Synthesis,chemical, and thermoelectric properties of n‐type π‐conjugated polymer composed of 1,2,4‐triazole and pyridine rings and its metal complexes

A soluble n‐type π‐conjugated polymer ( polymer 1 ) composed of a 1,2,4‐triazole ring substituted by a 4‐n‐octylphenyl subunit at the 4‐position of the 1,2,4‐triazole ring and pyridine‐2,5‐diyl rings was synthesized by Ni(cod)₂ (cod = 1,5‐cyclooctadiene) promoted dehalogenation polycondensation of 3,5‐bis(2‐bromopyridyl)‐4‐n‐octylphenyl‐1,2,4‐triazole ( monomer 1 ). A polymer complex ( polymer‐BiCl₃ ) was synthesized by the reaction of polymer 1 with BiCl₃. The UV–vis spectrum of polymer 1 exhibited an absorption maximum (λ_max value) at a longer wavelength than that exhibited by monomer 1 revealing that its π‐conjugation system was expanded along the polymer chain. Polymer 1 was electrochemically active in film, and the electrochemical reaction was accompanied with electrochromism. Thermoelectoric properties of polymer 1 and polymer‐BiCl₃ were investigated. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 39928.     

Ionic polymers with expanded π‐conjugation systems derived from through‐space interaction in piperazinium and homopiperazinium rings

Reactions of N‐(2,4‐dinitrophenyl)‐4‐arylpyridinium chlorides (aryl (Ar) = phenyl and 4‐biphenyl) with piperazine or homopiperazine caused opening of the pyridinium ring and yielded polymers that consisted of 5‐piperazinium‐3‐arylpenta‐2,4‐dienylideneammonium chloride (? N(CH₂CH₂)₂N⁺ (Cl^?)?CH? CH?C(Ar)? CH?CH? ) or 5‐homopiperazinium‐3‐arylpenta‐2,4‐dienylideneammonium chloride (? N(CH₂CH₂CH₂)(CH₂CH₂)N⁺ (Cl^?)?CH? CH?C(Ar)? CH?CH? ) units. ¹H NMR spectral analysis suggested that the π‐electrons of the penta‐2,4‐dienylideneammonium group of the polymers were delocalized. UV‐visible spectral measurements revealed that the π‐conjugation system expanded along the polymer chains because of the orbital interaction between electrons of the two nitrogen atoms of the piperazinium and homopiperazinium rings. However, the π‐conjugation length depended on the distance between the two nitrogen atoms; that is, the polymers containing the piperazinium ring had a longer π‐conjugation length than those containing the homopiperazinium ring. Conversion of the piperazinium and homopiperazinium rings from the boat to the chair form led to a decrease in the π‐conjugation length. The surface of pellets that were molded from the polymers exhibited metallic luster, and these polymers underwent electrochemical oxidation in solution. Copyright © 2010 Society of Chemical Industry     

Metal‐chloride‐anion‐containing polymers with expanded π‐conjugation systems derived from through‐space interactions in the piperazinium ring

Reactions of N‐(2,4‐dinitrophenyl)pyridinium chloride (salt(Cl)) with H⁺MCl₄^?1 (M ≡ Fe and Bi) resulted in an anion exchange between Cl^? and MCl₄^? to yield Zincke salts with metal chloride anions, namely salt(Fe) and salt(Bi), respectively. Reactions of the Zincke salts with piperazine resulted in ring‐opening of the pyridinium ring, yielding ionic polymers with 5‐piperazinium‐2,4‐dienylideneammonium metal chloride units, namely polymer(Fe) and polymer(Bi). The corresponding model compounds were synthesized via reactions using salt(Bi) or salt(Cl) as starting materials. The UV–visible spectra of the polymers had absorption maxima at longer wavelengths than those of the model compounds. This indicated that the π‐conjugation system is expanded along the polymer main chain. Superconducting quantum interference device measurements indicated that polymer(Fe) was paramagnetic. Cyclic voltammetry analysis suggested that the polymers underwent electrochemical oxidation. © 2019 Society of Chemical Industry     

Synthesis,extraction, and anti‐bacterial studies of some new bis‐1,2,4‐triazole derivatives part I

A series of new bis triazole Schiff base derivatives (4) were prepared in good yields by treatment of 4‐amino‐3,5‐diphenyl‐4H‐1,2,4‐triazole (3) with bisaldehydes (1). Schiff bases (4) were reduced with NaBH₄ to afford the corresponding bisaminotriazoles (5). All the new compounds were characterized by IR, ¹H NMR and ¹³C NMR spectral data. Their overall extraction (log K_ex) constants for 1 : 1 (M : L) complexes and CHCl₃/H₂O systems were determined at 25 ± 0.1°C to investigate the relationship between structure and selectivity toward various metal cations. The extraction equilibrium constants were estimated using CHCl₃/H₂O membrane transfer with inductively coupled plasma‐atomic emission spectroscopy spectroscopy. The stability sequence of the triazole derivatives in CHCl₃ for the metal cations was exhibited a characteristic preference order of extractability to metal ions [Fe(III) > Cu(II) > Pb(II) > Co(II) > Ni(II) > Mn(II) > Zn(II) > Mg(II) > Ca(II)]. The compounds were tested for anti‐microbial activity applying agar diffusion technique for 11 bacteria. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Optical and electrochemical properties of oligo(1,5‐dialkoxynaphthalene‐2,6‐diyl)s with self‐assembled ordered structures in solid state

Oligo(1,5‐dialkoxynaphthalene‐2,6‐diyl)s were synthesized by Ni(cod)₂ (cod = 1,5‐cyclooctadiene)‐promoted condensation reactions of 1,5‐dialkoxy‐2,6‐dibromonaphthalenes. The UV–Vis, photoluminescence (PL), and powder X‐ray diffraction (XRD) measurements suggested that the oligomers have a self‐assembling ordered structure in the solid state. The oligomers underwent electrochemical oxidation (p‐doping), which occurred at lower potentials for films than for acetonitrile solutions containing [Et₄N]BF₄. This effect is caused by the longer π‐conjugation lengths of the oligomers in films, which was attributed to molecular self‐assembly leading to ordered structures in the solid state. The electrochemical reaction of the oligomers was accompanied by electrochromism. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41840.     

Polymerization of 4‐(4′‐N‐1,8‐naphthalimidophenyl)‐1,2,4‐triazolidine‐3,5‐dione with diisocyanates

4‐(4′‐Aminophenyl)‐1,2,4‐triazolidine‐3,5‐dione ( 1 ) was reacted with 1,8‐naphthalic anhydride ( 2 ) in a mixture of acetic acid and pyridine (3 : 2) under refluxing temperature and gave 4‐(4′‐N‐1,8‐naphthalimidophenyl)‐1,2,4‐triazolidine‐3,5‐dione ( NIPTD ) ( 3 ) in high yield and purity. The compound NIPTD was reacted with excess n‐propylisocyanate in N,N‐dimethylacetamide solution and gave 1‐(n‐propylamidocarbonyl)‐4‐[4′‐(1,8‐naphthalimidophenyl)]‐1,2,4‐triazolidine‐3,5‐dione ( 4 ) and 1,2‐bis(n‐propylamidocarbonyl)‐4‐[4′‐(1,8‐naphthalimidophenyl)]‐1,2,4‐ triazolidine‐3,5‐dione ( 5 ) as model compounds. Solution polycondensation reactions of monomer 3 with hexamethylene diisocyanate ( HMDI ), isophorone diisocyanate ( IPDI ), and tolylene‐2,4‐diisocyanate ( TDI ) were performed under microwave irradiation and conventional solution polymerization techniques in different solvents and in the presence of different catalysts, which led to the formation of novel aliphatic‐aromatic polyureas. The polycondensation proceeded rapidly, compared with conventional solution polycondensation, and was almost completed within 8 min. These novel polyureas have inherent viscosities in a range of 0.06–0.20 dL g^?1 in conc. H₂SO₄ or DMF at 25°C. Some structural characterization and physical properties of these novel polymers are reported. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2861–2869, 2003     

Synthesis of 1,2,4‐Triazoles,N‐Fused 1,2,4‐Triazoles and 1,2,4‐Oxadiazoles via Molybdenum Hexacarbonyl‐Mediated Carbonylation of Aryl Iodides

A convenient and efficient protocol has been developed for the synthesis of 1,2,4‐triazoles, N‐fused 1,2,4‐triazoles and 1,2,4‐oxadiazoles using molybdenum hexacarbonyl where, for the first time, molybdenum hexacarbonyl acts as a convenient and reliable solid source of carbon monoxide. This procedure provides an easy access to a library of 1,2,4‐triazole, N‐fused 1,2,4‐triazole and 1,2,4‐oxadiazole derivatives in fair to good yields without the need of gaseous carbon monoxide and palladium catalysts.

     

Synthesis and Characterization of 3,4,5‐Triamino‐1,2,4‐Triazolium 5‐Nitrotetrazolate

3,4,5‐Triamino‐1,2,4‐triazolium 5‐nitrotetrazolate ( 2 ) was synthesized in high yield from 3,4,5‐triamino‐1,2,4‐triazole (guanazine) ( 1 ) and ammonium 5‐nitrotetrazolate. The new compound 2 was characterized by vibrational (IR and Raman) and multinuclear NMR spectroscopy (¹H, ¹³C, ¹⁵N), elemental analysis and single crystal X‐ray diffraction (triclinic, P(‐1), a=0.7194(5), b=0.8215(5), c=0.8668(5) nm, α=75.307(5), β=70.054(5), γ=68.104(5)°, V=0.4421(5) nm³, Z=2, ϱ=1.722 g cm⁻¹, R₁=0.0519 [F>4σ(F)], wR₂(all data)=0.1154). The ¹⁵N NMR spectrum and X‐ray crystal structure (triclinic, P‐1, a=0.5578(5), b=0.6166(5), c=0.7395(5) nm, α=114.485(5)°, β=90.810(5)°, γ=97.846(5)°, V=0.2286(3) nm³, Z=2, ϱ=1.658 g cm⁻¹, R₁=0.0460 [F>4σ(F)], wR₂(all data)=0.1153) of 1 were also determined.     

Photodegradation mechanism and stabilization of polyphenylene oxide and rigid‐rod polymers

Poly(2,4‐dimethyl‐1,4‐phenylene oxide) (PPO), poly(benzo[1,2‐d:5,4‐d′]bisoxazole‐2,6‐diyl‐1,4‐phenylene) (PBO) and poly(benzo[1,2‐d:4,5‐d′]bisthiazole‐2,6‐diyl‐1,4‐phenylene) (PBZT), which are polymers with extended conjugated structures, undergo a self‐sensitized photo‐induced electron‐transfer reaction. A second component is not required. This article presents many similar observations on these polymers when they are exposed to light and evidence to support the proposed photo‐induced electron‐transfer mechanism. Methods to stabilize these polymers against photo‐oxidation are also described. Workers investigating other conjugated polymeric systems may find the experimental methods, observations and polymer stabilization approaches discussed in this review useful. Copyright © 2005 Society of Chemical Industry     

Synthesis and proton conductivity studies of methacrylate/methacrylamide‐based azole functional novel polymer electrolytes

Anhydrous polymer electrolytes based on azole functional methacrylates and methacrylamides have been produced for use in proton exchange membrane fuel cells (PEMFCs). Poly(methacryloyl chloride) (PMAC) was prepared first by free‐radical polymerization of methacryloyl chloride, followed by side chain functionalization with 5‐aminotetrazole (ATet), 3‐amino‐1,2,4‐triazole (ATri) and 1H‐1,2,4‐triazole (Tri). Finally, the obtained polymers were doped with triflic acid (TA) at stoichometric ratios of 1.0, 2.0 and 4.0 with respect to azole units, and the anhydrous polymer electrolytes were obtained. The membranes were characterized by FT‐IR, ¹³C‐NMR, and elemental analysis. Thermal behaviour of polymers was explored by TGA and DSC. The samples were thermally stable up to approximately 200 ^oC. Proton conductivity was measured by impedance spectroscopy. Trifilic acid doped poly(methacryloyl aminotetrazole) (PMAATet‐(TA)₄), poly(methacryloyl‐3‐amino‐1,2,4‐triazole) (PMA‐Tri‐(TA)₄), and poly(methacryloyl‐1,2,4‐triazole) (PMA‐ATri‐(TA)₄) showed maximum proton conductivities of 0.01 Scm^?1, 0.02 Scm^?1 and 8.7x10^?4 Scm^?1, respectively, at 150^°C and anhydrous conditions. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 39915.     

Synthesis and characterization of poly(ester‐ether‐imide)s derived from 5‐(4‐trimellitimidophenoxy)‐1‐trimellitimido naphthalene

A series of novel aromatic poly(ester‐ether‐imide)s with inherent viscosity values of 0.44–0.74 dL g^?1 were prepared by the diphenylchlorophosphate‐activated direct polycondensation of an imide ring‐containing diacid namely 5‐(4‐trimellitimidophenoxy)‐1‐trimellitimido naphthalene ( 1 ) with various aromatic dihydroxy compounds in the presence of pyridine and lithium chloride. Owing to comparison of the characterization data, an ester‐containing model compound ( 2 ) was also synthesized by the reaction of 1 with phenol. The model compound 2 and the resulted polymers were fully characterized by FT‐IR and NMR spectroscopy. The ultraviolet λ_max values of the poly(ester‐ether‐imide)s were also determined. The resulting polymers exhibited an excellent organosolubility in a variety of high polar solvents such as N,N‐dimethylacetamide, N,N‐dimethylformamide, dimethyl sulfoxide, and N‐methyl‐2‐pyrrolidone. They were soluble even in common less polar organic solvents such as pyridine, m‐cresol, and tetrahydrofuran on heating. Crystallinity of the polymers was estimated by means of wide‐angle X‐ray diffraction. The resulted polymers exhibited nearly an amorphous nature. From differential scanning calorimetry thermograms, the polymers showed glass‐transition temperatures between 221 and 245°C. Thermal behaviors of the obtained polymers were characterized by thermogravimetric analysis, and the 10% weight loss temperatures of the poly(ester‐ether‐imide)s were found to be over 410°C in nitrogen. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Synthesis and characterization of poly[(1‐vinyl‐1,2,4‐triazole)‐co‐(monomer with carboxylic acid group(s))] and determination of monomer reactivity ratios: I. Acrylic acid

Copolymers of 1‐vinyl‐1,2,4‐triazole (VTAz) and acrylic acid (AA) having different mole ratios were synthesized using free radical‐initiated solution polymerization in dimethylformamide at 70 °C with α,α′‐azobisisobutyronitrile as initiator in nitrogen atmosphere. The compositions of the synthesized copolymers for a wide range of monomer feeds were determined using Fourier transform infrared (FTIR) spectroscopy through recorded absorption bands for VTAz (1510 cm^?1, C?N (triazole ring) stretching mode) and AA (1710 cm^?1, C?O stretching mode) units. The structures of the copolymers were characterized using FTIR and ¹H NMR spectroscopy. The copolymer compositions were also determined from ¹H NMR analysis following proton signals of carboxyl group at 11.8–12.5 ppm of AA and of triazole ring at 7.5–8.1 ppm of VTAz. Monomer reactivity ratios for the VTAz‐AA pair were estimated using linear methods, i.e. Fineman–Ross (FR) and Kelen–Tüdös (KT). From FTIR evaluation, monomer reactivity ratios were calculated as r₁ = 0.404 and r₂ = 1.496 using the FR method and r₁ = 0.418 and r₂ = 1.559 using the KT method. These values were found to be very close to those obtained from NMR evaluation. The two cases r₁r₂ < 1 and r₁ < r₂ indicated the random distribution of the monomers in the final copolymers and the presence of a greater amount of AA units in the copolymer than in the feed, respectively. The observed relatively high activity of complexed growing radical‐AA^? … VTAz was explained by the effect of complex formation between carbonyl groups and triazole fragments in chain growth reactions. Thermal behaviours of copolymers with various compositions were investigated using thermogravimetric and differential scanning calorimetric analyses. It was observed that thermal stabilities and glass transition temperatures of the copolymers increased resulting from complex formation between acid and triazole units. © 2012 Society of Chemical Industry     

Dinitrophenyl Triazoles – “A Class of Energetic Azoles”: Synthesis,Characterisation, and Performance Evaluation Studies

Energetic azoles have shown great potential as powerful energetic molecules, which find various applications in both military and civilian fields. This work describes the synthesis, characterization and performance evaluation of two energetic triazole derivatives, viz. N‐(2,4‐dinitrophenyl)‐3‐nitro‐1H‐1,2,4‐triazole ( 1a ) and N‐(2,4‐dinitrophenyl)‐3‐azido‐1H‐1,2,4‐triazole ( 1b ). The compounds were synthesized from 3‐nitro‐1,2,4‐triazole and 3‐azido‐1,2,4‐triazole, by a simple synthetic route and structurally characterized using FT‐IR and NMR (¹H, ¹³C) spectroscopy as well as elemental analysis. Thermal analyses on the molecules were performed using simultaneous TG‐DTA. Both compounds ( 1a , 1b ) showed good thermal stability with exothermic decomposition peaks at 348 °C and 217 °C, respectively, on DTA. The energetic and sensitivity properties of both compounds like friction sensitivities and heats of formation are reported. The heats of combustion at constant volume were determined using oxygen bomb calorimetry and the results were used to calculate the standard molar heats of formation (Δ_fH^m). The azido derivative ( 1b ) showed a higher positive heat of formation. The thermo‐chemical properties of the compounds as well as the thermal decomposition products were predicted using the REAL thermodynamic code.     

Synthesis and Characterization of New Aromatic Polyamides with N,N′‐Di(4‐n‐alkylphenyl)benzodiimide Unit on the Main Chain

Summary: New aromatic polyamides containing two n‐alkylphenylimide units fused to the main chain were prepared by the activated polyamidation of 3,6‐di(4‐carboxyphenyl)‐N,N′‐di(4‐n‐alkylphenyl)pyromellitimides ( C _m DA , m = 0, 8, 12, 16) with oxy‐4,4′‐dianiline in a mixture of N‐methylpyrrolidone and pyridine (Py) in the presence of triphenyl phosphite and CaCl₂. The imide‐containing dicarboxylic acid monomers were synthesized by the imidization of 3,6‐di(4‐carboxyphenyl)pyromellitic dianhydride with 4‐n‐alkylanilines. The polymers showed both enhanced thermal stability and excellent solubility due to the presence of thermally stable pendent imido groups and internally plasticizing n‐alkyl chains. Their glass transition temperatures were between 225 and 285 °C and decreased with increasing side chain length. Wide‐angle X‐ray diffraction investigations revealed that all the polymers are amorphous and have typical layered structures formed by n‐alkyl side chains.

     

Synthesis and properties of new aromatic poly(ester‐imide)s derived from 4‐p‐biphenyl‐2,6‐bis(4‐trimellitimidophenyl) pyridine and various dihydroxy compounds

A novel class of wholly aromatic poly(ester‐imide)s, having a biphenylene pendant group, with inherent viscosities of 0.32–0.49 dL g^?1 was prepared by the diphenylchlorophosphate‐activated direct polyesterification of the preformed imide‐ring‐containing diacid, 4‐p‐biphenyl‐2,6‐bis(4‐trimellitimidophenyl)pyridine (1) with various aromatic dihydroxy compounds in the presence of pyridine and lithium chloride. A reference diacid, 2,6‐bis(trimellitimido)pyridine (2) without a biphenylene pendant group and two phenylene rings in the backbone, was also synthesized for comparison purposes. At first, with due attention to structural similarity and to compare the characterization data, a model compound (3) was synthesized by the reaction of compound 1 with two mole equivalents of phenol. Moreover, the optimum condition of polymerization reactions was obtained via a study of the model compound synthesis. All of the resulting polymers were characterized by Fourier transform infrared and ¹H NMR spectroscopy and elemental analysis. The ultraviolet λ_max values of the poly(ester‐imide)s were also determined. All of the resulting polymers exhibited excellent solubility in common organic solvents, such as pyridine, chloroform, tetrahydrofuran, and m‐cresol, as well as in polar organic solvents, such as N‐methyl‐2‐pyrrolidone, N,N‐dimethylacetamide, N,N‐dimethylformamide, and dimethyl sulfoxide. The crystalline nature of the polymers obtained was evaluated by means of wide‐angle X‐ray diffraction. The resulting poly(ester‐imide)s showed nearly an amorphous nature, except poly(ester‐imide) derived from 4,4′‐dihydroxy biphenyl. The glass transition temperatures (T_g) of the polymers determined by differential scanning calorimetry thermograms were in the range 298–342 °C. The 10% weight loss temperatures (T_10%) from thermogravimetric analysis curves were found to be in the range 433–471 °C in nitrogen. Films of the polymers were also prepared by casting the solutions. Copyright © 2006 Society of Chemical Industry     

Synthesis and spectroelectrochemistry of dithieno(3,2‐b:2′,3′‐d)pyrrole derivatives

New π‐conjugated polymers containing dithieno(3,2‐b:2′,3′‐d)pyrrole (DTP) were successfully synthesized via electropolymerization. The effect of structural differences on the electrochemical and optoelectronic properties of the 4‐[4H‐dithieno(3,2‐b:2′,3′‐d)pyrrol‐4‐yl]aniline (DTP–aryl–NH₂), 10‐[4H‐dithiyeno(3,2‐b:2′,3′‐d)pirol‐4‐il]dekan‐1‐amine (DTP–alkyl–NH₂), and 1,10‐bis[4H‐dithieno(3,2‐b:2′,3′‐d)pyrrol‐4‐yl] decane (DTP–alkyl–DTP) were investigated. The corresponding polymers were characterized by cyclic voltammetry, NMR (¹H‐NMR and ¹³C‐NMR), and ultraviolet–visible spectroscopy. Changes in the electronic nature of the functional groups led to variations in the electrochemical properties of the π‐conjugated systems. The electroactive polymer films revealed redox couples and exhibited electrochromic behavior. The replacement of the DTP–alkyl–DTP unit with DTP–aryl–NH₂ and DTP–alkyl–NH₂ resulted in a lower oxidation potential. Both the poly(10‐(4H‐Dithiyeno[3,2‐b:2′,3′‐d]pirol‐4‐il)dekan‐1‐amin) (poly(DTP–alkyl–NH₂)) and poly(1,10‐bis(4H‐dithieno[3,2‐b:2′,3′‐d]pyrrol‐4‐yl) decane) (poly(DTP–alkyl–DTP)) films showed multicolor electrochromism and also fast switching times (<1 s) in the visible and near infrared regions. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40701.     

Studies on Energetic Compounds Part 23: Preparation,Thermal and Explosive Characteristics of Transition Metal Salts of 5‐Nitro‐2,4‐Dihydro‐3H‐1,2,4‐Triazole‐3‐One (NTO)

Five transition metal salts of 5‐nitro‐2,4‐dihydro‐3H‐1,2,4‐triazole‐3‐one, [namely M(NTO)_n⋅mH₂O where M is Ag, Hg, Cd, Cr, Fe where n=1,2,2,3,3 and m=1,2,2,8,2 respectively] were prepared and characterized (hereafter these compounds will be named as AgNTO, HgNTO, CdNTO, CrNTO and FeNTO, respectively). Their thermal decomposition was investigated by TG, DTA whereas explosive behaviour has been studied in terms of explosion delay, impact and friction sensitivities. Further, kinetic parameters have been derived using non‐isothermal TG data and mechanism of thermolysis has also been proposed. It seems that dehydration takes place prior to the evolution of NO₂ and the subsequent ring rupture yielding metal oxide. AgNTO on the other hand yields metallic silver. Dehydration in the case of HgNTO occurs in two steps: at each step one molecule is lost. All the salts are insensitive to impact and at the same time insensitive to friction up to 360 N.     

Light‐emitting polymers containing 2,3,4,5‐tetraphenylthiophenyl moiety and different pendent groups

By appropriate chemical reaction, different substituents can be selectively attached to the four phenyl rings present in 2,3,4,5‐tetraphenylthiophene (TP) to prepare monomers, namely 2,5‐bis(4‐bromophenyl)‐3,4‐diphenylthiophene (BTP), 2,5‐bis(4‐bromophenyl)‐3,4‐bis[4‐(nonan‐1‐one)phenyl] thiophene (BTP‐N2) and 2,5‐bis(4‐bromophenyl)‐3,4‐bis[4‐(2‐heptyl‐4‐phenylquinoline)phenyl]thiophene (BTP‐Qu2). Three light‐emitting polymers, PTP, PTP‐N2 and PTP‐Qu2, with the common TP backbone were prepared by zero‐valent nickel‐catalyzed polymerization of BTP, BTP‐N2 and BTP‐Qu2 monomers, respectively. The substituent on the 3,4‐phenyl rings of the TP framework has a profound effect on the polymer properties. Without any 3,4‐substituent, the rigid PTP polymer has low solubility in organic solvents. With the flexible nonanoyl substituent, the corresponding polymer, PTP‐N2, has improved solubility but low quantum efficiency (Φ_F) due to the carbonyl group which enhances intersystem crossing. With both flexible chain and bulky 4‐phenylquinoline (PQ) ring substituents, PTP‐Qu2 has good solubility and an enhanced Φ_F since the introduction of both flexible chain and bulky PQ ring substituents prevents close chain packing. All three polymers exhibit similar emission spectra despite the distinct difference in the absorption pattern of PTP‐Qu2 compared with those of PTP and PTP‐N2. In the case of PTP‐Qu2, there is energy transfer from the PQ pendent ring to the TP backbone and results in emission similar to PTP and PTP‐N2. The TP backbone common in all the three polymers is responsible for the emission from the corresponding excited states. The electrochemical properties of PTP‐Qu2 were also investigated. Copyright © 2005 Society of Chemical Industry     

Thiophene π‐bridge effect on photovoltaic performances of dithienosilole and bithiazole backboned polymers

In this article, two dithienosilole (DTS) and bithiazole (BTz) backboned donor–acceptor (D‐A) copolymers with (poly{5‐(5‐(4,4‐bis(2‐ethylhexyl)‐4H‐silolo[3,2‐b:4,5‐b']dithiophen‐2‐yl)thiophen‐2‐yl)‐4,4'‐dinonyl‐5'‐(thiophen‐2‐yl)‐2,2'‐bithiazole} (PDTS‐DTBTz)) and without (poly{5‐(4,4‐bis(2‐ethylhexyl)‐4H‐silolo[3,2‐b:4,5‐b']dithiophen‐2‐yl)‐4,4'‐dinonyl‐2,2'‐bithiazole} (PDTS‐BTz)) thiophene π‐bridge were synthesized to study the influence of thiophene π‐bridge on their photovoltaic performances. Both polymers show similar band gap, but polymer with thiophene π‐bridge (PDTS‐DTBTz) has a higher molecular weight, narrower polydispersity index (PDI), more planar geometry, higher crystallinity, higher hole mobility, and better miscibility with fullerene (polymer solar cells (PSCs) acceptor). Although PDTS‐BTz polymer based PSCs devices show higher open circuit voltage (V_oc), PDTS‐DTBTz polymer does show higher power conversion efficiency (PCE) with improved short circuit current density (J_sc) and fill factor (FF). The present results indicate that thiophene π‐bridge does contribute to the PSCs performances of dithienosilole and bithiazole backboned copolymer. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42798.     

Nonlinear optical studies on new conjugated poly{2,2l‐(3,4‐ dialkoxythiophene‐2,5‐diyl) bis[5‐(2‐thienyl)‐1,3,4‐oxadiazole]}s

Three new donor–acceptor type poly{2,2^l‐(3,4‐ dialkoxythiophene‐2,5‐diyl)bis[5‐(2‐thienyl)‐1,3,4‐oxadiazole]}s ( P1, P2, and P3 ) were synthesized starting from thiodiglycolic acid and diethyl oxalate through multistep reactions. The polymerization was carried out using chemical polymerization technique. The optical and charge‐transporting properties of the polymers were investigated by UV‐visible, fluorescence emission spectroscopic and cyclic voltammetric studies. The polymers showed bluish‐green fluorescence in solutions. The electrochemical band gaps were determined to be 2.03, 2.09, and 2.17 eV for P1 , P2, and P3, respectively. The nonlinear optical properties of new polymers were investigated at 532 nm using single beam Z‐scan and degenerate four‐wave mixing (DFWM) techniques with nanosecond laser pulses. The polymers exhibited strong optical limiting behavior due to “effective” three‐photon absorption. Values of the effective three‐photon absorption ( 3PA ) coefficients, third‐order nonlinear susceptibilities (χ⁽³⁾), and figures (F) of merit were calculated. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010