Synthesis of ω‐anthracenyl‐functionalized soluble polyphenylene: effect of the end‐group on optical and electrical properties

ω‐Anthracenyl‐functionalized soluble polyphenylene (AN‐SPP) with a well‐controlled polymer chain was synthesized. The optical and electrical properties were strongly affected by the anthracenyl end‐group. The UV absorption and photoluminescence emission were enhanced and shifted toward the longer wavelength region in comparison to that of soluble polyphenylene. The optical band gap energies of the main chain and the anthracenyl end‐group were 3.15 and 3.89 eV, respectively. The highest occupied molecular orbital/lowest unoccupied molecular orbital energy levels of the main chain and the anthracenyl end‐group of AN‐SPP were ?4.98/?1.81 eV and ?7.25/?3.36 eV, respectively. The current–voltage characteristics of AN‐SPP were controllable by the presence of the anthracenyl end‐group. Copyright © 2008 John Wiley & Sons, Ltd.     

Synthesis of porphyrin‐end‐functionalized polycyclohexane with well‐controlled and defined polymer chain structure

Tetraphenylporphyrin‐end‐functionalized polycyclohexane (H₂TPP‐PCHE) and its metal complexes (MTPP‐PCHE) were synthesized as the first successful example of porphyrin‐end‐functionalized transparent and stable polymers with a well‐controlled and defined polymer chain structure. Chloromethyl‐end‐functionalized poly(1,3‐cyclohexadiene) (CM‐PCHD) was synthesized as prerequisite prepolymer by the postpolymerization reaction of poly(1,3‐cyclohexadienyl)lithium and chloro(chloromethyl)dimethylsilane. CM‐end‐functionalized PCHE (CM‐PCHE) was prepared by the complete hydrogenation of CM‐PCHD with p‐toluenesulfonyl hydrazide. H₂TPP was incorporated onto the polymer chain end by the addition of 5‐(4‐hydroxyphenyl)‐10,15,20‐triphenylporphyrin to CM‐PCHE. The complexation of H₂TPP‐PCHE and Zn(OAc)₂ (or PtCl₂) yielded a zinc (or platinum) complex of H₂TPP‐PCHE. H₂TPP‐PCHE and MTPP‐PCHE were readily soluble in common organic solvents, and PCHE did not inhibit the optical properties of the H₂TPP, ZnTPP, and PtTPP end groups. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

Synthesis of fac‐Ir(ppy)3 end‐functionalized poly(1,3‐cyclohexadiene): single monomer addition of fac‐Ir(ppy)2(vppy) for well‐controlled polymer synthesis

Synthesis of the polymer whose end is functionalized by fac‐Ir(ppy)₃ (ppy = 2‐phenylpyridyl) was achieved by using (living) anionic polymerization of 1,3‐cyclohexadiene: the reaction of poly(1,3‐cyclohexadienyl)lithium (PCHDLi) with fac‐Ir(ppy)₂(vppy) [vppy = 2‐(4‐vinylphenyl)pyridyl] resulted in nucleophilic attack of the carbanion in PCHDLi on the vinyl group of fac‐Ir(ppy)₂(vppy) selectively. Complexation of the pyridyl ring protected the α‐carbons of fac‐Ir(ppy)₂(vppy) from the reaction of the anionic polymer. The homopolymerization of fac‐Ir(ppy)₂(vppy) did not occur, and only one molecule of fac‐Ir(ppy)₂(vppy) reacted with the carbanion of PCHDLi and was selectively incorporated into an end of poly(1,3‐cyclohexadiene) (PCHD). Thus, the PCHD with fac‐Ir(ppy)₃ end‐group was obtained with a well‐controlled and defined polymer structure and molecular weight. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012     

Synthesis of ω‐ and α,ω‐sulfonatotelechelics based on homopolymers and block copolymers of n‐butyl methacrylate and t‐butyl methacrylate

The synthesis of ω‐ and α,ω‐telechelics with sulfonate end groups through the sulfoalkylation of homopolymers and block copolymers of n‐butyl methacrylate and t‐butyl methacrylate with 1,3‐propane sultone is described. The polymerizations are initiated in tetrahydrofuran at −78 °C with either 1,1‐diphenyl‐3‐methylpentyllithium or dilithium 1,1,4,4‐tetraphenylbutane to obtain monofunctional or difunctional polymethacrylate anions, respectively. Narrow molecular weight distributions are obtained for the homopolymers and copolymers in the presence of LiCl in a 10/1 ratio relative to the initiator. The direct reaction of the poly(n‐butyl methacrylate) anions with the sultone results in low functionalization levels: f = 0.24–0.29 for the monofunctional anions and f = 0.32–0.35 for the difunctional anions. The reaction of the poly(t‐butyl methacrylate) anions or end‐capping of the poly(n‐butyl methacrylate) anions with t‐butyl methacrylate units before sulfoalkylation yields telechelics with f = 0.81–1.0 for the monofunctional anions and f = 1.74–1.94 for the difunctional anions. The telechelic polymers, purified by ultrafiltration, have been characterized by size exclusion chromatography, Fourier transform infrared, and ¹H NMR spectroscopy. The yield of the sulfoalkylation reactions, determined by colorimetric analysis of a complex formed with methylene blue, is in good agreement with the results obtained by nonaqueous titration of the acidified telechelics. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 3711–3721, 2000     

Anionic synthesis and characterization of ω‐carboaldehyde‐functionalized polybutadienes and polyisoprenes

Attempted preparation of ω‐formyl‐functionalized polydienes by termination of poly(butadienyl)lithium and poly(isoprenyl)lithium with 4‐morpholinecarboaldehyde resulted in 73 and 38% dimer formation (SEC), respectively, under conditions that quantitativey produced ω‐formyl‐functionalized polystyrene. Dimer formation was attributed to postfunctionalization, base‐catalyzed, aldol‐type condensation based on FTIR and ¹H‐NMR analysis of the dimer products. High yields (>97%) of ω‐formyl‐functionalized polydienes were formed by workup using acidic methanol; quantitative functionalization resulted from end capping the polymeric organolithium chain ends with 1,1‐diphenylethylene prior to the functionalization reaction. The ω‐formylpolydienes were characterized by hydroxylamine end‐group titration, FTIR, and both ¹H‐ and ¹³C‐NMR spectroscopy. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 1143–1156, 1999     

β‐Lactam functionalized poly(isoprene‐b‐ethylene oxide) amphiphilic block copolymers

Amphiphilic block copolymers containing β‐lactam groups on the polyisoprene block were synthesized from poly(isoprene‐b‐ethylene oxide) (IEO) diblock copolymer precursors, prepared by anionic polymerization. β‐Lactam functionalization was achieved via reaction of the polyisoprene (PI) block with chlorosulfonyl isocyanate and subsequent reduction. The resulting block copolymers were molecularly characterized by SEC, FTIR, and NMR spectroscopies and DSC. Functionalization was found to proceed in high yields, altering the solubility properties of the PI block and those of the functionalized diblocks. Hydrogen bond formation is assumed to be responsible for the decreased crystallinity of the poly(ethylene oxide) block (PEO) in the bulk state as indicated by DSC measurements. The self‐assembly behavior of the β‐lactam functionalized poly(isoprene‐b‐ethylene oxide) copolymers (LIEO) in aqueous solutions was studied by dynamic light scattering (DLS), static light scattering (SLS), fluorescence spectroscopy, and atomic force microscopy (AFM). Nearly spherical loose aggregates were formed by the LIEO block copolymers, having lower aggregation numbers and higher cmc values compared to the IEO precursors, as a result of the increased polarity of the β‐lactam rings incorporated in the PI blocks. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 24–33, 2010     

Linear π‐conjugated polymers containing 2,4,6‐tris(thiophen‐2‐yl)‐1,3,5‐triazine unit: Synthesis and optical properties

Some linear π‐conjugated polymers containing 2,4,6‐tris(thiophen‐2‐yl)‐1,3,5‐triazine unit were synthesized via Sonogashira or Suzuki reaction for the first time and characterized by IR, NMR, and GPC. Because of the introduction of 2,4,6‐tris(thiophen‐2‐yl)‐1,3,5‐triazine unit into π‐conjugated system, all polymers exhibited good thermal stability with high decomposition temperature. Their optical and electrochemical properties were investigated. Based on the 2,4,6‐tris(thiophen‐2‐yl)‐1,3,5‐triazine unit linked with different aromatic rings, the polymers showed the tunable fluorescence from blue to blue‐green emission with satisfied quantum yield. Cyclic voltammetry measurement indicated that the LUMO and HOMO levels of the polymers could be adjustable through the main‐chain structural modification. All polymers had low LUMO level (?2.86 to ?3.06 eV) due to the high‐electron affinity of triazine unit. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 702–712, 2008     

Oxidation of poly(1,3‐cyclohexadiene): Influence of the polymer chain structure

The influence of the microstructure on the oxidation of poly(1,3‐cyclohexadiene) (PCHD) homopolymer, obtained by anionic polymerization with alkyllithium/amine systems, was investigated for the first time. PCHD has a structure consisting of a main chain formed by 1,2‐addition (the 1,2‐CHD unit) and 1,4‐addition (the 1,4‐CHD unit). The molar ratio of 1,2‐CHD/1,4‐CHD units in the polymer chain strongly influenced the extent of oxidation of PCHD. A polymer chain with a high content of 1,4‐CHD units was easily oxidized by air and 2,3‐dichloro‐5,6‐dicyano‐1,4‐benzoquinone (DDQ). In contrast, the progress of oxidation was prevented in the case of PCHD containing 52% of 1,2‐CHD units. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 837–845, 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     

Synthesis of poly(p‐phenylene)‐poly(4‐diphenylaminostyrene) bipolar block copolymers with a well‐controlled and defined polymer chain structure

A poly(p‐phenylene) (PPP)‐poly(4‐diphenylaminostyrene) (PDAS) bipolar block copolymer was synthesized for the first time. A prerequisite prepolymer, poly(1,3‐cyclohexadiene) (PCHD)‐PDAS binary block copolymer, in which the PCHD block consisted solely of 1,4‐cyclohexadiene (1,4‐CHD) units, was synthesized by living anionic block copolymerization of 1,3‐cyclohexadiene and 4‐diphenylaminostyrene. To obtain the PPP‐PDAS bipolar block copolymer, the dehydrogenation of this prepolymer with quinones was examined, and tetrachloro‐1,2‐(o)‐benzoquinone was found to be an appropriate dehydrogenation reagent. This dehydrogenation reaction was remarkably accelerated by ultrasonic irradiation, effectively yielding the target PPP‐PDAS bipolar block copolymer. The hole and electron drift mobilities for PPP‐PDAS bipolar block copolymer were both on the order of 10^?3 to 10^?4 cm²/V·s, with a negative slope when plotted against the square root of the applied field. Therefore, this bipolar block copolymer was found to act as a bipolar semi‐conducting copolymer. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

Development of catalyst‐transfer condensation polymerization. Synthesis of π‐conjugated polymers with controlled molecular weight and low polydispersity

We describe the development of chain‐growth condensation polymerization for the synthesis of well‐defined π‐conjugated polymers via a new polymerization mechanism, catalyst‐transfer polymerization. We first studied the condensation polymerization of Grignard‐type hexylthiophene monomer with a Ni catalyst as a part of our research on chain‐growth condensation polymerization, and found that this polymerization also proceeded in a chain‐growth polymerization manner. However, the polymerization mechanism involving the Ni catalyst was different from that of previous chain‐growth condensation polymerizations based on substituent effects; the Ni catalyst catalyzed the coupling reaction of the monomer with the polymer, followed by the transfer of Ni(0) to the terminal C? Br bond of the elongated molecule. This catalyst‐transfer condensation polymerization is generally applicable for the synthesis of polythiophene with an etheric side chain and poly(p‐pheneylene), as well as for the synthesis of polyfluorene via the Pd‐catalyzed Suzuki–Miyaura coupling reaction. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 753–765, 2008     

Synthesis of π‐conjugated polymer containing both thiophene and phosphole sulfide in the main chain by simultaneous post‐element transformation of organotitanium polymer

The synthesis and unique optoelectronic features of a π‐conjugated polymer containing both thiophene and 1‐phenylphosphole sulfide units (multiple heteroles) in the main chain by the post‐element transformation of a regioregular organometallic polymer possessing titanacyclopentadiene‐2,5‐diyl unit are described. The π‐conjugated polymer containing multiple heteroles was obtained in 73% yield by the simultaneous reaction of the organotitanium polymer with sulfur monochloride and dichlorophenylphosphine (0.6 equiv each), whose number‐average molecular weight (M_n) and the molecular‐weight distribution (M_w/M_n) were estimated to be 11,000 and 3.4, respectively, by the size exclusion chromatography (SEC). The π‐conjugated polymer thus obtained was found to have the high HOMO and the low LUMO energy levels due to the electron‐rich thiophene and electron‐deficient phosphole sulfide units, respectively, as supported by its cyclic voltammetry (CV) analysis. Compared to a mixture of a polymer containing sole thiophene‐unit and that containing sole phosphole sulfide units, the π‐conjugated polymer‐containing multiple heteroles proved to exhibit interesting optical properties. For example, a specific emission peak was observed at 608 nm in the photoluminescence spectrum, which was not observed in the case of the thiophene‐containing polymer, the phosphole‐containing polymer, and their mixture. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019 , 57, 2519–2525     

A hybrid‐type,chiral π‐conjugated polymer wrapped with polyhedral oligomeric silsesquioxanes

A novel hybrid‐type chiral binaphthyl‐based polyarylene derivative with polyhedral oligomeric silsesquioxanes (POSS) units 2a was prepared by Suzuki–Miyaura coupling polymerization from a chiral (R)‐6,6′‐dibromo‐2,2′‐diPOSS‐substituted 1,1′‐binaphthyl derivative 1a and p‐biphenylene diboronic acid. As a reference, a binaphthyl‐based polyarylene derivative without POSS unit 2b was also prepared. The obtained polymers were studied with thermogravimetric analysis, optical rotations, circular dichroism (CD), ultraviolet‐visible, and photoluminescence (PL) spectra. Gel permeation chromatography measurements of 2a and 2b showed that their number‐average molecular weights were 13,300 and 16,500, respectively. The thermal stability of POSS‐modified polymer 2a (temperature of 10% weight loss; T₁₀ = 380 °C) was extremely high compared with that of polymer without POSS unit 2b (T₁₀ = 335 °C) due to the siliceous bulky POSS segments on the side chains. The specific optical rotation [α]_D was ?66.7° (c 0.06, CHCl₃) for 2a and ?62.3° (c 0.06, CHCl₃) for 2b . The CD spectra showed that these two polymers had very similar and strong Cotton effects. Film polymer 2a showed almost the same PL spectrum as that in dilute CHCl₃ solution, indicating that bulky POSS units strongly suppressed intermolecular aggregation of the π‐conjugated polymer backbone. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 6035–6040, 2008     

Synthesis of soluble poly(para‐phenylene) with a long polymer chain: Characteristics of regioregular poly(1,4‐phenylene)

Soluble poly(para‐phenylene) having a long polymer chain (more than six repeat units) was synthesized with a tert‐butyl end‐group (t‐PPP) and was found to have improved solubility and excellent optical properties. Poly(1,3‐cyclohexadiene) (PCHD) consisting of only 1,4‐cyclohexadiene (1,4‐CHD) units was synthesized with a tert‐butyl end‐group (t‐PCHD), and completely dehydrogenated to obtain t‐PPP. This end‐group effectively prevented the crystallization of t‐PPP, and polymers containing up to 16 repeat units were soluble in tetrahydrofuran. Soluble t‐PPP obtained had an ability to form a tough thin film prepared by spin‐coating method. Optical analyses of t‐PPP provided strong evidence for a linear polymer chain structure. A block copolymer of t‐PPP and a soluble polyphenylene (PPH) was then synthesized, and the excellent optical properties were retained by this block copolymer along with its solubility. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 5223–5231, 2008     

Hydrazine‐functionalized latexes

The noncommercial functional monomer 4‐vinylbenzyl hydrazine (VBH) was synthesized and subsequently copolymerized with styrene (St) by means of different batch and semicontinuous seeded emulsion polymerization processes, so as to obtain hydrazine‐functionalized nanoparticles. The effect of pH, surfactant and initiator amounts, ratio VBH/St, reaction temperature, and ratio acetone/water were studied. Due to the amphiphilic character of VBH at acid pH, the hydrazine groups of the functionalized comonomer were masked with acetone to form hydrazone groups. Secondary nucleations were avoided by using the protected VBH comonomer; however, a decreased radical efficiency achieving limited conversion was observed. Controlling the cationic initiator concentration, complete conversions together with the neat growth of the seed particles were obtained in the semicontinuous seeded emulsion polymerization of styrene and VBH protected with acetone. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 6201–6213, 2009     

End‐group composition of poly(3‐hexylthiophene)s prepared by in situ quenching of the grignard metathesis polymerization: Influence of additives and reaction conditions

The ability to prepare well‐defined semiconducting polymers is essential for understanding the link between structure and function in organic photovoltaic devices. A general, one‐pot method for altering the degree of functionality of end‐functionalized poly(3‐hexylthiophene)s (P3HT) prepared by Grignard metathesis (GRIM) polymerization has been developed. In the absence of additives, the degree of functionality of end‐functional P3HTs prepared by quenching of the GRIM polymerization with a Grignard reagent is dependent on the Grignard reagent utilized. In this study, additives such as styrene and 1‐pentene are shown to alter the end‐group composition of tolyl‐functionalized P3HTs as determined by Matrix‐assisted Laser Desorption Ionization Time‐of‐flight Mass Spectrometry. In particular, when quenching the GRIM polymerization with tolylmagnesium bromide, a modest decrease in the difunctional product is observed, and the yield of the monofunctional product increases significantly. Temperature and lithium chloride (LiCl) addition also play impactful roles. Monofunctional P3HT is found to be the major product (72% abundance) when the functionalization is done in the presence of LiCl and styrene at 0 °C, whereas in the absence of additives the monofunctional product is present at only 11% abundance. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012     

New imidazole‐functionalized polyfluorene derivatives: convenient postfunctional syntheses,sensitive probes for metal ions and cyanide,and adjustable output signals with diversified fluorescence color

Based on our previous work on the sensitive and selective conjugated fluorescent polymeric sensors toward cyanide, 2,1,3‐benzothiadiazole and 4,7‐bis(thiophen‐2‐yl)‐2,1,3‐benzothiadiazole were incorporated into the polyfluorene backbone to yield three new polymers bearing imidazole moieties in the side chains, with different fluorescence color. The fluorescence could be turned off by Cu²⁺ ions and then recovered on addition of cyanide, making them good cyanide sensors with the detection limit down to 1.9 μM. Moreover, by fully understanding this “turn off–turn on” strategy and using the cooperation of two polymers with different fluorescence color, the emission color of the mixture system of one of the imidazole‐containing polymers and one from the corresponding polymers without imidazole ones, could be adjusted by the concentrations of the added copper and cyanide ions, leading to the output fluorescent signals diversity. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

Functionalization of polymeric organolithium compounds with 3,4‐epoxy‐1‐butene: Precursors for diene‐functionalized macromonomers

The functionalization of polymeric organolithiums (PLi) with 3,4‐epoxy‐1‐butene (EPB) in a hydrocarbon solution yielded the corresponding hydroxybutene‐functionalized polymers in high yields (>95%). Three modes of addition of PLi to EPB were observed (1,4, 3,4, and 4,3). The products and chain‐end structures were characterized by ¹H NMR, ¹³C NMR, attached‐proton‐test ¹³C NMR, calculated ¹³C NMR chemical shifts, and matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry (MALDI‐TOF MS). The regioselectivity of the addition depended on the PLi chain‐end structure, the reaction conditions, and the addition of lithium salts or Lewis bases. In the absence of additives, the functionalization of poly(styryl)lithium (PSli) produced equal amounts of 1,4‐, 3,4‐, and 4,3‐addition, as determined by quantitative ¹³C NMR analysis. The use of a low temperature (6 °C), inverse addition, the addition of triethylamine (TEA; [TEA]/[PSLi] = 20) as a Lewis base, or dienyllithium chain ends produced polymers with only the 1,4‐addition product. Mild dehydration of the hydroxybutene‐functionalized polymer with p‐toluenesulfonic acid produced the corresponding diene‐functionalized macromonomer, as shown by MALDI‐TOF MS. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 947–957, 2003