Synthesis and characterization of soluble conjugated polymers having pyrene moiety in the main chain

Three new alternating conjugated polymers consisting of pyrene and 3‐dodecylthiophene ( PPyMT ), 4,4′‐didodecyl‐2,2′‐bithiophene ( PPyBT ), or 9,9‐didodecylfluorene ( PPyFlu ) moieties have been prepared using Suzuki coupling reaction or Sugimoto approaches. The polymers were readily soluble in common organic solvents and exhibited good thermal stability in nitrogen and air atmospheres. The structures and optical properties of the polymers were characterized by NMR, FTIR, XRD, UV–vis, and fluorescence spectroscopy. PPyMT and PPYBT showed blue‐light emission in solution, whereas PPyFlu performed blue‐light emitting in film state. The polymers exhibited an intermolecular aggregation and structural ordering due to pyrene–pyrene π–π stacking interaction. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010     

Synthesis and characterization of polyyne polymer containing nickel in the main chain

The synthesis of the nickel dialkynyl complex Ni(C?C? C₆H₄? C?CH)₂(PPh₃)₂ and of the corresponding polyyne polymer containing nickel in the main chain ? [Ni(PPh₃)₂? C?C? C₆H₄? C?C? ]_n are described and discussed. A new mixed solvent system DMSO/HNEt₂ and homogeneous step-wise condensation method used for their synthesis are presented for the first time. The Ni-polyyne polymer obtained is dark yellow powder and soluble in THF or CH₂Cl₂. Its M?_w is about 10⁴, and the MWD is less than 2. Both the prepared complex and polymer have been characterized by IR, UV, ¹H-NMR, and DTA. Preliminary results on photoluminesence of nickel polyyne polymers are present. © 1995 John Wiley & Sons, Inc.     

Synthesis and characterization of highly soluble fluorescent main chain copolyimides containing perylene units

A series of high molecular weight copolyimides containing various amount of perylene units in the main chain have been synthesized. The polymers were characterized by FT-IR, NMR, UV/Vis, fluorescence spectroscopy, gel permeation chromatography, differential scanning calorimetry and thermogravimetric analysis measurements. They are highly soluble in conventional solvents such as CHCl₃, THF, cyclohexanone etc. and form optically transparent films by solution casting or spin coating. The incorporation of various amount of perylene units in the main chain allows the control of the fluorescence intensity in solution and in solid thin films. The copolyimide containing 0.28 mol% perylene units exhibits the highest solid-state fluorescence. The observed fluorescence intensities of the copolyimides in solid state film decreased with the increasing amount of perylene units in the main chain when the mole ratio of perylene units greater than 0.28 mol% indicating the aggregation of chromophores. The copolyimides are thermally stable up to 400 °C and exhibit glass transition temperatures in the range of 340-360 °C. The number average molecule weight ranges from 1.72×10⁴ to 1.25×10⁵ and the molecule weight distribution mediated between 1.9 and 2.4.     

Synthesis and characterization of new unsaturated polyesters and copolyesters containing azo groups in the main chain

A new interesting class of linear unsaturated polyesters based on dibenzylidenecycloalkanones have been synthesized by interfacial polycondensation of 4,4^′-azodibenzoyl chloride or 3,3^′-azodibenzoyl chloride with: 2,5-bis(p-hydroxybenzylidene)cyclopentanone I, 2,6-bis(p-hydroxybenzylidene)cyclohexanone II, 2,6-divanillylidenecyclohexanone III, or 2,7-bis(p-hydroxybenzylidene)cycloheptanone IV at ambient temperature. The copolyesters are also synthesized from the monomers I, II, III or IV with the diacid chlorides. The resulting polyesters and their copolyesters were characterized by elemental analyses, IR spectroscopy and solubility. Additionally, inherent viscosity of the polyesters in the range 0.32-0.86 dL g⁻¹ and the inherent viscosity of the copolyesters in the range 0.28-0.65 dL g⁻¹ were determined. The UV-visible spectra of certain polymers were measured in m-cresol solution and showed a characteristic absorption band at 435-473 nm due to n-π^* transition. The thermal properties of the polymers were evaluated by thermo gravimetric analysis and differential scanning calorimetry measurements and correlated with their structural units. The crystallinity of some polyesters and copolyesters were tested. In addition, the electrical properties of all polyesters and copolyesters were measured.     

Synthesis and characterization of a new conjugated polymer: Polytrifluoromethylacetylene

Polytrifluoromethylacetylene (PTFMA) was synthesized from trifluoromethylacetylene (TFMA) using a PdCl₂/DMF catalyst solution or the anionic initiator n-butyl lithium. Although PdCl₂ proved to be an effective catalyst for the polymerization of TFMA, long reaction times and poor yields made characterization of the resultant polymer difficult. The use of n-butyl lithium, on the other hand, resulted in high yields of PTFMA in relatively short reaction times. The results of thermal analysis and the effects of n- and p-type doping on the electrical conductivity of the polymer are discussed.     

Synthesis,characterization and application of soluble fullerenated polymer materials

This article only deals with the topic of intense interest to us and to a considerable extent of our own experimental results on the synthesis,characterization and application of C60-con-taining functional polymers such as poly(N-vinylcarbazole),polystyrene and polyacrylonitrile-based fullerene polymers.The results demonstrate that [60] fullerene can be directly incorporated into a variety of functional polymers by copolymer-ization or grafting,but also can be used to modify or improve the electronic,optical and physicochemical properties of polymers.Both the stereo-electroniceffect and the steric hindrance of C60 have an important influence on the structure and physicochemical properties of the parent polymer.     

Synthesis and fluorescent properties of model compounds for conjugated polymer containing maleimide units at the main chain

2,3‐Diaryl substituted maleimides as model compounds of conjugated maleimide polymers [poly(RMI‐alt‐Ar) and poly(RMI‐co‐Ar)] were synthesized from 2,3‐dibromo‐N‐substituted maleimide (DBrRMI) [R= cyclohexyl (DBrCHMI) and n‐hexyl (DBrHMI)] and aryl boronic acid using palladium catalysts. To clarify structures of conjugated polymer containing maleimide units at the main chain, ¹³C NMR spectra of 2‐aryl or 2,3‐diaryl substituted maleimides were compared with those of N‐substituted maleimide polymers. Copolymers obtained with DBrRMI via Suzuki‐Miyaura cross‐coupling polymerizations or Yamamoto coupling polymerizations were dehalogenated structures at the terminal end. This dehalogenation may contribute to the low polymerizability of DBrRMIs. On the other hand, the π‐conjugated compounds showed high solubility in common organic solvents. The N‐substituents of maleimide cannot significantly affect the photoluminescence spectra of 2,3‐diaryl substituted maleimides derivatives. The fluorescence spectra of poly(RMI‐alt‐Ar) and poly(RMI‐co‐Ar) varied with N‐substituents of the maleimide ring. When exposed to ultraviolet light of wavelength 352 nm, a series of 1,4‐phenylene‐ and/or 2,5‐thienylene‐based copolymers containing N‐substituted maleimide derivatives fluoresced in a yellow to blue color. It was found that photoluminescence emissions and electronic state of π‐conjugated maleimide derivatives were controlled by aryl‐ and N‐substituents, and maleimide sequences of copolymers. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

Synthesis and characterization of a metal chelate-bridged quasi-ladder main chain discotic liquid crystal polymer

A metal chelate-bridged quasi-ladder discotic liquid crystal polymer (DLCP) has been prepared by a controlled chelation reaction of cupric ions with β-diketone groups on two adjacent poly(AADK-HMM) chains, synthesized by the hydrosilylation of a bis-allyl groupterminated β-diketone monomer and 1,1,3,3-tetramethylhydrodisiloxane (HMM). X-ray diffraction patterns of the samples annealed in the mesomorphic state or cooled from the isotropic phase demonstrated the existence of an ordered columnar structure on short or long range scales, respectively. The fact that the molecular weight of the cupric complex is approximately twice that of the parent polymer indicates that the quasi-ladder double chain polymer is the predominant product although some terminal defects are present.     

Synthesis and characterization of nitrogen-rich azo-linked conjugated polymer materials

Efficient azo-linked polymers of 2,4,6-tris(4-nitrophenyl)pyridine-melamine (TNPP-M), and 2,4,6-tris(4-nitrophenyl)pyridine-sulfanilamide (TNPP-S) were prepared by condensation polymerization technique from TNPP-based monomer reacting with amines as melamine and sulfanilamide. The synthesized polymer structure was confirmed by various experimental techniques, such as Fourier transform infrared spectroscopy, solid-state ¹³C NMR, and X-ray diffraction (XRD). Particle size was calculated using Williamson–Hall (W–H) plot from powder XRD pattern. The thermal analysis and scanning electron microscopy of TNPP-S polymer displayed an excellent thermal stability and capsule-like morphology was observed. UV/visible absorptions of TNPP-S and TNPP-M polymers exhibit two bands, a strong band at 365?nm, and a shoulder at 385?nm for TNPP-M; these polymeric semiconducting materials could be useful for solar fuel cell applications.     

Synthesis and thermal transitions of a soluble,main chain,nematic liquid crystalline polymer exhibiting a kinetically trapped,disordered structure

An aromatic copolyester composed of 25 mol % phenyl hydroquinone, 10 mol % isophthalic acid, 40 mol % chloroterephthalic acid, and 25 mol % t-butyl hydroquinone (PICT) has been synthesized. This amorphous, glassy polymer is soluble in common organic solvents such as methylene chloride. Thin, solution-cast films may be prepared which are in a metastable, vitrified, optically isotropic state. On first heating of an isotropic film at 20°C/min in a calorimeter, one glass transition is observed at low temperature (approximately 49°C) and is ascribed to the glass/rubber transition of the metastable, isotropic polymer. This thermal event is followed by a small exotherm due to the development of order during the scan, which results in a second T_g at approximately 125°C. This T_g is associated with the glass/rubber transition of the ordered polymer. Nematic order can be developed by thermal annealing. The lower T_g increases toward the upper T_g as annealing time is increased. For an initially isotropic film annealed at 90°C, the increase of the lower T_g with annealing time and the increase in birefringence observed by optical microscopy are governed by similar kinetics. Isotropization occurs in the temperature range of 250–300°C. The nematic polymer is slightly more dense than its isotropic analog. No detectable differences between isotropic and nematic samples were observed in rotating frame proton spin lattice relaxation times. © 1996 John Wiley & Sons, Inc.     

Studies of poly-yne polymers containing transition metals in the main chain : III. Synthesis and characterization of a poly-yne polymer containing mixed metals in the main chain,

By the reaction of trans-(PBu₃)₂Pt(CCCCH)₂ with trans-(PBu₃)₂PdCl₂, the title polymer,

(II), has been prepared and characterized by spectral and analytical data. The alternating regularity of the metal arrangement in II was confirmed by the selective formation of the trinuclear complex trans,trans,trans-ClPd(PBu₃)₂?CCC CPt(PBu₃)₂?CC-CCPd(PBu₃)₂(XXIII), in the depolymerization by trans- (PBu₃)₂PdCl₂ using CuI as catalyst in XXNEt₂.     

Synthesis of conjugated polymers with azobenzene moieties in the main chain

Poly(phenylenevinylene)‐based conjugated polymers with azobenzene groups in the main chains were prepared by the Pd‐catalyzed coupling polymerization of divinylarenes with dihaloarenes. The Pd‐catalyzed coupling polymerization of 4,4′‐divinylazobenzene with dihaloarenes such as 1,3‐dibromobenzene, 1,4‐dibromo‐2,5‐dihexylbenzene, 4,4′‐dibromoazobenzene, and 4,4′‐diiodoazobenzene resulted in polymers with poor solubility. In contrast, soluble polymers containing azobenzene moieties in the main chains were attainable from divinylbenzenes with 4,4′‐dihaloazobenzenes if either or both of the monomers possessed hexyl groups on the aromatic rings. The number‐average molecular weight of the polymer exceeded 10,000 under optimized conditions, and the polymer showed a remarkably redshifted absorption in the visible region (456 nm). ¹H NMR and IR spectra supported that the polymers having only trans‐geometry for the double bonds. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 1057–1063, 2000     

Synthesis and characterization of conjugated polymer containing azobenzene and oxadiazole units

A novel conjugated polymer containing azobenzene and oxadiazole units was synthesized through multi-step synthesis.The structures and properties of monomer and polymer were characterized and evaluated with IR,1H NMR,UV,TGA and GPC,respectively.Polymer with long side chain of alkoxy shows good solubility,thermal stability and photoisomerization property.     

Water‐soluble dendritic‐conjugated polyfluorenes: Synthesis,characterization, and interactions with DNA

Three generation of Boc‐protected dendritic‐conjugated polyfluorenes ( Boc‐PFP‐G_0‐2 ) were synthesized by Suzuki coupling 1,4‐phenyldiboronic ester with dendritic monomers that were synthesized through generation‐by‐generation approach. The gel permeation chromatography (GPC) analyses showed that the weight‐average molecular weight (M_w) of Boc‐PFP‐G_0‐2 was in the range of 11,400–20,400 Da with the polydispersity index (PDI) in the range of 1.32–1.96. Treatment of Boc‐protected polymers with 6 M HCl in dioxane yielded cationic dendritic‐conjugated polyfluorenes ( PFP‐G_0‐2 ). They were soluble in common polar solvents such as DMSO, DMF, and water with absorption maxima between 345 and 379 nm. The solutions of PFP‐G_0‐2 in water were highly fluorescent with emission maxima between 416 and 425 nm. Because higher generation dendrons could prevent the formation of π‐stacking aggregates of backbones of conjugated polymer, the fluorescence quantum efficiencies (QEs) of PFP‐G_0‐2 enhance as the dendritic generation grew. The interactions between 25 mer double‐stranded DNA (dsDNA) and PFP‐G_0‐2 were studied using ethidium bromide (EB) as fluorescent probe. The electrostatic bindings of PFP‐G_0‐2 with dsDNA/EB complex result in displacement of EB from DNA double helix to the solution accompanying by a quenching of EB fluorescence. The PFP‐G₂ with highest generation of dendritic side chains possessed a highest charge density and could form most stable complex with dsDNA. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 7462–7472, 2008     

Synthesis and characterization of sulfone containing main chain oligobenzoxazine precursors

The preparation of soluble and processable polybenzoxazine precursors capable of forming high performance networks is an important field of research with a broad spectrum of application. This study demonstrates an approach that utilizes aromatic sulfonediamine, bisphenol‐A, and formaldehyde in Mannich‐type polycondesation to prepare polybenzoxazine precursor. The structure of the oligomeric precursor (M_n = 2600) was confirmed by FTIR and ¹H NMR spectral analysis. The precursor contained both sulfone and benzoxazine ring structures in the backbone. It was shown that small amount of ring‐opened phenolic groups were also present. Thermally activated self‐curing behavior of precursor in the absence of catalyst was studied by differential scanning calorimetry. Thermal properties of the cured polymers were also investigated by thermo gravimetric analysis. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

Synthesis, processing and properties of conjugated polymer networks

Despite the diverse research activities focused on the chemistry, materials science and physics of conjugated polymers, the feature of conjugated cross-links, which can provide electronic communication between chains, has received little attention. This situation may be a direct consequence of the challenge to introduce such links while retaining adequate processability. Focusing on recent studies of materials for which charge transport or electrical conductivity data are available, this feature article attempts to present an overview of the synthesis, processing and electronic properties of conjugated polymer networks. For the purpose of this discussion, two distinctly separate architectures-featuring covalent cross-links on the one hand and non-covalent organometallic bridges on the other-are treated in separate sections. The available data indicate that cross-linking can have significant benefits for intermolecular charge transfer if the polymers are carefully designed.     

Synthesis of polymer containing o-nitrobenzyl ether structure in the main chain

The polycondensation of nitrated xylenedihalides with diphenols was carried out under various conditions. The polycondensation of 2-nitro-1, 3-xylylenedibromide (NXDB) with 4,4′-isopropylidenediphenol proceeded in competition with the decomposition of polymer in the mixed solvent of tetrahydrofuran (THF) and dimethylsulfoxide (DMSO). The viscosity of the resulting polymer was markedly affected by the concentration of aqueous sodium hydroxide, reaction time, and reaction temperature. When dibromomethane was used as a solvent, the polycondensation proceeded very smoothly without the decomposition to give a higher reduced viscosity polymer than that in THF-DMSO at 60°C. The polymer obtained in dibromomethane contained a very small amount of formal bonds determined from the ¹H-NMR spectrum. The formation of formal bonds seems to cause the molecular weight in increase. Furthemore, the polycondensation of NXDB with 2,2-bis (4-hydroxyphenyl) hexafluoropropane afforded high molecular-weight polyether in dibromomethane. However, either high reaction temperatures or the high concentrations of aqueous potassium hydroxide solution casused the viscosity of the resulting polymer to decrease during the polycondensation in dibromomethane. The obtained polyethers with o-nitrobenzyl groups showed relatively good solubility, and decomposed smoothly upon the irradiation with UV light. Therefore, these polymers might be useful for positive type photoresists.