共查询到20条相似文献,搜索用时 13 毫秒
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The electron impact mass spectrum of N,N′-diethyl-N,N′-diphenylurea contains the ion m/z 164 which is of low abundance at normal energy of ionizing electrons but prominent at 15-20eV. The mechanism of its formation has been revealed by means of labelled compounds. It is rationalized in terms of an unusual formation of styrene lost as a neutral molecule. 相似文献
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Well crystallized diquaternary piperazinium salts of perfluorocarboxylic acids can be prepared by thermal rearrangement of a primary product obtained from the appropriate fluorinated acid chloride and N,N‐dialkylamino‐ethanol. The mechanism of the ring closure step is discussed. The synthetic strategy easily gives access to structurally different piperazinium perfluorocarboxylates. The title compounds show surface activity and can be regarded as ionic amphiphiles. 相似文献
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Arno Kraft Lars Peters Roland Frhlich 《Acta Crystallographica. Section C, Structural Chemistry》2002,58(5):o272-o274
The crystal structure of the title 2:1 salt of tetrazole and a substituted terephthalamidine, C16H28N42+·2CHN4?, contains an infinite network of hydrogen bonds, with short N?N distances of 2.820 (2) and 2.8585 (19) Å between the tetrazolate anion and the amidinium cation. Involvement of the lateral N atoms of the tetrazole in the hydrogen bonding appears to be a typical binding pattern for the tetrazolate anion. 相似文献
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Yoshio Imai Mitsuru Ueda Susumu Kanno 《Journal of polymer science. Part A, Polymer chemistry》1975,13(7):1691-1698
The ring-opening polyaddition reaction of N,N′-disubstituted bisisomaleimides with various diamines in N-methyl-2-pyrrolidone at room temperature afforded polymaleamides having inherent viscosity up to 0.7 in almost quantitative yield. These polymers are a new class of homopolymaleamides and ordered alternating copolymaleamides. Almost all of the polyamides were soluble in a wide range of solvents such as dimethylsulfoxide, dimethylacetamide, m-cresol, and formic acid. They did not show any melt temperature, and began to decompose at a temperature ranging between 200 and 300°C. 相似文献
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Mitsuru Ueda Susumu Kanno Yoshio Imai 《Journal of polymer science. Part A, Polymer chemistry》1976,14(3):663-670
The ring-opening polyaddition reaction of N,N′-disubstituted bisphthalisoimides with various diamines in amide-type solvents at room temperature afforded polyphthalamides having inherent viscosity of up to 0.26 in excellent yields. Some of the polymers thus obtained are a new class of ordered alternating copolyphthalamides. These polyamides were soluble in polar aprotic solvents, as well as in acidic solvents. They showed relatively low melt temperature in the range of 120–220°C and further low level of thermal stability. 相似文献
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Mehmet Kabak Yalin Elerman Canan Ünaleroglu Yüksel Mert T. Nuri Durlu 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(2):e66-e67
The structure of the title compound, C6H18N22+.2Cl?, has been determined and has a centre of symmetry. The molecule has strong intermolecular hydrogen bonding between each Cl? and an N—H bond [Cl?N = 3.012 (3) Å]. 相似文献
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N,N,N′,N′‐tetraalkyaminoazoxybenzene derivatives were conveniently prepared by the coupling of N,N‐dialkylnitrosoaniline in the presence of acetone and KOH. The reaction mechanism was proposed and investigated, and the structure of compound 3b was also confirmed by single crystal X‐ray diffractometry. 相似文献
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Giuseppe Bruno Santo Lanza Francesco Nicol Giuseppe Tresoldi Giuseppe Rosace 《Acta Crystallographica. Section C, Structural Chemistry》2002,58(10):o608-o609
The title compound, alternatively known as N,N′‐dibenzylethanedithioamide, C16H16N2S2, lies about an inversion centre and contains a planar trans‐dithiooxamide fragment characterized by a strong intramolecular hydrogen bond between the S atom and the adjacent amide H atom in the solid state, with an S?N distance of 2.926 (1) Å. The aryl substituent is oriented orthogonal to the mean plane of the trans‐dithiooxamide fragment due to steric hindrance and this effect is discussed. 相似文献
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Adducts of N, N′ -dimethyl-2, 2′-bisimidazole (DMBIm) with diethyl- and dibutyl-tin(IV) dihalides (Cl, Br) have been isolated and characterized. IR data for [SnR2X2(DMBIm)] compounds are in keeping with a six-coordinate tin atom with DMBIm acting as a bidentate ligand, whereas in [(SnR2X2)2(DMBIm)] the tin is five-coordinate and DMBIm acts as a bridging ligand. Measurements of conductivity in acetonitrile show the adducts to behave as non-ionogens in this solvent. NMR data show them to undergo dissociation in CDCl3. 相似文献
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Yoshiyuki Oishi Munirathina Padmanaban Masa-Aki Kakimoto Yoshio Imai 《Journal of polymer science. Part A, Polymer chemistry》1987,25(12):3387-3393
NovelN-phenylated aromatic polyureas having inherent viscosities of 0.13–0.35 dL/g were synthesized by the solution polycondensation of N,N′-dichloroformyl-p-dianilinobenzene with N,N′-bistrimethylsilyl derivatives of bis(4-aminophenyl)ether, piperazine, and p-dianilinobenzene in sulfolane. Except the polyurea containing piperazine unit, the other polyureas were amorphous and readily soluble in a variety of organic solvents such as tetrahydrofuran. The polyurea derived from p-dianilinobenzene, which has no vulnerable hydrogen on the urea linkage, did not melt below 350°C and was stable up to 450°C in air. 相似文献
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Ketones and aldehydes undergo facile addition reaction with N,N′-thionyldiimidazole to give the monoimidazole and the diimidazole. 相似文献
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Bengt Wessln Gunnar Mattsson 《Journal of polymer science. Part A, Polymer chemistry》1990,28(5):1033-1042
Anionic polymerization of methyl methacrylate in toluene solution has been studied. The polymerizations were initiated by fluorenyllithium as well as by butyl-, benzyl-, and phenylmagnesium halides, and carried out in the presence of polar additives. Especially the organomagnesium initiators gave generally rise to highly isotactic polymers (mm = 0.90-0.95) in the absence of solvating additives. In the presence of the bidentate ligand N,N,N′,N′-tetramethylethylene diamine (TMEDA) at molar ratios of 1–2 relative to magnesium, highly syndiotactic polymers were obtained at ?78°C (rr = 0.8–0.9), while at higher temperatures stereoblock polymers or stereocomplexes were formed. It is proposed that at low temperatures the magnesium cations are strongly solvated under the influence of TMEDA, with the formation of monomeric ion pairs. The large solvated magnesium cations will not have any directional influence on the monomer in the propagation step, with syndiotactic propagation as a result. 相似文献