• Title/Summary/Keyword: 1H-NMR spectroscopy

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Effect of Polyisocyanate Hardener on Waterborne Polyurethane Adhesive Containing Different Amounts of Ionic Groups

  • Rahman Mohammad Mizanur;Kim Han-Do
    • Macromolecular Research
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    • v.14 no.6
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    • pp.634-639
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    • 2006
  • Waterborne polyurethane (WBPU) adhesive with varying amounts of dimethylol propionic acid (DMPA) was synthesized by prepolymer process and blended with polyisocyanate hardener. The mean particle size of the WBPU dispersion decreased with increasing DMPA content. $^1H$ NMR spectroscopy confirmed the formation of allophanate bonds and biuret bonds due to the reaction of hardener NCO with urethane/urea groups. The optimum NCO content with the greatest adhesive strength was dependent on the total content of urethane/urea groups in the WBPU molecules. The optimum NCO content increased with increasing number of urethane groups (DMPA content). The adhesion strength of WBPU adhesives was maximized at a molar ratio of hardener NCO to urethane/urea of about 0.28.

Novel Antibiotic Peptides, Tylopeptins A and B, from Tylopilus neofelleus: Isolation, Identification, and Biological Activity

  • Lee, Sang-Jun;Yun, Bong-Sik;Cho, Duk-Hyun;Yoo, Ick-Dong
    • Proceedings of the Korean Society of Applied Pharmacology
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    • 1998.11a
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    • pp.133-133
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    • 1998
  • Tylopeptins A and B are novel peptides from methanol extract of fruit body of mushroom, Tylopilus neofelleus, These novel peptides were isolated by reverse-phase HPLC. And they have been shown to consist of one acetylated N -terminal residue, fourteen amino acids, and leucinol, C-terminal amino alcohol. Sequencial determination and complete 1H and 13C resonance assignments were based on positive ion F AB mass spectroscopy and two dimensional NMR techniques using HOHAHA, ROSEY, HMQC, and HMBC. These compounds are active against some Gram-positive bacteria, but inactive against phathogenic fungi and Gram-negative bacteria.

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Studies on the Wood Extractives (III) - Isolation of Flavonoid and Sterol compounds - (목재추출성분(木材抽出成分)에 관(關)한 연구(硏究)(III) - 플라보노이드 및 스테로이드화합물(化合物)의 단리(單離))

  • Choe, Hyoung-Joo;Hwang, Byung-Ho
    • Journal of the Korean Wood Science and Technology
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    • v.14 no.3
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    • pp.30-35
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    • 1986
  • To elucidate chemical structure of the wood extracitives, softwood Larix leplolepis Gorden) metal was extracted with 95% ethanol at room temperature for 72 hours. The extract was fractionated with organic solvents such as n-hexane, chloroform. ether, and ethylacetate. From the n-hexane soluble fraction of the extratives, flavonoid and sterol compounds were isolated and identified as taxifolin(5,7,3',4'-tetrahydroxyflavanonol)(I) and ${\beta}$-sitosterol(II) by UV, IR, $^1$H-NMR spectroscopy and Mass spectrometry.

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A Study on the Synthesis of Cationic Fiber-Softener HEC-2-HP-AC Ether Derivatives (양이온성 섬유유연제 HEC-2-HP-AC Ether 유도체의 합성에 관한 연구)

  • Kang, Ik Joong
    • Applied Chemistry for Engineering
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    • v.9 no.4
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    • pp.603-607
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    • 1998
  • Cellulose was reacted with ethylene oxide to get hydroxyethylcellulose. Quaternary ammonium salt was produced by reaction of epichlorohydrin and trialkylamine. The epoxide ring was opened by acid addition to 3-chloro-2-hydroxypropyltrialkylammonium chloride. Previously unreported two compounds, hydroxyethylcellulose-2-hydroxypropylammonium chloride ether and hydroxyethylcellulose-2-hydroxypropyltriethylammonium chloride ether were synthesized by substitution reaction of hydroxyethylcellulose with glycidyltrialkylammonium chloride or 3-chloro-2-hydroxypropyl-glycidyltrialkylammonium trialkylammonium chloride. All of the compounds including starting materials and reaction intermediates were characterized by $^1H$-NMR and FT-IR spectroscopy.

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Synthesis and Characterization of Quaterrylene Bisimide as NIR Colorant (NIR Colorant용 Quaterrylene Bisimide의 합성 및 특성 연구)

  • Park, Keun-Soo;Jeong, Yeon-Tae
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.24 no.5
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    • pp.398-403
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    • 2011
  • Recently, Near-infrared (NIR)colorant is intriguing and attractive but full of challenges. Although some cyanine colorant have been commercialized, near-infrared colorant with intensive NIR absorption, good chemical and photo-stability, and high solubility still remain as target compound. Certain polycyclic aromatic compounds such as quaterrylene represent a key class of NIR colorant and also give rise to outstanding physical and chemical properties after appropriate chemical modification. In this study, We have tried to introduceimide functional group to quaterrylene in order to give chemical and thermal stability. Finally, N,N'-bis (2,6-diisopropylphenyl)-quarterrylene-3,4:13,14-tetracarboximide was synthesized and evaluated its properties using $^1H$ NMR, Maldi-tof, TGA, and UV/VIS/NIR spectroscopy as NIR colorant. The quaterrylene bisimide compound exhibit a excellent thermal stability and chemical stability.

Synthesis of Alkoxy Modified Silicone Using Alkali Catalyst

  • Lee, Kangseok;Shim, Sang Eun
    • Elastomers and Composites
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    • v.51 no.2
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    • pp.99-105
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    • 2016
  • Alkoxy modified silicone (PAMS) was synthesized from hydroxyl-terminated polydimethylsiloxane (OH-PDMS) and vinyltrimethoxysilane (VTMO) under alkali catalyst (NaOH and KOH) at room temperature ($25^{\circ}C$) via condensation polymerization. Then, the structural verification of the synthesized PAMS was confirmed using $^1H$-NMR and FT-IR spectroscopy. The reaction rate of PAMSs was studied in terms of the concentration variation of alkali catalyst. The reaction rate increased with the concentration of alkali catalyst, but no correlation between conversion and concentration of alkali catalyst was observed.

Synthesis and Characterization of Bis(silyl) Palladinum and -Platinum(II) Complexes (비스실릴팔라듐(II) 및 백금(II)착물의 합성 및 확인)

  • Cho, Jun-Churl;Kim, Yong-Joo
    • Journal of Integrative Natural Science
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    • v.2 no.3
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    • pp.190-193
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    • 2009
  • Bis(silyl)palladinum(II) and -platinum(II) complexes are key intermediates for the synthesis of organic silyllated compounds by the Pd or Pt-catalyzed reactions. Reactions of dialkylpalladinum and -platinum complexes with diphenylsilane gave the bis(silyl)palladinum and -platinum complexe in moderate to good yields. Isolated complexes were characterized by $^1H$, $^{13}C$ and $^{31}P$-NMR spectroscopy and elemental analyses. Some of the complexes were determined by X-ray crystallographic studies.

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Characterization and Modification of Low Molecular Water-Soluble Chitosan for Pharmaceutical Application

  • Jang, Mi-Kyeong;Nah, Jae-Woon
    • Bulletin of the Korean Chemical Society
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    • v.24 no.9
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    • pp.1303-1307
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    • 2003
  • The low molecular water-soluble chitosan nanoparticles (LMWSC-NPs) were prepared, which was modified with hydrophilic and hydrophobic moieties to evaluate the potential for pharmaceutics application. The synthesis of LMWSC-NPs was identified by FT-IR and $^1H$-NMR spectra. Also, we measured the photon correlation spectroscopy (PCS), transmission electron microscope (TEM) and atomic force microscope (AFM) to investigate the characteristics and morphology of the LMWSC-NPs. At the PCS measurement, the more increase the number of substitutive group, the more decrease the positive charge of LMWSC-NP surface. From the results of TEM and AFM, spherical morphologies were observed, and their sizes were 30-150 nm. Resultantly, LMWSC-NPs prepared in this experiment will be expected as a suitable device for the drug targeting system.

Synthesis and Characterization of New Azomethine Polymers Containing Bent-Core Mesogen with Sharp Bend Angle

  • Kim, Eun-Chol;Choi, E-Joon;Ok, Chang-Woo;Zin, Wang-Choel
    • 한국정보디스플레이학회:학술대회논문집
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    • 2007.08a
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    • pp.553-555
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    • 2007
  • Six azomethine polymers containing bent-core mesogen were synthesized with variation of a bent structure of central core (1,2-dioxyphenylene or 2,3-dioxynaphthylene), and a lateral halogen substituent (X = H, F or Cl ). The properties of the polymers were characterized by FT-IR, NMR spectroscopy, DSC, polarizing optical microscopy, and X-ray diffractometry.

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Preparation and Characterization of Folic Acid Linked Poly(L-glutamate) Nanoparticles for Cancer Targeting

  • Lee Yong-Kyu
    • Macromolecular Research
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    • v.14 no.3
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    • pp.387-393
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    • 2006
  • Nanoparticles of Poly(L-glutamic acid) (PG) conjugated to the anticancer drug paclitaxel and targeted moiety folic acid (FA) were synthesized and characterized in vitro. The nanoparticles were designed to take advantage of FA targeting to folate receptor (FR) positive cancer cells. The chemical composition of the conjugate was characterized by $^1H-NMR$, FTIR and UV/vis spectroscopy. The selective cytotoxicity of the FA-PG-paclitaxel conjugates was evaluated in FR positive cancer cells. The interaction of the conjugate was visualized by fluorescence microscopy with results confirming the successful preparation of the conjugate and the production of nanoparticles of about 200-300 nm in diameter. The amount of paclitaxel conjugated to FA-PG was 25% by weight. Cellular uptake of the conjugate was FA dependent, and the conjugate uptake was mediated specifically by the folate receptor. These results demonstrate the improved selective toxicity and effective delivery of an anticancer drug into FR bearing cells in vitro.