Synthesis and characterization of new fluorinated photoactive polyamides based on xanthene pendant: Evaluation of antibacterial and heavy metal ions removal behavior

A series of novel organosoluble polyamides (PAs) bearing different functional groups such as flexible ether, substituted imidazole, and xanthene rings and electron-withdrawing CF₃ groups were synthesized from diamines and various dicarboxylic acids. The structures of diamines and PAs were fully characterized by elemental analysis, Fourier transform infrared spectroscopy, and proton nuclear magnetic resonance spectroscopy. The PAs showed good solubility in aprotic and polar organic solvents, with high thermal stability exhibiting the glass transition temperatures (T_gs) and 10% weight loss temperatures (T₁₀%) in the range of 184–277°C and 410–480°C in N₂ atmosphere, respectively. These polymers showed fluorescence emission upon irradiation with UV light. Diamine compounds and two of synthesized polymers were also screened for antibacterial activity against gram-positive and gram-negative bacteria, and the obtained results for all four combinations showed good inhibition. Extraction capability for heavy metal ions such as Cr³⁺, Pb²⁺, Hg²⁺, Cd²⁺, and Co²⁺ from aqueous solutions was also tested at 25°C and pH 7–8.     

Synthesis and characterization of aromatic polyamides containing alkylphthalimido pendent groups

A series of polyisophthalamides containing pendent phthalimido groups and flexible side spacers were prepared from four novel diacids and three commercial aromatic diamines. These polyamides were prepared in high yields and with high molecular weights by direct polycondensation with triphenyl phosphite and pyridine as condensing agents. The weight‐average and number‐average molecular weights, measured by gel permeation chromatography, were 70,000–137,000 and 47,000–86,000 g/mol, respectively. The novel polyamides were amorphous and readily soluble and showed glass‐transition temperatures of 150–240 °C, as measured by differential scanning calorimetry. Thermogravimetric analysis showed that the 10% weight‐loss temperatures in nitrogen were 355–430 °C, a significant improvement in thermal stability having been observed with the increase in the side‐chain length. A theoretical quantum mechanical study was successfully carried out to explain these results. Flexible and tough films, cast from polymer solutions, showed tensile strengths of 50–125 MPa. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 3711–3724, 2002     

Synthesis and characterization of some novel organometallic aromatic polyamides

Some novel ferrocene containing aromatic polyamides were prepared by low‐temperature solution phase polycondensation of 1,1′‐ferrocenedicarboxylic acid chloride with some newly synthesized aromatic diamines in tetrahydrofuran, in the presence of triethylamine. The amorphous polymers were derived in good yields, and did not melt at >350 °C. The monomers and the resulting polymers were characterized by their physical properties, elemental analysis, ¹H‐NMR, FTIR spectroscopy, differential scanning calorimetry and thermogravimetric analyses. The polymeric products were insoluble in common solvents tested. However, all were miscible in concentrated H₂SO₄, forming reddish brown solutions at ambient conditions. The glass transition temperatures (T_g) of these polymers were quite high, which is characteristic of aramids. They are stable up to 500 °C, with 10% mass loss observed in the range 400–650 °C. The activation energies of pyrolysis for each of the products were calculated by Horowitz and Metzger's method. Solution viscosities of the polymers were reduced in concentrated sulfuric acid, which is due to their non‐Newtonian behavior. Copyright © 2006 John Wiley & Sons, Ltd.     

Aromatic polyamides with pendent acetoxybenzamide groups and thin films made therefrom

New aromatic polyamides containing 1,3,4-oxadiazole or benzonitrile units in the main chain and 5-(4-acetoxybenzamido) groups in the side chain have been synthesized and their properties have been characterized and compared with those of related polyamides and polyoxadiazole-amides. These polymers show good thermal stability, with initial decomposition temperature being at about 300 °C and glass transition temperature in the range of 260-280 °C. They are easily soluble in certain solvents such as N-methylpyrrolidinone (NMP), N,N^′-dimethylacetamide (DMA) and N,N^′-dimethylformamide (DMF) and can be cast from solutions into thin flexible films. The polymer films had tensile strengths in the range of 77-97 MPa, tensile moduli in the range of 2.3-2.6 GPa and elongation at break values ranging from 6% to 24%. One of the polymers containing the 1,3,4-oxadiazole ring exhibited blue fluorescence.     

Synthesis and characterization of novel N-carbazole end-capped oligothiophene-fluorenes

A series of novel N-carbazole end-capped oligothiophene-fluorenes was synthesized using Ullmann coupling, bromination, and Suzuki coupling reactions. The optical, thermal, and electrochemical properties of these materials can be tuned by varying the conjugation length of the oligothiophene segment. The terminal carbazole and central fluorene moieties of the resulting materials are beneficial for their morphology, conjugation length, and solubility.     

Synthesis, characterization, and properties of 7,7′-bis(3,6-di-tert-butylcarbazol-N-yl)-substituted fluorenyl-oligothiophenes

A series of new 7,7′bis(3,6-di-tert-butylcarbazol-N-yl)-substituted fluorenyl-oligothiophenes bearing 0-, 2-, 4-, 6-, and 8-thiophene rings, namely BCFTn, were synthesized using palladium catalyzed Stille dimerization coupling reactions of their corresponding brominated thiophenes. The relationship between the chemical structure and the properties of these oligomers was evaluated. With respect to the electronic properties, the longest wavelength absorptions, emissions, and also the oxidation potentials can be tuned by varying the conjugation length of the oligothiophene segments. The terminal carbazole and fluorene moieties of the resulting materials are beneficial for their morphology, conjugation length, and solubility.     

A novel generation of photoactive comb‐shaped polyamides for the photoalignment of liquid crystals

A new approach to the synthesis of photoactive comb‐shaped homo‐ and copolyamides containing azobenzene, cinnamate, and coumarin side groups for photoalignment of liquid crystals was elaborated. Photooptical properties and photoorientational ability of these polymers with respect to liquid crystals were studied. It was shown that polarized UV irradiation of all spin‐coated polyamides leads to orientation of liquid crystalline molecules deposited on the polyamide thin films. The synthesized polymers containing cinnamate and coumarin side groups as well as azobenzene‐containing cyano‐ and nitro‐substituted polymers demonstrated good orientation ability in relation to liquid crystals displaying photoinduced planar orientation with high dichroism values within the range of 0.68–0.72. Contrary to the above‐mentioned polyamides, azobenzene‐containing fluorosubstituted polymers induced a homeotropic orientation of liquid crystals. It was shown that the synthesized photoactive polyamides can be considered as promising photoalignment materials for application in display technology, photonics, and other “smart” optical devices. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013 , 51, 4031–4041     

Polyisophthalamides with benzoyl pendent groups: Synthesis,characterization, and evaluation of properties

Polyisophthalamides containing benzoyl pendent groups were prepared from 5-benzoylisophthaloyl chloride and seven aromatic diamines, and their properties were compared with those of unsubstituted polyisophthalamides. The incorporation of one pendent benzoyl group per repeat unit brought about a decrease in the glass transition temperature of 10–30°C, relative to the unmodified polymers, while the thermal resistance (programmed TGA) remained unchanged or went down slightly. Other properties investigated were mechanical properties, solubility, and water absorption. © 1993 John Wiley & Sons, Inc.     

Anti-inflammatory and antibacterial activity study of some novel quinazolinones

Anti-inflammatory and antibacterial activities of some novel quinazolinones were determined. Evaluation of anti-inflammatory activity of test compounds was performed using carrageenan induced paw edema in rats. Oral administration of test compounds 25 mg/kg and 50 mg/kg reduced the paw edema significantly (P < 0.05) in a dose dependent manner compared to carrageenan induced rats. The test compounds were also screened for their antibacterial activity against the strains of Staphylococcus aureus and Escherichia coli at the concentrations of 200 μg/ml and 1 mg/ml. The test compounds showed better activity as that of the standard lincomycin at the tested higher concentration against S. aureus. None of the compounds exhibit comparable activity to that of the standard ceftazidime against E. coli.     

Synthesis of Cu-TiNT,characterization, and antibacterial properties evaluation

Copper ion–exchanged titanate nanotubes (Cu-TiNTs) had been prepared from a simple ion-exchange reaction between copper salt and sodium titanate nanotubes (Na-TiNT) which was synthesized by alkaline hydrothermal synthesis starting from titanium oxide of anatase phase. A thorough structural and morphological characterization of Cu-TiNT (and Na-TiNT) was done by using various material characterization techniques, such as X-ray diffraction, Raman spectroscopy, energy-dispersive X-ray spectroscopy, and transmission electron microscopy to reveal retention of tubular structure of titanate nanotubes with decoration of copper (II) oxide on the surface of the tubes as well as an exchange of Na⁺ ion by Cu²⁺ ion in the interlamellar space. The antibacterial properties of the Cu-TiNT were evaluated by broth macrodilution method using microtiter trays, with concentration ranging between 512 and 0.5 μg/mL. The Cu-TiNT demonstrated no clinically relevant antibacterial activity alone (minimum inhibitory concentration ≥ 1024 μg/mL), but when associated with gentamicin, this compound enhanced the antibiotic activity of this drugs against strains of Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli. The results were very promising to the utilization of the Cu-TiNT as an adjuvant to the antibiotic therapy.     

Synthesis,antibacterial evaluation and survey on the thermophysical characteristics of novel medically applicable polyamides containing pharmaceutically outstanding triazole moieties

There are many different strategies to decrease the incidence of infection of medical device and food related containers. One way to prevent infection is by modifying the polymers used in making the devices and containers. Incorporation of antimicrobial agents in the bulk material or in formulations of medical devices production has been considered a viable alternative for systemic application of antibiotics. In this article, preparation of a series of triazole containing polymers, poly(triazole-amide-imide)s (PTAI)s and poly(triazole-amide) (PTA)s, and their monomers are reported. These polymers were readily soluble in a variety of organic solvents, showed significant thermal properties and also viscosities in the range of 0.55–0.66 dL/g. They have been tested against a range of Gram-positive and Gram-negative pathogens. The results indicated that these novel polymers containing triazole moiety in their repeating units can effectively control Gram-positive and negative pathogens and their physic-chemical properties besides their antibacterial characteristics make them unique candidate for using in the manufacturing of the medical devices.     

Synthesis and characterization of optically active polyamides derived from carbohydrate-based monomers

The synthesis of three new stereoregular AB-type polyamides based on D -ribono-1,4-lactone, L -arabinose, and D -xylose has been carried out by the active ester polycondensation method. These polyamides were characterized by elemental analysis, IR and NMR spectroscopies, and powder X-ray diffraction. They displayed optical activity and had a pronounced affinity to water, although they were not soluble in this solvent. The polyamide obtained from D -ribono-1,4-lactone was highly crystalline and yielded films with spherulitic texture. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35: 3645–3653, 1997     

Synthesis and photoluminescence properties of novel polyarylates bearing pendent naphthylamine chromophores

A new series of blue photoluminescent aromatic polyesters (polyarylates) were synthesized from 1-[N,N-di(4-carboxyphenyl)amino]naphthalene with various bisphenols by the diphenylchlorophosphate (DPCP) activated direct polycondensation in a medium of pyridine and lithium chloride. The synthesis, basic characterizations, photoluminescence and electrochemical properties of this series of novel polyarylates bearing pendent naphthylamine chromophores were investigated. All polymers not only had good solubility in many polar aprotic solvents and excellent thin-film-forming ability, but also exhibited high T_g values, good thermal stability and lower highest occupied molecular orbital (HOMO) level. Thus, these naphthylamine-containing polyarylates may be widely applied in P-LED as hole-transporting layer and blue light-emitting materials due to their proper HOMO level, excellent thermal stability and fluorescence quantum efficiency.     

Synthesis,characterization and antibacterial screening of some novel 1,2,4-triazine derivatives

A new series of 1, 2, 4-triazine derivatives possessing indole nucleus were synthesized with an aim to explore their effect on in vitro growth of microorganisms causing microbial infection. In vitro antimicrobial activity was performed against S. aureus, S. epidermidis, P. mirabilis and E. coli using disk diffusion method. The MIC was detected using the double dilution method. The results were compared by calculating percent inhibition area/μg of the compounds with the standard drug "Ciprofloxacin". Selected compounds were evaluated for toxic effects using human hepatocellular carcinoma (HepG2) cell line by MTT-assay. Results revealed that some compounds of the series were found to exhibit better activity with less toxicity than Ciprofloxacin.     

Synthesis of novel steroidal oxazolo quinoxaline as antibacterial agents

Steroidal[oxazolo(4,5-b)quinoxaline-2-yl-hydrazone] derivative (7a–9a) (7b–9b) were prepared by the multi-step reactions of steroid. It is prepared via the reaction of steroidal semicarbazones with 2,3-dichloroquinoxaline at 80 °C in ethanol. The structures of the compounds were evident by IR, ¹H NMR and mass spectrometry and their purities were confirmed by elemental analyses. The antibacterial activity of these compounds was evaluated by the disk diffusion assay against two Gram-positive and two Gram-negative bacteria and then the minimum inhibitory concentration (MIC) of compounds was determined. The results showed that compounds (7a, 7b, 8a, 8b) are better antibacterial agent as compared with the standard drug amoxicillin.     

Synthesis and properties of new aromatic polyisophthalamides with adamantylamide pendent groups

A new diacid monomer containing a pendent adamantyl ring was reacted with various aromatic diamines to prepare novel aromatic polyisophthalamides (PIPAs). The polymers were obtained in high yield and high molecular weight by the Yamazaki‐Higashi phosphorylation method of polycondensation. Inherent viscosities ranged from 0.40 to 0.82 dL/g, which corresponds to weight‐average and number‐average molecular weights (GPC) in the range 21,000–63,000 g/mol and 9000–31,000 g/mol, respectively. The polymers were essentially amorphous and soluble in a variety of polar aprotic solvents, and they afforded transparent, creasable films by the solution‐casting method. The great size of the polyhedral adamantyl moiety brought about a significant restriction of segmental mobility, which translated into a strong increase of T_g, so that very high glass transition temperatures were observed, in the range 335–370 °C (DSC), which are 70–90 °C above the glass transition temperatures of homologous PIPAs without pendent groups. Thus, it can be stated that these adamantyl containing polyamides are among the soluble aromatic PIPAs with highest T_g ever described. Conversely, the initial decomposition temperature, as measured by thermogravimetric analysis, was about 400 °C, which is lower by 40–70° than that of unsubstituted counterparts. Polymer films exhibited good mechanical properties, with tensile strengths over 65 MPa and tensile moduli between 2.0 and 2.6 GPa. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1743–1751, 2010     

Preparation and characterization of novel organosoluble and thermally stable poly(benzimidazole-amide)s bearing phthalimide pendent groups

Novel aromatic poly(benzimidazole-amide)s, PBAs, have been synthesized by direct polycondensation of a new dicarboxylic acid, N-[3,5-bis(5-carboxylic acid-2-benzimidazole) phenyl]phthalimide (1), containing performed benzimidazole rings and a phthalimide pendent group with various aromatic diamines. The dicarboxylic acid was synthesized by reaction of 5-(N-phthalimide)isophthalic acid with 4-methyl-1,2-phenylenediamine in polyphosphoric acid, followed by its oxidation into relative dicarboxylic acid. To study the structure-property relationships of 1,3-bis(5-carboxylic acid-2-benzimidazole)benzene (2, as a reference) this compound was also synthesized. The chemical structure of 1 and 2 were confirmed by the spectroscopic methods and elemental analyses. The characterization of the polymers was performed with inherent viscosity measurements, solubility tests, FT-IR, Ultraviolet and ¹H NMR spectroscopy and thermogravimetry. The polymers were obtained in quantitative yields with inherent viscosities between 0.53 and 0.91 dl g⁻¹. The effects of the phthalimide pendent group on the polymer properties such as solubility and thermal behavior were investigated and compared with those of the corresponding unsubstituted poly(benzimidazole-amide)s. The modified poly(benzimidazole-amide)s showed enhanced solubilities in some solvents, such as m-cresol and pyridine, in comparison to the unmodified analogues. In addition, the incorporation of the pendent phthalimide groups in the poly(benzimidazole-amide)s backbone increased remarkably the thermal stability of the polymer. The glass transition temperature and 10% weight loss temperature of the poly(benzimidazole-amide)s were in range of 291-334 °C and 466-540 °C, respectively, in nitrogen.     

Synthesis,in vitro antibacterial and antifungal evaluation of novel 1,3,4-oxadiazole thioether derivatives bearing the 6-fluoroquinazolinylpiperidinyl moiety

A series of structurally novel 1,3,4-oxadiazole thioether derivatives(6a-6z) containing a 6-fluoroquinazolinylpiperidinyl moiety were designed and synthesized using pharmacophore hybrid approach,and their structures were fully characterized by ^1H NMR,¹³C NMR and HRMS spectra.Among them,the structure of compound 6 d was further corroborated via single-crystal X-ray diffraction analysis.In vitro antibacterial bioassays showed that compounds 6 a,6 g,6 u and 6 v possessed EC₅₀ values of 30.4,30.6,27.5 and 26.0 μg/mL against phytopathogenic bacterium Xanthomonas oryzae pv.oryzae,respectively,which were significantly superior to that of commercially-available bactericide Bismerthiazol(85.1 μg/mL).Moreover,in vitro antifungal bioassays indicated that seven compounds demonstrated broad-spectrum fungicidal acitivties against six types of phytopathogenic fungi at 50 μg/mL.The present work showed the potential of 1,3,4-oxadiazole thioether derivatives carrying a 6-fluoroquinazolinylpiperidinyl moiety as effective antimicrobial agents for crop protection,deserving further investigations in the future.     

Synthesis and antibacterial evaluation of new sulfanyltetrazole derivatives bearing piperidine dithiocarbamate moiety

A series of new alkyl or aryl sulfanyltetrazole derivatives containing dithiocarbamate moiety (5a–6e) were synthesized. The structures of the compounds were characterized by IR, ¹H NMR, ¹³C NMR spectra, and elemental analysis data. The present study examines the antibacterial potential of novel synthetic sulfanyltetrazole compounds against clinically important gram-positive and -negative strains. The results of screening showed that attachment of dithiocarbamate to sulfanyltetrazole derivatives results in enhancement of antibacterial activity. The compound 6d showed the best activity among the tested compounds. Also, the less polar 2,5-disubstituted sulfanyltetrazole regioisomers showed an increased antibacterial activity compared with the corresponding more polar regioisomers.     

Preparation and properties of aromatic polyamides from 1,4-bis(p-carboxyphenoxy)naphthyl and aromatic diamines

A new aromatic dicarboxylic acid, 1,4-bis (p-carboxyphenoxy)naphthyl ( 3 ), was synthesized by the reaction of p-fluorobenzonitrile with 1,4-naphthalenediol, followed by hydrolysis. Aromatic polyamides having inherent viscosities of 1.27–2.22 dL/g were prepared by the triphenyl phosphite activated polycondensation of diacid 3 with various aromatic diamines. Most of the resulting polymers showed an amorphous nature and were readily soluble in a variety of organic solvents including N,N-dimethyl-acetamide (DMAc), N-methyl-2-pyrrolidone (NMP), and m-cresol. Transparent, tough, and flexible films of these polymers could be cast from the DMAc or NMP solutions. The cast films had tensile strengths ranging from 64–104 MPa, elongations-at-break from 6 to 10%, and initial moduli from 1.52 to 2.14 GPa. These polyamides had glass transition temperatures in the range of 195 to 240°C. Almost all polymers were thermally stable up to 400°C, with 10% weight loss being recorded above 480°C in air and nitrogen atmospheres. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35 : 2273–2280, 1997