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International audience; Two series of new dicationic stilbazolium salts containing tosylate and triflimide counterions, respectively, were synthesized and characterized by spectroscopic techniques and elemental analysis. Despite of their promesogenic structures, none of these salts are mesomorphous, and instead they solely exhibit crystalline polymorphism, as deduced from differential scanning calorimetry, polarizing optical microscopy and variable temperature X-ray measurements. These salts were also found to be highly thermally stable with decomposition temperatures occurring well above 300 °C, and up to 367 °C for the triflimide salts, as determined by thermogravimetric analysis. UV–Vis absorption and photoluminescent properties were examined in both solution and in the solid state. They exhibited higher absolute quantum yields in the powdered state than in solution. The dielectric response was evaluated by impedance spectroscopy, revealing notable values of short-range conductivity in triflimide salts through amorphous regions. Our work demonstrates the potential of these new stilbazolium salts as advanced materials in optoelectronic devices, with performances that can be tailored by molecular design of the spacer’s flexibility and choice of counter anions.

Safe and inexpensive methods for synthesis of a series of four substituted 2,4,6-triphenylyrylium tosylate salts with different substituents are reported. The synthesis methods use p-toluenesulfonic acid monohydrate instead of conventional acid catalysts including perchloric acid or boron trifluoride diethyl etherate that pose explosion danger and difficult storage problems, respectively. The chemical structures of these salts were established using FTIR, 1H and 13C NMR spectroscopic techniques and elemental analysis. Thermogravimetric analysis (TGA) showed that these salts have good thermal stability, and differential scanning calorimetry (DSC) analysis showed that they have lower melting transitions than the corresponding tetrafluoroborate and perchlorate salts. Solutions of the salts in organic solvents (such as acetonitrile and methanol) absorbed strongly in the blue-near-ultraviolet spectral range and emitted efficiently in the blue-green spectral range depending on the substituents in 2- and 6-positions of phenyl groups. The fluorescence quantum yields of the salts ranged from 0.33 to 0.56. Under intense ultrashort laser pumping, an acetonitrile solution of the salt, 2,4,6-triphenylpyrylium tosylate, the salt with the highest quantum yield, demonstrated stimulated emission and laser action with only nominal feedback.

Monomeric dialkyl and monoalkyl viologens rapidly catalyze O2-oxidation of carbohydrates in alkaline solution to form carbonate and formate at pH >11. Optimization of these catalytic reactions is important for alkaline carbohydrate fuel cell applications. Use of these monomeric viologens is not optimal because they exit the fuel cell with the reaction products and would need to be recovered and recycled for continued use. Polymeric or immobilized viologens would reduce or avoid these recovery problems. Here, we report the evaluation of water-soluble polymeric viologens as potential fuel-cell-catalysts and show that they rapidly catalyze O2-oxidation of carbohydrates to carbonate and formate at high efficiency. The rates of reduction of polymeric viologens by carbohydrates were rapid and found to be first order in carbohydrate and one-half order in polymer concentration. An unusual feature of the reduction reaction is that the rate of polymer reduction is two-fold faster if carbohydrate is equilibrated with the buffer prior to addition of the catalyst rather than adding the carbohydrate in the presence of the catalyst. Advantages and disadvantages of polymeric viologens as fuel cell catalysts are discussed.

Six new rugged, high-temperature tolerant phosphine oxide-containing poly(4,4&prime, (p-phenylene)-bis(2,6-diphenylpyridinium)) polymers P-1, P-2, P-3, P-4, P-5, and P-6 are synthesized, characterized, and evaluated. Synthesis results in high yield and purity, as confirmed by elemental, proton (1H), and carbon 13 (13C) nuclear magnetic resonance (NMR) spectra analyses. High glass transition temperatures (Tg &gt, 230 &deg, C) and high char yields (&gt, 50% at 700 &deg, C) are determined by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA), respectively. These new ionic polymers exhibit excellent processability, thin-film forming, high-temperature resistance, fire-resistance and retardation, coating, adhesion, mechanical and tensile strength, and n-type (electron transport) properties. The incorporation of phosphine oxide and bis(phenylpyridinium) moieties in the polymer backbones leads to high glass transition temperatures and excellent fire retardant properties, as determined by microcalorimetry measurements. The use of organic counterions allows these ionic polymers to be easily processable from several common organic solvents. A large variety of these polymers can be synthesized by utilizing structural variants of the bispyrylium salt, phosphine oxide containing diamine, and the counterion in a combinatorial fashion. These results make them very attractive for a number of applications, including as coating and structural component materials for automobiles, aircrafts, power and propulsion systems, firefighter garments, printed circuit boards, cabinets and housings for electronic and electrical components, construction materials, mattresses, carpets, upholstery and furniture, and paper-thin coatings for protecting important paper documents.

A set of poly(pyridinium) salts containing various diamine moieties, as molecular connectors, and poly(ethyleneglycol)-4-nonylphenyl-3-sulfopropyl ether, thereafter referred to as &ldquo, Macroion&rdquo, as the hydrophilic counterion, were prepared by metathesis reaction from the respective precursory tosylated poly(pyridinium)s in methanol. The structure of these ionic polymers was established by spectroscopy and chromatography techniques. The shape-persistent ionic poly(pyridinium) materials, inserting rigid or semi-rigid diamine spacers, display thermotropic liquid-crystalline properties from room-temperature up to their isotropization (in the temperature range around 160&ndash, 200 &deg, C). The nature of the LC phases is lamellar in both cases as identified by the combination of various complementary experimental techniques including DSC, POM and variable-temperature SAXS. The other polymers, inserting bulky or flexible spacers, only form room temperature viscous liquids. These new macromolecular systems can then be referred to as polymeric ionic liquid crystals (PILCs) and or polymeric ionic liquids (PILs). All the ionic polymers show excellent thermal stability, in the 260&ndash, 330 &deg, C temperature range as determined by TGA measurements, and a good solubility in common organic solvents as well as in water. Their optical properties were characterized in both solution and solid states by UV&minus, Vis and photoluminescent spectroscopies. They emit blue or green light in both the states and exhibit a positive solvatochromic effect.

A series of poly(pyridinium salt)s-fluorene main-chain ionic polymers with various organic counterions were synthesized by using ring-transmutation polymerization and metathesis reactions. Their chemical structures were characterized by Fourier Transform Infrared (FTIR), proton (1H), and fluorine 19 (19F) nuclear magnetic resonance (NMR) spectrometers. These polymers showed a number-average molecular weight (Mns) between 96.5 and 107.8 kg/mol and polydispersity index (PDI) in the range of 1.12–1.88. They exhibited fully-grown lyotropic phases in polar protic and aprotic solvents at different critical concentrations. Small-angle X-ray scattering for one polymer example indicates lyotropic structure formation for 60–80% solvent fraction. A lyotropic smectic phase contains 10 nm polymer platelets connected by tie molecules. The structure also incorporates a square packing motif within platelets. Thermal properties of polymers were affected by the size of counterions as determined by differential scanning calorimetry and thermogravimetric analysis measurements. Their ultraviolet-visible (UV-Vis) absorption spectra in different organic solvents were essentially identical, indicating that the closely spaced π-π* transitions occurred in their conjugated polymer structures. In contrast, the emission spectra of polymers exhibited a positive solvatochromism on changing the polarity of solvents. They emitted green lights in both polar and nonpolar organic solvents and showed blue light in the film-states, but their λem peaks were dependent on the size of the counterions. They formed aggregates in polar aprotic and protic solvents with the addition of water (v/v, 0%–90%), and their λem peaks were blue shifted.

Hypothesis Properties of catanionic surfactants can be tailored by the choice of appropriate headgroups and hydrocarbon tails. Thermal behavior of catanionic surfactants can be influenced by the length and number of alkyl chains. Experiments A series of eight catanionic surfactants were synthesized from quaternary ammonium surfactants as the cationic counterpart and bis(2-ethylhexyl)sulfosuccinate (AOT) as the anionic counterpart. The thermal properties and the liquid crystalline properties of these catanionic surfactants were studied by the following methods: Thermal Gravimetric Analysis (TGA), Differential Scanning Calorimetry (DSC), Hot-Stage Polarized Light Microscopy (HSPLM), and X-ray Diffraction (XRD). Findings The results indicate that transition temperatures, enthalpies of transition, and mesophase structures vary with the length and number of chains attached to the quaternary nitrogen. These compounds exhibit room temperature liquid crystalline (LC) textures that are predominantly “fan-like,” as observed by HSPLM, and phases that are hexagonal columnar, as observed by XRD, with the exception of one compound which exists as a nematic liquid crystal at 25 °C. Additionally, all of the surfactants also exhibit thermal stability in the range of 256–300 °C.

Bis(pyridinium salt)s containing different alkyl chain lengths and various organic counterions were prepared by the ring-transmutation reaction of bis(pyrylium tosylate) with aliphatic amines in dimethyl sulfoxide at 130–135 °C for 18 h and their tosylate counterions were exchanged to other anions such as triflimide, methyl orange, and dioctyl sulfosuccinate by the metathesis reaction in a common organic solvent. Their chemical structures were established by using 1H, 19F, and 13C NMR spectra. The thermal properties of bis(pyridinium salt)s were studied by DSC and TGA measurements. Some of the dicationic salts provided low melting points below 100 °C and some of them displayed amorphous properties. Polarized optical microscopy studies revealed the crystal structures prior to melting temperatures in some cases. Their optical properties were examined by using UV–Vis and photoluminescent spectrometers; and they emitted blue light both in the solution and solid states regardless of their microstructures, counterions, and the polarity of organic solvents. However, most of these salts exhibited hypsochromic shifts in their emission peaks in the solid state when compared with those of their solution spectra. Due to unique properties of methyl orange anion as a pH indicator, two of the salts showed different color change in varying concentrations of triflic acid in common organic solvents, demonstrating their potential use as an acid sensor in methanol, acetonitrile and acetone.

Several poly(pyridinium salt)s containing various aromatic diamine moieties and tosylate counterions were prepared by the ring-transmutation polymerization reaction of bis(pyrylium tosylate) with aromatic diamines in dimethyl sulfoxide at 130−135 °C for 48 h and their tosylate counterions were exchanged to triflimide polymers by a metatheses reaction in an organic solvent. Their chemical structures were established by using various spectroscopic techniques. Their number-average molecular weights (Mn) were in the range of 38–46 kg/mol and polydispersities in the range of 1.13–1.43 as determined by gel permeation chromatography. They showed excellent thermal stabilities in nitrogen in the range of 326–477 °C. They exhibited lyotropic liquid-crystalline phase in polar aprotic and protic organic solvents above their critical concentrations depending on their microstructures and counterions. Their optical properties were examined by using UV–Vis and photoluminescent spectroscopy, which revealed that some polymers emitted UV light, some emitted blue light, and some emitted green light (both in solutions and solid states) depending on their microstructures, counterions, and on solvent polarity of organic solvents.

Several new poly(pyridinium salt)s with quinoline diamine moieties in their backbones with tosylate and triflimide counterion were prepared by either a ring-transmutation polymerization reaction with bis(pyrylium tosylate) with a series of isomeric quinoline diamines in dimethyl sulfoxide (DMSO) for 48 h at 130–140 °C or a metathesis reaction of the tosylate polymers with lithium triflimide in DMSO at about 60 °C. Their chemical structures were confirmed by FTIR, 1H and 13C NMR spectroscopy, and elemental analysis. Their number-average molecular weights (Mn) were in the range of 18,000–58,000, and their polydispersities were in the range of 1.12–1.53 as determined by gel permeation chromatography. They had thermal stability in the temperature range of 353–455 °C and glass-transition temperatures >240 °C. They had good solubility in common organic solvents and were characterized with polarizing optical microscopy (POM) studies for their lyotropic liquid-crystalline properties. Their light-emission properties were examined by spectrofluorometry in both the solution and film states. Their quantum yields were also determined. Additionally, their morphologies in the thin-film states and melt-drawn fibers were examined with POM, scanning electron microscopy, and transmission electron microscopy techniques. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011

Several novel poly(pyridinium salt)s with heterocy- clic pyridine moieties in their backbones with tosylate and trifli- mide counterions were prepared by either ring-transmutation polymerization reaction of phenylated-bis(pyrylium tosylate) with isomeric pyridine diamines of 4-phenyl-2,6-bis(4-amino- phenyl)pyridine in dimethyl sulfoxide (DMSO) for 48 h at 130- 140 � C or by metathesis reaction of the respective tosylate polymers with lithium triflimide in DMSO at about 60 � C. Their chemical structures were characterized by FTIR, 1 H, 13 C NMR spectroscopy, and elemental analysis. Their number-average molecular weights (Mn) were in the range of 8,000-51,000 and their polydispersities in the range of 1.18-2.13 as determined by gel permeation chromatography. They had excellent ther- mal stabilities of 340-458 � C and high glass transition tempera- tures >200 � C. As they showed good solubilities in common organic solvents, their solution properties were also character- ized for their lyotropic liquid-crystalline properties with polariz- ing optical microscopy (POM) studies. Their photoluminescent properties were examined by using a spectrofluorometer in both solution and solid states. Their quantum yields were rather low, which were in the range of 1.3-2.0%. Additionally, hand-drawn fibers from the melts were examined to determine their morphologies with a number of microscopic techniques including POM, scanning electron microscopy, and transmis- sion electron microscopy. V C 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 4408-4418, 2010

Several poly(pyridinium salt)s containing various organic counterions and oxyethylene unit in their backbones were synthesized by either the ring-transmutation polymerization reaction of 4,4′-(1,4-phenylene)bis(2,6-diphenylpyrylium tosylate) with 1,2-bis(4-aminophenoxy)ethane on heating in dimethyl sulfoxide or the metathesis reaction of the tosylate polymer with the corresponding lithium or sodium salts in acetonitrile. Their chemical structures were determined by 1H and 13C NMR spectroscopy, and elemental analyses. Their number-average molecular weights and polydispersity indices were in the range of 59,000–63,000 and 1.41–1.65, respectively, as determined by gel permeation chromatography. They were characterized for their thermotropic and lyotropic liquid-crystalline properties by using differential scanning calorimetry and polarizing optical microscopy. Since these polymers exhibited liquid-crystalline phase both in the melt and in solutions, they belong to an amphotropic class of ionic polymers. Their light-emitting properties both in polar organic solvents and in films cast from methanol and acetonitrile were also studied by using spectrofluorometry.

The interaction of a main-chain viologen polymer containing bromide as counterions with water and aqueous potassium bromide over a broad range of concentrations was studied with isothermal titration calorimetry. The dilution process of this polymer was endothermic as opposed to flexible poly(sodium acrylate) and poly(sodium styrenesulfonate). This result may be related to the different mechanism of hydration of pyridinium and bromide groups in the main chain. It also exhibited aggregation phenomenon in both water and aqueous potassium bromide solutions as detected by transmission electron microscopy like other flexible and rigid-rod polyelectrolytes. As the polymer concentrations in aqueous solutions increase, the aggregated polymer exhibited more defined ordered structures than random structures observed at low polymer concentrations. Field emission scanning electron microscopy also revealed the effect of variation of concentration of aqueous potassium bromide on the morphology of the polymer matrix. At increasing concentrations of aqueous potassium bromide, the polymer structures became more ordered than those in low concentrations.

Several novel poly(pyridinium salt)s with oxyalkylene moieties in the main chain with bulky organic counterions (tosylate and triflimide) were prepared by either the ring-transmutation polymerization of phenylated bis(pyrylium tosylate) salt with a series of oxyalkylene containing diamines in dimethyl sulfoxide on heating for 48 h or the metathesis reaction of the corresponding tosylate polymers with lithium triflimide in methanol. Their chemical structures were determined by elemental analysis and 1H and 13C NMR spectroscopies, and their polyelectrolyte behavior in dimethyl sulfoxide was determined by solution viscosity measurements. Their weight average molecular weights were in the range 14,000–22,000 and polydispersity indices were in the range 1.20–1.70 as determined by gel permeation chromatography. They were characterized both for their thermotropic and lyotropic liquid–crystalline properties by using differential scanning calorimetry and polarizing optical microscopy. Since these polymers exhibited liquid–crystalline phase both in the melt and in solution, they can be appropriately classified as amphotropic class of ionic polymers. Their light-emitting properties were also determined by using spectrofluorometry.

A series of 4,4ʹ-dialkoxy-3,3ʹ-diaminobiphenyl compounds were synthesised by three-step procedure that involves alkylation, nitration and reduction reactions. Their chemical structures were characterised by FTIR, 1H and 13C spectroscopy and elemental analysis. Their thermotropic liquid–crystalline (LC) properties were examined by a number of experimental techniques including differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), polarising optical microscopy (POM) and variable temperature X-ray diffraction (VT-XRD). The 4,4ʹ-dialkoxy-3,3ʹ-dinitrobipheyl compounds, precursors to the diamine compounds, were also examined for their thermotropic LC properties. POM studies of focal conic textures and VT-XRD of the 3,3ʹ-diaminobiphenyl derivatives having flexible alkyl chains (C6–C12) exhibited the smectic A (SmA) phase independent of the length of alkyl chains. Similarly, the 3,3ʹ-dinitrobiphenyl derivatives containing alkyl chains C7, and C9–C11 exhibit the SmA phase, those containing C8 formed the smectic C (SmC) phase and C12 formed both the SmA and smectic B (SmB) phases, respectively. The 3,3ʹ-diaminobiphenyl derivatives had excellent thermal stability in the temperature range of 237–329°C, while those of 3,3ʹ-dinitrobiphenyl derivatives were in the temperature range of 270–321°C. The 3,3ʹ-diaminobiphenyl derivatives emitted UV light both in chloroform and acetonitrile.

A series of main chain, thermotropic, liquid crystalline (LC) hydrogen‐bonded polymers based on 4,4′‐bipyridyl as a hydrogen bond acceptor and 4,4′‐dicarboxy‐α,ω‐diphenoxyalkanes as hydrogen bond donors were prepared by a slow evaporation technique from a pyridine solution and characterized for their thermotropic LC properties using a variety of experimental techniques. The homopolymer of 4,4′‐bipyridyl with 4,4′‐dicarboxy‐1,9‐diphenoxynonane exhibited relatively low T m at 205°C and low T i at 230°C, giving an LC phase range of 25°C. The other two homopolymers with 4,4′‐dicarboxy‐1,6‐diphenoxyhexane and 4,4′‐dicarboxy‐1,9‐diphenoxydecane exhibited relative low T m values, above which each of them formed high‐order smectic phases. With further heating at higher temperature they transformed into low‐order smectic phases that persisted up to their decomposition temperatures. Several copolymers also had relatively low T m values as well as low T i values and, therefore, had a broad LC phase range (22–77°C). ...

Two poly(pyridinium salt)s with anthracene moieties in the main chain as well as tosylate and triflimide as counterions were prepared by either the ring-transmutation polymerization of phenylated bis(pyrylium tosylate) salt with 2,6-diaminoanthracene in dimethyl sulfoxide or the metathesis reaction of the corresponding tosylate polymer with lithium triflimide in acetonitrile. They were characterized for their lyotropic liquid-crystalline and UV light-emitting properties, with various experimental techniques. These ionic, conjugated anthracene polymers are the recent addition to the class of UV light-emitting polymers, since they emit UV light both in solution and in the solid state.

Two poly(pyridinium salt)s with bulky organic counterions (tosylate and triflimide) were synthesized by either the ring-transmutation polymerization reaction of 4,4‘-(1,4-phenylene)bis(2,6-diphenyl...

Two poly(pyridinium salt)s with bulky organic counterions (tosylate and triflimide) were synthesized by either the ring-transmutation polymerization reaction of 4,4'-(1,4-phenylene)bis(2,6-diphenylpyrylium tosylate) with 1,12-diaminododecane on heating in dimethyl sulfoxide (DMSO) at 145-150 °C for 24 h or the metathesis reaction of the corresponding tosylate polymer with lithium triflimide in a common organic solvent such as acetonitrile. Their polyelectrolyte behavior in DMSO was determined by solution viscosity measurements, and their chemical structures were determined by Fourier transform infrared and Fourier transform NMR spectroscopy. They were characterized for their thermotropic liquid-crystalline properties with a number of experimental techniques. Poly(pyridinium salt) with tosylate as a counterion had a crystal-to-smectic phase transition at 116 °C that persisted up to its decomposition temperature. The corresponding polymer with triflimide as a counterion had not only lower crystal-to-smectic phase transition at 80 °C but also a smectic-to-isotropic transition at about 180 °C. Both of these transitions were well below its decomposition temperature. It had better thermal stability than that of the corresponding tosylate polymer. Their fluorescence property in solutions of tetrahydrofuran and methanol as well as in the solid state was also included in this study.

Two dicationic salts with bis(triflimide) as counterions exhibited crystal-to-smectic liquid crystalline phase transitions (T m=41 and 37°C) and smectic-to-isotropic liquid phase transitions (T i=112, 136°C). They had a broad liquid crystalline phase range (71–99°C) and an excellent range of thermal stability (360–364°C). Their mixtures of various compositions also displayed liquid crystalline properties from r.t. to an extended range of temperatures. They exhibited fluorescence in 1, 2-dimethoxyethane and methanol.

A series of main-chain, thermotropic, liquid-crystalline (LC), hydrogen-bonded polymers or self-assembled structures based on 4,4'-bipyridyl as a hydrogen-bond acceptor and aliphatic dicarboxylic acids, such as adipic and sebacic acids, as hydrogen-bond donors were prepared by a slow evaporation technique from a pyridine solution and were characterized for their thermotropic, LC properties with a number of experimental techniques. The homopolymer of 4,4'-bipyridyl with adipic acid exhibited high-order and low-order smectic phases, and that with sebacic acid exhibited only a high-order smectic phase. Like the homopolymer with adipic acid, the two copolymers of 4,4'-bipyridyl with adipic and sebacic acids (75/25 and 25/75) also exhibited two types of smectic phases. In contrast, the copolymer of 4,4'-bipyridyl with adipic and sebacic acids (50/50), like the homopolymer with sebacic acid, exhibited only one high-order smectic phase. Each of them, including the copolymers, had a broad temperature range of LC phases (36-51 °C). The effect of copolymerization for these hydrogen-bonded polymers on the thermotropic properties was examined. Generally, copolymerization increased the temperature range of LC phases for these polymers, as expected, with a larger decrease in the crystal-to-LC transition than in the LC-to-isotropic transition. Additionally, it neither suppressed the formation of smectic phases nor promoted the formation of a nematic phase in these hydrogen-bonded polymers, as usually observed in many thermotropic LC polymers. The thermal transitions for all of them, measured by differential scanning calorimetry, were well below their decomposition temperatures, as measured by thermogravimetric analysis, which were in the temperature range of 193-210 °C.

A poly(pyridinium salt) was synthesized from 4,4′-(1,4-phenylene)bis(2,6-diphenylpyrilium)tosylate and 3,3′-dimethylnaphthidine. Tosylate counterion was exchanged with other organic counterions such as triflimide, 1-napthalenesulfonate, and 2-napthalenesulfonate in DMSO to yield a total of four poly(pyridinium salt)s. Their chemical structures were established by using various spectroscopic techniques. Gel permeation chromatography showed that their number-average molecular weights (Mn) were in the range of 56–76 kg/mol and polydispersities in the range of 1.09–1.32. Their thermal stabilities ranged from 290 to 425 °C, under nitrogen atmosphere. Even though these polymers didn’t show thermotropic liquid crystalline phases, counterion-dependent lyotropic liquid-crystalline phase were observed in some polar aprotic solvents above their critical concentrations. Each of these polymers emitted green light (500–572 nm) both in solutions and solid states as observed by UV–vis and photoluminescent spectroscopies.

The solution-phase behavior of three main-chain viologen polymers, which are composed of isomeric xylyl units and triflimide as a counterion, was studied in methanol, dimethylformamide, acetonitrile, and dimethyl sulfoxide as solvents microscopically under crossed polarizers. Each of them exhibited a lyotropic lamellar phase in both polar protic and aprotic solvents. Their C* for the formation of biphasic solutions (1-5 wt %) and concentrations (20-30 wt %) for the lyotropic solutions in methanol was much lower than those in polar aprotic solvents (20-71 and 60-81 wt %, respectively). Their high solubility, high C* for the formation of biphasic solutions, and high concentrations for the formation of lyotropic solutions in polar aprotic solvents were related to the significant reduction of strong ionic interactions between triflimide and 4,4'-bipyridinium ions in each of these viologen polymers. They were the first examples of viologen polymers that exhibited a lyotropic phase in polar aprotic solvents.

A series of viologen polymers with bromide, tosylate, and triflimide as counterions were prepared by either the Menshutkin reaction or metathesis reaction in a common organic solvent. Their polyelectrolyte behavior in methanol was determined by solution viscosity measurements, and their chemical structures were determined by Fourier transform infrared and Fourier transform NMR spectroscopy. They were characterized for their thermotropic liquid-crystalline properties with a number of experimental techniques. Each of the viologen polymers with organic counterions had a low melting transition or fusion temperature above which it formed either a high-order smectic phase or a low-order smectic phase. Each of them also exhibited a smectic-to-isotropic transition. The ranges of the liquid-crystalline phase were 80–88 °C for viologen polymers with tosylate as a counterion and 120–146 °C for viologen polymers with triflimide as a counterion. They had excellent thermal stability. The ranges of thermal stability were 288–329 °C for viologen polymers with tosylate as a counterion and 343–350 °C for viologen polymers with triflimide as a counterion. The fluorescence property for all of the viologen polymers in either aqueous or methanol solution was also included in this study. For example, the viologen polymer containing the 4,4′-bipyridinium and p-xylyl units along the backbone of the polymer chain with triflimide as a counterion had an absorption spectrum (λmax = 265 nm), an excitation spectrum (λex values = 357, 443, and 454 with monitoring at 533 nm), and an emission spectrum (λem = 536 nm with excitation at 430 and 450 nm) in methanol. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 659–674, 2002; DOI 10.1002/pola.10134

A series of viologen polymers based on 4,4'-bipyridyl and the ditosylates of trans-1,4-cyclohexanedimethanol and 1,8-octanediol was prepared by the quaternization reaction in acetonitrile. Their polyelectrolyte behavior in a common organic solvent was studied by viscosity measurements, and their chemical structures were determined by FTIR and 1D and 2D NMR spectroscopies. They were characterized for their lyotropic properties in a number of polar organic solvents by polarizing light microscopy and differential scanning calorimetry and for their photochromic properties by UV-vis spectroscopy. As expected, their inherent viscosity in methanol decreased dramatically with the increase in concentration in the absence of an added electrolyte. Although each of these polymers contained the ionic group along the backbone of the polymer chain, there was an array of weak ion-pair dipoles between the tosylate ion and the 4,4'-bipyridinium ion in each of them, which was indicated by the appearance of symmetric stretching band of S=O at a lower frequency (1034 cm -1 ) when compared with that of -SO 3 Na (1064 cm -1 ) in its IR spectrum. The aromatic protons of 4,4'-bipyridinium ion in each of these polymers exhibited three pairs of signals as opposed to a pair of doublets that generally occurs in small molecules containing this ion. These three pairs of signals were related to the structure and dynamics of these ionic polymers in a polar solvent such as methanol, which were studied by DEPT, 1 H- 1 H COSY, and NOESY spectroscopies. Each of them showed a lyotropic lamellar phase in methanol, ethanol, ethylene glycol, diethylene glycol, glycerine, and benzyl alcohol. Their critical concentrations (C * values) were as low as 5 wt % and as high as 20-40 wt %, and their concentrations for the development of fully grown lyotropic phase were as low as 10-20 wt % and as high as 40-50 wt % in various alcohols depending on the polarity of the solvents, the hydrophilicity and hydrophobicity of the solvents, and the microstructures of these polymers. Additionally, their lyotropic solutions in either glycerine or benzyl alcohol, on irradiation with UV light, produced a deep blue color in the presence of air, but in absence of both a photosensitizer and a sacrificial donor. This deep blue solution had two absorption bands at 390 and 608 nm, which are the characteristic absorption bands of the viologen cation radical. The generation of this blue color occurred due to the photoreduction of the 4,4'-bipyridinium moiety via the electron transfer from the tosylate counterion.

A series of wholly aromatic, thermotropic polyesters, derived from 3,3′-bis(phenyl)-4,4′-biphenol (DPBP), nonlinear 4,4′-benzophenone dicarboxylic acid (4,4′-BDA), and various linear comonomers, were prepared by the melt polycondensation reaction and characterized for their thermotropic properties by a variety of experimental techniques. The homopolymer of DPBP with 4,4′-BDA had a fusion temperature (Tf) at 265°C, exhibited a nematic phase, and had a liquid crystalline range of 105°C. All of the copolyesters of DPBP with 4,4′-BDA and either 30 mol % 4-hydroxybenzoic acid (HBA), 6-hydroxy-2-naphthoic acid (HNA), or 50 mol % terephthalic acid (TA), 2,6-naphthalenedicarboxylic acid (2,6-NDA) had low Tf values in the range of 220–285°C, exhibited a nematic phase, and had accessible isotropization transitions (Ti) in the range of 270–420°C, respectively. Their accessible Ti values would enable one to observe a biphase structure. Each of the copolymers with HBA or HNA had a much broader range of liquid crystalline phase. In contrast, each of the copolymers with TA or 2,6-NDA had a relatively narrow range of liquid crystalline phase. Each of these polyesters had a glassy, nematic morphology that was confirmed with the DSC, PLM, WAXD, and SEM studies. As expected, they had higher glass transition temperatures (Tg) in the range of 161–217°C than those of other liquid crystalline polyesters, and excellent thermal stabilities (Td) in the range of 494–517°C, respectively. Despite their noncrystallinity, they were not soluble in common organic solvents with the exception that the homopolymer and its copolymer with TA had limited solubility in CHCl3. However, they were soluble in the usual mixture of p-chlorophenol/1,1,2,2-tetrachloroethane (60/40 by weight) with the exception of the copolymer with 2,6-NDA. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35: 769–785, 1997

A series of [Pt(II)Cl2(4,4'-dialkoxy-2,2'-bipyridine)] complexes of the general formula of [Pt(II)Cl2(4,4'-bis(RO)-2,2'-bipyridine)] (where R = -(CH2)n-1CH3, n = 2-6, 8) were synthesized and characterized using (1)H NMR, (13)C NMR spectroscopy, elemental analysis, mass spectroscopy, and differential scanning calorimetry measurements. The in vitro anti-proliferative activities of these compounds were evaluated against human cancer cell lines A549 (lung adenocarcinoma), DU145 (prostate carcinoma), MCF-7 (breast adenocarcinoma), and MDA-MB-435 (melanoma) using the MTS cell proliferation assay. Several Pt(II) coordination compounds were found to have greatly enhanced activity compared to cisplatin after a one hour treatment in all cell lines tested. A structure-activity relationship was observed, that is, the activity increases as the carbon chain length of the alkyl group increases. The activity was maximum when the carbon chain length reached four or five carbons and decreased with the longer carbon chain length. Fluorescence microscopy and flow cytometry data indicate that the main mode of cell death is through apoptosis with some necrotic responses.

Wholly aromatic, thermotropic homopolyesters, derived from 4,4′-biphenol, substituted biphenols, or 1,1′-binaphthyl-4,4′-diol and 3,4′-benzophenone dicarboxylic acid, and two copolyesters, each of which contained 30 mol % of 6-hydroxy-2-naphthoic acid, were prepared by acidolysis polycondensation reactions and characterized for their liquid crystalline properties. The solubility behavior of these polymers has also been investigated. The two homopolymers of phenyl-substituted biphenols with 3,4′-benzophenone dicarboxylic acid were soluble in many common organic solvents. All of the homopolymers had lower Tm/Tf values than those with terephthalic acid, which was attributed to the incorporation of the asymmetric 3,4′-benzophenone dicarboxylate units in a head-to-head and head-to-tail fashion along the polyester chain. Two copolymers had lower Tm values than those of the respective homopolymers, as expected. They formed nematic phases which persisted up to 400°C, except those of phenyl-substituted biphenols with 3,4′-benzophenone dicarboxylic acid. Each of these two polymers also exhibited an accessible Ti transition, and had a broad range of LC phase. They had glass transition temperatures, Tg, in the range of 139-209°C and high thermal stabilities in the temperature range of 465-511°C. © 1995 John Wiley & Sons, Inc.

A series of viologen polymers based on 4,4‘-bipyridyl and the ditosylates of trans-1,4-cyclohexanedimethanol and 1,8-octanediol was prepared by the quaternization reaction in acetonitrile. Their polyelectrolyte behavior in a common organic solvent was studied by viscosity measurements, and their chemical structures were determined by FTIR and 1D and 2D NMR spectroscopies. They were characterized for their lyotropic properties in a number of polar organic solvents by polarizing light microscopy and differential scanning calorimetry and for their photochromic properties by UV−vis spectroscopy. As expected, their inherent viscosity in methanol decreased dramatically with the increase in concentration in the absence of an added electrolyte. Although each of these polymers contained the ionic group along the backbone of the polymer chain, there was an array of weak ion-pair dipoles between the tosylate ion and the 4,4‘-bipyridinium ion in each of them, which was indicated by the appearance of symmetric stretch...

A series of fully aromatic, thermotropic homopolyesters, derived from 3,4'-benzophenone dicarboxylic acid and various aromatic diols, was prepared by the melt polycondensation method. The aromatic diols used in the study were hydroquinone, 2,6-, 1,4-, 1,5-, 2,3-, and 2,7-naphthalenediol isomers. All of the homopolyesters of 3,4'-benzophenone dicarboxylic acid with aromatic diols (except that with 2,7-naphthalenediol) formed a nematic LC phase in the melt. They had the T g 's in the range of 133-164°C, the melting transitions (T m ) in the range 305-360°C and the high thermal stabilities (T d ) in the range of 410-483°C

Fully aromatic, thermotropic homopolyesters, derived from either phenyl-substituted 4,4'-biphenols or 1,1'-binaphthyl-4,4'-dioland 2-bromoterephthalic acid or 2-phenylterephthalic acid, were prepared by acidolysis condensation polymerization reactions. The two homopolymers of substituted biphenols with 2-phenylterephthalic acid were soluble in common organic solvents. All of the polymers had lower T m /T f values than those of respective unsubstituted homopolymers, as expected, and formed nematic LC phases which persisted up to 400°C

Two poly(pyridinium salt)s containing a bulky organic counterion such as 2-naphthalenesulfonate were synthesized by the ring-transmutation polymerization reaction of bis(pyrylium 2-naphthalenesulfonate) with the corresponding aromatic diamines on heating in dimethyl sulfoxide (DMSO) at 145–150 °C for 24 h, and characterized for their lyotropic liquid crystalline as well as fluorescence properties in both polar protic and aprotic solvents such as methanol and DMSO. Their polyelectrolyte behavior in DMSO was also determined by solution viscosity measurements.

Several poly(pyridinium salt)s containing various organic counterions and tetraoxyethylene units in their backbones were synthesized by either ring-transmutation polymerization reaction of 4,4'-(1,4-phenylene)bis(2,6-diphenylpyrylium tosylate) with bis(2-(2-(4-aminophenoxy)ethoxy)ethyl) ether on heating in dimethyl sulfoxide or metathesis reaction of the tosylate polymer with the corresponding lithium or sodium salts in acetonitrile. Their chemical structures were determined by 1H-NMR and 13C-NMR spectroscopy, and elemental analyses. Their number-average molecular weights and polydispersity indices were in the range of 34,000–52,000 and 1.14–1.38, respectively, as determined by gel permeation chromatography. They were characterized both for their thermotropic and lyotropic liquid-crystalline properties by using differential scanning calorimetry and polarizing optical microscopy. As these polymers exhibited liquid-crystalline phase both in the melt and in solutions, they are classified as an amphotropic class of ionic polymers. Their light-emitting properties in a large number of organic solvents that ranged from nonpolar to polar solvents and in films cast from methanol and acetonitrile were also studied by using spectrofluorometry. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010

Dispersion of single-walled carbon nanotubes (SWNTs) with poly(pyridinium salt)s via non-covalent interactions in DMSO is demonstrated. The resulting composites display high quenching efficiency in the photoluminescent properties of this class of ionic polymers, and TEM study shows that SWNTs are wrapped by ionic polymers with thickness around 3 nm.

Compounds bearing electrostatic charges have unique properties including outstanding ionic-conductivity when compared with neutral ones. On the other hand, amorphous molecular materials harness the advantages of small molecules with high purity, defined structures and monodispersity, while still being easily processable into thin films and fibers. Here, we report a series of bis(pyridinium salt)s that combine these properties to form ionic amorphous molecular materials. Their design allowed them to vitrify efficiently upon slow cooling. They exhibited glass-transition temperatures in the range of 81–191 °C and had excellent thermal stabilities of up to 461 °C. Fibers were easily drawn from their melts that were visible to the naked eye. Although they were completely conjugated and had large molecular sizes, they were soluble in many common organic solvents. Additionally, they fluoresced blue and green light in both solution and solid states. They could be useful for high-performance applications in opto- and microelectronic fields, among others.

Several novel poly(pyridinium salt)s with heterocyclic bisquinoline moieties having both tosylate and triflimide counterions were prepared by either ring-transmutation or metathesis reaction. Their chemical structures were established by using 1H and 13C NMR, FTIR and elemental analysis. Their number-average molecular weights (Mn) ranged from 53,000 to 79,000 and their polydispersities ranged from 1.30 to 3.24 as determined by gel permeation chromatography. They had excellent thermal stabilities in the temperature range of 336–447 °C and glass transition temperatures in the range of 119–174 °C. They had good solubilities in common organic solvents and in several cases their critical concentrations (*C) were exceeded to form lyotropic liquid-crystalline phases. Additionally, they emitted light in the blue and green region in both solution and solid state. Their quantum yields were also determined by using a spectrofluorometer.