Synthesis and characterization of poly(phenylacetylene)s carrying oligo(ethylene oxide) pendants

A group of new amphiphilic poly(phenylacetylene)s bearing polar oligo(ethylene oxide) pendants, poly{4‐[2‐(2‐hydroxyethoxy)ethoxy]phenylacetylene} ( 1 ), poly(4‐{2‐[2‐(2‐hydroxyethoxy)‐ethoxy]ethoxy}phenylacetylene) ( 2p ), poly(3‐{2‐[2‐(2‐hydroxyethoxy)ethoxy]ethoxy}phenylacetylene) ( 2m ), poly(4‐{2‐[2‐(2‐methanesulfonyloxyethoxy)ethoxy]ethoxy}phenylacetylene) ( 3 ), poly(4‐{2‐[2‐(p‐toluenesulfonyloxyethoxy)ethoxy]ethoxy}phenylacetylene) ( 4 ), poly(4‐{2‐[2‐(2‐trimethylsilyloxy‐ethoxy)ethoxy] ethoxy}phenylacetylene) ( 5 ), and poly(4‐{2‐[2‐(2‐chloroethoxy)ethoxy]ethoxy}phenylacetylene) ( 6 ), were synthesized with organorhodium complexes as the polymerization catalysts. The structures and properties of the polymers were characterized with IR, UV, NMR, and thermogravimetric analysis. 1 , 2p , and 2m , the three polymers containing pendants with hydroxyl groups, were oligomeric or insoluble. The organorhodium complexes worked well for the polymerization of the monomers without hydroxyl groups, giving soluble polymers 3 – 6 with a weight‐average molecular weight up to ～160 × 10³ and a yield up to 99%. Z‐rich polymers 3 – 6 could be prepared by judicious selections of the catalyst under optimal conditions. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 1153–1167, 2006     

Improved properties of polyfluorenevinylenes by introduction of carbazole units

New electroluminescent polyfluorenevinylenes (PFV) copolymers with carbazole group, CzPFVs, have been synthesized by the GILCH polymerization. The carbazole groups were introduced as pendant to increase the electron rich ability of the copolymers. All CzPFVs exhibited absorption spectra with maximum peaks at around 417 nm. In the PL emission spectra of CzPFVs, maximum peaks around 463 nm and shoulder peaks around 490–500 nm were exhibited. By adjusting the feed ratios of carbazole groups in the CzPFVs, it is possible to have the higher current density and brightness, and the lower turn‐on voltage due to increasing hole injection ability. The maximum luminescence of CzPFV9 was 2003 cd/m² at 7 V. The introduction of carbazole contents in PFVs can enhance the device performance to result in stable PL and EL spectra with high current density and brightness due to the increased hole injection ability and reduced interchain interaction between polymer backbones. Especially, the 1:1 mixture of CzPFV10 and PVK didn't show aggregation effect in PL spectra even after annealing the thin film at 80 °C up to 60 min, since the interchain interaction among polymer backbones with fluorenevinylene units was reduced. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 4407–4419, 2008     

Synthesis and properties of polyacetylenes with salicylideneaniline groups

Acetylenes containing salicylideneaniline groups—N‐salicylidene‐3‐ethynylaniline ( 1 ), N‐(3‐t‐butylsalicylidene)‐3‐ethynylaniline ( 2 ), and N‐(3‐t‐butylsalicylidene)‐4‐ethynylaniline ( 3 )—polymerized smoothly and gave yellow to red polymers in excellent yields when a rhodium catalyst was employed. Polymers with alkyl substituents on the aromatic rings [poly( 2 ) and poly( 3 )] were soluble in CHCl₃, tetrahydrofuran, and so forth, whereas the polymer without alkyl substituents [poly( 1 )] was insoluble in any solvent. N‐(3‐t‐Butylsalicylidene)propargylamine did not provide any polymer. Thermogravimetric analyses of the resultant polymers exhibited good thermal stability (T_o, onset temperature of weight loss > 300 °C). The ultraviolet–visible spectra of the polymers showed absorption maxima and cutoff wavelengths around 360 and 520 nm, respectively. The polymers exhibited largely Stokes‐shifted fluorescence (emission wavelength ? 550 nm) upon photoexcitation at 350 nm, which resulted from the photoinduced intramolecular proton transfer. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 2458–2463, 2002     

Synthesis and properties of conjugated polymers containing 3,9‐ and 2,9‐linked carbazole units in the main chain

Novel conjugated polymers containing 3,9‐ or 2,9‐linked carbazole units in the main chain were synthesized by the polycondensation of ethynyl‐ and iodo‐substituted 9‐arylenecarbazolylene monomers, and their optical and electrical properties were studied. Polymers with weight‐average molecular weights of 3400–12,000 were obtained in 76–99% yields by the Sonogashira coupling polycondensation in piperidine or tetrahydrofuran (THF)/piperidine at 30 °C for 48 h. All the 3,9‐linked polymers absorbed light around 300 nm. The para‐phenylene‐linked polymer also absorbed light around 350 nm, while meta‐phenylene‐linked one did not. The 3,9‐linked polymers absorbed light at a wavelength longer than the 2,9‐linked one. The polymers emitted blue fluorescence with high quantum yields (0.21–0.78) upon excitation at the absorption maxima. The polymers were oxidized around 0.6 V, and reduced around 0.5 V. Poly( 1 ) showed the dark conductivity of 3.7 × 10^?11 S/cm (10³ V/cm). © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 3506–3517, 2009     

New ladder‐type conjugated polymer containing carbazole and fluorene units in backbone: Synthesis,optical, and electrochemistry properties

This article describes the synthesis and characterization of a new ladder‐type poly (p‐phenylene) (LPFC) containing alkylcarbazole and dialkylfluorene units in backbone, and its optical and electrochemical properties as well as its light‐emitting device performance. LPFC shows the well‐defined structure, high molecular weights, excellent thermal stability, and good solubility in common organic solvents. And it also shows strongly blue emission (λ_max = 465 nm) with quantum efficiency of 70% in solution, while its solid emission (λ_max = 470 nm) is almost the same as its solution. Electrochemical studies show that the highest occupied molecular orbital (HOMO) energy levels of LPFC is up to 5.29 eV, which is significantly higher than that of LPPP without carbazole in backbone, indicating an enhanced ability of hole injection from anodes. Furthermore, the single layer light‐emitting device using LPFC as the active layer shows blue emission (λ_max = 470 nm) with maximum luminescence of ～ 2000 cd/m² and maximum luminance efficiency of 0.43 cd/A. The attractive properties exhibited from new ladder‐type polymer establish LPFC as a good candidate for the potential application as transporting and emitting layer in polymeric light emitting diodes. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 3120–3127, 2008     

Helical poly(phenylacetylene)s containing schiff‐base and amino groups: Synthesis,secondary structures,and responsiveness to benzoic acid

Novel acetylenic monomers containing Schiff‐base and amino groups, (S)‐N‐(4‐ethynylbenzylidene)‐1‐phenylethanamine ( 1a ), (R)‐N‐(4‐ethynylbenzylidene)‐1‐phenylethanamine ( 1b ), N‐(4‐ethynylbenzylidene)‐1‐phenylethanamine ( 1c ), (R)‐N‐(4‐ethynylbenzyl)‐1‐phenylethanamine ( 1d ), and (R)‐N‐(4‐ethynylbenzyl)‐1‐phenylethanamine ( 1e ) were synthesized and polymerized with [(nbd)RhCl]₂/Et₃N catalyst to afford the corresponding polymers 2a ‐ e with moderate molecular weights (M_n = 9000–60,000) in high yields (85–97%). All the polymers were soluble in common organic solvents including toluene, CHCl₃, CH₂Cl₂, THF, and DMF. Large optical rotations and strong CD signals demonstrated that 2a , 2b , 2d , and 2e take helical structures with a predominantly one‐handed screw sense. The effects of solvents and temperature revealed that these polymers took dynamic helical structure based on the steric effect of side groups. The CD patterns of 2d and 2e containing free amino moieties were completely inverted by the addition of benzoic acid. Upon further addition of NaOH, the CD pattern returned to the original one, indicating the reversible conformational change of these polymers according to pH. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013 , 51, 5248–5256     

Synthesis and properties of carbamate‐ and amine‐containing poly(phenylacetylenes)

The 3‐ and 4‐aminophenylacetylenes protected by t‐butoxycarbonyl (t‐Boc) and 9‐fluorenylmethoxycarbonyl (Fmoc) groups ( 3a – 6a ) were synthesized and polymerized using [(nbd)RhCl]₂ ( 1 ) and [(nbd)Rh⁺‐η⁶‐PhB^?Ph₃] ( 2 ) catalysts. The t‐Boc‐containing polymers [poly( 3a ) and poly( 4a )] were obtained in high yield (82–91%). Among the Fmoc‐protected monomers, the para‐derivative polymerized well [poly( 6a ); yield = 85–94%], whereas its meta‐substituted analogue did not afford high molecular weight polymer in good yield [poly( 5a ); yield = 10–15%]. The use of KN(SiMe₃)₂ as a cocatalyst in conjunction with 1 led to a dramatic increase in the molecular weight of the polymers. The acid‐ and base‐catalyzed removal of the t‐Boc and the Fmoc groups, respectively, generated primary amine‐containing polymers [poly( 3b )–poly( 6b )] which cannot be obtained directly by the polymerization of the corresponding monomers. The solubility characteristics of the polymers bearing protected amino groups were quite different from those of the unprotected ones, the former being soluble in polar solvents, whereas the latter displayed poor solubility even in polar protic or highly polar aprotic solvents. The attempts to accomplish the free‐standing membrane fabrication by solution casting were successful only for poly( 3a ), and an augmentation in the gas permeability and CO₂/N₂ permselectivity was discerned in comparison with the unsubstituted poly(phenylacetylene) and poly(m‐t‐butyldimethylsiloxyphenylacetylene). © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 1853–1863, 2009     

Helical chirality of π‐conjugated main‐chain induced by polymerization of phenylacetylene with chiral bulky pinanyl groups: Effects of the flexible spacer and polymerization catalyst

Three optically active phenylacetylene polymers with chiral bulky pinanyl groups, (?)‐poly[4‐(dimethylpinanylsilyl)phenylacetylene] [(?)‐poly(PSPA)], (+)‐poly{4‐[3‐(10‐pinanyl)tetramethyldisiloxy]phenylacethylene} [(+)‐poly(PDSPA)], and their copolymer [(?)‐copoly(PSPA/PDSPA)], were synthesized. We observed high chirality in the main‐chain chromophore of (?)‐poly(PSPA), due to the presence of a chiral helix, with circular dichroism spectroscopy. In contrast, (+)‐poly(PDSPA),with flexible SiOSi spacers between the chiral pinanyl group and the main chain, had lower chirality. (?)‐Poly(PSPA), with large circular dichroism signals, was prepared by polymerization with a rhodium catalyst and had a highly stereoregular main chain (high cis‐configuration percentage). However, (?)‐poly(PSPA) prepared with a tungsten catalyst had lower chirality and lower stereoregularity in the main chain. A membrane from (?)‐poly(PSPA) showed enantioselective permeability for tryptophan in an aqueous solution. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 1689–1697, 2002     

Two modes of asymmetric polymerization of phenylacetylenes having an L‐amino alcohol residue and two hydroxy groups

Four novel chiral phenylacetylenes having an L ‐amino alcohol residue and two hydroxymethyl groups were synthesized and polymerized by an achiral catalyst ((nbd)Rh⁺[η⁶‐(C₆H₅)B^?(C₆H₅)₃]) or a chiral catalytic system ([Rh(nbd)Cl]₂/(S)‐ or (R)‐phenylethylamine ((S)‐ or (R)‐PEA)). The two resulting polymers having an L ‐valinol or L ‐phenylalaninol residue showed Cotton effects at wavelengths around 430 nm. This observation indicated that they had an excess of one‐handed helical backbones. Positive and negative Cotton effects were observed only for the polymers having an L ‐valinol residue produced by using (R)‐ and (S)‐PEA as a cocatalyst, respectively, although the monomer had the same chirality. Even when the achiral catalyst was used, the two resulting polymers having an L ‐valinol or L ‐phenylalaninol residue showed Cotton effects despite the long distance between the chiral groups and the main chain. We have found the first example of a new type of chiral monomer, that is, a chiral phenylacetylene monomer having an L ‐amino alcohol residue and two hydroxy groups that was suitable for both modes of asymmetric polymerization, that is, the helix‐sense‐selective polymerization ( HSSP ) with the chiral catalytic system and the asymmetric‐induced polymerization ( AIP ) with the achiral catalyst. The other two monomers having L ‐alaninol and L ‐tyrosinol were found to be unsuitable to neither HSSP nor AIP because of their polymers' low solubility. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012     

Helicity induction on a poly(phenylacetylene) bearing a phosphonate residue by chiral dendrons

A series of optically active dendrons with a primary amino group at the terminal were prepared from L - or D -glutamic acid, and their helicity induction abilities for a poly(phenylacetylene) bearing a phosphonate pendant were characterized with ultraviolet–visible and circular dichroism spectroscopy. The magnitude of the Cotton effects of the polymer induced by the dendrons significantly increased upon complexation with a higher generation dendron. The effect of the chirality of the glutamate residues (L and D ) on the helicity induction was also studied. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 4580–4586, 2004     

Synthesis,light emission,and photovoltaic properties of perylene‐containing polyacetylenes

Perylene (Py)‐containing polyacetylenes with different skeleton structures ? [HC?C(C₆H₄)CO₂? Py]_n? (P 1 ), ? [HC?C(CH₂)₈CO₂? Py]_n? (P 2 ), and ? {[(C₆H₅) C?C(CH₂)₉NH₂]? co? [(C₆H₅)C?C(CH₂)₉? Py]}_n? (P 3 ) are synthesized in satisfactory yields by Rh‐catalyzed polymerization (for P 1 and P 2 ) and polymer reaction (for P 3 ). All the polymers are soluble and possess high molecular weights (M_w up to 2.8 × 10⁵). Their structures and properties are characterized and evaluated by IR, NMR, UV, TGA, PL, and photovoltaic (PV) analyses. The polymers are thermally stable, losing little of their weights when heated to 330 °C. When their solutions are irradiated, their perylene pendants emit intense red fluorescence at 610 nm. PV cells with a configuration of ITO/PEDOT:PSS/polymer/LiF/Al are fabricated, which show maximum current density of 10.3 μA/cm². The external quantum efficiency is sensitive to the polymer structure, with P 3 exhibiting the highest value of 0.23%. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 2025–2037, 2008     

Synthesis and optical and electrochemical properties of novel copolymers containing alternating 2,3‐divinylquinoxaline and hole‐transporting units

For the enhancement of charge affinity, electron‐affinitive 2,3‐divinylquinoxaline and a series of hole‐transporting chromophores (iminodibenzyl, phenothiazine, dihexyloxybenzene, and didodecyloxydistyrylbenzene) were incorporated alternately into the polymeric main chain. The resulting copolymers ( P1 – P4 ) were basically amorphous materials and were thermally stable below 300 °C. The electronic structures, photoluminescence, and electrochemical properties of these copolymers were mainly determined by the electron‐donating chromophores in the backbone. They showed significant positive solvatochromism in formic acid. An electrochemical study revealed that they exhibited lower band gaps (<2.3 eV) due to alternating donor and acceptor conjugated units (push–pull structure). Single‐layer light‐emitting diodes of aluminum, P1 – P4 , and indium tin oxide glass were fabricated, and preliminary electroluminescence spectra showed that P1 , P3 , and P4 were orange‐emitting materials. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 4570–4580, 2002     

Synthesis and properties of optically active amino acid based polyacetylenes bearing eugenol and fluorene moieties

Novel optically active amino acid based polyacetylenes bearing eugenol and fluorene moieties were synthesized, and their properties, including chiroptical ones, were analyzed. N‐[1‐(3,4‐Dimethoxyphenyl)‐2‐propyloxycarbonyl]‐L ‐alanine N′‐propargylamide ( 1 ), N‐[1‐(3,4‐dimethoxyphenyl)‐2‐propyloxycarbonyl]‐L ‐alanine propargyl ester ( 2 ), N‐(9‐fluorenylmethoxycarbonyl)‐L ‐alanine N′‐propargylamide ( 3 ), and N‐(9‐fluorenylmethoxycarbonyl)‐L ‐alanine propargyl ester ( 4 ) were polymerized with a rhodium‐zwitterion catalyst in tetrahydrofuran to afford the corresponding polymers with moderate molecular weights ranging from 10,800 to 17,300 in good yields. Because of the large specific rotation and circular dichroism (CD) signal, it was concluded that the poly(N‐propargylamide)s [poly( 1 ) and poly( 3 )] took a helical structure with a predominantly one‐handed screw sense. The solvent and temperature could tune the helical structure of poly( 1 ). On the other hand, the poly(propargyl ester)s [poly( 2 ) and poly( 4 )] exhibited only small specific rotations and CD signals. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 810–819, 2006     

Synthesis and characterization of blue‐light emissive carbazole containing perfluorocyclobutyl arylene ether polymers

A series of N‐alkyl/aryl carbazole 3,6‐substituted arylene trifluorovinyl ether (TFVE) monomers were synthesized in high purity and yield from a concise four‐step synthesis using carbazole as a starting material. Condensate‐free, step‐growth chain extension of the monomers afforded perfluorocyclobutyl (PFCB) arylene ether homo‐ and copolymers as solution processable, optically transparent blue‐light emissive materials. Arylene TFVE monomers and conversion to PFCB arylene ether polymers were structurally elucidated and purity confirmed by high resolution mass spectroscopy, NMR (¹H, ¹³C, and ¹⁹F) spectroscopy, gel permeation chromatography, and attenuated total reflectance Fourier transform infrared analysis. Thermal analysis by differential scanning calorimetry and thermogravimetric analysis revealed glass transition temperatures >150 °C and onset of decomposition in nitrogen >410 °C with 40 wt % char yield up to 900 °C. Optical and electrochemical studies included solution (tetrahydrofuran) and solid state (spin cast thin film) UV–vis/fluorescence spectroscopy and cyclic voltammetry which showed structure dependence of these blue emissive systems on the nature of the N‐alkyl/aryl carbazole substitution in either homo‐ or copolymer configurations. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 552–560     

Synthesis and electrical properties of polyacetylene derivatives

Cyclopolymerization of 1,6‐heptadiyne derivatives containing the bulky substitutents was carried out by metathesis catalyst systems. The catalytic activity of molybdenum (V) chloride (MoCl₅) in homopolymerization is greater than that of the MoCl₅‐cocatalyst system, and copolymerization is vice versa in catalytic activity. Newly synthesized homo‐ and copolymers were soluble in common organic solvents and could afford thin film by solution‐casting onto the indium–tin oxide coated glass substrate. The NMR, Fourier transform infrared spectroscopic, and UV–visible spectra indicated that these polymers have a linear conjugated cyclic polyene structure having a bulky substitutent as a pendant group. The number‐average molecular weight of these polymers was in the range of 2.4–6.27 × 10³. The copolymers exhibited a relatively higher molecular weight than that of the homopolymers. The copolymers were stable up to 380 °C. The electrical conductivities of the I₂‐doped copolymer thin film by the four‐point probe method and surface plasmon resonance spectroscopy were about 500 and 600 S/cm, respectively. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 958–964, 2002     

Luminescence properties of PPV derivatives bearing substituted carbazole pendants

A series of PPV derivatives bearing substituted and unsubstituted carbazole and 2-ethylhexyloxy pendants were prepared and their photo- (PL) and electroluminescence (EL) properties were studied. Substituted carbazole structures were N-phenylcarbazole and 3,6-dimethoxycarbazole. The substituents on the carbazole pendants caused little change in UV-vis absorption, PL, and EL when compared with the polymer bearing the unsubstituted carbazole pendants. The presence of the benzene ring between the main chain and the carbazole pendant increased the threshold electric field in EL. We could obtain maximum brightness of ca. 17,000 - 30,000 cd/m² for the polymers carrying the unsubstituted and dimethoxy substituted carbazole pendants.     

Synthesis and chiroptical properties of optically active poly(N‐propargylamide) bearing photoisomerizable azobenzene moieties

A chiral azobenzene‐containing N‐propargylamide monomer, that is, (R)‐2‐(4‐phenylazophenoxy)‐n‐prop‐2‐ynyl‐propionamide, was prepared and polymerized in the presence of a rhodium catalyst to yield an optically active polyacetylene. The ¹H NMR analysis of the polymer indicated a predominant cis structure of the backbone (cis concentration = 80%); and the chiroptical property studies showed an enhanced optical rotatory power and a strong Cotton effect, indicating the formation of a secondary helical conformation. A reversible optical modulation of chiroptical properties of the polymer due to the reversible photoisomerization of the azobenzene was observed. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 6047–6054, 2006     

Synthesis,optical and electrochemical properties of arylenevinylene‐based π‐conjugated polymers with imidazolium units in the main chain

Arylenevinylene‐based π‐conjugated polymers containing imidazolium cationic units in the main chain and their model compounds were synthesized and characterized in terms of optical and electrochemical properties. 9,9‐Bisoctylfluorene, 2,5‐bisdodecyloxybenzene, and 3‐dodecylthiophene were introduced as arylene units with different donor characteristics to evaluate the effect on the highest occupied molecular orbital‐lowest unoccupied molecular orbital (HOMO‐LUMO) gap energy. The UV–vis and fluorescence spectra of cationic polymers and model compounds with iodide counter anion exhibited a significant blue shift with respect to the parent neutral molecules. X‐ray single crystal analysis for model compounds revealed that the effective π‐conjugation length of cationic model compounds decreased compared to the neutral model compounds by means of twisted conformation directed by CH‐π interactions between N‐methyl groups of imidazolium and neighboring aryl units. The cyclic voltammetry measurement suggested the negative shift of LUMO levels by the conversion of imidazole to imidazolium, indicating the electron‐accepting characteristics of cationic imidazolium unit. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

Water‐soluble conjugated polymers: Synthesis and optical properties

Two sets of water‐soluble poly(phenylene vinylene)s were synthesized and their optical properties were studied. The aqueous solubility of all these polymers is rendered by pendant sulfonate groups. One set of polymers (polymer I series) contains, in addition to the sulfonate pendants, dimethoxy substituents, while the other (polymer II series) contains oligo(ethylene oxide) side chains. Within each set, polymers containing lithium (Ia and IIa), sodium (Ib and IIb), and potassium (Ic and IIc) counter ions were prepared. The two sets of polymers showed different properties from physical appearance (fiber vs film) to thermal properties and to optical properties. It was found that set I polymers, with shorter side chains, exhibit stronger aggregation in aqueous solutions than set II polymers, which led to their lower fluorescence quantum yields and lower polymer‐to‐MV²⁺ quenching efficiencies. Within each set, the effect of counter ions on optical properties was noted. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 5123–5135, 2007