, 569-593.

01.02.05 ws 04/05-functional π-systems: part 3 45

1,3-Dipolar cycloaddition of fullerenes

» D. M. Guldi, et. al,, J. Phys. Chem.B 2003, 107, 7293.

CN

C

R

H

HC

NOH

HC

R

HHH

CO2H+

» M. Prato, M. Maggini, Acc. Chem.Res. 1998, 31, 519.

01.02.05 ws 04/05-functional π-systems: part 3 46

Functionalized fullerenes

» Die Chemie der Fullerene, A. Hirsch, Chemie in unserer Zeit 1994, 28, 79-87.

N

C5H11

NO2

EtOOC COOEt

1 32

01.02.05 ws 04/05-functional π-systems: part 3 47

Endohedral fullerenes

Ø encapsulation of molecular hydrogen

» Synthesis of H2@1 : M. Murata, J. Am. Chem. Soc. 2003, 125, 7152.

» Synthesis of H2@2 : K. Komatsu, Science 2005, 307, 238.

H2@2H2@1

01.02.05 ws 04/05-functional π-systems: part 3 48

Encapsulation of molecular hydrogen in fullerene C60

» K. Komatsu, M. Murata, Y. Murata, Science (Washington,DC, United States) 2005, 307, 238-240.

01.02.05 ws 04/05-functional π-systems: part 3 49

Nanotubes

» ChemPhysChem 2001, 2, 78-105; Chem. Rev. 1999, 99, 1787-1799. lcnf/sfg

01.02.05 ws 04/05-functional π-systems: part 3 50

gff_lcnf

Isoalloxazine an important heterocycle 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)

01.02.05 ws 04/05-functional π-systems: part 3 51

Flavins: absorption and emission

∗ color of flavin: yellow; color of fluorescence: bright yellow, inaqueous 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

fluorescence

01.02.05 ws 04/05-functional π-systems: part 3 52

Isoalloxazines: Synthetic route

F

NO2

NH2

Br

N

Br

H

NO2

N

NH2

H

Br

N

NO

OO

O

H

H

N

N

N

N O

OH

Br

N

N

N

N O

OCH3

Br

N

N N

N

O

O

OH

H H

H

+KOH/DMSO Zn/AcOH AcOH/H3BO3

H2OK2CO3, CH3I

DMF

HNO3

(Alloxane/Hydrate)

3-Methyl-10-(4-Bromphenyl)-isoalloxazine

» P. Kirsch, et.al., Liebigs Ann. 1995, 1275.

01.02.05 ws 04/05-functional π-systems: part 3 53

Reduction of the isoalloxazine unit in FAD

N

N

N

N O

OH

R

N

N

N

N O

OH

R H

H

N

N

N

N O

OH

R

H

FADH-FAD

two electronstwo protons

FADH2

01.02.05 ws 04/05-functional π-systems: part 3 54

Repair of light damaged DNA

» T. Carell, R. Epple, Eur. J. Org. Chem. 1998, 1245-1258.

N

N

N

N O

OH

R

CH3

CH3

H

N

N

N

N O

OH

R

CH3

CH3

H

antenna

excited energy transfer

N

N

O

O

CH3H

P

N

N

O

O

HCH3

N

N

O

O

CH3H

P

N

N

O

O

HCH3 N

N

O

O

CH3H

N

N

O

O

HCH3

P

FADH- FADH-*

*

electron transferelectrontransfer

01.02.05 ws 04/05-functional π-systems: part 3 55

Ribbon diagram of a DNA photolyase (Eschericia coli)

Science 1995, 268,1866-1872.

αα/ββ domain: whiteMTHF: light grayhelical domain: goldFAD: greenAMP: red

01.02.05 ws 04/05-functional π-systems: part 3 56

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

01.02.05 ws 04/05-functional π-systems: part 3 57

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.

01.02.05 ws 04/05-functional π-systems: part 3 58

fl_lcnf

Organic light emitting diodes (LED): basicprocesses

» Angew. Chem. 1998, 110,416-443.

a: photoluminescence

b: electroluminescence

01.02.05 ws 04/05-functional π-systems: part 3 59

fds_lcnf

Organic light emitting diodes (LED): polymerblend technology

» 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.

01.02.05 ws 04/05-functional π-systems: part 3 60

fds_lcnf

Organic light emitting diodes (LED): polymer-LED

» Nature 1990, 347, 539-541; Angew. Chem. 1998, 110, 416-443.