An investigation into the synthesis of polycarbazole squaraine derivatives

The polycondensation of squaric acid with 1,2-(9-Ethylcarbazol-3-yl)ethene and N-ethyliminostilbene in polyphosphoric acid yielded insoluble polymers which included substituted phosphate groups on the phenyl rings. The presence of phosphorus in these polymers was identified using solid-state ³¹P NMR and EDAX techniques. Furthermore the phosphate groups were not ionic, hence no charge-balancing anions were present. Both polymers did not electrically conduct but exhibited dielectric breakdown values of 0.1 and 0.06 MV cm⁻¹ respectively. Received: 16 December 1996/Revised: 10 March 1997/Accepted: 10 March 1997     

Sonochemical Synthesis of a Nanocrystalline Tin(IV) Complex based on a Bulky Anthracene Carboxylate Ligand: Spectroscopic and Photophysical Properties

In order systematically investigate the effect of ligand with a large conjugated π-system on the structure and optical properties of tin complex, anthracene-9-carboxylic acid (L¹) is selected as a primary ligand, and quinoline-2-carboxylic acid (L²) used as second ligand to incorporate with anthracene-9-carboxylic acid to construct a new tin(IV)-carboxylate coordination complex under thermal gradient condition. Prepared complex was fully characterized based on its ¹H and ¹³C NMR, IR and UV spectra and elemental analysis. The molecular structure of complex was determined by single-crystal X-ray analysis. The nanocrystalline complexes of the prepared complex were successfully obtained at 30, 50 and 60 °C by a facile sonochemical route. The new nanocrystalline complexes were characterized by scanning electron microscopy, X-ray powder diffraction, IR spectroscopy and elemental analysis. The photoluminescence properties of the nanocrystalline complexes and crystalline bulk complex in the solid-state indicated that the size of the complex particles has a remarkable effect on the optical properties of it. Absorption and emission peaks of the nanocrystalline complexes blue shifted significantly in comparison with those of in the single-crystal form. Application of the prepared complex in fabrication of an organic light-emitting diode has been demonstrated. The current–voltage (I–V) characteristics and the electroluminescence (EL) properties of the complex have been investigated. The EL of the compound exhibits green emission at 552 nm.     

Polymerization of cyclic monomers 6. Synthesis and radical polymerization of asymmetric disubstituted 2-vinylcyclopropanes

Summary Asymmetric disubstituted 1-phenoxy-2-vinylcyclopropanes 1 were synthesized either by the esterification of the corresponding 1-alkoxycarbonyl-2-vinylcyclopropane-1-carboxylic acid with phenol or by the reaction of asymmetric malonates with trans-1,4-dibromo-2-butene. The structure of the new vinylcyclopropanes was confirmed by elemental analysis, IR, ¹H NMR and ¹³C NMR spectroscopy. The radical polymerization of the asymmetric substituted 2-vinylcyclopropanes in bulk with 2,2'-azoisobutyronitrile (AIBN) results in transparent polymers. The glass transition temperature of the formed polymers varries between 41 und 61°C. Received: 14 November 1997/Accepted: 20 November 1997     

Copolymerization of styrene and methyl methacrylate with nickel acetylacetonate/methylaluminoxane catalyst system

The present work deals with copolymerization of styrene (STY) and methyl methacrylate (MMA) catalysed by nickel acetylacetonate - Ni(acac) ₂ , employing methylaluminoxane (MAO) as cocatalyst. This catalyst system presented low catalyst activities for STY homopolymerization and very high activities for MMA. It seems that the catalyst system based on Ni(acac) ₂ /MAO is effective for the copolymerization of MMA and STY to give block copolymer but it also produced polystyrene and poly(methyl methacrylate) homopolymers. The polymers were characterized by ¹³ C NMR, GPC and FTIR. The polystyrene homopolymer was identified by IR and NMR analyses of the cyclohexane soluble fraction. The presence of absorption bands correspondent to carbonyl group and aromatic ring was observed in the IR spectrum of the acetic acid soluble part. This result is a clue that STY-MMA copolymer with low molecular weight was produced. The high molecular weight copolymer (acetic acid insoluble fraction) was also characterized by IR analysis which indicated the presence of characteristic absorption bands of carbonyl group and aromatic ring. These results were confirmed by ¹³ C NMR analysis. Received: 6 August 1997/Revised version: 29 December 1997/Accepted: 7 January 1998     

A sandwich-type assay based on quantum dot/aptamer bioconjugates for analysis of E. Coli O157:H7 in microtiter plate format

An optical assay based on CdSe/ZnS quantum dots (QD)/NH₂-Apt bioconjugates for the pathogen detection was presented. QDs with carboxyl functional groups and 72-mer aptamer (against E. coli outer membrane proteins) were used as probes and sensing element. E. coli O157:H7 was selected as a model pathogen and 96-well plate assay in the sandwich hybridization format was constructed. Poly-L-lysine-coated 96-well plate surfaces were used as support material where thiol functionalized aptamers were immobilized by 4-(N-Maleimidomethyl)cyclohexane-1-carboxylic acid 3-sulfo-N-hydroxysuccinimide (sulfo-SMCC). After incubation with the bacteria, CdSe/ZnS QDs/aptamer bioconjugates were added. The fluorescence signals were followed before and after addition of bioconjugates. Probe concentrations, incubation time with E. coli O157:H7 were also optimized. The bioassay could detect the pathogen down to 10² CFU/mL with high selectivity. The detection system was successfully employed in samples, in the presence of interfering compounds.     

Synthesis and characterization of liquid crystalline polymers from p-hydroxybenzoic acid,poly(ethylene terephthalate), and third monomers

Eight new p-hydroxybenzoic acid (PHB) and poly(ethylene terephthalate) (PET) copolymers containing vanillic acid (VA), p-aminobenzoic acid, m-hydroxybenzoic acid, hydroquinone/terephthalic acid (TPA), bisphenol A/TPA, 1,5-naphthalenediol/TPA, 2,7-naphthalenediol/TPA, and 1,4-dihydroxyanthraquinone/TPA as eight third monomers with a variety of structural features were synthesized by melted-state copolycondensation and were characterized through a thermal analyzer, proton nuclear magnetic resonance, wide-angle X-ray diffraction (WAXD), and a scanning electron microscope (SEM). The experimental results show that PHB/PET/VA copolymers exhibit a faster polycondensation rate, lower melting temperature, and higher thermostability than do the other seven copolymers and third monomer-free PHB/PET polymers. The as-spun fibers derived from the PHB/PET/VA copolymers with different VA contents show tensile strengths, Young's moduli, and break elongations of 0.6–1.5 GPa, 28–67 GPa, and 7–9%, respectively. A highly oriented fibrillar structure in the PHB/PET/VA copolymer fibers was observed using WAXD and SEM. The most effective third monomer of the eight third monomers for an enhancing polycondensation rate and molecular weight of the PHB/PET polymers and for improving their thermal and mechanical properties is found to be vanillic acid (VA). © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 66: 2129–2138, 1997     

Biocompatible α-aminoacids based aliphatic polyamides

Summary. Biodegradable aliphatic polyamides have been prepared from C10 and C14 dicarboxylic acids and amide-diamines containing one or two preformed amide linkages susceptible to enzymatic cleavage in their molecules. L-phenylalanine, either by itself or together with L-valine, was used to generated amide bonds which are cleavable by chimotrypsine. Improved chain flexibility and hydrophilicity of the polyamides was obtained using a triethyleneoxy based amide-diamine. Characterization of the novel monomers and polymers by FTIR and ¹H-NMR spectroscopy confirms the expected structures. Thermal data and solubility tests indicate that both T _m and solubility depend on the length and nature of the aliphatic segment present in the amide-diamine as well as on the "density" of interchain hydrogen bonds. Finally the polymers tested are capable of supporting fibroblast adherence and proliferation, and proved to be non cytotoxic. Received: 28 May 1997/Revised: 16 July 1997/Accepted: 16 July 1997     

Poly(ester)s and poly(amide)s with fluorene and diphenyl-silane units in the main chain: Effects of iodine doping on the structure and electrical conductivity

Intramolecular charge transfer interaction between the electron donor and electro acceptor units within the polymeric structure and its optoelectronic properties were studied. The monomer, 9H-fluorene-2,7-dicarboxylic acid, was prepared from 9H-fluorene-2,7-dicarbonitrile using CuCN/N,N-dimethylformamide followed by the decomposition of the complex with FeCl₃x6H₂O in HCl and KOH/H₂O. The formation of two new classes of polymers was reported at different reaction times. The poly(ester) (PEF) was synthesized by the reaction of the diacid monomer with bis(4-hydroxiphenyl)diphenylsilane using tosyl chloride/pyridine/dimethylformamide system as condensing agent. Alternatively, the poly(amide) (PAF) was synthesized by the direct polycondensation of the diacid monomer and bis(4-aminophenyl)diphenylsilane in N-methyl-2-pyrrolidine solution containing dissolved calcium chloride. The resulting new polymers were obtained in good yields and were characterized by FTIR, NMR (¹H, ¹³C, and ²⁹Si), ESI, Raman, UV (optical gap) and fluorescence spectroscopy. The thermal properties were characterized by DSC and TGA. The electrical conductivity of the polymers was measured before and after exposure to iodine vapor, utilizing films of different thickness. Ellipsometric studies were used for the determination of the film thickness. Morphological differentiation was carried out by SEM-EDX analysis. Oxidation of the polymer films of low thickness decreased their conductivities, mainly due to the small structural changes. For a polymeric sample with a higher thickness, the doping process slightly increased the conductivity. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Synthesis and biological activities of endo-3,6-epoxy-1,2,3,6-tetrahydrophthalimide and its polymers

Photocopolymerizations of endo-3,6-epoxy-1,2,3,6-tetrahydrophthalimide (ETPI) with acrylic acid (AA), vinyl acetate (VAc), and maleic anhydride (MAH) were carried out in a mixed solvent of 2-butanone and acetone using 2,2-dimethoxy-2-phenylacetophenone as an initiator at 25°C. Synthesized ETPI, poly(ETPI), poly(ETPI-co-AA), poly(ETPI-co-VAc), and poly(ETPI-co-MAH) were characterized by IR and ¹H-NMR spectroscopies, elemental analysis, and gel permeation chromatography. The synthesized polymers have a number-average molecular weight (M_n) in the range of 3500-27,400. The in vitro cytotoxicities of poly(ETPI), poly(ETPI-co-AA), poly(ETPI-co-VAc), and poly(ETPI-co-MAH) against fibroblast and K-562 human leukemia cells were lower than that of monomeric ETPI at a low concentration (0.02 mg/mL). The in vivo antitumor activities of the polymers were evaluated by the survival time with sarcoma 180 tumor-bearing mice. The polymers showed higher antitumor activity and lower toxicity than both monomeric ETPI and 5-fluorouracil at all doses tested. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 64: 2605–2612, 1997     

Synthesis and characterization of novel hyperbranched fluorescent polymers that can be precisely used for metal ion detection and quantification

Four novel hyperbranched polymers with 4 or 5 ring-closed rhodamine units in each were achieved through RAFT polymerization followed by modification with rhodamine moieties. The solubility, thermostability, and photophysical properties of the polymers were studied. The polymers showed high selectivity and sensitivity to Fe³⁺ among various metal ions in CH₃CN/H₂O (75/25, v/v) and could signal Fe³⁺ through multichannels: emerging a new absorption around 558 nm, over 30 nm fluorescence redshift and significant fluorescence enhancement (including 33–37 folds in intensity and 8.3–12.8 folds in quantum yield), accompanied by visual and fluorescent color changes. The polymers could be applied in the analysis of Fe³⁺ in real water samples. © 2020 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48933.     

Synthesis and characterization of poly(p-phenylene vinylene) polymers containing the quinoxaline group

Summary Novel poly (p-phenylenevinylene) polymers containing the quinoxaline group were prepared by the Horner-Wadsworth-Emmons reaction of the various diphosphonic acid diethyl ester with a dialdehyde monomer. The spectral properties of products so obtained were characterized by UV-visible and fluorescence spectroscopy. The UV-visible absorbance of these polymers showed absorption bands at ca. 432∼440 nm, which corresponding to the π-π* transition of the conjugated system. Their maximum fluorescence appeared at ca. 488 ∼ 498 nm. The resulting polymers showed greenish blue emission in solution and an orange emission in solid state. Received: 13 December 2002/Revised version: 27 February 2003/ Accepted: 1 March 2003 Correspondence to Jae Yun Jaung     

Studies on the synthesis and properties of thermotropic liquid crystalline copoly(amide–ester–imide) derived from N-(hydroxyphenyl)phthalimide-4-carboxylic acid with amino acid

Three series of copoly(amide–ester–imide)s were prepared from amino acid (4-aminobenzoic acid, 3-aminobenzoic acid, or 6-aminohexanoic acid) and N-(4-hydroxyphenyl)phthalimide-4-carboxylic acid (M1), N-(3-hydroxyphenyl)phthalimide-4-carboxylic acid (M2), or N-(2-methyl-4-hydroxyphenyl)phthalimide-4-carboxylic acid (M3) in the presence of diphenylchlorophosphate (DPCP) and pyridine as direct condensation agents. The inherent viscosities of copoly(amide–ester–imide)s were in the range of 0.13–0.95 dL/g. Thermotropic liquid crystalline (LC) behavior of these polymers was examined by differential scanning calorimetry (DSC) and optical polarizing microscopy. These copoly(amide–ester–imide)s ( IIa, IIe, IIIa , and IIIc ) polymerized from 3-aminobenzoic acid or 6-aminohexanoic acid with M1 or M3, respectively, showed thermotropic liquid crystalline behavior in the range of 190–426°C. © 1995 John Wiley & Sons, Inc.     

Nonlinear biodegradable polyanhydrides synthesized from natural fatty acids through a new way

Ricinoleic acid was esterified by fatty diacid chlorides to yield intermediate diacids, which were next converted to corresponding polyanhydrides by vacuum-melt polycondensation. The intermediates and polymers were characterized by means of ¹H NMR, IR spectroscopy, differential scanning calorimetry (DSC), X-Ray diffraction and light scattering. The optimized reaction conditions of melt polycondensation were investigated and copolyanhydride with molecular weight (weight average) up to 1.38 × 10⁵ and intrinsic viscosity of 126 cm³/g was obtained. DSC and X-ray diffraction analysis showed that the synthesized copolyanhydrides exhibited much lower crystallinity and improved thermal properties in comparison with aliphatic linear homopolyanhydrides. Received: 8 October 1996/Revised: 14 April 1997/Accepted: 22 April 1997     

Synthesis and characterization of pendent hydroxy fluoroesters of secondary high molecular weight guayule rubber

The epoxidation of secondary high molecular weight guayule rubber (SHMWGR) and subsequent ring opening with fluoroacids to give hydroxyfluoroesters (FGR) is reported. Structural characterization was performed with FTIR; ¹H-, ¹³C-, and ¹⁹F-NMR; and DSC. The percent epoxidation was quantitatively determined by ¹H-NMR. It was noted that the glass transition temperatures (T_g) of the FGR polymers increased with increasing fluoro acid content; however, reactions with longer chain, highly fluorinated acids lowered the T_g. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 63: 1077–1089, 1997     

Syntheses and antitumor activities of polymers containing 2-acrylamido-2-methyl-1-propanesulfonic acid or 5-fluorouracil

Summary The polymers containing 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPA) were prepared by radical polymerizations. The polymers were identified by FT-IR, ¹H-, and ¹³C-NMR spectroscopies. The contents of AMPA unit in poly(AMPA-co-MAH), terpoly(AMPA-MAH-FUR), and poly(AMPA-co-EETFU) were 67, 73 and 49 mol %, respectively. The number average molecular weights of the polymers determined by GPC were in range from 5,600 to 9,200. The IC₅₀ values of the synthesized polymers against cancer cell lines were in the range of 0.02 to 127. The in vivo antitumor activities of polymers against Balb/C mice bearing the sarcoma 180 tumor cells were greater than those of 5-FU. Received: 6 September 2000/Revised version: 12 March 2001/Accepted: 22 March 2001     

Asymmetric polymerization of N-substituted maleimides with organolithium — bisoxazolines complex

Asymmetric anionic polymerizations of achiral N-substituted maleimide (RMI) (N-cyclohexyl (CHMI), N-phenyl (PhMI), N-tert-butyl (TBMI)) by n-butyllithium (n-BuLi) or fluorenyllithium (FlLi) complexes of chiral bisoxazoline derivatives in toluene gave optically active polymers ([α]²⁵ ₄₃₅− 2.9° to − 8.2°). The polymers prerared with initiator of n-BuLi – 2,2′-bis(4,4′-isopropyl-,3-oxazoline) showed negative specific rotations (poly(RMI), [α]²⁵ ₄₃₅− 5.8° to − 8.2°) which were greater than those ([α]²⁵ ₄₃₅− 2.9° to − 5.9°) with other chiral 2,2′-bis(4,4′-alkyl-1,3-oxazoline) (alkyl group = iso-butyl and benzyl). Received: 29 July 1997/Revised: 27 August 1997/Accepted: 1 September 1997     

Synthesis and fluorescence properties of terbium-polybis(benzylsulfinyl) ethane complexes

A functional polymer polybis (benzylsulfiny) ethane (PBBSE) and Tb³⁺-PBBSE-L (where L is low-molecular-weight organic ligands) ternary complexes were synthesized. The structures of the polymer complexes were investigated by elementary analysis and by comparison of infrared (IR) and fluorescence spectra between the polymer complexes and the corresponding low-molecular-weight complexes. Emission bands of f → f transition of Tb³⁺ in the polymer complexes were characterized. There are 4–7 emission peaks in the fluorescence spectra of the polymer complexes at excitation of ultraviolet light at room temperature. Of particular interest is the strong fluorescence intensity of the polymer ternary complex Tb-PBBSE-Phen. The fluorescence intensity of the complexes was increased in the following order: Tb-PBBSE (27.0) < Tb-PBBSE-TTA (82.3) < Tb-PBBSE-Phen (172.2). The maximum excitation energy and the apparent Stokes shift were increased just as this order in the Tb-PBBSE-low-molecular-weight ligand system complexes. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 64: 1575–1583, 1997     

Synthesis and spectral,thermal, and photocrosslinking studies of poly(benzylidene phosphoramide ester)s

A new class of poly(benzylidene phosphoramide ester)s containing a photoreactive benzylidene chromophore in the main chain were synthesized from bis(4-hydroxy-3-methoxy benzylidene) acetone with various substituted N-aryl phosphoramidic dichlorides by an interfacial polycondensation technique. The synthesized polymers were characterized by inherent viscosity, IR, and ¹H-, ¹³C-, and ³¹P-NMR spectroscopy. The molecular weights of these polymers were determined by gel permeation chromatography. These polymers were studied for their thermal stability and photochemical properties. Thermal properties were evaluated by thermogravimetric analysis and differential scanning calorimetry. It was found that halogen-containing polymers show a higher thermal stability than that of nonhalogenated polymers. The photocrosslinking property of these polymers was studied by ultraviolet spectroscopy. The photoreactive benzylidene chromophore in the main chain dimerizes via 2π + 2π cycloaddition reaction to form a cyclobutane derivative and leads to crosslinking. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 65: 2151–2157, 1997     

Novel poly(3,4‐dialkoxythiophene)s carrying 1,3,4‐oxadiazolyl‐biphenyl moieties: synthesis and nonlinear optical studies

Two new donor–acceptor types of polymer, poly{2‐(biphenyl‐4‐yl)‐5‐[3,4‐dialkoxy‐5‐(1,3,4‐oxadiazol‐2‐yl)thiophen‐2‐yl]‐1,3,4‐oxadiazole}s, were synthesized starting from 2,2′‐sulfanediyldiacetic acid and diethyl ethanedioate through multi‐step reactions. The polymerization was carried out via the polyhydrazide precursor route. The optical and charge‐transporting properties of the polymers were investigated using UV‐visible and fluorescence emission spectroscopic and cyclic voltammetric studies. The polymers showed bluish‐green fluorescence in solutions. The electrochemical band gaps of the polymers were determined to be 2.16 and 2.22 eV. The nonlinear optical properties of the polymers were investigated at 532 nm using the single‐beam Z‐scan technique with nanosecond laser pulses. The polymers showed strong optical limiting behaviour due to effective three‐photon absorption. The values of the three‐photon absorption coefficients for the polymers were found to be 9 × 10^?24 and 17 × 10^?24 m³ W^?2, which are comparable to those of good optical limiting materials. Copyright © 2010 Society of Chemical Industry     

Synthesis, characterization and thermal properties of soluble aromatic poly(amide imide)s

Novel diamines such as N,N′-bis(aminoaryl)terephthalamido-2-carboxylic acids (BATCA), which contain primary amine, amide and carboxylic acid groups and are soluble in dilute aqueous NaOH solution, were synthesized by reacting aromatic diamines with trimellitic anhydride chloride in dimethylformamide. Poly(amide imide)s containing 3:1 ratio of amide:imide groups in the polymer chain were prepared by low temperature solution polymerization of BATCAs with isophthaloyl chloride or terephthaloyl chloride in dimethylformamide at 5-10 °C to form poly(amide amic acid)s, and followed by treating with a mixture of triethylamine and acetic anhydride. The PAIs were soluble in polar aprotic solvents like dimethylformamide, dimethylacetamide, dimethylsulphoxide and N-methylpyrrolidone, and have inherent viscosities in the range of 0.30-0.66 dL/g. The PAIs were characterized by IR, ¹H NMR and ¹³C NMR techniques. Thermogravimetric analysis (TGA) has shown that the initial decomposition temperatures of the polymers are in the range of 250-440 °C, depending upon the structures of diamine and diacid chloride. The glass transition temperatures of the PAIs are in the range of 128-320 °C. The IDT and T_g values of the polymers containing terephthaloyl unit are higher by about 20-40 °C than those of the polymers with isophthaloyl unit. BATCA could be utilized for the preparation of thin film composite membranes having PAA/PAI barrier layer on PES by in situ interfacial polymerization with IPC/TPC/TMC.