Structure Of Dimethyl Research Articles

Enter the multifunctional trifluoromethylated epoxy Resin: Excellent flame retardant, better dielectric, low thermal expansion, etc

In order to obtain epoxy resins with flame retardant, dielectric properties, and easier industrialization, thus meeting the future development requirements in the field of electronic encapsulation, a trifluoromethylated epoxy resin (DGEBAF) was synthesized by using a two-step method, and the cured epoxy resin (DGEBAF/DDM) was prepared with DDM as the curing agent. Detailed studies of DGEBAF/DDM including curing kinetics, mechanical properties, and dielectric properties, etc. were conducted by using DGEBA/DDM (with dimethyl structure in DGEBA) and DGEBF/DDM (with dihydrogen structure in DGEBF) as the comparative samples. The results indicate that DGEBAF/DDM has higher storage modulus and strength, better dielectric properties, and hydrophobicity, and lowest thermal expansion coefficient, due to the existence of trifluoromethyl. Importantly, deeply study about the flame retardancy and its mechanism of DGEBAF/DDM was processed, which was of great significance for its application in the field of electronic packaging. Its vertical combustion level reaches UL-94 V-0. The limiting oxygen index of DGEBAF/DDM is 34.5 %, which is improved by 35.8 % and 30.2 % compared to DGEBA/DDM and DGEBF/DDM, respectively. The thermal decomposition mechanism of DGEBAF was explored by Py-GC/Mass, XPS, and FTIR analysis. It can be inferred that trifluoromethylated epoxy resin releases •CF3 at high temperatures and effectively enhances the flame retardant of the epoxy resin through radical trapping. The smoke toxicity of DGEBAF/DDM combustion was detected in real time by conical thermal method combined with gas infrared analysis. In addition, we have found that DGEBAF/DDM decomposes at first but produces most residual carbon among the three epoxy resins. Based on the characteristics, an intelligent fire alarm system was designed.

New Cycloadditon Reaction of 2-Chloroprop-2-enethioamides with Dialkyl Acetylenedicarboxylates: Synthesis of Dialkyl 2-[4,5-bis(alkoxycarbonyl)-2-(aryl{alkyl}imino)-3(2H)-thienylidene]-1,3-dithiole-4,5-dicarboxylates.

The 1,3-dipolar cycloaddition of 1,2-dithiole-3-thiones with alkynes to form 1,3-dithioles is one of the most studied reactions in this class of polysulfur-containing heterocycles. Nucleophilic substitution of chlorine atoms in dimethyl 2-(1,2-dichloro-2-thioxoethylidene)-1,3-dithiole-4,5-dicarboxylate, which was obtained by addition one molecules of DMAD to 4,5-dichloro-3H-1,2-dithiole-3-thione, led to a series of 2-chloro-2-(1,3-dithiol-2-ylidene)ethanethioamides. Cycloaddition reaction of 2-chloro-2-(1,3-dithiol-2-ylidene)ethanethioamides with activated alkynes led to the unexpected formation of 2-(thiophen-3(2H)-ylidene)-1,3-dithioles via new intermediate, 1-(1,3-dithiol-2-ylidene)-N-phenylethan-1-yliumimidothioate. Structure of dimethyl 2-(4,5-bis(methoxycarbonyl)-2-(phenylimino)thiophen-3(2H)-ylidene)-1,3-dithiole-4,5-dicarboxylate was finally proven by single crystal X-ray diffraction study. Optimized reaction conditions and a mechanistic rationale for the 1,3-dipolar cycloaddition of novel intermediate are presented.

Crystal structure of dimethyl 1,4-dioxaspiro[4,5]dec-6-ene-(8R)-[(3,5- dinitrobenzoyl)oxa]-(2R,3R)-dicarboxylate, C19H18N2O12

Abstract C19H18N2O12, orthorhombic, P212121 (no. 19), a = 6.2472(6) Å, b = 17.576(2) Å, c = 18.848(3) Å, V = 2069.6 Å3, Z = 4, Rgt(F) = 0.0393, wRref(F2) = 0.0694, T = 210 K.

ChemInform Abstract: Synthesis and Structure of Dimethyl 3,6‐Diphenyl‐1,2‐dihydro‐1,2,4,5‐tetrazine‐1,2‐dicarboxylate.

AbstractIn connection with the preparation of biologically interesting derivatives, treatment of substrate (I) with ester (II) is investigated.

ChemInform Abstract: Reaction of N-Benzoyl-4,7-phenanthrolinium Salt with Trimethyl Phosphite and Crystal Structure of Dimethyl N,N′-Dibenzoyl-3,4,7,8- tetrahydro-4,7-phenanthroline-3,8-diphosphonate.

ChemInform Abstract: Reaction of N-Benzoyl-4,7-phenanthrolinium Salt with Trimethyl Phosphite and Crystal Structure of Dimethyl N,N′-Dibenzoyl-3,4,7,8- tetrahydro-4,7-phenanthroline-3,8-diphosphonate.

Synthesis and Structure of Dimethyl 3,6-Diphenyl-1,2- Dihydro-1,2,4,5-Tetrazine-1,2-Dicarboxylate

Dimethyl 3,6-diphenyl-1,2-dihydro-1,2,4,5-tetrazine-1,2-dicarboxylate was prepared from methyl chloroformate and 3,6-diphenyl-1,2(or 1,4)-dihydro-1,2,4,5-tetrazine and its structure elucidated by X-ray analysis. This reaction yields the title compound rather than dimethyl 3,6-diphenyl-1,4-dihydro-1,2,4,5-tetrazine-1,4-dicarboxylate. The 2,3-diazabutadiene group in the central six-membered ring of tetrazine is not planar and the tetrazine ring has a twist conformation.

Isolation, cloning, sequence analysis and X-ray structure of dimethyl sulfoxide/trimethylamine N-oxide reductase from Rhodobacter capsulatus.

The periplasmic enzyme dimethyl sulfoxide/trimethylamine N-oxide reductase (DMSOR/TMAOR) from the photosynthetic purple bacterium Rhodobacter capsulatus functions as the terminal electron acceptor in its respiratory chain. The enzyme catalyzes the reduction of highly oxidized substrates like dimethyl sulfoxide (DMSO) or trimethylamine N-oxide (TMAO). At a molybdenum redox centre, two single electrons are transferred from cytochrome c556 to the substrate, e.g. DMSO, generating dimethyl sulfide (DMS) and water. The operon encoding this enzyme was isolated, cloned and sequenced, and its chromosomal location determined. It was shown by analytical and crystallographic data that DMSOR and TMAOR are identical enzymes. Degenerate primers were derived from short peptide sequences and a 700 bp fragment was amplified by nested PCR, subsequently cloned and radioactively labeled to screen a prepared lambda DASH library. Positive lambda clones were subcloned into pBluescript and subsequently transformed into Escherichia coli to sequence the DMSOR/TMAOR operon. By an optimized protein purification high yields (5 mg protein/l culture) with a specific activity of 30 U/mg were obtained. The molecular mass was experimentally determined by electrospray mass spectroscopy (MS) to be 85034 Da and from the deduced amino acid sequence of the apoenzyme to be 85033 Da. The enzyme was crystallized in space group P4(1)2(1)2 with unit cell dimensions of a = b = 80.7 A and c = 229.2 A diffracting beyond 1.8 A. The three-dimensional structure was solved by a combination of multiple isomorphous replacement (MIR) and molecular replacement techniques. The atomic model was refined to an R-factor of 0.169 for 57394 independent reflections. The spherical protein consists of four domains with a funnel-like cavity that leads to the freely accessible metal-ion redox center. The sole bis(molybdopterin guanine dinucleotide)molybdenum cofactor (1541 Da) of the single chain protein has the molybdenum ion bound to the cis-dithiolene group of only one molybdopterin guanine dinucleotide (MGD) molecule. In addition, two oxo ligands and the oxygen of a serine side chain are bound to the molybdenum ion.

Dimethylthallium(III) complexes with sulfur-nitrogen and sulfur-oxygen ligands: the molecular structure of Me2TlL (L = 1-oxidopyridinium-2-thiolato)

The reaction of heterocyclic thiolic derivatives HLnwith dimethylthallium(III) hydroxide yields Me2TlL compounds. The structure of dimethyl(1-oxidopyridinium-2-thiolato)thallium(III), Me2TlL5T, has been determined by X-ray analysis. Me2TlL5 crystals are monoclinic, space group P21/c, with a = 9.812 (3) A, b = 7.616 (1) A, c = 12.851 (3) A, β = 97.48 (3) °, and Z = 4. The structure was refined to R = 0.016 for 929 unique data. In this compound the thallium atom is six-coordinate, if weak bridging interactions are considered, in lattices with polymeric chains. Spectroscopic data for the complexes OH, 13C, and 205T1 NMR, IR, and Raman) are discussed in order to determine possible structural/spectroscopic correlations. © 1988, American Chemical Society. All rights reserved.

Structure of dimethyl(picrato)(trifluoromethyl)tellurium

Structure of dimethyl(picrato)(trifluoromethyl)tellurium

An unusual furan cycloadduct from N-phenylbetaine and dimethyl acetylenedicarboxylate. The crystal and molecular structure of dimethyl 5-(3-N-phenyliminoprop-1-enyl)furan-2,3-dicarboxylate

Cycloaddition of dimethyl acetylenedicarboxylate with betaines such as 1-phenyl-3-oxidopyridinium does not yield the expected bicyclic product; instead, addition occurs at the exocyclic oxygen atom and ring carbon 2 of the betaine, with concomitant opening of the pyridine ring.

Synthesis and structure of dimethyl 3-(2-furoyl)pyrazole-4,5-dicarboxylate

1,3-Dipolar cycloaddition to the diazomethine grouping takes place in the reaction of 2-diazoacetylfuran with dimethyl acetylenedicarboxylate. The structure of the crystalline reaction product, viz., dimethyl 3-(2-furoyl)pyrazole-4,5-dicarboxylate, was investigated by x-ray diffraction analysis. The entire molecule, except for one of the two CO2CH3 groups, forms a planar conjugated system. The spectral characteristics of the synthesized compounds are presented.

The Raman and Infrared Spectra and the Structures of Dimethyl, Methyl Germyl and Digermyl Sulfide

Abstract The Raman and infrared spectra of dimethyl sulfide (CH3−S-CH3) have been assigned in terms of a D3d model1. The structurally related compounds, digermyl sulfide (GeH3−S-GeH3) and methyl germyl sulfide(CH3−S-GeH3) are prepared according to the literature2–4, and their vibrational spectra are measured. The analysis of these spectra comparing with those of CH3−S-CH3 allows us to determine the molecular structures to be D3d for GeH3−S-GeH3 and a C3v for CH3−S-GeH3 with a linear—S—.

ChemInform Abstract: MOLECULAR STRUCTURE OF DIMETHYL(TRIFLUOROSILYL)ARSINE

Chemischer InformationsdienstVolume 7, Issue 41 Physical Organic Chemistry ChemInform Abstract: MOLECULAR STRUCTURE OF DIMETHYL(TRIFLUOROSILYL)ARSINE HEINZ OBERHAMMER, HEINZ OBERHAMMERSearch for more papers by this authorREINHARD DEMUTH, REINHARD DEMUTHSearch for more papers by this author HEINZ OBERHAMMER, HEINZ OBERHAMMERSearch for more papers by this authorREINHARD DEMUTH, REINHARD DEMUTHSearch for more papers by this author First published: October 12, 1976 https://doi.org/10.1002/chin.197641062AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume7, Issue41October 12, 1976 RelatedInformation

Molecular structure of dimethyl(trifluorosilyl)arsine

The molecular structure of dimethyl(trifluorosilyl)arsine has been determined by gas-phase electron diffraction. The following geometric parameters (ra values) have been obtained: r(As–Si) 2.334(9), r(As–C) 1.979(5), r(Si–F) 1.569(2), and r(C–H) 1.096(12)A; FSiF 107.3(5), CAsC 97.5(2.8), and SiAsC 93.5(9)°. The bond shortening due to SiH3–SiF3 substitution is discussed.

The crystal and molecular structure of dimethylglyoxal bisguanylhydrazone dihydrochloride dihydrate, C6H14N8.2HCl.2H2O

has, in contrast to the monomethyl compound, no activity toward human acute myelocytic leukemia. The crystal and molecular structure of the crystalline dihydrochloride dihydrate, C6H14N 8. 2HCI. 2H20, has been determined by X-ray diffraction. The salt crystallizes in the monoclinic space group P21/c (C~h); a= 5.799 (4), b = 9.239 (8), c= 14.447 (12) A, fl= 113.98 (3)°; Z= 2; D~ = 1.432 and Dm= 1 44 (1) g.cm -3. Data were collected on a Picker automated four-circle diffractometer, employing 0-20 scans with a scintillation counter and crystal-monochromated Mo K~ radiation (2=0.71069 /~,). A combination of Patterson and direct-method techniques revealed the positions of all nonhydrogen atoms; the final structure (including hydrogen atoms) was refined by full-matrix least-squares analysis to an R of 0-055 (Rw=0045). The structure consists of planar dipositive C6H~6N8 2+ ions hydrogen-bonded to both CIand H20. The dominant interaction found in the monomethyl compound, an interaction involving rc-orbitals on adjacent parallel molecules, is less pronounced in the dimethyl structure. The mean interplanar spacing for the latter is 3.40 A compared with 3.19 A in the monomethyl structure.

The structure of dimethyl 1, 1′‐dimethylbicyclopropyl‐2,2′‐dicarboxylate

The structure of dimethyl 1, 1′‐dimethylbicyclopropyl‐2,2′‐dicarboxylate

Preparation and Structure of Dimethyl α-Conidendrin-8-methyl Sulfonate

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPreparation and Structure of Dimethyl α-Conidendrin-8-methyl SulfonateG. M. Barton and J. F. ManvilleCite this: J. Org. Chem. 1965, 30, 2, 659–660Publication Date (Print):February 1, 1965Publication History Published online1 May 2002Published inissue 1 February 1965https://doi.org/10.1021/jo01013a513RIGHTS & PERMISSIONSArticle Views28Altmetric-Citations1LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (251 KB) Get e-Alerts Get e-Alerts