Preservation of epoxy groups on surfaces in the covalent attachment of butadiene monoxide on Si(111)-(7×7): the effect of a vinyl substituent

2015 ◽  
Vol 51 (75) ◽  
pp. 14195-14198
Author(s):  
Wei Mao ◽  
Jing Hui He ◽  
Jia Qiang Gu ◽  
Wei Chen ◽  
Kai Wu ◽  
...  
Keyword(s):  
Epoxy Group ◽  
Covalent Attachment ◽  
Epoxy Groups

A vinyl substituent ensures that butadiene monoxide selectively binds to Si(111)-(7×7) through a [2+2]-like cycloaddition, maintaining an epoxy group in the cycloadduct.

Synthesis of New Bio-Based Thermoset Resin from Palm Oil

2014 ◽  
Vol 931-932 ◽  
pp. 78-82 ◽  
Author(s):  
Alireza Fakhari ◽  
Abdul Razak Rahmat ◽  
Mat Uzir Wahit ◽  
Yeong Shoot Kian
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Fourier Transform ◽  
Palm Oil ◽  
Epoxy Group ◽  
Resonance Spectroscopy ◽  
Thermosetting Resin ◽  
H Nmr ◽  
Thermoset Resin ◽  
Epoxidized Palm Oil ◽  
Epoxy Groups

New bio-based thermosetting resin was synthesized from palm oil. In this study the epoxy groups presented on the epoxidized palm oil (EPO) were first acrylated and then further maleinized. The acrylation reaction was done by introducing acrylic acid into epoxy group of the epoxidized palm oil. Hydroquinone and triethylamine were used as inhibitor and catalyst, respectively. This reaction was confirmed by Fourier Transform Infrared Spectroscopy (FTIR). To render acid groups on the resulting monomer, the acrylated epoxidized palm oil (AEPO) was further reacted with maleic anhydride. The resulting maleinated acrylated epoxidized palm oil (MAEPO) was characterized by FTIR and Nuclear Magnetic Resonance Spectroscopy (1H NMR).

Photo-Induced Optical Anisotropy and Morphological Study in Azobenzene Containing Block Copolymers

2012 ◽  
Vol 714 ◽  
pp. 43-50
Author(s):  
Raquel Fernández ◽  
Iñaki Zalakain ◽  
José Angel Ramos ◽  
Loli Martin ◽  
Iñaki Mondragon
Keyword(s):  
Block Copolymers ◽  
Microphase Separation ◽  
Covalent Attachment ◽  
Nanostructured Systems ◽  
One Step ◽  
Covalently Linked ◽  
Epoxy Matrices ◽  
Epoxy Groups ◽  
Azobenzene Groups ◽  
Thermosetting Epoxy

In this work, different types of nanostructured systems containing azobenzene groups were studied. With that aim, firstly, novel azo-functionalised block copolymers (BCP) were synthesized from epoxidized poly (styrene-b-butadiene-b-styrene) (SBS) modified with azobenzene units by one-step facile reaction between the epoxy groups and an azo-amine. The epoxy/amine reaction was verified by Fourier transform infrared spectroscopy. In addition, the effect of covalent attachment of the azobenzene moieties was investigated by analyzing the morphology and the optical anisotropic response of the resulting azo-containing BCP, with respect to solution mixing of the azobenzene as a guest in the BCP host without chemical bonding. On the other hand, epoxidized SBS was also used as template for the generation of nanostructured thermosetting epoxy matrices with azobenzene groups covalently linked. This BCP can self-assemble in the epoxy matrix to produce microphase-separated domains, thanks to the selective segregation of polystyrene blocks due to reaction induced microphase separation. In this case, the influence of the azobenzene content and the amount of epoxidized SBS on the generated morphologies and the photo-induced anisotropy was studied.

THE BAND ENERGY ENGINEERING ON HIGH EPOXY (OR HYDROXYL) CONTENT GRAPHENE OXIDE

2019 ◽  
Vol 26 (01) ◽  
pp. 1850135 ◽  
Author(s):  
BANAFSHEH ALIZADEH ARASHLOO ◽  
MOHAMMAD TAGHI AHMADI ◽  
SAEED AFRANG
Keyword(s):  
Graphene Oxide ◽  
Energy Levels ◽  
Epoxy Group ◽  
Metal Structure ◽  
The Other ◽  
Hydroxyl Group ◽  
Bandgap Energy ◽  
Hydroxyl Groups ◽  
Adsorption Effect ◽  
Epoxy Groups

Nowadays, the superior properties of carbon-based materials especially nano structural derivation like graphene and graphene oxide (GO) spot light to the researchers. The GO has been suggested as an alternate material in device miniaturization due to its atomic structure. The memristors and nonvolatile memories are settled in these categories as a solution for the scaling limitation problem in the Moor’s law. Therefore, the GO can influence the memristor performance and characteristics. The current–voltage characteristics as the most significant parameter in the memristor design are considered. On the other hand [Formula: see text]–[Formula: see text] characteristic depends on the active layer (GO) bandgap energy in the metal/oxide/metal structure and therefore, needs to be explored. In the GO-based memristor, the bandgap energy can be changed by the percentage of the oxygen groups in comparison to the carbon on graphene sheets. Thus, the other parameters are overstated by the bandgap energy. In the presented work, the energy bandgap of a high epoxy group content of GO sheets is engineered. The opening of the bandgap in the graphene oxide by high epoxy groups content with the ratio of (O/C [Formula: see text] 50%) is studied. In other words, the oxygen adsorption effect on the Hamiltonian of the system is explored. For the proposed structure, the bandgap energy is modeled and the acceptable value (approximately equal to 2.799[Formula: see text]ev for epoxy groups) is obtained. Moreover, the hydroxyl group adsorption effect on the bandgap of the graphene oxide by high content hydroxyl group is considered (approximately equal to 2.647[Formula: see text]ev for epoxy groups). Consequently, the different absorption energy effects on the bandgap of the GO is participated and the opening bandgap in the range of 2[Formula: see text]ev to 3[Formula: see text]ev is obtained. The excitonic effect on the suggested model by epoxy groups and hydroxyl groups is explored and it is realized that the energy levels in the Dirac points of epoxy groups are closer than those of the hydroxyl groups.

Immobilization-Stabilization of Enzymes by Multipoint Covalent Attachment on Supports Activated With Epoxy Groups

2006 ◽  
pp. 47-55 ◽  
Author(s):  
Cesar Mateo ◽  
Olga Abian ◽  
Gloria Fernández-Lorente ◽  
Benevides C. C. Pessela ◽  
Valeria Grazu ◽  
...  
Keyword(s):  
Covalent Attachment ◽  
Multipoint Covalent Attachment ◽  
Epoxy Groups

Organic-Inorganic Hybrids for Bioinert Coating on Implantable Electronic Devices

2011 ◽  
Vol 493-494 ◽  
pp. 508-512 ◽  
Author(s):  
Ill Yong Kim ◽  
K. Nomura ◽  
Koichi Kikuta ◽  
J. Ohta ◽  
T. Tokuda ◽  
...  
Keyword(s):  
Epoxy Group ◽  
Electronic Devices ◽  
Sol Gel ◽  
Chemical Properties ◽  
Maximum Load ◽  
Scratch Test ◽  
Adhesion Property ◽  
Element Analysis ◽  
Adhesion Properties ◽  
Epoxy Groups

For the purpose of bioinert coating on electronic devices, we developed the non-hydrolytic sol-gel derived organic-inorganic hybrid materials by addition of epoxy groups which can adhere strongly to the surface of electronic silicon device. The adhesion and chemical properties of hybrids were investigated as a function of epoxy group contents. The hybrids were prepared from 3-metacrloxypropyltrimethoxysilane (MPTS) and 3-glycidoxypropyltrimethoxysilane (GPTS) and diphenylsilanediol. The transparent hybrids were obtained after curing by UV irradiation. The adhesion properties of the hybrids were estimated by the maximum load to resist in a scratch test. The adhesion property of the hybrids increased with addition of GPTS and the highest adhesion was obtained from the hybrid with 5-10 mol% of GPTS. From the element analysis, Si concentrations of all the solutions were less than 2 mM after soaking for 7 d. The Si concentrations were not changed with increasing soaking period. The addition of epoxy groups is effective on improvement of adhesion property of the silica-based hybrid without loosening its chemical stability.

scholarly journals Epoxyethylglycyl peptides as inhibitors of oligosaccharyltransferase: double-labelling of the active site*

1997 ◽  
Vol 322 (1) ◽  
pp. 95-102 ◽  
Author(s):  
Ernst BAUSE ◽  
Marko WESEMANN ◽  
Achim BARTOSCHEK ◽  
Wilhelm BREUER
Keyword(s):  
Active Site ◽  
Catalytic Mechanism ◽  
Epoxy Group ◽  
Covalent Attachment ◽  
Current View ◽  
Double Labelling ◽  
Acceptor Site ◽  
Hydrogen Bond Acceptor ◽  
Suicide Inactivation

Pig liver oligosaccharyltransferase (OST) is inactivated irreversibly by a hexapeptide in which threonine has been substituted by epoxyethylglycine in the Asn-Xaa-Thr glycosylation triplet. Incubation of the enzyme in the presence of Dol-PP-linked [14C]oligosaccharides and the N-3,5-dinitrobenzoylated epoxy derivative leads to the double-labelling of two subunits (48 and 66 kDa) of the oligomeric OST complex, both of which are involved in the catalytic activity. Labelling of both subunits was blocked competitively by the acceptor peptide N-benzoyl-Asn-Gly-Thr-NHCH3 and by the OST inhibitor N-benzoyl-α,γ-diaminobutyric acid-Gly-Thr-NHCH3, but not by an analogue derived from the epoxy-inhibitor by replacing asparagine with glutamine. Our data clearly show that double-labelling is an active-site-directed modification, involving inhibitor glycosylation at asparagine and covalent attachment of the glycosylated inhibitor, via the epoxy group, to the enzyme. Double-labelling of OST can occur as the result of either a consecutive or a syn-catalytic reaction sequence. The latter mechanism, during the course of which OST catalyses its own ‘suicide’ inactivation, is more likely, as suggested by indirect experimental evidence. The syn-catalytic mechanism corresponds with our current view of the functional role of the acceptor site Thr/Ser acting as a hydrogen-bond acceptor, not a donor, during transglycosylation [Bause, Breuer and Peters (1995) Biochem. J. 312, 979Ő985].

Preparation and Application of Microencapsulated Flame Retardant Containing Phosphorus-Silicon

2012 ◽  
Vol 535-537 ◽  
pp. 419-424
Author(s):  
Yong Yang ◽  
Jia Long Fang ◽  
Miao Lin
Keyword(s):  
Flame Retardant ◽  
Spectrum Analysis ◽  
Epoxy Group ◽  
Sol Gel ◽  
Vertical Direction ◽  
Silica Sol ◽  
Test Results ◽  
Particle Size Analyzer ◽  
Ft Ir ◽  
Epoxy Groups

The silica sol containing epoxy groups was prepared with tetraethoxysilane and silane coupling agent GPTMS as precursors by sol-gel technique and was used to encapsulate the microencapsulated flame retardant to enhance its flame retarding efficiency and water fastness for textile material. The prepared silica sol and gel were characterized by nano particle size analyzer, FT-IR spectrum analysis, energy spectrum analysis and SEM. The experimental results were proved that silica gel containing epoxy group was assuredly deposited on the surface of microencapsulated flame retardant. The cotton fabric was finished by the modified flame retardant and the test results (including the test of flame spread properties of textiles in vertical direction and the fastness to washing) showed that it had better flame retarding efficiency and water fastness.

Advances in the design of new epoxy supports for enzyme immobilization–stabilization

2007 ◽  
Vol 35 (6) ◽  
pp. 1593-1601 ◽  
Author(s):  
C. Mateo ◽  
V. Grazú ◽  
B.C.C. Pessela ◽  
T. Montes ◽  
J.M. Palomo ◽  
...  
Keyword(s):  
Physical Adsorption ◽  
Immobilized Enzymes ◽  
Covalent Immobilization ◽  
Covalent Attachment ◽  
Industrial Enzymes ◽  
Protein Surface ◽  
Strong Stabilization ◽  
Support Surfaces ◽  
Multipoint Covalent Attachment ◽  
Epoxy Groups

Multipoint covalent immobilization of enzymes (through very short spacer arms) on support surfaces promotes a very interesting ‘rigidification’ of protein molecules. In this case, the relative positions of each residue of the enzyme involved in the immobilization process have to be preserved unchanged during any conformational change induced on the immobilized enzyme by any distorting agent (heat, organic solvents etc.). In this way, multipoint covalent immobilization should induce a very strong stabilization of immobilized enzymes. Epoxy-activated supports are able to chemically react with all nucleophile groups placed on the protein surface: lysine, histidine, cysteine, tyrosine etc. Besides, epoxy groups are very stable. This allows the performance of very long enzyme–support reactions, enabling us to get very intense multipoint covalent attachment. In this way, these epoxy supports seem to be very suitable to stabilize industrial enzymes by multipoint covalent attachment. However, epoxy groups exhibit a low intermolecular reactivity towards nucleophiles and hence the enzymes are not able to directly react with the epoxy supports. Thus a rapid physical adsorption of enzymes on the supports becomes a first step, followed by an additional rapid ‘intramolecular’ reaction between the already adsorbed enzyme and the activated support. In this situation, a suitable first orientation of the enzyme on the support (e.g. through regions that are very rich in nucleophiles) is obviously necessary to get a very intense additional multipoint covalent immobilization. The preparation of different ‘generations’ of epoxy supports and the design of different protocols to fully control the first interaction between enzymes and epoxy supports will be reviewed in this paper. Finally, the possibilities of a directed immobilization of mutated enzymes (change of an amino acid by cysteine on specific points of the protein surface) on tailor-made disulfide-epoxy supports will be discussed as an almost-ideal procedure to achieve very intense and very efficient rigidification of a desired region of industrial enzymes.

scholarly journals Comparison of vasodilatory properties of 14,15-EET analogs: structural requirements for dilation

2003 ◽  
Vol 284 (1) ◽  
pp. H337-H349 ◽  
Author(s):  
J. R. Falck ◽  
U. Murali Krishna ◽  
Y. Krishna Reddy ◽  
P. Srinagesh Kumar ◽  
K. Malla Reddy ◽  
...  
Keyword(s):  
Double Bond ◽  
Vascular Tone ◽  
Epoxy Group ◽  
Structural Features ◽  
Epoxyeicosatrienoic Acids ◽  
Acidic Group ◽  
Structural Requirements ◽  
Full Activity ◽  
Group A ◽  
Epoxy Groups

Epoxyeicosatrienoic acids (EETs) are endothelium-derived eicosanoids that activate potassium channels, hyperpolarize the membrane, and cause relaxation. We tested 19 analogs of 14,15-EET on vascular tone to determine the structural features required for activity. 14,15-EET relaxed bovine coronary arterial rings in a concentration-related manner (ED50 = 10−6 M). Changing the carboxyl to an alcohol eliminated dilator activity, whereas 14,15-EET-methyl ester and 14,15-EET-methylsulfonimide retained full activity. Shortening the distance between the carboxyl and epoxy groups reduced the agonist potency and activity. Removal of all three double bonds decreased potency. An analog with a Δ8 double bond had full activity and potency. However, the analogs with only a Δ5 or Δ11 double bond had reduced potency. Conversion of the epoxy oxygen to a sulfur or nitrogen resulted in loss of activity. 14( S),15( R)-EET was more potent than 14( R),15( S)-EET, and 14,15-( cis)-EET was more potent than 14,15-( trans)-EET. These studies indicate that the structural features of 14,15-EET required for relaxation of the bovine coronary artery include a carbon-1 acidic group, a Δ8 double bond, and a 14( S),15( R)-( cis)-epoxy group.

Photochemical and Electrochemical Reduction of Carbon Dioxide Catalyzed by a Polyoxometalate-Organic Photosensitizer Complex

2018 ◽  
Author(s):  
Chandan Dey ◽  
Ronny Neumann
Keyword(s):  
Carbon Dioxide ◽  
Cyclic Voltammetry ◽  
Formic Acid ◽  
Electrochemical Reduction ◽  
Mass Spectroscopy ◽  
Photochemical Reactions ◽  
Reducing Agent ◽  
Covalent Attachment ◽  
Hybrid Complex ◽  
Open Face

<p>A manganese substituted Anderson type polyoxometalate, [MnMo<sub>6</sub>O<sub>24</sub>]<sup>9-</sup>, tethered with an anthracene photosensitizer was prepared and used as catalyst for CO<sub>2</sub> reduction. The polyoxometalate-photosensitizer hybrid complex, obtained by covalent attachment of the sensitizer to only one face of the planar polyoxometalate, was characterized by NMR, IR and mass spectroscopy. Cyclic voltammetry measurements show a catalytic response for the reduction of carbon dioxide, thereby suggesting catalysis at the manganese site on the open face of the polyoxometalate. Controlled potentiometric electrolysis showed the reduction of CO<sub>2</sub> to CO with a TOF of ~15 sec<sup>-1</sup>. Further photochemical reactions showed that the polyoxometalate-anthracene hybrid complex was active for the reduction of CO<sub>2</sub> to yield formic acid and/or CO in varying amounts dependent on the reducing agent used. Control experiments showed that the attachment of the photosensitizer to [MnMo<sub>6</sub>O<sub>24</sub>]<sup>9-</sup> is necessary for photocatalysis.</p><div><br></div>

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