Synthesis and characterization of light‐absorbing cyclopentadithiophene‐based donor–acceptor copolymers

Cyclopentadithiophene and benzothiadiazole based donor–acceptor polymers are fast emerging as the most promising class of materials for organic solar cells. Here we report on a series of Cyclopentadithiophene and benzothiadiazole based conjugated polymers, namely poly[4,7‐bis(4,4‐dioctyl‐4H‐cyclopenta[2,1‐b;3,4‐b′]dithiophene‐2‐yl)benzo[1,2,5]thiadiazole] (P1), poly[4,7‐bis(4,4‐dioctyl‐4H‐cyclopenta[2,1‐b;3,4‐b′]dithiophene‐2‐yl)benzo[1,2,5]thiadiazole‐alt‐9‐(heptadecan‐9‐yl)‐2,7‐bis(4,4,5,5‐tetramethyl)‐1,3,2‐dioxaborolan‐2‐yl)‐9H‐carbazole] (P2) and poly[4,7‐bis(4,4‐dioctyl‐4H‐cyclopenta[2,1‐b;3,4‐b′]dithiophene‐2‐yl)benzo[1,2,5]thiadiazole‐alt‐5,11‐bis(2‐hexyldecyl)‐3,9‐bis(4,4,5,5‐tetramethyl)‐1,3,2‐dioxaborolan‐2‐yl)‐5,11‐dihydroindolo[3,2‐b]carbazole] (P3), with alternating donor and acceptor units and discuss their photophysical and electrochemical properties. Stille coupling of 2‐tributylstannyl‐4,4‐dioctylcyclopenta[2,1‐b:3,4‐b′]dithiophene with 4,7‐dibromobenzo[1,2,5]thiadiazole generated the alternating donor–acceptor monomer 4,7‐bis(4,4‐dioctyl‐4H‐cyclopenta[2,1‐b;3,4‐b′]dithiophene‐2‐yl)benzo[1,2,5]thiadiazole (CPDT‐BT‐CPDT). Homopolymer P1 of CPDT‐BT‐CPDT was synthesized by oxidative polymerization using FeCl₃. Copolymers P2 and P3 were synthesized by palladium‐catalysed Suzuki polycondensation. The synthesized polymers showed good solubility in common organic solvents, and UV‐visible measurements showed that the absorption maxima of the polymers lie in the range 624 to 670 nm. The energy gaps of these polymers were found to lie in the range 1.29 to 1.50 eV. Gel permeation chromatography measurements against polystyrene standards showed the number‐average molecular weight to be in the range (2.2–6.0) × 10⁴ g mol^?1. Thermogravimetric analysis showed the polymers to possess high thermal stability. A preliminary study of photodiode devices prepared using polymers P1, P2 and P3 when blended with the PC₇₁BM electron acceptor found that P2 is the optimum chemical structure for pursuing further device optimization.© 2015 Society of Chemical Industry     

Fluorene‐based conjugated polymer with tethered thymines: click postpolymerization synthesis and optical response to mercury(II)

A kind of fluorene‐based conjugated polymer with tethered thymine (T) groups {poly[(9,9‐dioctyl)‐2,7‐fluorene‐{9,9‐dioctyl‐4–1,2,3‐triazol‐[5‐(hydroxymethyl)tetrahydrofuran‐2‐yl]‐5‐methylpyrimidine‐2,4(1H,3H)‐dione}‐2,7‐fluorene]‐co‐[(9,9‐dioctyl)‐2,7‐fluorene‐4,7‐bis(5‐thiophen‐2‐yl)benzo‐2,1,3‐thiadiazole] ( P‐3 )} was successfully synthesized by a Cu(I)‐catalyzed click reaction between the acetylene‐substituted polymer precursor {poly[(9,9‐dioctyl)‐2,7‐fluorene‐(9,9‐dioctyl‐4‐phenylacetylene fluorene)]‐co‐[(9,9‐dioctyl)‐2,7‐fluorene‐4,7‐bis(5‐thiophen‐2‐yl)benzo‐2,1,3‐thiadiazole]} and 3′‐azido‐3′‐deoxythymidine. The chemical structures of the intermediates and target polymer were verified by Fourier transform infrared spectroscopy and ¹H‐NMR analyses. The specific binding with Hg²⁺ of P‐3 was corroborated by ultraviolet–visible spectroscopy and photoluminescence analyses against other metal ions. The results show that P‐3 possessed selectivity and sensitivity toward Hg²⁺. Around 77% of photoluminescence intensity of P‐3 was quenched when the concentration of Hg²⁺ reached 7.7 × 10^?4 M and with a detection limit in the range of about 4.8 μM. A comparison experiment suggested that a synergic effect of the tethered T and S atoms interrelated with Hg²⁺ existed in P‐3 . Most of the fluorescence intensity of P‐3 was recovered upon the addition of iodide anions to the P‐3 /Hg²⁺ complex; this suggested that P‐3 could be used as a potential reversible optical Hg²⁺ probe. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Polyamides obtained by direct polycondesation of 4‐[4‐[9‐[4‐(4‐aminophenoxy)‐3‐methyl‐phenyl] fluoren‐9‐YL]‐2‐methyl‐phenoxy]aniline with dicarboxylic acids based on a diphenyl‐silane moiety

Polyamides (PAs) containing fluorene, oxyether, and diphenyl‐silane moieties in the repeating unit were synthesized in > 85% yield by direct polycondesation between a diamine and four dicarboxylic acids. Alternatively, one PA was synthesized from an acid dichloride. The diamine 4‐[4‐[9‐[4‐(4‐aminophenoxy)‐3‐methyl‐phenyl]fluoren‐9‐yl]‐2‐methyl‐phenoxy]aniline ( 3 ) was obtained from the corresponding dinitro compound, which was synthesized by nucleophilic aromatic halogen displacement from p‐chloronitrobenzene and 9,9‐bis (4‐hydroxy‐3‐methyl‐phenyl)fluorene ( 1 ). Monomers and polymers were characterized by FTIR and ¹H, ¹³C, and ²⁹Si‐NMR spectroscopy and the results were in agreement with the proposed structures. PAs showed inherent viscosity values between 0.14 and 0.43 dL/g, indicative of low molecular weight species, probably of oligomeric nature. The glass transition temperature (T_g) values were observed in the 188–211°C range by DSC analysis. Thermal decomposition temperature (TDT_10%) values were above 400°C due to the presence of the aromatic rings in the diamine. All PAs showed good transparency in the visible region (>88% at 400 nm) due to the incorporation of the fluorene moiety. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Synthesis of isoelectronic polyazomethine and poly(arylene vinylene) by a palladium‐catalyzed Suzuki coupling method

Two fully conjugated copolymers containing 2,7‐(9,9‐dioctyl) fluorene and 3,6‐(N‐hexyl‐9H‐carbazole) disubstituted rings and arylene vinylene or azomethine units in the main chain were synthesized through a palladium‐catalyzed Suzuki coupling method of 2,7‐bis(4,4,5,5‐tetramethyl‐1,3,2‐dioxaborolan‐2‐yl)‐9,9‐dioctyl fluorene with 1,4‐bis(6‐bromo‐N‐hexyl‐9H‐carbazole‐3‐yl vinyl) benzene or N,N‐bis(6‐bromo‐N‐hexyl‐9H‐carbazole‐3‐yl methylidene) 1,4‐phenylenediamine. Bisbromine arylene vinylene and arylenazomethine monomers were synthesized by condensation of 3‐formyl‐N‐hexyl‐6‐bromo carbazole with tetraethyl‐p‐xylylene diphosphonate or 1,4‐phenylenediamine. Copolymers were characterized by FTIR, ¹H‐NMR, DSC, UV‐visible and photoluminescence methods. Copyright © 2005 Society of Chemical Industry     

Homopolymerization and copolymerization of N‐substituted maleimides with chiral anionic initiators

Novel optically active anionic initiators bearing a chiral oxazole substituent on the fluorene ring, (S)‐1‐(9H‐fluoren‐2‐yl)‐4‐isopropyl‐4,5‐dihydrooxazole lithium (Li‐(S)‐1‐FIDH) and (S)‐2‐(9H‐fluoren‐2‐yl)‐4‐isopropyl‐4,5‐dihydrooxazole lithium (Li‐(S)‐2‐FIDH), were prepared. Anionic homopolymerizations of achiral N‐substituted maleimide (RMI) with the chiral initiators were investigated. The optically active polymers obtained were attributed to asymmetric induction of the chiral initiators. The very crowded chiral initiator Li‐(S)‐1‐FIDH was found to play a better asymmetric induction role in the polymers than Li‐(S)‐2‐FIDH. Anionic copolymerization of (R)‐(+)‐N‐1‐phenylethyl maleimide and optically inactive RMI with Li‐(S)‐1‐FIDH were also studied. © 2014 Society of Chemical Industry     

A carboxylic acid‐functionalized polyfluorene as fluorescent probe for protein sensing

A new water‐soluble fluorescent conjugated polyelectrolyte, poly[9,9‐bis(3′‐butyrate)fluoren‐2,7‐yl] sodium (BBS‐PF), was studied as a fluorescent probe for protein sensing. The conjugated polyelectrolyte BBS‐PF shows high fluorescence sensitivity to cytochrome c, lysozyme, and bovine serum albumin (BSA). The Stern–Volmer constant (K_sv) in cytochrome c was measured to be as high as 6.1 × 10⁷ L/mol, approximately twice as that of the other two. Interestingly, it is found that BSA slightly enhances the fluorescence of BBS‐PF rather than quenches the fluorescence at its micromolar concentrations. The excitation spectra confirm that the interaction of BBS‐PF with the proteins could be different. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Synthesis of poly(urethane)s based on diphenyl‐silane/germane and oxyphenyl units: Structure–properties relationship

A series of poly(urethane)s (PUs) based on diphenyl‐silane or ‐germane and oxyphenyl units were synthesized by polycondesation of 4‐[4‐[9‐[4‐(4‐aminophenoxy)‐3‐methyl‐phenyl]fluoren‐9‐yl]‐2‐methyl‐phenoxy]aniline (3) and four bis(chloroformate)s ( I–IV ). These monomers were prepared and characterized in previous works. The best conditions for the polymerization reactions were investigated by a kinetic study. Also, a selection of the best solvent for the reaction was developed. Polymers were characterized by IR and ¹H, ¹³C, and ²⁹Si‐NMR spectroscopy and the results were in agreement with the proposed structures. Poly(urethane)s showed inherent viscosity values between 0.12 and 0.31 dL/g, indicative of low molecular weight species, probably of oligomeric nature. The glass transition temperature (T_g) values were observed in the 127–168°C range by DSC analysis. Thermal decomposition temperature (TDT_10%) values were above 300°C. All PUs showed good transparency in the visible region (>80% at 350 nm) due to the incorporation of the bulky monomer (fluorene) and oxyether linkages. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

6,7‐Dimethoxy‐2‐{2‐[4‐(1H‐1,2,3‐triazol‐1‐yl)phenyl]ethyl}‐1,2,3,4‐tetrahydroisoquinolines as Superior Reversal Agents for P‐Glycoprotein‐Mediated Multidrug Resistance

P‐glycoprotein (P‐gp)‐mediated multidrug resistance (MDR) is a major obstacle for successful cancer chemotherapy. Based on our previous study, 17 novel compounds with the 6,7‐dimethoxy‐2‐{2‐[4‐(1H‐1,2,3‐triazol‐1‐yl)phenyl]ethyl}‐1,2,3,4‐tetrahydroisoquinoline scaffold were designed and synthesized. Among them, 2‐[(1‐{4‐[2‐(6,7‐dimethoxy‐3,4‐dihydroisoquinolin‐2(1H)‐yl)ethyl]phenyl}‐1H‐1,2,3‐triazol‐4‐yl)methoxy]‐N‐(p‐tolyl)benzamide (compound 7 h ) was identified as a potent modulator of P‐gp‐mediated MDR, with high potency (EC₅₀=127.5±9.1 nM ), low cytotoxicity (TI>784.3), and long duration (>24 h) in reversing doxorubicin (DOX) resistance in K562/A02 cells. Compound 7 h also enhanced the effects of other MDR‐related cytotoxic agents (paclitaxel, vinblastine, and daunorubicin), increased the accumulation of DOX and blocked P‐gp‐mediated rhodamine 123 efflux function in K562/A02 MDR cells. Moreover, 7 h did not have any effect on cytochrome (CYP3A4) activity. These results indicate that 7 h is a relatively safe modulator of P‐gp‐mediated MDR that has good potential for further development.     

Electroluminescent fluorene‐based alternating polymers bearing triarylamine or carbazole moieties in the main chain: Synthesis and properties

Two soluble conjugated polyfluorenes, poly{9,9‐dioctylfluorene‐2,7‐diyl‐co‐4,4′‐bis[2‐(4‐phenyl)‐2‐cyanovinyl]triphenylamine}(PF‐BCT) and poly{9,9‐dioctylfluorene‐2,7‐diyl‐co‐3,6‐bis[2‐(4‐phenyl)‐2‐cyanovinyl]‐9‐octyl carbazole}(PF‐BCC), have been synthesized from 2,7‐dibromo‐9,9‐dioctylfluorene and 4,4′‐bis[2‐(4‐bromophenyl)‐ 2‐cyanovinyl]triphenylamine or 3,6‐bis[2‐(4‐bromophenyl)‐2‐cyanovinyl]‐9‐octyl carbazole comonomers through a Suzuki polymerization reaction. The copolymers are characterized by gel permeation chromatography, elemental analysis, thermogravimetric analysis. The polymers have good thermal stability with 5 wt % loss temperatures of more than 380°C. Cyclic voltammetry measurements show that the polymers present good electron and hole‐injection abilities. PF‐BCC possesses higher oxidization potential than that of PF‐BCT, which indicates that PF‐BCT has better hole injection ability. The photophysical properties of the polymers are investigated in both solutions and spinning‐coated films. Compared to that of PF‐BCC, the absorption and emission peaks of PF‐BCT bathochromic shift in the solid film or solution states. Single layer light‐emitting devices have been fabricated in the ITO/PEDOT: PSS/polymer/Ca/Al configuration. The electroluminescence (EL) device based on PF‐BCT shows yellow emission with the current efficiency of 0.21 cd/A, while PF‐BCC shows greenish yellow emission with the current efficiency of 0.08 cd/A. In addition, to improve the electroluminescence of PF‐BCC, a PVK layer is introduced, the brightness and efficiency get improved to 700 cd/m² and 0.12 cd/A, respectively. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Isoxazole‐Based‐Scaffold Inhibitors Targeting Cyclooxygenases (COXs)

A new set of cyclooxygenase (COX) inhibitors endowed with an additional functionality was explored. These new compounds also contained either rhodamine 6G or 6,7‐dimethoxy‐1,2,3,4‐tetrahydroisoquinoline, two moieties typical of efflux pump substrates and inhibitors, respectively. Among all the synthesized compounds, two new COX inhibitors with opposite selectivity were discovered: compound 8 [N‐(9‐{2‐[(4‐{2‐[3‐(5‐chlorofuran‐2‐yl)‐4‐phenylisoxazol‐5‐yl]acetamido}butyl)carbamoyl]phenyl‐6‐(ethylamino)‐2,7‐dimethyl‐3H‐xanthen‐3‐ylidene}ethanaminium chloride] was found to be a selective COX‐1 inhibitor, whereas 17 (2‐[3,4‐bis(4‐methoxyphenyl)isoxazol‐5‐yl]‐1‐[6,7‐dimethoxy‐3,4‐dihydroisoquinolin‐2‐(1H)‐yl]ethanone) was found to be a sub‐micromolar selective COX‐2 inhibitor. However, both were shown to interact with P‐glycoprotein. Docking experiments helped to clarify the molecular aspects of the observed COX selectivity.     

Water‐soluble and polymerizable thioxanthone photoinitiator containing imidazole

A novel free radical photoinitiator, 3‐allyl‐1‐[2‐hydroxy‐3‐(thioxanthen‐9‐one‐2‐yl)oxypropyl]imidazolium chloride ([AIPTX]Cl), is synthesized by the addition reaction of 2‐(2,3‐epoxy)propoxylthioxanthone (ETX) with a heterocyclic compound imidazole firstly, and the achieved intermediate 1‐[2‐hydroxy‐3‐(thioxanthen‐9‐one‐2‐yl)oxypropyl]imidazole (IPTX) is then reacted with allyl chloride. IPTX is chosen to evaluate the photoefficiency of [AIPTX]Cl. FTIR and ¹H‐NMR confirm the structures of [AIPTX]Cl and IPTX. UV‐Vis spectra of the two photoinitiators are similar and both exhibit the maximal absorption about 400 nm. Fluorescence spectra show [AIPTX]Cl/IMZ has slightly higher fluorescence intensity than IPTX system. Photopolymerization studies indicate that [AIPTX]Cl/IMZ is more efficient for the polymerization of water‐soluble monomer than IPTX. Moreover, due to its advantages of water solubility and polymerizability, [AIPTX]Cl is an environmental‐friendly photoinitiator and has potential for application in UV‐curing systems. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40659.     

Controllable preparation and near infrared optical limiting properties of fluorene‐containing polyacetylenes

Two novel fluorene functionalized polyacetylenes with different conjugation bridge architectures (stilbene and azobenzene), poly[2‐[4‐vinyl‐4′‐(N‐methyl, N‐ethyl‐yl propargyloxy) phenyl azo]‐9,9‐dioctylfluorene] ( PC1 ), poly[2‐[4‐vinyl‐4′‐(N‐methyl, N‐ethyl‐yl propargyl group) stilbene ethenyl]‐9,9‐dioctylfluorene] ( PC2 ), were designed and prepared through using [Rh(nbd)Cl]₂‐Et₃N as the catalysts, respectively. These polymers are soluble in common organic solvents, such as toluene, chloroform, 1,2‐dichloromethane, and tetrahydrofuran, which their structures and properties were systematically characterized by means of Fourier transform infrared spectroscopy, nuclear magnetic resonance, elemental analyses, UV–vis, photoluminescence, thermogravimetric analysis, gel permeation chromatography, and Z‐scan technique. The optical limiting properties were investigated at 780 nm with 450 fs laser pulses. Remarkably, it is expected that, by incorporation of fluorene into functional polyacetylene has endowed the resultant polymers with well optical limiting properties and thermal stability. Additionally, the nonlinear optical properties of functionalized polyacetylenes were significantly affected by different molecular structure of conjugated bridge of substituted group. The polyacetylenes with azobenzene ( PC2 ) conjugated bridge displaying well two‐photon absorption cross‐sections of 3950 cm/GM (2010 cm/GM for PC1 containing stilbene), owning to stronger π‐conjugated chromophores of objective polymer and intramolecular charge transfer effect. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46100.     

Synthesis and spectroelectrochemical investigation of low‐bandgap polymer: Integrated quinoxaline and benzimidazole in one electron acceptor unit

Two novel π‐conjugated monomers, 6‐(4‐octyloxyphenyl)‐4,8‐bis(thiophene‐2‐yl)‐3H‐[d] imidazole[1,2,5] benzothiadiazole (M3) and 4‐(4‐octyloxyphenyl)‐2,6‐bis(thiophene‐2‐yl)‐3H‐[d] imidazole‐acenaphtho[1,2‐b]quinoxaline (M4), were synthesized. The monomer M4 contains a thiophene electron‐donating unit and electron withdrawing unit in which quinoxaline and benzimidazole integrated in one benzene ring. Electrochemical polymerization of the monomers was carried out in acetonitrile/dichloromethane solvent mixture containing tetra‐n‐butylammonium hexafluorophosphate and electrochromic properties of polymers (P3 and P4) are described in this article. Furthermore, the effects of structural difference on electrochemical redox behavior and spectroelectrochemical properties of the two resulting polymers were examined. The results showed that an anodic wave at +0.48 V versus Ag wire pseudo‐reference electrode corresponding to the monomer M4 oxidation was observed, while one anodic wave at +0.70 V was observed in oxidation of M3 as it contains stronger electron withdrawing thiadiazole structure. The UV‐vis‐Near‐infrared (Near‐infrared spectroscopy) (NIR) spectra analysis revealed that the two polymers have one absorbance band centered at 603 nm. The band gaps, defined as the onset of the absorption band at 603 nm of these polymers, were determined as 1.60 eV for P3 and as 1.55 eV for P4. The electrochromic results showed that P3 revealed about 20% optical contrast at 980 nm and the P4 has 30% optical contrast at 806 nm with low response time (1 s for each polymer). © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40861.     

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.     

Synthesis and Biological Evaluation of Imidazo[2,1‐b][1,3,4]thiadiazole‐Linked Oxindoles as Potent Tubulin Polymerization Inhibitors

A series of imidazo[2,1‐b][1,3,4]thiadiazole‐linked oxindoles composed of an A, B, C and D ring system were synthesized and investigated for anti‐proliferative activity in various human cancer cell lines; test compounds were variously substituted at rings C and D. Among them, compounds 7 ((E)‐5‐fluoro‐3‐((6‐p‐tolyl‐2‐(3,4,5‐trimethoxyphenyl)‐imidazo[2,1‐b][1,3,4]thiadiazol‐5‐yl)methylene)indolin‐2‐one), 11 ((E)‐3‐((6‐p‐tolyl‐2‐(3,4,5‐trimethoxyphenyl)imidazo[2,1‐b][1,3,4]thiadiazol‐5‐yl)methylene)indolin‐2‐one), and 15 ((E)‐6‐chloro‐3‐((6‐phenyl‐2‐(3,4,5‐trimethoxyphenyl)imidazo[2,1‐b][1,3,4]thiadiazol‐5‐yl)methylene)indolin‐2‐one) exhibited potent anti‐proliferative activity. Treatment with these three compounds resulted in accumulation of cells in G₂/M phase, inhibition of tubulin assembly, and increased cyclin‐B1 protein levels. Compound 7 displayed potent cytotoxicity, with an IC₅₀ range of 1.1–1.6 μM , and inhibited tubulin polymerization with an IC₅₀ value (0.15 μM ) lower than that of combretastatin A‐4 (1.16 μM ). Docking studies reveal that compounds 7 and 11 bind with αAsn101, βThr179, and βCys241 in the colchicine binding site of tubulin.     

Synthesis and characterization of a novel fluorene‐alt‐carbazole polymer to host green,blue, and red phosphorescence

A novel fluorene‐alt‐carbazole polymer host Poly(9,9‐dioctyl‐9H‐fluorene‐2,7‐diyl‐alt‐N‐tetrahydropyran‐3,6‐carbazole) (PFCz), composed of N‐tetrahydropyran‐3,6‐carbazole and 9,9‐dioctyl‐2,7‐fluorene in the polymer backbone, was synthesized by Suzuki coupling. The PFCz possesses good thermal stability and proper lowest unoccupied molecular orbital (LUMO)/highest occupied molecular orbital (HOMO) energy levels to facilitate the injection and transport of electrons and holes. Upon doping with blue, green, and red phosphors, red ‐ green ‐ blue (R‐G‐B) phosphorescent devices hosted by PFCz have been fabricated and investigated. In contrast to those of blue and green devices, the red devices give better performances with a maximum luminous efficiency of 4.88 cd/A and a maximum power efficiency of 1.85% at 149.84 cd/m², due to favorable triplet energy level (E_T) of PFCz for red phosphor, bis(2‐methyldibenzo[f,h]quinoxaline)(acetylacetonate)iridium(III) [Ir(MDQ)₂(acac)]. Additionally, with different doped concentrations of Ir(MDQ)₂(acac), the PFCz‐related red devices emit nearly pure red light with Commission Internationale de L'Eclairage (CIE) coordinates of (0.57, 0.38), (0.60, 0.38), (0.61, 0.38), and (0.62, 0.38), which were very close to the standard red (0.66, 0.34) by the National Television System Committee. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43234.     

Preparation and characterization of bis‐[1,3,5]triazinyl diazenes and their utilization as flame retardants in polypropylene films

A series of bis‐[1,3,5]triazinyl diazenes and two metal complexes thereof were synthesized and tested as new flame retardants in polypropylene films. It was observed that electron withdrawing triazinyl ring substituent (i.e., Cl and phenyl moieties) improved the thermal stability of diazene compounds, whereas electron donating groups (i.e., methoxy, dimethylamino, and ethylthio moieties) had a destabilizing effect. TGA, DTA/DSC, NMR, and ATR‐FTIR were used for the characterization. Quantum mechanical modeling (Gaussian 09) was also utilized to facilitate the interpretation of the NMR data. Bis‐(4,6‐dichloro‐[1,3,5]triazin‐2‐yl)‐diazene 1 and bis‐(4,6‐dimethoxy‐[1,3,5]triazin‐2‐yl)‐diazene 2 were found to be effective flame retardants in polypropylene films and DIN4102‐1 B2 classification was reached already at a loading of 0.5 wt %. Interestingly, the copper complex of 2 showed even higher fire retardant activity than its precursor 2 , whereas the corresponding zinc complex exhibited lower flame retardant efficacy than its precursor. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40413.     

Synthesis and luminescence properties of new blue‐light‐emitting polyconjugated poly{1,1′‐biphenyl‐4,4′‐diyl‐[1‐(4‐t‐butylphenyl)]vinylene} polymers and copolymers

Three new soluble polyconjugated polymers, all of which emitted blue light in photoluminescence and electroluminescence, were synthesized, and their luminescence properties were studied. The polymers were poly{1,1′‐biphenyl‐4,4′‐diyl‐[1‐(4‐t‐butylphenyl)]vinylene}, poly((9,9‐dioctylfluorene‐2,7‐diyl)‐alt‐{1,4‐phenylene‐[1‐(4‐t‐butylphenyl)vinylene‐1,4‐phenylene]}) [P(DOF‐PVP)], and poly([N‐(2‐ethyl) hexylcarbazole‐3,6‐diyl]‐alt‐{1,4‐phenylene‐[1‐(4‐t‐butylphenyl)]vinylene‐1,4‐phenylene}). The last two polymers had alternating sequences of the two structural units. Among the three polymers, P(DOF‐PVP) performed best in the light‐emitting diode devices of indium–tin oxide/poly(ethylenedioxythiophene) doped with poly(styrene sulfonate) (30 nm)/polymer (150 nm)/Li:Al (100 nm). This might have been correlated with the balance in and magnitude of the mobility of the charge carriers, that is, positive holes and electrons, and also the electronic structure, that is, highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) levels, of the polymers. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 307–317, 2006     

Improved conversion of 6‐endo‐tosyloxybicyclo[2.2.2]octan‐2‐ones into 6‐exo‐acetoxy and 6‐exo‐benzoyloxybicyclo[2.2.2]octan‐2‐ones

The reaction conditions for the conversion of 6‐endo‐tosyloxybicyclo[2.2.2]octan‐2‐one ( 7b ) into 6‐exo‐acetoxy ( 8b ) and 6‐exo‐benzoyloxybicyclo[2.2.2]octan‐2‐one ( 8a ), respectively, were improved. Thus known 6‐endo‐tosyloxy‐bicyclo[2.2.2]octan‐2‐ones (+)‐(1RS,6SR,8SR,11RS)‐11‐[(4‐toluenesulfonyl)oxy]tricyclo[6.2.2.0^1,6]dodecan‐9‐one ( 1a ), 13‐methyl‐15‐oxo‐9β,13b‐ethano‐9β‐podocarpan‐12β‐yl‐4‐toluenesulfonate ( 3a ), and methyl (13R)‐16‐oxo‐13‐[(4‐tolylsulfonyl)oxy]‐17‐noratisan‐18‐oate ( 5 ), were converted,in comparable yields, as previously recorded, but much shorter times, into (+)‐(1RS,6SR,8SR,11SR)‐11‐(benzoyloxy) tricyclo[6.2.2.0^1,6]dodecan‐9‐one ( 2 ), 13‐methyl‐15‐oxo‐9β,13β‐ethano‐9β‐podocarpan‐12α‐yl benzoate ( 4 ), and methyl (13S)‐13‐(benzoyloxy)‐16‐oxo‐17‐noratisan‐18‐oate ( 6 ), respectively.     

Donor copolymer with benzo[1,2‐b:4,5‐b′]dithiophene and quinoxaline derivative segments for photovoltaic applications

A donor copolymer Poly{2,6‐4,8‐bis(2‐ethylhexyl)benzo[1,2‐b:3,4‐b′]dithiophene‐5,8‐2,3‐bis(5‐octylthiophen‐2‐yl)quinoxaline} (PBDTThQx) with benzo[1,2‐b:4,5‐b′]dithiophene and quinoxaline derivatives was synthesized and characterized with NMR, ultraviolet–visible spectroscopy, thermogravimetric analyses, and cyclic voltammetry. Photovoltaic devices with the configuration indium tin oxide–poly(3,4‐ethylenedioxythiophene)–poly(styrene sulfonate)–PBDTThQx–[6,6]‐phenyl‐C₆₁‐butyric acid methyl ester (PC₆₁BM)–LiF–Al were fabricated, in which PBDTThQx performed as the electron donor and PC₆₁BM was the electron acceptor in the active layer. The device presented reasonable photovoltaic properties when the weight ratio of PBDTThQx:PC₆₁BM reached 1:3. The open‐circuit voltage, fill factor, and power conversion efficiency were gauged to be 0.75 V, 0.59, and 0.74%, respectively. The experimental data implied that PBDTThQx would be a promising donor candidate in the application of polymer solar cells. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40279.