Snythesis of Polymers [Kompatibilitätsmodus] · Introduction and Synthesis of...
Transcript of Snythesis of Polymers [Kompatibilitätsmodus] · Introduction and Synthesis of...
LINZ LECTURES
Lecture 1. The Development of Organic Conductors: M t l S d t d S i d tMetals, Superconductors and Semiconductors
Lecture 2A Introduction and Synthesis of ImportantLecture 2A. Introduction and Synthesis of Important Conjugated Polymers
Lecture 2B. Solid State Polymerization
Lecture 3 Fullerene ChemistryLecture 3. Fullerene Chemistry
Lecture 3B. Molecular Engineeringg g
Introduction and Synthesis of Important Conjugated Polymers
Linz, June 10, 2008
General Introduction
Solution PolymerizationSolution Polymerization
OligolyacenesOligolyacenes
Types of Polymers
A A A A A A A A H l-A-A.A-A.A-A-A-A- Homopolymer
-A-B-B-A-B-A-A-B- Random copolymerA B B A B A A B Random copolymer
-A-B-A-B-A-B-A-B- Alternating copolymer
-A-A-A-A-B-B-B-B- Block copolymer
-A-A-A-A-A-A-A-A Graft copolymer||B-B-B-B-B-B
Malcolm P. Stevens “Polymer Chemistry: an Introduction” 3rd Ed. Oxford, 1999
Types of Chains
(a) Linear chain, (b) branched chain, (c) network
Malcolm P. Stevens “Polymer Chemistry: an Introduction” 3rd Ed. Oxford, 1999
Types of Architectures
(h)
(a) Star (b) comb (c) ladder (d) pseudo ladder (e) rotaxane (f) catenane (g) dendrimer (h)
(h)
Malcolm P. Stevens “Polymer Chemistry: an Introduction” 3rd Ed. Oxford, 1999
(a) Star, (b) comb, (c) ladder, (d) pseudo ladder, (e) rotaxane, (f) catenane, (g) dendrimer (h) rigid rod
Malcolm P. Stevens “Polymer Chemistry: an Introduction” 3rd Ed. Oxford, 1999
“For drawn samples, values for the Young's modulus as high as 37 GPa and tensile strength up to 500 MPa have been measured in the machine direction. g pThese properties approach those of many high performance fibers.”
Machado J M ; Masse M A ; Karasz F E Polymer 1989 30 1992Machado, J.M.; Masse, M.A.; Karasz, F.E. Polymer, 1989, 30, 1992
Step Growth or Condensation Polymerization
O O O O
H2N(CH2)6NH2 Cl (CH2)4 Cl HN(H2C)6-HN (CH2)4 n
+
A B -(A-B)-n
Nylon 66
O
H2N(CH2)5 CO2H HN(H2C)5-n
A -(A-)n
M l K l K t PPT PT PP
Nylon 6
Mylar, Kevlar, Kapton, PPT, PT, PPy
Carothers Equation
Malcolm P. Stevens “Polymer Chemistry: an Introduction” 3rd Ed. Oxford, 1999
Chain Growth or Addition Polymerization
Free Radical
Ph OO Ph
O
NN
CNCN
Initiator RΔor hν
RG G
Initiators:Thermal
O O
Ph O
OR H2C CH R CH2CH
R CH2CHG
H2C CHG
R CH2CHG
CH2CHG
+
+
PhPh
O
OH
PhPh
O
RS-SR
Photochemical
R CH2CHG
CH2CHG
H2C CHG
[CH2CH(G)]n
Photochemical
R + HC CH Intractable products
Chain-Growth Polymerization
Malcolm P. Stevens “Polymer Chemistry: an Introduction” 3rd Ed. Oxford, 1999
Ziegler-Natta Polymerization
H2C CHG
Z-N[CH2CH(G)]n2 [ 2 ( )]n
Z-N: Ti(OR)4 AlR3
Z-NHC CH
Z N[CH=CH]n
Anionic, LivingCationic,
Ring Opening Metathesis Polymerization (ROMP)
LnRu=CHPh-(CH=CH)n
R
LnRu=CHPh-(CH=CH-CH=CH-CH=CH-CH=CR)n
R
QuickTime™ and aTIFF (Uncompressed) decompressor
are needed to see this picture.LnRu=CHPh =
Scherman O. A; Rutenberg I. M; Grubbs R. H J. Am. Chem. Soc. 2003, 125, 8515
Organometallic Methods:
Br-Ar-Br (Ar)nCat
Kumada, Yamamoto, Colon
Cat: PdL4, NiL2
Suzuki
Br-Ar-Br (RO)2BAr'-B(OR)2 (Ar-Ar')nCat
+
HeckHeck
Br-Ar-Br Ar' Ar' Arn
Cat
R R
GRIM/Kumada
n
X BrBrGRIMCat
X S
X n
X = S
Sheina, E.E.; Iovu, M.C.; McCullough, R.D. Polym. Prepr. 2005, 46(1), 682
Oxidative (Cationic) Polymerization
R
FeIII
R R
XH
-2H
R
X
X
Fe
X2 2
X
RH
R
2H
R R R
X
X
R
-e(-)
X
R
X FeIII
X
R
X
X
R
X X
X
R
-e(-)
R RR R R R
R R
X
X
R
X
R
X-2H
X
X X
R
XFeIII
X = S, N
R R R R
Oxidative Polymerization
RR RR
Thiophene as a “handle”
X
R
ArX
R
FeIII
X
R
ArX
R
nXX XX n
Polyaniline
NH2
-e(-)
(NH4)2S2O8
NH
x
Ny
e x N
Reductive (Anionic) Polymerization
BrBr O
O Hg( )
O
O
O +e(-)
nBr Br
Utley, J.H.; Gao, Y.; Gruber, J.; Zhang, Y.; Munoz-Escalona, A. Chem Mater. 1995, 5, 1837
Reductive Polymerization
BrBr O
O
O
Hg
+e(-)
O
Br Brn
B B BBr Br
O Hg( )
O
OBr
O
O
O
O
BrHg
BrBr
O +e(-)
nBr
O
nBr
+e(-)
Utley, J.H.; Gao, Y.; Gruber, J.; Zhang, Y.; Munoz-Escalona, A. Chem Mater. 1995, 5, 1837
PPV Synthesis
SMe2SMe2 SMe2
*
Me2S*
*
* = (-) or (•)
SMe2
Δ+ (CH3)2S
( ) or ( )
nn
Processable Polyelectrolyte
Δ
P. M. Lahti, D. A. Modarelli, F. R. Denton, III, R. W. Lenz, F. E. Karasz J. Am. Chem. Soc.
L. Hontis, V. Vrindts, D. Vanderzande, L. Lutsen Macromolecules, Vol. 36, No. 9, 20031988, 110, 7258
The Last Challenge:e ast C a e geLinear Polyacenesy
The Lower Oligoacenes
Polyacenes??o yace es??
AcenesAcenes
Surprisingly, we have discovered that at the
tripletRB3LYP/6-31G(d) level of theory, the wavefunction for as small an oligoacene ashexacene (and all longer oligoacenes) becomes
close shell
hexacene (and all longer oligoacenes) becomesunstable.Re-optimization using the unrestricted
open shellRe-optimization, using the unrestrictedbroken symmetry B3LYP method (UB3LYP),leads to a singlet state with large amounts ofg gdiradical character.
HOMO LUMO G i AHOMO-LUMO Gap in Acenes
8.0
eV)
Cl d h ll
4.0
6.0
MO
gap
(e Closed shellBiradical
0 0
2.0
OM
O-L
UM
0.00 2 4 6 8 10
Acene
H
Plateau at ca. 1.8 eV
Bendikov, M.; Duong, H.M.; Starkey, K.; Houk, K.N.; Carter, E.A.; Wudl, F.; J. Am. Chem. Soc., 2004, 126(24) 7416
A t i l b dAcenes, terminal bond
1.4351.440
1 4101.4151.4201.4251.430
Close shellBiradicalT i l t
1.3901.3951.4001.4051.410 Triplet
0 2 4 6 8 10
Acene
Connection Between Band Theory and Molecular Orbital Theory
According to the Su-Schrieffer-Heeger (SSH) model, the cco d g o e Su Sc e e eege (SS ) ode , eeffective length of a soliton in a σ-system is about 14 carbon atoms.
This is in agreement with our calculations, predicting diradical character in oligoacenes, and thus, hexacene-gheptacene have already enough σ -length (two 13-15 carbon atom chains, respectively) to produce two oligoacetylene
litsolitons.
The instabilities found for heptacene-octacene appear toThe instabilities found for heptacene-octacene appear to indicate that they are the “connector” between band theory and molecular orbital theory.y
Heeger, A. J.; Kivelson, S.; Schrieffer, J. R.; Su, W.-P. Rev. Mod. Phys. 1988, 60, 781.
Spin Densityp y
Bendikov, M.; Duong, H.M.; Starkey, K.; Houk, K.N.; Carter, E.A.; Wudl, F.; J. Am. Chem. Soc., 2004, 126(24) 7416
Summary
In contrast to the common view that acenes are closed shellsystems or have triplet ground states, we predict that largeroligoacenes possess an open-shell singlet ground state,where the triplet lies above singlet.
We have shown computationally that oligoacenes andprobably a variety of polyacene derivatives and analoguesp y y p y gshould exhibit a nonzero band gap.
It should be possible to prepare a linear polyacene, providedit is formed as a solid, with minimum lifetime in solution. Inanalogy with oligoenes vs polyacetyleneanalogy with oligoenes vs polyacetylene.
EXPERIMENTAL RESULTS
Matrix Isolated Heptacene
R. Mondal, B. K. Shah, D. C. Neckers J. Am. Chem. Soc. 2006, 128, 9612
R. Mondal, B. K. Shah, D. C. Neckers J. Am. Chem. Soc. 2006, 128, 9612
Isolable But Very Short-Lived Substituted Heptacene
Marcia M. Payne, Sean R. Parkin, and John E. Anthony 2005, 127, 8028
Marcia M. Payne, Sean R. Parkin, and John E. Anthony 2005, 127, 8028
Marcia M. Payne, Sean R. Parkin, and John E. Anthony 2005, 127, 8028
TIPS ACETYLENE TETRAARYLHEPTACENE ISOLABLE AND RELATIVELY STABLE
Si(iPr) SiSi(iP )
Br
B
OBr
Br
Si(iPr)3 SiSi(iPr)3
PhPh
O Oa b c
Ph Ph
BrO
Br
Si(iPr)3 SiSi(iPr)3
PhPhPh Ph
a, (i) TipsCCLi (ii) SnCl2; b, LTMP/DPIBF; c, Zn/AcOH
D. Chun, F. Wudl, unpublished
CRYSTAL STRUCTURE OF BIS(TIPSTHYNYL) TETRAPHENYL HEPTACENE
QuickTime™ and aTIFF (LZW) decompressor
are needed to see this picture.
D. Chun, F. Wudl, unpublished
Electronic Spectroscopy
PHOTOINDUCED OXYGEN DEGRADATION
Si SiSi
PhPh
Si
PhPh O
OO2
Si
PhPh
Si
PhPh
Ohν
LIMITED CYCLIC VOLTAMMETRY
Photoinduced Charge Generation
H. F. Bettinger, R. Mondalb and D. C. Neckers Chem. Commun., 2007, 5209