Syntheses of PFV-(PS-Br)2 by Cu catalyzed ATRP of styrene initiated by

OHC *

Scheme 2-2. Syntheses of PFV-(PS-Br)2 by Cu catalyzed ATRP of styrene initiated by

styrene in the presence of CuBr, dNbipy (4,4-dinonyl-2,2'-dipyridyl) at 90 °C for conducting subsequent atom transfer radical polymerization (ATRP, Scheme 2-2) .

Br—IM 40 \ 41,--11R R

R R n-1 •--O \

IM = OCOMe2C or CH2 C

uBr/dNbipy

Initiating moiety° /90C

M®\\R R

BC m441\

®R R n-1

poly(styrene-b/-PFV-b/-styrene)s PFV-(PS-Br)2

44I IM-Br

le

^-Br

//

Scheme 2-2. Syntheses of PFV-(PS-Br)2 by Cu catalyzed ATRP of styrene initiated by PFV(C6H4OCOCMe2Br)2, PFV(C6H4CH2Br)2

The NMR spectra of the resultant copolymers (Figure 2-2, Figure 2-3), indicate that styrene repeat units were incorporated and the styrene contents [in the 1H NMR spectra aromatic protons of styrene b 7.16-6.82 (br, 3H), 6.81-6.23 (br, 2H) and styrene aliphatic back bone 6 2.05 (br, 3H),

1.63-1.32 (br, 3H)], increased over time course (upon increasing

+ the yields, conversion). As shown in (Figure 2-4), relatively linear relationships between Mn values estimated by their 1H NMR spectra (based on integration ratios of protons between styrene and PFV) and the conversion or polymerization time were observed, and relatively close relationships were observed when the M„ values by GPC were employed for the plots. These would suggest that these polymerizations proceeded in a living manner, the results are summarized in (Table 2-1).

Br 0

i0-01\((v.

R=n-octyl

run 5, Table 1

\ /„ rt

I®

7.5 7.0 6.5 6.0 5.5 5.0 4.5 4.0 3,5 3.0 2.5 2.0 1.5 1.0 0.5 ppm

Figure 2-2. 1H NMR spectra of PFV-(PS-Br)2 initiated by PFV(C6H4OCOCMe2Br)2

Br 0

PFV-(PS-Br)2

Mn=6.10x104, MW/Mn=1.48 (run 3, Table 1)

/-\

k+p

7.5 7.0 55 6.0 5.5 5.0 4.5 4.0 3.5 3.0 25 2.0 1.5 1.0 0.5 ppm

Figure 2-3. 1H NMR spectra of PFV-(PS-Br)2 initiated by PFV(C6H4CH2Br)2

Table 2-1. Synthesis of block copolymers, poly(styrene-bl-PFV-bl-styrene)s [PFV-(PS-Br)2], by Cu catalyzed atom transfer radical polymerization (ATRP) of styrene initiated from macroinitiators containing PFV [PFV(C6H4CH2Br)2 or PFV(C6H4000CMe2Br)2].a

run initiator time/ h PFV-(PS-Br)2

Mn(GPC)cx 104 Mn(NMR)ax 10-4 Mw!Mnc ConV.e / % 1 PFV(C6H4CH2Br)2

2 PFV(C6H4CH2Br)2 3 PFV(C6H4CH2Br)2

24 35 48

2.99 3.51 6.10

1.55 1.77 3.60

1.49 1.49 1.48

4.3 5.5 7.5

4 PFV(C6H4OCOCMe2Br)2 5 PFV(C6H4OCOCMe2Br)2 6 PFV(C6H4OCOCMe2Br)2

12 24 36

2.86 3.40 4.10

1.40 1.60 2.00

1.70 1.50 1.58

5.0 6.0 7.0

aConditions: PFV(C

6H4CH2Br)2 or PFV(C6H4OCOCMe2Br)2/CuBr/DNbipy = 1/8.5/17 (molar ratio), the polymerization of styrene was conducted in bulk at 90 °C (details are shown in the Supporting Information), dNbipy: 4,4-dinonyl-2,2'-dipyridyl. bEstimated molecular weight: Mn(NmR) = 1.22x104 [PFV(C6H4CH2Br)2],

1.24x104 [PFV(C6H4OCOCMe2Br)2]. cGPC data in THE vs polystyrene standards. dEstimated by 1H NMR spectra (integration ratios of protons between styrene and PFV). 'Styrene conversion in %.

6 5

°4 x 3

10 1020304050 3---4 5 6 7 8

Time/ hCony./ %

Figure 2-4. Plots of Mn values (by GPC, NMR) vs. time (left), conversion (right) in ATRP of styrene. Mn values of PFV-(PS-Br)2 from PFV(C6H4CH2Br)2 by • (GPC), O (NMR); from PFV(C6H4OCOCMe2Br)2 by • (GPC), 0 (NMR). The detailed results are shown in Table 1.

However, the initiation efficiencies in the macromoinitiator were uncertain through these experiments, and therefore, the bromide in the chain end was converted (the sample in run 4, Table 2-1) by treating NaN3 and the resultant polymer, PFV-(PS-N3)2, was reacted with 4-pentanoate terminated poly(ethylene glycol) methyl ether (Mn = 2000, Aldrich) in the presence of CuBr and dNbipy in THE (at 35 °C for 5 days, Scheme 2-3). The results are shown in (Table 2-2).

' H NMR spectra for the res

ultant copolymers possessed protons ascribed to PEG units [b 3.62 (br), -CH -CH -] (Figure 2-5), suggesting incorporation of PEG segment. Note that the Mn values of PFV-(PS-b/-PEG)2 estimated by I H NMR spectra (on the basis of methylene protons in the PEG segment) were very close to those calculated (based on Mn value of PFV and integration ratio of PFV and styrene). The results are reproducible, as demonstrated in (Table 2-2). These results strongly demonstrate that precise, exclusive synthesis of amphiphilic ABCBA type block copolymers have been attained by adopting this approach. Moreover, importantly , the results strongly demonstrate that the end-functionalization of PFV chain ends [preparation of macroinitiators], ATRP of styrene, and subsequent treatment with NaN3 took place with exclusive yields in all cases.

-CH-CH-of PEG

CDCI3

SiMe

7.5 7.0 6.5 6.0 5.5 Figure 2-5. 1

5.0 4.5 4.0 3.5 3.0 25 2.0 1.5 1.0 0.5 ppm

H NMR spectra of PFV-(PS-b/-PEG)2

Table 2-2. Synthesis of ABCBA block copolymers, PFV-(PS-b/-PEG)2. ^a

copolymer Mn (GPC)

X10-4 Mn

(NMR)C X 10-4

Mn (calcd.) X 10-4

Mw/Mn yieh

PFV-(PS-Br)2g PFV-(PS-N3)2 PFV-(PS-b/--PEG)2 PFV-(PS-b/-PEG)2

2.86

2.50

2.46

1.40

1.29 1.30

1.32

1.70 1.60

1.44

95.0 91.6

90.0

'Conditions: PFV-(PS-N3)2/4-pentanoate terminated poly(eth 'lene glycol) methyl ether /CuBr /dNbipy = 1/3.5/5/10 (molar ratio) in THF 2.0 mL at 35 °C for 5 days. GPC data in THF vs polystyrene standards.

'Estimated value by 1H NMR spectra (integration ratios of protons between styrene and PFV

, or on the basis of PEG). dCalculated value based on the exact Mn value of PFV (corrected from GPC data, 1.22 x104)21 and integration ratio of PFV and styrene in the 1H NMR spectra. -'Isolated yield. gSample in run 4, Table 2-1.

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In summary, various block (graft) copolymers have been prepared by adopting combination of ADMET polymerization of 9,9-dialkyl-2,7-divinyl-fluorene with ATRP of styrene from macroinitiators prepared by introductions of initiating functionalities into the PFV chain ends (grafting from approach). Moreover, the precise synthesis of amphiphilic ABCBA type block copolymers has been attained by subsequent combination with click reaction. As described in the introductory, formation of regular one-dimensional conjugated structures on the nanoscale should be thus expected by exploiting the specific assembling properties of rod-coil block copolymers and the precise control not only of amphiphilic nature as well as of the block lengths via synthesis shall open the way to fine tuning the lateral dimensions of these nanostructures. Since the methodology presented here should also have many applications (with various monomers for ATRP, and click reactions), the results presented here should be highly promising for designing precise conjugated materials for the desired purposes.

2-5. Reference and Notes

(1) (a) Special Issue in Organic Electronics: Chem. Mater. 2004, 16, 4381. (b) Organic Light Emitting Devices, Mullen, K.; Scherf, U., Eds.; Wiley-VCH: Winheim, 2006. (c) Handbook of Conducting Polymers, 3rd ed., Skotheim, T. A.; Reynolds, J. Eds.; CRC Press: Boca Raton, 2007.

(2) (a) Grimsdale, A. C.; Mullen, K. In Macromolecular Engineering; Matyjaszewski, K.;

Gnanou, Y.; Leibler, L. Eds.; Wiley-VCH: Weinheim, 2007, vol. 4, p. 2225. (b) Bielawski, C.

W.; Wilson, C. G. In Macromolecular Engineering; Matyjaszewski, K.; Gnanou, Y.; Leibler, L.

Eds.; Wiley-VCH: Weinheim, 2007, vol. 4, p. 2263. (c) Laclerc, N.; Heiser, T.; Brochon, C.;

Hadziioannou, G. In Macromolecular Engineering; Matyjaszewski, K.; Gnanou, Y.; Leibler, L.

Eds.; Wiley-VCH: Weinheim, 2007, vol. 4, p. 2369.

(3) Selected reviews, (a) Fumitomo, H.; Diaz-Garcia,-M. A.; Schwartz, B. J.; Heeger, A. J. Acc.

Chem. Res. 1997, 30, 430. (b) Kraft, A.; Grimsdale, A. C.; Holmes, A. B. Angew. Chem. Int.

Ed. Engl. 1998, 37, 402. (c) Friend, R. H.; Gymer, R. W.; Holmes, A. B.; Burroughes, J. H.;

Marks, R. N.; Taliani, C.; Bradley, D. C. C.; Dos Santos, D. A.; Bredas, J. L.; Logdlund, M.;

Salaneck, W. R. Nature 1999, 397, 121. (d) Grimsdale, A. C.; Chan, K. L.; Martin, R. E.; Jokisz, P. G.; Holmes, A. B. Chem. Rev. 2009, 109, 897. (e) Li, C.; Liu, M.; Pschirer, N. G.;

Baumgarten, M.; Muullen, K. Chem. Rev. 2010, 110, 6817. (f) Zade, S. S.; Zamoshchik, N.;

Bendikov, M. Acc. Chem. Res. 2011, 44, 14. (g) Zhou, H.; Yang, L.; You, W. Macromolecules 2012, 45, 607.

(4) (a) Stirringhaus, H.; Brown, P. J.; Friend, R. H.; Nielsen, M. M.; Bechgaard, K.;

Langeveld-Voss, B. M. W.; Spiering, A. J. H.; Janssen, R. A. J.; Meijer, E. W.; de Leeuw, D. M.

Nature 1999, 401, 685. (b) Hoofman, J. O. M.; de Haas, M. P.; Siebbeles, L. D. A.; Warman, J.

M. Nature 1998, 392, 54. (c) Son, S.; Dodabalapur, A.; Lovinger, A. J.; Galvin, M. E. Science 1995, 269, 376.

(5) (a) Nomura, K.; Morimoto, H.; Imanishi, Y.; Ramhani, Z.; Geerts, Y. J. Polym. Sci., PartA:

Polym. Chem. 2001, 39, 2463. (b) Nomura, K.; Yamamoto, N.; Ito, R.; Fujiki, M.; Geerts, Y.

Macromolecules 2008, 41, 4245. (c) Yamamoto, N.; Ito, R.; Geerts, Y.; Nomura, K.

Macromolecules 2009, 42, 5104. (d) Kuwabara, S.; Yamamoto, N.; Sharma, P. M. V.;

Takamizu, K.; Fujiki, M.; Geerts, Y.; Nomura, K. Macromolecules 2011, 44, 3705.

(6) Selected examples for synthesis of oligo-, poly-(9,9-dialkylfluorene-2,7-vinylene) by other approaches and the property analysis: (a) Jin, S.-H.; Park, H.-J.; Kim, J. Y.; Lee, K.; Lee, S.-P.;

Moon, D.-K.; Lee, H.-J.; Gal, Y.-S. Macromolecules 2002, 35, 7532. (b) Jin, S.-H.; Kang,

S.-Y.; Kim, M.-Y.; Chan, Y. U.; Kim, J. Y.; Lee, K.; Gal, Y.-S. Macromolecules 2003, 36, 3841.

2005, 46, 2555. (d) Gruber, J.; Li, R. W. C.; Aguiar, L. H. J. M. C.; Garcia, T. L.; de Oliveira, H. P. M.; Atvars, T. D. Z.; Nogueira, A. F. Synth. Met. 2006, 156, 104. (e) Anuragudom, P.;

Newaz, S. S.; Phanichphant, S.; Lee, T. R. Macromolecules 2006, 39, 3494. (f) Mikroyannidis, J. A.; Yu, Y.-J.; Lee, S.-H.; Jin, J.-I. J. Polym. Sci., Part A: Polym. Chem. 2006, 44, 4494. (g) Barberis, V. P.; Mikroyannidis, J. A.; Cimrova, V. J. Polym. Sci., Part A: Polym. Chem. 2006, 44, 5750. (h) Liu, Q.; Liu, W.; Yao, B.; Tian, H.; Xie, Z.; Geng, Y.; Wang, F. Macromolecules 2007, 40, 1851.

(7) For examples, (a) Wu, H. Y.; Wang, K. L.; Jiang, J. C.; Liaw, D. J.; Lee, K. R.; Lai, J. Y.;

Chen, C. L. J. Polym. Sci., Part A: Polym. Chem. 2010, 48, 3913. (b) Scheler, E.; Strohriegl, P.

Chem. Mater. 2010, 22, 1410. (c) Li, K.; Liu, B. Polym. Chem. 2010, 1, 252.

(8) Selected recent reviews concerning ADMET polymerization, (a) Lehman, S. E. Jr.;

Wagener, K. B. In Handbook of Metathesis; Grubbs, R. H. Ed.; Wiley-VCH: Weinheim, 2003;

Vol. 3, p. 283. (b) Baughman, T. W.; Wagener, K. B. In Metathesis Polymerization;

Buchmeiser, M. R. Ed.; Springer: Heidelberg, 2005; p. 1.

(9) Synthesis of high molecular weight poly(2,5-dialkyl-1,4-phenylene vinylene)s (PPVs):

Nomura, K.; Miyamoto, Y.; Morimoto, H.; Geerts, Y. J. Polym. Sci., Part A: Polym. Chem. 2005, 43, 6166.

(10) Another synthetic protocol for poly(arylene vinylene)s by ADMET polymerization using RuC12(PCy3)(IMesH2)(CHPh) (Ru), Weychardt, H.; Plenio, H. Organometallics 2008, 27, 1479.

(11) For example, see: (a) Schrock, R. R. In Alkene Metathesis in Organic Synthesis; FUrstner, A, Ed.; Springer-Verlag: Berlin Heidelberg, 1998; p 1. (b) Schrock, R. R. In Metathesis Polymerization of Olefins and Polymerization of Alkynes; Imamoglu, Y. Ed.; NATO ASI Series, Kluwer Academic Publishers: 1998; p 1 and p 357. (c) Schrock, R. R. In Handbook of Metathesis; Grubbs, R. H. Ed.; Wiley-VCH: Weinheim, 2003; vol. 1, p. 8. (d) Schrock, R. R.

Chem. Rev., 2009,109, 3211.

(12) For examples (end functionalization of ROMP polymers and their application for further grafting), see: (a) Nomura, K.; Takahashi, S.; Imanishi, Y. Macromolecules 2001, 34, 4712. (b) Murphy, J. J.; Kawasaki, T.; Fujiki, M.; Nomura, K. Macromolecules 2005, 38, 1075. (c) Murphy, J. J.; Nomura, K. Chem. Commun. 2005, 4080. (d) Murphy, J. J.; Furusho, H.; Paton, R. M.; Nomura, K. Chem. Eur. J 2007, 13, 8985. (e) Nomura, K.; Abdellatif, M. M. Polymer 2010, 51,1861.

(13) Synthesis of alternating block copolymers consisting of oligo poly(phenylene) and oligo-, poly(ethylene glycol): (a) Wagner, Z. R.; Roenigk, T. K.; Goodson, F. E. Macromolecules 2001, 34, 5740. (b) Hargadon, M. T.; Davey, E. A.; McIntyre, T. B.; Gnanamgari, D.; Wynne, C. M.; Swift, R. C.; Zimbalist, J. R.; Fredericks, B. L.; Nicastro, A. J.; Goodson, F. E.

Macromolecules 2008, 41, 741. Highly regular organization of conjugated polymer chains via block copolymer self-assembly, Leclere, P.; Calderone, A.; Marsitzky, D.; Francke, V.; Geerts, Y.; Mallen, K.; Bredas, J. L.; Lazzaroni, R. Adv. Mater. 2000, 12, 1042.

(14) Synthesis of poly(phenylene vinylenes) with well-defined poly(s-caprolactone) or polystyrene, Colak, D. G.; Cianga, I.; Yagci, Y.; Cirpan, A.; Karasz F. E. Macromolecules 2007, 40, 5301.

(15) Synthesis of block copolymers by coupled ring-opening metathesis polymerization with ATRP, Coca, S.; Paik, H.-J.; Matyjaszewski, K. Macromolecules 1997, 30, 6513.

(16) For recent reviews, book chapters for ATRP, see: (a) Tsarevsky, N. V.; Matyjaszewski, K. Chem. Rev. 2007, 107, 2270. (b) Ouchi, M.; Terashima, T.; Sawamoto, M. Acc. Chem. Res.

2008, 41. 1120. (c) Ouchi, M.; Terashima, T.; Sawamoto, M. Chem. Rev. 2009, 109, 4963. (d)

Controlled and Living Radical Polymerizations: From Mechanisms to Applications; MUiler, A. H. E.;

Matyjaszewski, K. Eds.; Wiley-VCH: Weinheim (2009). (e) Pintauer, T.; Matyjaszewski, K. in Metal Catalysts in Olefin Polymerization; Guan, Z. Ed.; Springer-Verlag: Berlin Heidelberg (2009). (f) Matyjaszewski, K.; Tsarevsky, N, V. Nature Chem. 2009, 1, 276. (f) di Lena, F.; Matyjaszewski, K. Prog.

Polym. Sci. 2010, 35, 959.

(17) Reviews, perspectives in click chemistry in synthesis of soft materials, see: (a) Iha, R. K.; Wooley, K.

L.; Nystrom, A. M.; Burke,. D. J.; Kade, M. J.; Hawker, C. J. Chem. Rev. 2009, 109, 5620. (b) Sumerlin, B.

S.; Vogt, A. P. Macromolecules 2010, 43, 1. (c) Qin, A.; Lam, J. W. Y.; Tang, B. Z. Macromolecules 2010, 43, 8693. (d) Golas, P. L.; Matyjaszewski, K. Chem. Soc. Rev. 2010, 39, 1338.

(18) Schrock, R. R.; Murdzek, J. S.; Bazan, G. C.; Robbins, J.; Dimare, M.; O'Regan, M. B. J Am. Chem. Soc. 1990, 112, 3875.

(19) (a) Nomura, K.; Miyamoto, Y.; Morimoto, H.; Geerts, Y. J Polym. Sci., PartA: Poly.

Chem. 2005, 43, 6166-6177. (b) Nomura, K.; Yamamoto, N.; Ito, R.; Fujiki, M.; Geerts, Y.

Macromolecules 2008, 41, 4245-4249.

Chapter 3 Precise synthesis of oligo(2,5-dialkoxy-1,4-phenylene vinylene)s via

combined olefin metathesis and Wittig-type coupling: precise control of repeating units and end functional groups

Contents

3-1.

3-2.

3-3.

3-4.

3-5.

Abstract Introduction Experimental

Results and Discussion References and Notes

3-1. Abstract

Precise, exclusive synthesis of oligo(2,5-dialkoxy-1,4-phenylene vinylene)s [OPV, alkoxy = O(CH2)2OSilPr3] with strictly controlled both repeating units (up to 15 repeating units) and well-defined end functional groups, has been achieved by adopting an olefin metathesis reaction of 2,5-dialkoxy-1,4-divinylbenzene or the oligomer derivatives with molybdenum-alkylidene complex and the subsequent Wittig-type cleavage with their dicarboxaldehyde analogues. The resultant chemically, analytically pure OPVs were fully identified by NMR spectra, GPC traces and elemental analysis. Effects of both the repeating units and the end functional groups toward their UV-vis and the fluorescence spectra have been clearly demonstrated.

3-2. Introduction

Organic electronics are one of the most important emerging technologies, and conjugated polymers, such as poly(p-arylene vinylene)s, poly(thiophene)s, are promising semiconducting materials.1-4 Synthesis of structurally regular, chemically pure polymers by development of new synthetic methods attracts considerable attention,1 because their device performances are affected by polymer structural regularity, chemical purity, and supramolecular order.2'3

Nomura et al. recently demonstrated syntheses of defect free, stereo-regular (all-trans), high molecular weight poly(9,9-dialkylfluorene-2,7-vinylene)s (PFVs),5 poly(2,5-dialkyl-phenylene-1,4-vinylene)s (PPVs),6 poly(N-alkylcarbazole-2,7-vinylene)s5c by acyclic diene metathesis (ADMET) polymerization.5-11 The resultant defect-free PFVs possessed higher absolute quantum yields (1 = 92-99 %) than especially those prepared by the previous (precursor) method.12 Moreover, since the resultant polymers prepared by Ru-carbene catalyst possessed well-defined polymer chain ends (as vinyl group),5b-e,6 a facile, exclusive end-functionalization can be achieved by treating the vinyl groups with Mo-alkylidene (Mo cat.) followed by Wittig-type cleavage with aldehyde.5b,d,e,13,14 Alsoprecise syntheses of ABA type,5b ABCBA typese amphiphilic (multi)block copolymers, and of PFV's containing oligo(thiophene)s in the both chain ends which exhibit unique emission properties by an energy transfer have been demonstrated.5d

Synthesis of oligo(2,5-dialkoxy-1,4-phenylene vinylene)s (OPV) by ADMET technique were reported by Thorn-Csanyi et al.9a-g and Mecking et al..9h However, oligomers up to 7 repeating units were prepared,9b and synthesis of high molecular weight polymers seemed difficult due to

coordination of oxygen atom toward the centered metal (Mo, Ru etc.) and/or accompanied

catalyst decomposition.9g On the basis of the fact that the Wittig-type reactions of

molybdenum-alkylidene species [of the conjugated polymer (PFV) chain ends] with aldehydes

took place in quantitative yields,sb'd'e in this chapter, a precise, exclusive synthesis of analytically

pure OPV with both strictly controlled repeating units and well-defined chain ends has been

achieved by (stepwise) coupling of "bis-alkylidene" species with OPV containing aldehyde at the

both chain ends.15

3-3. Experimental

Materials

General procedure

All experiments were carried out under a nitrogen atmosphere in a Vacuum Atmospheres drybox or using standard Schlenk techniques. All chemicals used were of reagent grades and were purified by the standard purification procedures. Anhydrous grade toluene (Kanto Chemical Co., Inc.) was transferred into a bottle containing molecular sieves (mixture of 3A 1/16, 4A 1/8, and 13X 1/16) in the drybox, and was stored over sodium/potassium alloy in the drybox, and then passed through an alumina short column prior to use. Anhydrous grade dichloromethane (Kanto Chemical Co., Inc.) was passed through an alumina short column prior to use.

Mo(CHCMe2Ph)(N-2,6-Me2C6H3)[OCMe(CF3)2]2 (Mo cat.)16 was prepared according to the literature, and RuC12(PCy3)(IMesH2)(CH-2-OIPr-C6H4) [Cy = cyclohexyl, IMesH2 = 1,3-bis(2,4,6-trimethylphenyl)imidazolin-2-ylidene] were used in the drybox as received (Strem Chemicals, Inc.). 2,2' :5',2"-terthiophene-5-carboxaldehyde, benzaldehyde and pentafluorobenzaldehyde were also used in the drybox as received (Sigma-Aldrich Co.) without further purification. 1,4-Bis(2' -hydroxyethoxy)benzene, 2-butanone, N-bromo- succinimide, imidazole, triisopropylsilylchloride, tetrakis(triphenylphosphine)palladium, tributyl(vinyl)tin and n-butyl lithium were used as received without further purification.

All 1H and13C NMR spectra were recorded on a Bruker AV500 spectrometer (500.13 MHz for 1H, 125.77 MHz for 13C) and all chemical shifts are given in ppm and are referenced to SiMe4.

Obvious multiplicities and routine coupling constants are usually not listed, and all spectra were obtained in the solvent indicated at 25 °C unless otherwise noted. Molecular weights and the molecular weight distributions of the resultant polymers were measured by gel-permeation chromatography (GPC). HPLC grade THF was used for GPC and was degassed prior to use. GPC were performed at 40 °C on a Shimadzu SCL-10A using a RID-10A detector (Shimadzu Co. Ltd.) in THF (containing 0.03 wt % of 2,6-di-tert-butyl-p-cresol, flow rate 1.0 mL/min). GPC columns (ShimPAC GPC-806, 804 and 802, 30 cm x 8.0 mm diameter, spherical porous gel made of styrene/divinylbenzene copolymer, ranging from < 102 to 2x107 MW) were calibrated versus

polystyrene standard samples. UV-vis spectra for the resultant polymers were measured by using a Jasco V-550 UV/vis spectrophotometer (conc. 1.0x10-6 M in THF at 25 °C), and the fluorescence spectra were measured by an Hitachi F-4500 fluorescence spectrophotometer (conc.

1.0x10-6 M in THF at 25 °C) with excitation wavelength at 450 nm. Preparative gel-permeation chromatography (GPC) was performed on a YMC LC-Forte/R (YMC group) using UV detector in toluene with flow rate 10.0 mL/min, equipped with YMC-GPC T4000 and YMC-GPC T30000 columns, ranging from 4x103 to 30x103 MW.

Synthesis of starting compounds.

OCH2CH2OHOCH2CH2OHOCH

2CH2OROCH2CH2OR (i)

Br (ii)Br (iii)

0 MEKP. NBS ,_ 0TIPSCIPd(PPh3)4\ fel

65 °C BrImidazoleH2C=CH-Sn(Bu)3 Dry DMF BrStille coupling \

OCH2CH2OHOCH2CH2OH r.tOCH2CH2OROCH2CH2OR

R= 'Pr3Si(iv)

"Bu Li / DMF OCH

2CH2OR

40 Et2O/TH FCH O

OHC

OCH2CH2OR

(i) Synthesis of 1,4-dibromo-2,5-di(2'-hydroxyethoxy)benzene. Into a dry two neck flask containing 1,4-bis(2'-hydroxyethoxy)benzene (3.0 g, 15 mmol) and 2-butanone (30 mL) was added N-bromosuccinimide (6.5 g, 36 mmol, 2.4 equiv) at 65 °C, and the mixture was stirred overnight at 70 °C. The mixture was then poured into water (150 mL) and the resultant precipitates were washed in water for 2 h, and was collected on a filter paper. The resultant solids were dissolved in acetone and dried over anhydrous MgSO4. The solution was then poured into cold n-hexane, and the precipitates were collected by filtration, dried in vacuo to give white solids.

Yield 4.8 g (90.0 %). 1H NMR (CDC13 at 25 °C): 6 7.20 (s, 2H), 4.08 (t, 4H), 4.00 (t, 4H).

(ii) Protection of 1,4-dibromo-2,5-di(2'-hydroxyethoxy)benzene with triisopropylsilyl chloride (TIPSC1). Into a dry two neck flask containing 1,4-dibromo-2,5-bis(2'-hydroxyethoxy)benzene (2.3 g, 6.5 mmol), imidazole (2.2 g, 32.3 mmol, 5 equiv) and DMF (20 mL) was added a DMF (10 mL) solution containining triisopropylsilyl chloride (3.05 g, 15.75

mmol, 2.5 equiv) dropwisely at 0 °C. The mixture was then stirred overnight at room temperature, and the solution was poured into 5 % NaOH aq. solution (100 mL), and the precipitates were washed by continued stirring for 2 h and were collected on a filter paper. The resultant solids were then dissolved in acetone and were dried over anhydrous MgSO4. The resultant solids after removal of acetone were recrystallized using n-hexane, and were collected by filtration and dried in vacuo to give white solids. Yield 4.0 g (93.0 %). 1H NMR (CDC13 at 25 °C): 8 7.20 (s, 2H), 4.08 (t, 4H), 4.00 (t, 4H), 1.13 (m, 6H), 1.11 (d, 36H).

(iii) Synthesis of 2,5-bis(2'-triisopropylsilyloxyethoxy)-1,4-divinylbenzene. In the drybox, 1,4-dibromo-2,5-di(2'-triisopropylsilyloxyethoxy)benzene (1.7 g, 2.57 mmol), Pd(PPh3)4 (0.19 g, 0.16 mmol, 0.063 equiv), toluene (34 mL) and tributyl(vinyl)tin (2.1 g, 6.68 mmol, 2.6 equiv) were charged into a sealed Schlenk-type tube. The mixture was then stirred at 110 °C for 12 h with protection from light by using aluminum foil. After the reaction, the reaction mixture was cooled to room temperature and was poured in erlenmeyer flask containing 1N NaOH aq. solution (100 mL), and the solution was stirred for 1 h. The mixture was filtered through Celite pad was filtercake was washed with n-hexane. The organic layer was then washed with 1N NaOH aq.

solution and brine twice, and the resultant water layer was extracted with n-hexane. The combined two organic extracts were dried over anhydrous MgSO4, and was placed in a rotary evaporator to remove volatiles. The resultant solids were purified by a silica gel column chromatography (n-hexane:ethyl acetate = 95:5) twice, affording colorless oil, which eventually purified as white microcrystals after recrystallization. Yiled 0.72 g (50.0 %). 1H NMR (CDC13 at 25 °C): 8 7.21 (dd, 2H), 7.20 (s, 2H), 5.70 (d, 2H), 5.25 (d, 2H), 4.09 (br, 8H), 1.13 (m, 6H), 1.11 (d, 36H).

(iv) Synthesis of 2,5-bis(2'-triisopropylsilyloxyethoxy)benzene-1,4-dicarboxaldehyde. Into a sealed Schlenk-type tube containing 1,4-dibromo-2,5-di(2'-triisopropylsilyloxy- ethoxy)benzene (2.1 g, 3.14 mmol) and THF (30 mL) was added n-BuLi (1.55M n-hexane solution, 10.45 mmol, 3.33 equiv, 6.8 mL) at -78 °C dropwisely. The mixture was warmed gradually to room temperature and was stirred at room temperature for 1.5 h. The reaction solution was added dry DMF (0.84 mL, 12.15 mmol, 3.87 equiv) and THF (0.9 mL) dropwisely at -78 °C, and the solution was stirred for 12 h at room temperature. The stirred was then cooled at 0 °C and was added 2 N HC1 aq. solution (10 mL, 16.96 mmol, 5.4 equiv), and the product was diluted with

THF. The organic layer was washed with dilute solution of NaOH aq. solution and was dried over anhydrous MgSO4. The organic layer was placed in a rotary evaporator to remove volatiles, and the resultant solids were purified by a silica gel column chromatography (n-hexane:ethyl acetate =

90:10), affording yellow microcrystals after recrystallization. Yield 1.07 g (60.0 %). 1H NMR (CDC13 at 25 °C): 8 10.60 (s, 2H), 7.50 (s, 2H), 4.08 (t, 4H), 4.00 (t, 4H), 1.13 (m, 6H), 1.11 (d, 36H).

Synthesis of oligomers by ADMET polymerization.17 A toluene solution (0.4 mL) containing 2,5-bis(2'-triisopropylsilyloxyethoxy)-1,4-divinylbenzene (20 mg, 35.53 limo', 178 µmol/mL) in a sealed Schlenk-type tube, RuC12(PCy3)(IMesH2)(CH-2-O1Pr-C6H4) [Cy = cyclohexyl, IMesH2 = 1,3-bis(2,4,6-trimethylphenyl)imidazolin-2-ylidene] (20 equiv) was added. The reaction mixture was stirred at 55 °C for 66 h. During the reaction, the mixture was placed into a liquid nitrogen.

bath with a certain period to remove ethylene from the reaction medium by opening the valve connected to the vacuum line, and then placed into the oil bath to continue the reaction (1st h every 10 min, 2nd h every 20 min, 3rd h every 30 min, 4 h — every 1 h). The polymerization was quenched by adding ethyl vinyl ether in excess amount (ca. 3-4 drops). The reaction mixture was then stirred for 1 h for completion. The resultant solution was poured into cold methanol, (stirring the mixture for 2 h), and was then collected by filteration. The resultant precipitate was then dried in vacuo, affording orange precipitate. [Mn(GPC) = 2.9x103, Mn( 1R) = 1.87x103, MWIMn = 1.27].

Yield 16.0 mg (79.0 %). 1H NMR (CDC13 at 25 °C): 8 7.42 (br, 2H), 7.19 (br, 2H), 7.16 (dd, 2H), 5.79 (d, 2H), 5.27 (d, 2H), 4.15 (br, 8H), 1.12 (br, 42H). 13C NMR (CDC13 at 25 °C): 8 151.2, 151.1, 150.0, 127.8, 118.1, 112.4, 110.9, 71.8, 71.1, 71.0, 62.3, 62.2, 18.0, 12.0.

Synthesis of OPV-3T and OPV-C6F5. In the dry box poly(p-phenylene vinylene) [Mn =

2.9x103, Mn(NMR) = 1.87x103, MW/Mn = 1.27] (10 mg, 0.82 µmol), 1.5 mL toluene (2.0 mM) and

Mo(CHCMe2Ph) (N-2,6-Me2C6H3) [OCMe(CF3)2]2 (12 mg, 17.2µmol ,Seq) stirred for 2 h at

room temperature then adding solution of 3PV-CHO (— < 0.5 eq) and then stirred for 1 h and

terminated by adding aldehyde solution in excess (-20 eq) of 2'

:5',2"-terthiophene-5-carboxaldehyde and pentafluorobenzaldehyde with stirring 1 h to get OPV-3T and OPV-C6F5

respectively, the resulted polymer precipitated in methanol with stirring for 2 h and collected by

filtration, the filtrate recovered by using chloroform, then dried in vacuo, orange precipitate was

resulted.

OPV-3T.1H NMR (CDC13 at 25 °C): 8 [6.20-7.20, terthiophene], 7.45 (br, 2H),7.18 (br, 2H), 4.15 (br, 8H), 1.12 (br, 42H). 13C NMR (CDC13 at 25 °C): 8 124.1, 123.7, 123.3, 121.9, 118.7, 116.5, 110.5, 71.1, 62.4, 18.1, 12.1. [Mn(GPC) = 5.1 x 1.03, Mn(NMR) = 4.64x103, Mw/Mn = 1.19].

Yield > 99.0 %

OPV-C6F5. NMR (CDC13 at 25 °C): 6 7.45 (br, 2H),7.18 (br, 2H), 4.15 (br, 8H), 1.12 (br, 42H). 13C NMR (CDC13 at 25 °C): 6 151.1, 135.7, 125.5, 118.0, 110.9, 62.3, 18.0, 17.9, 12.0. 19F NMR (CDC13 at 25 °C): -159, -165, -167. [Mn(GPC) = 4.90x103, Mn(calcd) = 4.50x103, Mw/Mn =

1.20] . Yield > 99.0 %

Synthesis of 3PV-CHO. In the ' drybox, a toluene solution (9.0 mM) containing 2,5-bis(2'-triisopropylsilyloxyethoxy)-1,4-divinylbenzene (DVB, 10.0 mg, 17.76 µmol) was added Mo(CHCMe2Ph)(N-2,6-Me2C6H3)[OCMe(CF3)2]2 (Mo cat.,1 25.0 mg, 35.53 [mot, 2.0 equiv), and the solution was stirred for 2 h at room temperature. The mixture was then added to a dichloromethane (0.5 mL) solution containing 2,5-bis(2'-triisopropylsilyloxyethoxy)-benzene-1,4-dicarboxaldehyde (22 mg, 39.07 µmol, 2.2 equiv), and was stirred for 1 h. The resultant oligomer was precipitated by pouring the solution into methanol (stirring the mixture for 2 h), and was then collected by filteration. The filtrate was recovered by using chloroform, the concentrated solution was then poured into cold methanol. The resultant combined precipitates were then dried in vacuo, affording orange precipitate. Yield 25.0 mg (85.0 %). 1H NMR (CDC13

at 25 °C): 8 10.50 (s, 2H), 7.54 (d, 2H), 7.44 (d, 2H), 7.38 (s, 2H), 7.25 (s, 2H), 7.18 (s, 2H), 4.20 (br, 12H), 4.11 (br, 12H), 1.11 (m, 18H), 1.08 (d, 108H). 13C NMR (CDC13 at 25 °C): 6 142.7, 126.7, 125.5, 118.1, 112.4, 110.9, 62.3, 62.2, 62.1, 18.0, 12.0. Anal.Calcd for C90H162O14Si6 : C, 66.04; H 9.98; N, 0.0, Found: C, 66.11; H, 9.76; N, 0.0.

Synthesis of 7PV-CHO. In the drybox, a toluene solution (9.0 mM) containing 2,5-bis(2'-triisopropylsilyloxyethoxy)-1,4-divinylbenzene (DVB, 1.0 mg, 1.77 [mop was added Mo(CHCMe2Ph)(N-2,6-Me2C6H3)[OCMe(CF3)2]2 (Mo cat., 2.5 mg, 3.55 µmol, 2.0 equiv.), and the solution was stirred for 2 h at room temperature. The mixture was then added to a toluene (0.5 mL) solution containing 3PV-CHO (6.0 mg, 3.67 [Imo', ca. 2.2 equiv.) and was stirred for 1 h.

then dried in vacuo, affording orange precipitates. Yield 5.50 mg (80.0 %). 1H NMR (CDC13 at 25

°C): 6 10.50 (s, 2H), 7.46 (br,14H), 7.19 (br, 14H), 4.18 (br, 28H), 4.12 (br, 28H), 1.13 (m, 42H), 1.08 (d, 252H). 13C NMR (CDC13 at 25 °C): 6 142.7, 126.7, 125.5, 118.0, 110.9, 71.1, 18.0, 12.0.

Anal.Calcd for C21oH378O30Si14: C, 66.79; H 10.09; N, 0.0, Found: C, 66.59; H, 9.98; N, 0.0.

Synthesis of 15PV-CHO. In the drybox, a toluene solution (9.0 mM) containing 2,5-bis(2'-triisopropylsilyloxyethoxy)-1,4-divinylbenzene (DVB, 0.5 mg, 0.89 µmol) was added Mo(CHCMe2Ph)(N-2,6-Me2C6H3)[OCMe(CF3)2]2 (Mo cat., 2.5 mg, 3.55 limo', 2.0 equiv), and the solution was stirred for 2 h at room temperature. The mixture was then added to a toluene (0.5 mL) solution containing 7PV-CHO (7.5 mg, 1.98 µmol, ca. 2.2 equiv) and was stirred for 1 h.

The resultant oligomer was precipitated by pouring the solution into cold methanol (stirring the mixture for 2 h), and was then collected by filteration. The resultant precipitate was further purified by using preparative GPC. The desired fraction was placed in a rotary evaporator to remove volatiles, then collected and dried in vacuo, affording orange precipitates. Yield (6.5 mg, 82.0 %). 1H NMR (CDC13 at 25 °C): 6 10.50 (s, 2H), 7.46 (br, 30H), 7.19 (br, 30H), 4.18 (br, 60H), 4.12 (br, 60H), 1.13 (m, 90H), 1.08 (d, 540H). 13C NMR (CDC13 at 25 °C): 6 142.7, 126.7, 125.5, 118.1, 112.4, 110.9, 71.1, 18.0, 12.0.

Synthesis of 5PV-3T, 5PV-C6H5 and 5PV-C6F5. In the drybox, a toluene solution (9.0 mM) containing 2,5-bis(2'-triisopropylsilyloxyethoxy)-1,4-divinylbenzene (DVB, 5.0 mg, 8.88 gmol) was added Mo(CHCMe2Ph)(N-2,6-Me2C6H3)[OCMe(CF3)2]2 (Mo cat., 13.0 mg, 17.7 µmol, 2.0 equiv), and the solution was stirred for 2 h at room temperature. A toluene (0.5 mL) solution contaning 3PV-CHO (6 mg, 3.67 µmol, ca. < 0.5 equiv) then added to the mixture and was stirred for 1 h. A dichloromethane (0.5 mL) solution containing a prescrtibed aldehyde (2':5',2"-terthiophene-5-carboxaldehyde, benzaldehyde, pentafluorobenzaldehyde, ca. > 5 equiv) was then added to afford the 5 mers (5PV-3T, 5PV-C6H5, 5PV-C6F5, repectively). The resultant oligomer was precipitated by pouring the solution into cold methanol (stirring the mixture for 2 h), and was then collected by filteration. The precipitates were further purified by preciptation in cold n-hexane, and was then collected by filteration. The filtrate was recovered by using chloroform, the concentrated solution was then poured into cold methanol. The resultant precipitates were then dried in vacuo, affording (red, orange, orange) precipitates for (5PV-3T, 5PV-C6H5, 5PV-C6F5, repectively).

5PV-3T: 1H NMR (CDC13 at 25 °C): 6 7.44 (br, 10H), 7.26 (br, 3H), 7.18 (br, 10H), 7.15- 6.98 (br, 11H), 4.17 (br, 20H), 4.12 (br, 20H), 1.13 (m, 30H), 1.09 (d, 180H). 13C NMR (CDC13 at 25

°C): 6 124.1, 123.7, 123.3, 121.9, 118.7, 116.5, 110.5, 71.1, 62.4, 18.1, 12.1. Anal.Calcd for C176H286O20S6Si10: C, 66.15; H 9.02; N, 0.0, Found: C, 66.38; H, 9.07; N, 0.0. Yield 10.0 mg

(85.0 %).

5PV-C6H5: 1H NMR (CDC13 at 25 °C): 6 7.59-7.44 (br, 10H), 7.39 (br, 3H), 7.25 (br, 3H), 7.19 (br, 10H), 7.01 (s, 4H), 4.18 (br, 20H), 4.12 (br, 20H), 1.13 (m, 30H), 1.08 (d, 180H). 13C NMR (CDC13 at 25 °C): 6 151.1, 128.5, 126.6, 123.7, 123.4, 110.9, 110.6, 71.2, 71.0, 62.4, 62.3, 18.0, 12.1, 12.0, 11.8. Anal.Calcd for C164H282O20Si10: C, 69.00; H, 9.96; N, 0.0, Found: C, 68.40; H, 9.95; N, 0.0. Yield 8.8 mg (85.0 %).

5PV-C6F5: 1H NMR (CDC13 at 25 °C): 6 7.45 (br, 10H), 7.18 (br, 10H), 4.18 (br, 20H), 4.11 (br, 20H), 1.13 (m, 30H), 1.08 (d, 210H). 13C NMR (CDC13 at 25 °C): 6 151.1, 135.7, 125.5, 118.0, 110.9, 62.3, 18.0, 17.9, 12.0. 19F NMR (CDC13 at 25 °C): 6 -143, -156, -164. Anal.Calcd for C164H272F10O20Si10: C, 64.91; H, 9.03; N, 0.0, Found: C, 65.20; H, 8.79; N, 0.0. Yield 10.5 mg (95.0 %).

Synthesis of 9PV-3T and 9PV-C6F5. In the drybox, a toluene solution (9.0 mM) containing 2,5-bis(2'-triisopropylsilyloxyethoxy)-1,4-divinylbenzene (DVB, 5.0 mg, 8.88 [mop was added Mo(CHCMe2Ph)(N-2,6-Me2C6H3)[OCMe(CF3)2]2 (Mo cat., 13.0 mg, 17.7 µmol, 2.0 equiv), and the solution was stirred for 2 h at room temperature. A toluene (0.5 mL) solution containing 7PV-CHO (12 mg, 3.17 µmol, ca. < 0.5 equiv) then added to the mixture and was stirred for 1 h.

A dichloromethane (0.5 mL) solution containing a prescrtibed aldehyde (2':5',2"-terthiophene-5-carboxaldehyde, pentafluorobenzaldehyde, ca. > 5 equiv) was then added to afford the 9 mers (9PV-3T, 9PV-C6F5, repectively). The resultant oligomer was precipitated by pouring the solution into cold methanol (stirring the mixture for 2 h), and was then collected by filteration. The precipitates were further purified by preciptation in cold n-hexane, and was then collected by filteration. The filtrate was recovered by using chloroform, the concentrated solution was then poured into cold methanol. The resultant precipitates were then dried in vacuo, affording (red, orange) precipitates for (9PV-3T, 9PV-C6F5, repectively).

9PV-3T: 1H NMR (CDC13 at 25 °C): 6 7.44 (br, 18H), 7.18 (br, 18H), 7.16 — 6.99 (br, 14H), 4.18 (br, 36H), 4.13 (br, 36H), 1.13 (m, 54H), 1.08 (d, 324H). 13C NMR (CDC13 at 25 °C): 6

124.1, 123.7, 123.3, 121.9, 118.7, 116.5, 110.5, 71.1, 62.4, 18.1, 12.1. Anal.Calcd for C296HSO2O36S6Si18: C, 66.64; H, 9.50; N, 0.0, Found: C, 66.95; H, 9.83; N, 0.0. Yield 16.0 mg (90.0 %).

9PV-C6F5: 1H NMR (CDC13 at 25 °C): 6 7.45 (br, 18H), 7.18 (br, 18H), 4.18 (br, 36H), 4.11 (br, 36H), 1.13 (m, 54H), 1.08 (d, 324H). 13C NMR (CDC13 at 25 °C): 6 151.1, 135.7, 125.5, 118.0, 110.9, 62.3, 18.0, 17.9, 12.0. 19F NMR (CDC13 at 25 °C): 6 -143, -156, -164. Yield 15.5 mg (95.0 %).

3-4. Results and Discussion.

Although, as reported by Thorn-Csanyi et a1.,9a-g an attempted synthesis of high molecular weight polymers by ADMET polymerization of

2,5-bis(2'-triisopropylsilyloxyethoxy)-1,4-divinylbenzene (DVB) using Ru-carbene catalyst, RuC12(PCy3)(IMesH2)(CH-2- OIPr-C6H4) [Cy = cyclohexyl, IMesH2 = 1,3-bis(2,4,6-trimethylphenyl)-imidazolin-2-ylidene], was not successful [Mn(GPC) = 2.9x103, Mn(NMR) = 1.87x103, MW/Mn = 1.27], therefore, a stepwise approach for synthesis of conjugated oligomers by adopting a methodology has been chosen (Scheme 3-1).

The vinyl groups in DVB were treated with Mo(CHCMe2Ph)(N-2,6- Me2C6H3)[000H3(CF3)2]2, (Mo cat., 2 equiv), to form the "bis-alkylidene" species (expressed as Mo=DB=Mo) in situ, and subsequent reaction with corresponding aldehyde (2,5-dialkoxybenzene-1,4-dicarboxaldehyde, DBDA) in rather excess amount (2.2 equiv to DVB) afforded 3 mer of oligo(2,5-dialkoxy-1,4-phenylene vinylene) containing aldehyde as the end groups (3PV-CHO).

3PV-CHO was isolated as an analytically pure form by simple fractional separation (yield 85.0 %), and was identified by NMR spectra, GPC trace (unimodal distribution, MW/Mn = 1.0) (Figure 3-1) and elemental analysis. In the 1H NMR spectra (Figure 3-2a) the corresponding peaks for the protons of vinyl groups [S 7.21 (dd, 2H), 5.70 (d, 2H), 5.25 (d, 2H)] completely disappeared and new peaks assigned to the resulted olefinic double bonds [6 7.54 (d, 2H), 7.44 (d, 2H)] and peaks assigned to protons of chain end group (aldehyde groups) also appeared [6 10.5 (s, 2H)]. The Mn value estimated by 1H NMR spectrum (on the basis of integration ratio of aromatic protons in OPV vs chain end group) was very close to that by the calculated value (Table 3-1).

Moreover, 3PV-CHO was treated with less than 0.5 equiv of "bis-alkylidene" species to afford the 7 mer (7PV-CHO) as the sole coupled product. Then, the resultant 7PV-CHO was treated with less than 0.5 equiv of "bis-alkylidene" species to afford the 15 mer (15PV-CHO) exclusively. 7PV-CHO was isolated as an analytically pure form by a fractional separation (isolated yield 80.0 %), and were identified by NMR spectra, GPC trace (MW/ Mn = 1.0) and by elemental analysis: 15PV-CHO was also isolated as a pure form confirmed by fractional GPC (in addition to ordinary GPC traces, MwIMn = 1.0) (Figure 3-1), and was identified by NMR spectra (isolated yield 82.0 %). The Mn values in 7PV-CHO and 15PV-CHO estimated by 1H NMR spectra (Figure 3-2b,c) were very close to those by the calculated values. Note that a synthesis of high molecular weight oligomers [ex. 15PV-CHO, Mn = 8.07x103] has been achieved by

adopting this methodology, and the resultant oligomer are analytically pure and possessed strictly repeating units and well-defined end groups. In the vinylic region of 1H NMR spectra, two doublet peaks observed at (b 7.45-7.6, 4H) in case of 3PV-CHO, and resonances corresponding to cis-vinyl-H (cis double bonds) were not seen, which confirmed also at higher repeating units 15PV-CHO [b 7.46 (br, 30H)] (Figure 3-2), which indicate that the olefinic double bond in the OPV possessed high stereo regularity (highly trans).

~ ® Mo cat.

2 equiv.

RO OR (

\O RO

OR O

3PV-CHO RO

R = OCH2CH2OSi'P.,

Ar CHOv 3T

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