Synthesis and optical properties of novel blue‐light‐emitting poly(p‐phenylene vinylene) derivatives with pendant oxadiazole or cyano groups

Two novel poly(p‐phenylene vinylene) polymers, which carried side substituents with cyano groups or 1,3,4‐oxadiazole, were synthesized by Heck coupling. They consisted of alternating conjugated segments and nonconjugated aliphatic spacers. The polymers had moderate molecular weights, were amorphous, and dissolved readily in tetrahydrofuran and halogenated organic solvents. They were stable up to approximately 340 °C in N₂ and 290 °C in air, and the anaerobic char yield was around 60% at 800 °C. The polymer with cyano side groups emitted blue light in solutions and thin films with identical photoluminescence (PL) maximum at 450 nm; this supported the idea that chain interactions were hindered even in the solid state. The PL maximum of this polymer in thin films was blueshifted upon annealing at 120 °C, indicating a thermochromic effect as a result of conformational changes in the polymer backbone. The polymer containing side substituents with oxadiazole rings emitted blue light in solutions with a PL maximum at 474 nm and blue‐greenish light in thin films with a PL maximum at 511 nm. The PL quantum yields of the polymers in tetrahydrofuran were 0.13–0.24. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 1768–1778, 2004     

New highly luminescent cationic polyelectrolytes based on poly(phenylenevinylene‐alt‐fluorenevinylene) or poly(fluorenevinylene) derivatives and their neutral precursors

Poly(phenylenevinylene‐alt‐fluorenevinylene) ( PF ) or poly(fluorenevinylene) ( F ) derivatives that carried alkyl chains with terminal tertiary amino groups were successfully synthesized via Heck coupling. They were postquaternized by reacting with bromoethane to the corresponding cationic polyelectrolytes PFQ and FQ . The neutral polymers PF and F as well as the quaternized polymer FQ were soluble in common organic solvents such as THF, chloroform, dichloromethane, and toluene. In contrast, the quaternized polymer PFQ did not dissolve in these solvents but was soluble in environmentally friendlier solvents like water and alcohols. The neutral precursors exhibited higher thermal stability and glass‐transition temperatures than the corresponding quaternized counterparts. All polymers emitted intense blue‐greenish light in solution (462–489 nm) with relatively high photoluminescence (PL) quantum yields 0.32–0.57, and as thin films (475–557 nm) with optical band gaps of 2.48–2.57 eV. The water soluble PFQ could find potential applications as chemo or biosensor. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 1481–1491, 2007     

Novel thermally stable poly(amine hydrazide)s and poly(amine‐1,3,4‐oxadiazole)s for luminescent and electrochromic materials

We describe the preparation, characterization, and luminescence of four novel electrochromic aromatic poly(amine hydrazide)s containing main‐chain triphenylamine units with or without a para‐substituted N,N‐diphenylamino group on the pendent phenyl ring. These polymers were prepared from either 4,4′‐dicarboxy‐4″‐N,N‐diphenylaminotriphenylamine or 4,4′‐dicarboxytriphenylamine and the respective aromatic dihydrazide monomers via a direct phosphorylation polycondensation reaction. All the poly(amine hydrazide)s were amorphous and readily soluble in many common organic solvents and could be solution‐cast into transparent and flexible films with good mechanical properties. These poly(amine hydrazide)s exhibited strong ultraviolet–visible absorption bands at 346–348 nm in N‐methyl‐2‐pyrrolidone (NMP) solutions. Their photoluminescence spectra in NMP solutions or as cast films showed maximum bands around 508–544 and 448–487 nm in the green and blue region for the two series of polymers. The hole‐transporting and electrochromic properties were examined by electrochemical and spectroelectrochemical methods. All obtained poly(amine hydrazide)s and poly(amine‐1,3,4‐oxadiazole)s exhibited two reversible oxidation redox couples at 0.8 and 1.24 V vs. Ag/AgCl in acetonitrile solution and revealed excellent stability of electrochromic characteristics, changing color from original pale yellow to green and then to blue at electrode potentials of 0.87 and 1.24 V, respectively. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 3245–3256, 2005     

Synthesis,photophysics, structure‐tunable photoluminescence,and electrochemical properties of soluble poly(p‐phenylenevinylene)‐based polymers with adjacent 1,3,4‐oxadiazoles in the backbone

Three new poly(p‐phenylenevinylene)‐based polymers containing two 1,3,4‐oxadiazole moieties in the main chain per repeat unit were synthesized by Heck coupling. A single, double, or triple bond was introduced between the oxadiazoles to provide a means for modifying the polymer properties. The polymers were readily soluble in common organic solvents and showed T_g values lower than 50 °C. The color of the emissive light in both the solid state and the solution could be tuned by a change in the nature of the bond between the oxadiazole rings. The polymers emitted ultraviolet‐green light in solution with a photoluminescence (PL) emission maximum at 345–483 nm and blue‐green light at 458–542 nm in thin films. The PL quantum yields in solution were 0.36–0.43. The electrochemical properties are affected by the nature of the bond between the oxadiazoles as well. In polymers with a single bond between the oxadiazoles, a lower ionization potential was observed than in polymers with a double or triple bond. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 3079–3090, 2005     

Coumarin‐containing poly(fluorenediylvinylene)s: Synthesis,photophysics, and electroluminescence

Two new poly(fluorenediylvinylene)s (CV and CF) with coumarin side chains were synthesized via Heck coupling. The coumarin segments were attached to the C‐9 of fluorene through alkyl spacers. The polymers were soluble in common organic solvents such as tetrahydrofuran (THF), chloroform, dichloromethane, and toluene. The photoluminescence (PL), electroluminescence (EL), and electrochemical behavior of these polymers were studied. CV and CF thin films exhibited broad‐band, bluish‐green and orange PL emissions, with maxima at 475 and 585 nm, respectively. These PL maxima were redshifted in comparison with those measured in THF solutions. Aggregate formation played an important role in the solid state. The aggregation was more pronounced in CF thin films than CV thin films. Both polymers oxidized and reduced irreversibly. Light‐emitting devices (LEDs) with indium tin oxide hole‐injecting and aluminum electron‐injecting electrodes were prepared and studied. The LEDs made of CV emitted green light, and the LEDs made of CF exhibited an orange EL emissions. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 5750–5762, 2006     

New poly(p‐phenylene vinylene) derivatives with two oxadiazole rings per repeat unit: Synthesis,photophysical properties,electroluminescence, and metal ion recognition

Two new poly(p‐phenylene vinylene) derivatives OX1‐PPV and OX2‐PPV bearing two 1,3,4‐oxadiazole rings per repeat unit and a fully conjugated backbone with solubilizing dodecyloxy side groups were synthesized and investigated. The amorphous conjugated polymers had glass‐transition temperature values of 60–75 °C and emitted intense blue or greenish‐blue light in solution with photoluminescence (PL) emission maxima at 379–492 nm and PL quantum yields of 0.41–0.52. In the solid state they emitted yellowish‐green light with PL emission maxima at 533–555 nm. Cyclic voltammetry showed that both conjugated polymers had reversible reduction and irreversible oxidation, making them n‐type materials. The electron affinity of OX2‐PPV was estimated as 2.85 eV whereas that of OX1‐PPV was 2.75 eV. Yellow electroluminescence (EL) was achieved from single‐layer light‐emitting diodes of OX2‐PPV with an EL emission maximum at 555 nm and a brightness of 70 cd/m². Polymer OX2‐PPV, which was functionalized with 2,6‐bis(1,3,4‐oxadiazole‐2‐yl)pyridine, demonstrated sensitivity to various metal ions as a fluorescence‐mode chemosensor. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 2112–2123, 2004     

Synthesis and optical properties of a poly(p‐phenylenevinylene) derivative and polyfluorenes with bipolar groups along the main chain

A poly(p‐phenylenevinylene) derivative (PPV–TPA)] and a series of statistical copolyfluorenes (PF–TPA)] containing oxadiazole and triphenylamine segments along the main chain were synthesized by the Heck reaction and nickel‐mediated coupling, respectively. The PF–TPA copolyfluorenes with relatively low contents of oxadiazole and triphenylamine units were readily soluble in common organic solvents, whereas the other copolyfluorenes displayed lower solubility. PPV–TPA showed excellent solubility in solvents such as tetrahydrofuran (THF), dichloromethane, chloroform, and toluene. Thin films of the polymers absorbed light in the range of 375–396 nm and had optical band gaps of 2.76–2.98 eV. They emitted blue‐green light with a maximum at 414–522 nm. The fluorescence quantum yields in THF solutions were 0.08–0.53. The copolyfluorene PF–TPA thin films with high contents of oxadiazole and triphenylamine moieties emitted pure blue light that remained stable even after annealing at 150 °C for 4 h in air. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 3556–3566, 2006     

Synthesis,optical properties,and electroluminescence of conjugated poly(p‐phenylenevinylene) derivatives containing 1,3,4‐oxadiazole and pyridine rings in the main chain

Three new poly(p‐phenylenevinylene) derivatives—PO, POD, and POP—with oxadiazole and pyridine rings along the main chain were synthesized via Heck coupling. The polymers were amorphous and dissolved readily in common organic solvents. They showed relatively low glass‐transition temperatures (up to 42 °C) and satisfactory thermal stability. Solutions of the polymers emitted blue‐greenish light with photoluminescence (PL) emission maxima around 460 nm and PL quantum yields of 0.28–0.49. Thin films of the polymers displayed PL emission maxima at 461–521 nm, and their tendency to form aggregates was significantly influenced by the chemical structure. Light‐emitting diodes with polymers PO and POP, with an indium tin oxide/poly(ethylenedioxythiophene) (PEDOT)/polymer/Ca configuration, emitted yellow and green light, respectively, and this could be attributed to excimer emission. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 3212–3223, 2004     

Aromatic poly(1,3,4‐oxadiazole)s and poly(amide‐1,3,4‐oxadiazole)s containing ether sulfone linkages

Polyhydrazides and poly(amide‐hydrazide)s were prepared from two ether‐sulfone‐dicarboxylic acids, 4,4′‐[sulfonylbis(1,4‐phenylene)dioxy]dibenzoic acid and 4,4′‐[sulfonylbis(2,6‐dimethyl‐1,4‐phenylene)dioxy]dibenzoic acid, or their diacyl chlorides with terephthalic dihydrazide, isophthalic dihydrazide, and p‐aminobenzhydrazide via a phosphorylation reaction or a low‐temperature solution polycondensation. All the hydrazide polymers were found to be amorphous according to X‐ray diffraction analysis. They were readily soluble in polar organic solvents such as N‐methyl‐2‐pyrrolidone and N,N‐dimethylacetamide and could afford colorless, flexible, and tough films with good mechanical strengths via solvent casting. These hydrazide polymers exhibited glass‐transition temperatures of 149–207 °C and could be thermally cyclodehydrated into the corresponding oxadiazole polymers in the solid state at elevated temperatures. Although the oxadiazole polymers showed a significantly decreased solubility with respect to their hydrazide prepolymers, some oxadiazole polymers were still organosoluble. The thermally converted oxadiazole polymers had glass‐transition temperatures of 217–255 °C and softening temperatures of 215–268 °C and did not show significant weight loss before 400 °C in nitrogen or air. For a comparative study, related sulfonyl polymers without the ether groups were also synthesized from 4,4′‐sulfonyldibenzoic acid and the hydrazide monomers by the same synthetic routes. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 2271–2286, 2001     

Synthesis and evaluation of photoluminescent and electrochemical properties of new aromatic polyamides and polyimides with a kink 1,2‐phenylenediamine moiety

A series of novel triphenylamine‐containing aromatic polyamides and polyimides having a crank and twisted noncoplanar structures were synthesized in inherent viscosities of 0.14–0.64 dL/g and 0.11–0.67 dL/g, respectively. These polymers had useful levels of thermal stability associated with relatively high glass‐transition temperatures (174–311 °C). They exhibited strong UV–Vis absorption bands at around 300 nm in NMP solutions. The PL spectra of these polymers in NMP solutions (1 × 10^?5 M) showed maximum peaks around 396–479 nm. The hole‐transporting and electrochromic properties were examined by electrochemical and spectroelectrochemical methods. Cyclic voltammetry (CV) of the polymer films cast onto an indium‐tin oxide (ITO)‐coated glass substrate exhibited two reversible oxidation redox couples at potentials of 0.70–1.01 V and 1.10–1.46 V, respectively, vs. Ag/AgCl in acetonitrile solution. The polymer films revealed electrochromic characteristics, with a color change from neutral pale yellowish to green and then to a blue oxidized form at applied potentials ranging from 0.00 to 1.75 V. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 2587–2603, 2006     

New series of highly phenyl‐substituted polyfluorene derivatives for polymer light‐emitting diodes

A new series of highly phenyl‐substituted polyfluorene derivatives were synthesized and characterized. The resulting polymers were amorphous and showed excellent solubility in common organic solvents, such as chloroform, tetrahydrofuran, xylene, toluene, chlorobenzene, and so forth. All possessed satisfied thermal stability with glass‐transition temperatures (T_g's) in the range of 79–115 °C. They emitted blue light with photoluminescent (PL) maximum peaks at about 408–412 nm in thin films. The PL efficiencies of the polymer films were measured around 30–33%. The highly phenylated pendants improved the T_g of polyfluorene without forming defects in the polymers and reduced their tendency to form aggregate/excimers. Polymer light‐emitting diodes were fabricated from these polymers with the configuration of indium tin oxide/polyethylenedioxythiophene:polystyrene sulfonic acid/polymer/Ba/Al, which emitted bright blue light with maximum peaks at 418–420 nm. The maximum external quantum efficiencies of these devices were 0.41–0.6%. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 2985–2993, 2004     

Poly(pyridinium salt)s with stilbene or distyrylbenzene chromophores

A new series of poly(pyridinium salt)s that contained side stilbenyl groups or p‐distirylbenzene segments in the main chain were synthesized from the reactions of bis(pyrylium salts) with diamines. They were characterized by viscometry, Fourier transform infrared spectroscopy, NMR, X‐ray scattering, differential scanning calorimetry, thermomechanical analysis, ultraviolet–visible analysis, and luminescence spectroscopy. The polymers were amorphous and soluble in polar aprotic solvents such as dimethylacetamide, dimethylformamide, and dimethyl sulfoxide. The glass‐transition temperatures were in the range of 59–123 °C. These polymers had initial decomposition temperatures of 240–295 °C and afforded anaerobic char yields of 29–53% at 800 °C. Both the absorption and photoluminescence (PL) spectra of the polymers were studied, and the PL quantum yields in solution were determined. The polymers showed violet‐blue fluorescence in solution with PL maxima at 408–416 nm and violet‐green fluorescence in thin film with PL maxima at 454–523 nm. The structure of the diamine utilized for the preparation of the polymers did not influence their PL maxima. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 2454–2462, 2001     

Synthesis and properties of through‐space conjugated polymers based on cyano‐substituted poly(p‐arylenevinylene)s

New through‐space cyano‐substituted poly(p‐arylenevinylene)s containing a [2.2]paracyclophane unit were synthesized by the Knoevenagel reaction. Polymers 5 and 7 have cyano groups at α‐positions and β‐positions from the dialkoxyphenylene unit, respectively. Their optical and electrochemical behaviors were investigated in detail in comparison with their model compounds. Polymers 5 and 7 exhibited through‐space conjugation via the cyclophane units. Polymer 5 showed greenish blue emission (λ_max = 477 nm) in diluted solution with fluorescence quantum efficiency (?_F) of only 0.007, whereas polymer 7 emitted in the bluish green region (λ_max = 510 nm) with ?_F of 0.32. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 5979–5988, 2009     

Synthesis and characterization of novel germanium‐containing poly(p‐phenylenevinylene) derivatives

Novel blue‐emitting germanium‐containing poly(p‐phenylenevinylene) (PPV) derivatives with well‐defined conjugation lengths were synthesized via Wittig‐condensation polymerizations. The polymers can be color‐tuned by the introduction of various chromophores into the PPV‐based polymer backbones. The photoluminescence (PL) spectra of the polymers, GePVK (containing carbazole moieties), GeMEH (containing dialkoxybenzene moieties), and GePTH (containing phenothiazine moieties), were found to exhibit blue, greenish blue, and green emissions, respectively. GePTH produces more red‐shifted emission than GeMEH and GEPVK, resulting in green emission, and the solution and solid state PL spectra of GePVK consist of almost blue emission. The electroluminescence spectra of GeMEH and GePTH contain yellowy green and yellow colors, respectively. Interestingly, GePVK exhibits white emission with CIE coordinates of (0.33, 0.37) due to electroplex emission in the light‐emitting diodes. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 979–988, 2008     

Novel electroluminescent cationic polyelectrolyte based on poly[(fluorene‐2,7‐diylvinylene)‐alt‐(1,4‐phenylenevinylene)] and its precursor

A novel conjugated poly[(fluorene‐2,7‐vinylene)‐alt‐(1,4‐phenylenevinylene)] derivative 2 with quaternizable tertiary amino groups was synthesized by Heck coupling of a substituted 2,7‐dibromofluorene and 1,4‐dialkoxy‐2,5‐divinylbenzene. The corresponding quaternary ammonium cationic polyelectrolyte 3 was obtained by the treatment of 2 with bromoethane. Both polymers were soluble in common organic solvents, like tetrahydrofuran, chloroform, and dichloromethane. Polymer 3 showed a limited solubility in alcohols and was insoluble in water. Photophysical and electrochemical properties of the resulting polymers were fully investigated. An intensive green photoluminescence (PL) with maxima at 550 and 545 nm was observed from thin films of 2 and 3 polymers, respectively, red‐shifted compared with the PL emission spectra measured in the solution. The electrochemical band gaps were 2.38–2.45 eV. Single‐layer and double‐layer (with poly[3,4‐(ethylenedioxy)thiophene]/poly (styrenesulfonate) (PEDOT:PSS)) light‐emitting devices (LEDs) with ITO and Al electrodes were prepared and studied. They emitted a green light and their electroluminescence (EL) spectra were similar to those of PL thin films. The external EL efficiency was determined to be 0.43 and 0.32% for ITO/PEDOT:PSS/ 2 /Al and ITO/PEDOT:PSS/ 3 /Al LEDs, respectively. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 1016–1027, 2007     

Synthesis and characterization of soluble,fluorescent poly(arylene ether)s,poly(arylene thioether)s,and poly(arylene sulfone)s containing 1,3,5‐triphenylbenzene segments

The bisphenol 4,4″‐dihydroxy‐5′‐phenyl‐m‐terphenyl ( 4 ), containing a 1,3,5‐triphenylbenzene moiety, was synthesized from a pyrylium salt obtained by the reaction of benzaldehyde with p‐methoxyacetophenone with boron trifluoride etherate as a condensing agent. Polymers were obtained from 4 by a nucleophilic displacement reaction with various activated difluoro monomers and with K₂CO₃ as a base. A series of new poly(arylene ether)s ( 8a – 8f ) were obtained that contained phenyl‐substituted m‐terphenyl segments in the polymer chain. Polymers with inherent viscosities of 0.41–0.99 dL/g were obtained in yields greater than 96%. The polymers were soluble in a variety of organic solvents, including nonpolar solvents such as toluene. Clear, transparent, and flexible films cast from CHCl₃ showed high glass‐transition temperatures (T_g = 198–270 °C) and had excellent thermal stability, as shown by temperatures of 5% weight loss greater than 500 °C. 4 was converted via N,N‐dimethyl‐O‐thiocarbamate into the masked dithiol 4,4″‐bis(N,N′‐dimethyl‐S‐thiocarbamate)‐5′‐phenyl‐m‐terphenyl and was polymerized with activated difluoro compounds in the presence of a mixture of Cs₂CO₃ and CaCO₃ as a base in diphenyl sulfone as a solvent. A series of new poly(arylene thioether)s ( 9a – 9e ) were obtained with T_g values similar to those of 8a – 8e . 9a – 9e were further oxidized into poly(arylene sulfone)s with T_g values 40–80 °C higher than those for 8a – 8e and 9a – 9e . These polymers also had good solubility in organic solvents. A sulfonic acid group was selectively introduced onto the pendent phenyl group of polymers 8a and 8f by reaction with chlorosulfonic acid. The polymers were soluble in dipolar aprotic solvents and formed films via casting from dimethylformamide. Polymers 8a – 8f , 11a , and 11f showed blue and red fluorescence under ultraviolet–visible light with emission maxima at 380–440 nm. © 2002 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 40: 496–510, 2002; DOI 10.1002/pola.10136     

Versatile route for tuning optical properties of poly(2‐methoxy‐5‐(2′‐ethylhexyloxy)‐1,4‐phenylenevinylene)

In this contribution, we report a versatile method for tuning optical properties of poly(2‐methoxy‐5‐(2′‐ethylhexyloxy)‐1,4‐phenylenevinylene) (MEH‐PPV) in its solution with 1,2‐dichloroethane, accomplished by reacting with pyridinium formate (PF), a volatile organic salt. We can systematically control the positions of absorption and photoluminescent (PL) spectra of MEH‐PPV by adjusting the concentration of PF in the solution. The addition of 10 vol % PF caused a blue‐shift in the absorption spectra by about 65 nm. When the concentration of PF decreased to 0.1 vol %, the blue‐shift occurred to a lesser extent, about 25 nm. The measurements of PL spectra showed similar behaviors. The λ_max shifted from 558 nm to 546 and 552 nm when 10 and 0.1 vol % of PF were added, respectively. The changes of PL colors from orange to yellow and green, respectively, were observed by naked eyes. Structural investigation by nuclear magnetic resonance and Fourier‐transformed infrared spectroscopy indicated that the changes of the optical properties were due to chemical modifications along the main chain and the side groups of MEH‐PPV. These results implied a simple route for engineering the HOMO–LUMO energy gap of MEH‐PPV, which could be utilized in advanced applications such as organic light‐emitting devices and solar cells. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 696–705, 2009     

Novel blue‐greenish electroluminescent poly(fluorenevinylene‐alt‐dibenzothiophenevinylene)s and their model compounds

Poly(9,9‐dihexylfluorene‐2,7‐vinylene‐alt‐dibenzothiophene‐2,8‐vinylene) (PS) and poly(9,9‐dihexylfluorene‐2,7‐vinylene‐alt‐dibenzothiophene‐5,5‐dioxide‐2,8‐ vinylene) (PSO) as well as corresponding model compounds were synthesized by Heck coupling. Both the polymers and model compounds were readily soluble in common organic solvents such as tetrahydrofuran, dichloromethane, chloroform, and toluene. The polymers showed a decomposition temperature at ～430 °C and a char yield of about 65% at 800 °C in N₂. The glass‐transition temperatures of the polymers were almost identical (75–77 °C) and higher than those of the model compounds (26–45 °C). All samples absorbed around 390 nm, and their optical band gaps were 2.69–2.85 eV. They behaved as blue‐greenish light emitting materials in both solutions and thin films, with photoluminescence emission maxima at 450–483 nm and photoluminescence quantum yields of 0.52–0.72 in solution. Organic light‐emitting diodes with an indium tin oxide/poly(ethylene dioxythiophene):poly(styrene sulfonic acid)/polymer/Mg:Ag/Ag configuration with polymers PS and PSO as emitting layers showed green electroluminescence with maxima at 530 and 540 nm, respectively. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 6790–6800, 2006     

Deep‐red emissive conjugated poly(2,6‐BODIPY‐ethynylene)s bearing alkyl side chains

Novel deep‐red emissive poly(2,6‐BODIPY‐ethynylene)s bearing dodecyl side chains (polymers A , B , and C ) have been prepared by palladium‐catalyzed Sonogashira polymerization of 2,6‐diiodo‐functionalized BODIPY monomers with 2,6‐diethynyl‐functionalized BODIPY monomers. These polymers emit in the deep‐red region with emission maxima at up to 690 nm, and exhibit significant red shifts (up to 166 and 179 nm) of both absorption and emission maxima compared with their parent BODIPY dyes due to significant extension of π‐conjugation. These polymers possess good thermal stability with decomposition temperature between 270 and 360 °C. The polymers exhibit a little larger Stokes shifts and shorter lifetime than their corresponding BODIPY dyes. The solid state thin films of polymers A , B , and C emit in near‐infrared region between 723 and 743 nm, and show significantly red shifts (up to 57 nm) in absorption and emission maxima relative to their polymer solution. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 5354–5366, 2009     

Synthesis of poly(p‐phenylene vinylene)‐ and poly(phenylene ethynylene)‐based polymers containing p‐terphenyl in the main chain with alkoxyphenyl side groups

Starting from the pyrylium salt and following a facile synthetic route, we synthesized and polymerized 4,4″‐diiodo‐2′,6′‐di[4‐(2′‐ethylhexyl)oxy]phenyl‐p‐terphenyl with p‐divinylbenzene or p‐diethynylbenzene. The resulting polymers had moderate molecular weights, were amorphous, and dissolved in tetrahydrofuran and chloroform, with glass‐transition temperatures of 120–131 °C. The polymers behaved as violet‐blue‐emitting materials with photoluminescence maxima around 420 and 450 nm in solution and in thin films, respectively. They possessed well‐defined chromophores resulting from steric interactions in the polymer chain. The photoluminescence quantum yields were up to 0.29. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 2591–2600, 2002