Recombination luminescence of poly(arylene phthalide) films: 1. Electronic and optical features of poly(arylene phthalide)s

Features of the luminescence and absorption spectra of poly(biphenylene phthalide), poly(fluorenylene phthalide), and poly(terphenylene phthalide) films were analyzed. Experimental results obtained for these films by optical methods and thermally stimulated current spectroscopy were compared. Long-lasting afterglow emission from the films after photoexcitation was observed. Possible explanations for the observed optical and thermally stimulated processes in the poly(arylene phthalide)s were suggested in terms of reversible electronic phase transitions induced by external factors in unconjugated polymers.     

The suzuki–heck polymerization as a tool for the straightforward obtainment of poly(fluorenylene‐vinylene) sensitizers for dye‐sensitized solar cells

This article describes the synthesis and properties of the first poly(arylene‐vinylene)‐based sensitizers for application in dye‐sensitized solar cells (DSSC). The polymers were prepared by the Suzuki–Heck copolymerization of potassium vinyltrifluoroborate (PVTB) with a mixture of dibromoaryl comonomers designed to obtain macromolecules able to bind onto the photoelectrode by means of carboxyphenylene units. The copolymerization reactions were carried out in the presence of an excess of PVTB to lower the molecular weights of the polymers, which were obtained as soluble materials. The polymers poly[(9,9‐didodecyl‐2,7‐fluorenylene)‐vinylene‐co‐(carboxy‐2,5‐phenylene)‐vinylene] ( P1 ), poly[(9,9‐didodecyl‐2,7‐fluorenylene)‐vinylene‐co‐(carboxy‐2,5‐phenylene)‐vinylene‐co‐(4,7‐benzothiadiazolylene)‐vinylene] ( P2 ), and poly[(9,9‐didodecyl‐2,7‐fluorenylene)‐vinylene‐co‐(carboxy‐2,5‐phenylene)‐vinylene‐co‐2,5‐thienylene‐vinylene] ( P3 ) were used in DSSC devices, obtaining conversion efficiencies up to 0.88% ( P3 ). © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

Preparation and emission properties of various poly(dimethylsilylenearylenevinylene)s: Effects of geometric structures and π units on their emission properties

trans‐Poly(dimethylsilylenearylenevinylene)s (trans‐rich) and cis‐poly(dimethylsilylenearylenevinylene)s (cis‐rich) containing phenylene, biphenylene, and phenylenesilylenephenylene units were prepared by hydrosilylation catalyzed with the RhI(PPh₃)₃ complex. The addition of a phenylene π unit to poly(silylenephenylenevinylene) expanded the conjugation in the main chain, whereas the insertion of a dimethylsilylene σ unit in the biphenylene moiety reduced the conjugation. UV spectra of the trans‐type polymers showed redshifts and hyperchromic effects with respect to those of the cis‐type polymers, indicating wider conjugation, and the quantum yields of emission of the former polymers were much higher than those of the latter polymers. The quantum yield of the trans‐rich polymer with the biphenylene moiety reached 0.15, which was about 10² times as large as those of trans‐type polymers with phenylene (3.4 × 10^?3) and phenylenesilylenephenylene (1.9 × 10^?3) moieties. The effects of the geometric structure and π unit on the absorption and emission properties of these polymers were examined with molecular orbital methods. © 2002 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 40: 535–543, 2002; DOI 10.1002/pola.10139     

Structure-property correlation of light-emitting polymers containing alternating phenylene and thienylene/bithienylene repeating units

A number of series of fluorescent and conducting polymers containing alternating 3-functionalized thienylene/ bithienylene and phenylene/ pyridyl/ biphenylene units were synthesized from a number of central symmetric high oligomers and characterized using UV-Vis, photoluminescence, conductivity measurement, thermal analysis, electrochemistry, XRD and XPS. Structural variation of the polymers was realized by both side chain and polymer backbone modifications. Close structure-property correlation of the polymers was observed. This paper mainly reports the results of two families of them, those substituted by alkyl pendant chains and electro-withdrawing and donating groups.     

New high-temperature polymers. II. Ordered aromatic copolyamides containing fused and multiple ring systems

Symmetrical diamines, containing preformed carbonamide linkages, were prepared by reacting nitrobenzoyl chlorides with aromatic diamines and reducing the dinitro intermediates. The diamines were polymerized with aromatic diacid chlorides to give wholly aromatic ordered copolyamides of exceptionally high thermal stability. Ordered diamines were prepared containing only phenylene units as the aromatic portion, and others containing phenylene and naphthylene or biphenylene groups. Low-temperature solution polymerization of these diamines with isophthaloyl chloride, 4,4′-bibenzoyl chloride, or 2,6-naphthalenedicarbonyl chloride, gave thirteen ordered copolyamides, each containing a naphthylene and/or biphenylene group in its repeating unit. Differential thermal analyses and thermogravimetric analyses showed these polymers to have melting points or decomposition temperatures of from 420 to over 500°C. Films of one of the polymers had a breakdown voltage of 3000 v./mil at 180°C. Fibers of the same composition had tenacities of up to 8 g/den.; a 5.5 g/den. sample retained 85% of its tenacity after 17 hr. at 300°C. and 21% after 9 days.     

Polyaromatic ether-ketones containing various biphenylene units as crosslinking sites

Polyaromatic ether-ketones were prepared from diphenyl ether, isophthaloyl dichloride, and small amounts of 2,6-, 2,7-, 1,5-, and 1,8-dicarboxylic acid chloride of biphenylene, respectively, by Friedel–Crafts reaction. Biphenylene units were incorporated as crosslinking sites. Crosslinking is achieved by curing the polymers at 310–350°C for several hours. While the uncured resins are soluble in concentrated sulfuric acid, the fully crosslinked polymers are completely insoluble.     

Chalkogenidgläser mit organischen Komponenten. II. Über Gläser der Zusammensetzung Selen-Arsen-Jod-Biphenylen

Chalcogenide Glasses with Organic Components, II. Glasses of the Selenium-Arsenic-Iodine-Biphenylene System New solids were prepared by melting suitable glasses of the system Se? As? I and of 4,4′-Bis(diiodoarsa)biphenyle, and cooling them subsequently. The transformation temperatures, densities, dc-conductivities, and i.r. spectra of the solids are reported. These solids exhibit chain-like structures. The biphenylene groups are connected with the inorganic matrix by arsenic-carbon bonds. The structure especially of the biphenylene units as wall as the conductivity behaviour is discussed.     

Electronic Properties of Two Series of Blue-Emitting Conjugated Oligomers and Polymers Based on Cyanostilbene： A Quantum Chemistry Study

One of the drawbacks of the electroluminescence （EL） polymers is that they are usually much better at accepting and transporting holes than electrons due to their inherent richness of π-electrons. One approach improving electron injection and transport in conjugated polymers is to incorporate moieties with high electron affinities. In this theoretical work, to gain an insight into the chemical structure-property relationships was aimed by controllable modification of the main chain structures. Two cyanovinylene derivatives with 2,7-fluorenylene and p-phenylene moieties in the main chains, namely, poly { （2,5-dimethoxy-p-phenylene- 1,4-ylene）-alt-[ 1,2-bis（p-phenylene）- 1- cyanovinylene]} （PPhCN） and poly{[9,9-dimethyl-2,7-fluorenylene]-alt-[1,2-bis（p-phenylene）-1-cyanovinylene]} （PFCN）, were studied employing density functional theory （DFT） and time dependent density functional theory （TD-DFT） with B3LYP functional. The electronic properties of the neutral molecules, extrapolated ionization potentials （IP） and electron affinities （EA）, and energy gaps were investigated in comparison with pristine poly（2,7- fluorenylene）. From comparison with poly（2,7-fluorenylene） （PF）, the 1,2-bis（p-phenylene）-1-cyanovi-nylene unit was found to be a good electron-withdrawing moiety for electronic materials and the incorporation of 1,2-bis（p- phenylene）-1-cyanovinylene resulted in a narrow band gap and a red shift of both the absorption and photoluminescence emission peaks. Most importantly, the LUMO energies of PFCN are around 1 eV lower than those of PF, which results in the decrement of EA about 0.9 eV, indicating that the 1,2-bis（p-phenylene）-1-cyanovinylene unit has significantly improved the electron-accepting properties of the copolymer PFCN. Substitution of 2,5-dimethoxy-p-phenylene for 9,9-dimethyl-2,7-fluorenylene induced larger band gaps and thus a blue-shift in absorption and emission peaks, which can be attributed to the better conjugated backbone in PFCN.     

Synthesis and absorption/emission properties of novel poly(silylenearylenevinylene)s

Polymerization of p-(dimethylsilyl)phenylacetylene in toluene at 25 and 80 °C with RhI(PPh₃)₃ catalyst afforded highly regio- and stereoregular poly(dimethylsilylene-1,4-phenylenevinylene)s [cis- and trans-poly( 1a )s] containing 98% cis- and 99% trans-vinylene moieties, respectively. The trans-type polymers exhibited redshifts and hyperchromic effects in the ultraviolet–visible spectrum as compared with the cis-type counterparts. Photoirradiation of cis- and trans-poly( 1a )s gave cis-rich mixtures at equilibrium states. The trans and cis polymers exhibited different emission properties, for example—trans polymer, emissn λ_max = 400 nm, quantum yield: 3.4 × 10⁻³ and cis polymer, emissn λ_max = 380 nm, quantum yield: 1.5 × 10⁻³. Besides poly( 1a ), poly(dimethylsilylenearylenevinylene)s containing biphenylene and phenylenesilylenephenylene units [poly( 3 )] were prepared. The extent of conjugation in these polymers decreased in the orders of biphenylene > phenylene > phenylenesilylenephenylene as well as trans-vinylene > cis-vinylene. The quantum yield of the trans-rich polymer with biphenylene moiety was fairly large and 0.15. Polyaddition of 1,4-bis(dimethylsilyl)benzene and three types of diethynylarenes (4,4′-diethynylbiphenyl, 2,7-diethynylfluorene, and 2,6-diethynylnaphthalene) catalyzed by RhI(PPh₃)₃ provided novel regio- and stereoregular polymers [poly( 6 )]. These polymers displayed blue light emission with high quantum yields (4–81%). © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 3615–3624, 2003     

Crosslinking of polyaromatic ether-ketones with biphenylene derivatives

Polyaromatic ether-ketones prepared from isophthaloyl dichloride, diphenyl ether, and various amounts of biphenylene and its derivative, were compressed to films under various conditions, and their crosslinking behaviors were studied. Although strong and flexible films could be obtained from low melting crosslinkable polymers, the low molecular weight polymers, which melt below 300°C, decompose at the biphenylene ring opening temperature of over 290°C, giving films full of gas bubbles. The addition of metal complexes to decrease the biphenylene ring opening temperature did not improve the film quality, although gas bubbles could be avoided. The strong and flexible films were amorphous, and the brittle films were mixtures of crystalline and amorphous polymers.     

STUDY ON CHIRAL LIQUID CRYSTALLINE POLYMERS WITH BIPHENYLENE AND AZOBENZENE AS THE MESOGENS

Chiral liquid crystalline polymers containing biphenylene and azobenzene as the mesogensand S(-)-2-methyl-1-butanol as the chiral end group were synthesized and characterized by DSC,POM and X-ray diffraction. These polymers show crystalline or glassy liquid crystalline phase atroom temperature. Most polymers show smectic A or highly ordered smectic phases abovemelting temperature.     

Preparation and properties of polyamides containing p-terphenyl units

Novel polyamides that contained p-terphenyl units were prepared with inherent viscosities in the range of 0.4–1.7 dL/g by the polycondensation of 4,4″-dichloroformyl-p-terphenyl with aromatic diamines and 4,4″-diamino-p-terphenyl with aromatic dicarbonyl chlorides. Polyamides composed of only paraoriented phenylene units were insoluble in all solvents and showed a high degree of crystallinity. A series of polyamides that contained p-terphenyl units were more thermostable than corresponding polymers with p-phenylene or biphenylene linkages.     

New polymers with mesogens in the side chain and kinked aromatic structures in the main chain from the polyaddition of bis(epoxide)s and di(ester)s

Nine polymers with kinked aromatic structures in the main chain and biphenylene‐type mesogenic groups in the side chain were synthesized by the polyaddition of bis(epoxide)s and thio‐ and O‐esters. Tetrabutylphosphonium chloride and tetraphenylphosphonium chloride effectively catalyzed the polymerization. The thermal behavior of the polymers was measured by DSC and polarizing optical microscopy. The effect of annealing time on the degree of crystallization was investigated by DSC analysis. Polymers containing 100% of the kinked aromatic groups and 1,3‐propylene glycol in the main chain were amorphous. However, when half of the main‐chain aromatic moieties were composed of kinked groups and the other half of the aromatics were linear rodlike groups, the polymers were crystalline. The incorporation of kinked groups into the main chain of side‐chain liquid‐crystalline polymers suppressed the formation of liquid crystallinity. The polymer with mesogenic aromatic structures in both the main chain and the side chain was capable of forming a liquid‐crystalline phase. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 988–998, 2000     

Structure-property relations and processing of rod-like aromatic polyamides

Homopolyamides and copolyamides with structural characteristics such as bulky lateral substituents, non-coplanar, 2, 2′-dimethylbiphenylene units and comonomers of different length were prepared and their structure-property relations investigated. Polyamides with high solubilities and very low or no degree of crystallinity are obtainable by a combination of monomers with bulky lateral substituents and non-coplanar biphenylene units. These polyamides form tough, transparent films with good mechanical and thermal properties. Lyotropic liquid crystalline behavior was found in some cases for polyamides with non-coplanar biphenylene units. The incorporation of monomers with bulky substituents on the terephthalic acid unit lowers the chain stiffness and significantly influences the formation of lyotropic solutions.     

Flame retardancy and heat resistance of phenol-biphenylene-type epoxy resin compound modified with benzoguanamine

The flame retardancy and heat resistance of a phenol-biphenylene-type epoxy resin compound, which forms a self-extinguishing network structure, were increased by the inclusion of a benzoguanamine-modified phenol biphenylene resin. The benzoguanamine-modified phenol biphenylene resin contains a benzoguanamine unit to release non-flammable nitrogen substances during ignition and to increase the resin's reactivity toward epoxy resins, and biphenylene units to keep the resin's thermal degradation and water resistance. The addition of the benzoguanamine-modified phenol biphenylene resin in the epoxy resin compound improved the epoxy resin compound's flame retardancy and heat resistance, and also increased its glass transition temperature while maintaining its water resistance and mechanical properties. Copyright © 2003 John Wiley & Sons, Ltd.     

Synthesis of poly(biphenylene ketone)s via palladium catalyzed cross-coupling reactions with ketone diacetals

Dibromobenzophenone diacetals (BrC₆H₄)₂C(OR)₂ undergo cross-coupling reactions with (Bu₃SnC₆H₄)₂O in the presence of palladium catalysts to give poly (diacetal ether)s whose molecular weights reflect the solubility changes of the growing polymer chains as a function of the diacetal precursors, R = Me < 1/2 CH₂CH₂ < 1/2 CH₂CHMe and are significantly higher than those of polymers derived from dibromobenzophenone. New di-zinc reagents based on diacetal derivatives were synthesized and used as organometallic coupling reagents with a range of dibromoarenes, resulting in a series of previously inaccessible poly (biphenylene ketone)s and poly (biphenylene ketone sulfone)s. While poly (biphenylene ether ketone)s are insoluble, poly (biphenylene ketone)s readily dissolve in concentrated sulfuric acid. The effects of reaction parameters on the molecular weight of poly (biphenylene ketone) were determined. © 1994 John Wiley & Sons, Inc.     

Synthesis and characterization of new blue‐light‐emitting polymers based on PPP and PPV having fluorene pendant at vinyl bridge

The new poly(arylene vinylene) derivatives, which are composed of biphenylene vinylene phenylene vinylene, biphenylene vinylene m‐phenylene vinylene, terphenylene vinylene phenylene vinylene, and terphenylene vinylene m‐phenylene vinylene as backbone and bulky fluorene pendants at each vinyl bridge, were designed, synthesized, and characterized. The obtained polymers showed weight‐average molecular weights of 11,100–39,800 with polydispersity indexes ranging from 1.5 to 2.1. The resulting polymers were amorphous with high thermal stability and readily soluble in common organic solvents. The obtained polymers showed blue emission (λ_max = 456–475 nm) in PL spectra, and polymer 4 containing terphenylene vinylene m‐phenylene vinylene showed the most blue shifted blue emission (λ_max = 456 nm). The double layer light‐emitting diode devices fabricated by using obtained polymers as emitter emitted bright blue light. The device showed turn on voltage around 6.5 V and brightness of 70–250 cd/m². © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 4923–4931, 2006     

Synthesis and properties of photochromic liquid-crystalline polyacrylates containing a spirooxazine group

The novel photochromic liquid-crystalline polyacrylates containing a spirooxazine group were synthesized. The photochromic polymer containing (4-penta- methyleneoxy)biphenylene moiety at the 5-position of spironaphthoxazine showed nematic phase from 122.9 to 133.8°C. The photochromic polymer containing undeca- methylene instead of pentamethylene showed smectic phase from 93.1 to 169.7°C. On the other hand, the photochromic polymer containing both undecamethylene as a spacer and spironaphthoxazine-bound biphenylene moiety at 9′-position did not show any liquid crystallinity. All spirooxazine-containing liquid-crystalline polymers showed photochromism in the solid state at room temperature. Because the shape of the absorption spectra of the photochromic quenched liquid-crystalline polymer films was almost the same as those of the photochromic amorphous polymer films, the photochromic properties did not depend on the mesophase in the polymers examined. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 3513–3522, 1999     

Conjugated polymers for the fluorescent detection of nitroaromatics: Influence of side‐chain sterics and π‐system electronics

A series of eight poly(p‐phenylene vinylene) (PPV) and poly(p‐phenylene ethynylene) (PPE) ( P1–P8 ) derivatives were tested for their ability to detect the nitroaromatic explosive 2,4,6‐trinitrotoluene (TNT) and its model compound 2,6‐dinitrotoluene (DNT). The polymers P1–P8 represent five structural classes that have not been examined for nitroaromatic sensing. These new motifs include PPE derivatives with a main‐chain m‐terphenyl unit ( P1 ) or oxacyclophane canopy‐like structure ( P2 ) and PPV derivatives with 2,6‐mesitylenephenylene repeats ( P3 and P4 ), 9,9‐dialkyl‐1,4‐fluorenylene repeats ( P5 and P6 ), or m‐phenylene units that periodically disrupt π‐conjugation along the backbone of the polymer ( P7 and P8 ). The time‐dependent photoluminescent response of films to TNT and DNT and the solution‐phase Stern‐Volmer quenching constants for both TNT and DNT were determined. The results are rationalized in terms of side‐chain sterics and π‐system electronics and are discussed relative to known conjugated polymers. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 1487–1492     

Biphenylene units possessing flammable and nonflammable characteristics in fluoroalkyl end-capped vinyltrimethoxysilane oligomeric silica gel matrices after calcination at 800 °C

Two kinds of fluoroalkyl end-capped vinyltrimethoxysilane oligomer [R_F-(VM) _n -R_F] silica nanocomposites containing biphenylene units were prepared by the sol-gel reactions of the corresponding oligomer with biphenylene-bridged ethoxysilanes or 4,4′-biphenol under alkaline conditions, respectively. One is the fluorinated oligomer/silica nanocomposites containing biphenylene units [R_F-(VM-SiO₂) _n –R_F/Ar-SiO ₂ ], of whose biphenylene units were incorporated into nanocomposite cores through the siloxane bondings, and the other is the fluorinated oligomer/silica nanocomposites containing biphenylene units [R_F-(VM-SiO₂) _n –R_F/Biphenol], of whose biphenylene units were directly encapsulated into nanocomposite cores through the sol–gel process. Interestingly, the shape of R_F-(VM-SiO₂) _n –R_F/Ar-SiO ₂ nanocomposites is morphologically controlled cubic particles; although the shape of R_F-(VM-SiO₂) _n –R_F/Biphenol nanocomposites is spherically fine particles. Thermogravimetric analyses ²H magic-angle spinning nuclear magnetic resonance, Ultraviolet visible, and fluorescent spectra showed that biphenylene units in R_F-(VM-SiO₂) _n –R_F/Ar-SiO ₂ nanocomposites have a flammable characteristic after calcinations at 800 °C; in contrast, biphenylene units in R_F-(VM-SiO₂) _n –R_F/Biphenol nanocomposites have a nonflammable characteristic even after calcination at 800 °C. X-ray photoelectron spectroscopy analyses of these two kinds of fluorinated nanocomposites showed that nonflammable characteristic toward biphenylene units in the silica gel matrices is due to the formation of ammonium hexafluorosilicate during the sol–gel process.