共查询到20条相似文献,搜索用时 15 毫秒
1.
John A. Schlueter Russell J. Funk Urs Geiser 《Acta Crystallographica. Section C, Structural Chemistry》2005,61(6):m304-m306
In the title compound, (C10H9N2)2[Pt(CN)6]·2C10H8N2 or [(Hbpy)+]2[Pt(CN)6]2−·2bpy, where bpy is 4,4′‐bipyridine, the Hbpy+ cations and bpy molecules form a hydrogen‐bonded two‐dimensional cationic approximately square grid parallel to the (110) plane. The [Pt(CN)6]2− dianions reside in the cavities within this grid, with the nitrile N atoms forming weak hydrogen bonds with the CH groups in the cationic lattice. 相似文献
2.
Norman Lu Wen‐Han Tu Zong‐Wei Wu Yuh‐Sheng Wen Ling‐Kang Liu 《Acta Crystallographica. Section C, Structural Chemistry》2010,66(6):o289-o291
As part of a homologous series of novel polyfluorinated bipyridyl (bpy) ligands, the title compound, C16H14F6N2O2, contains the smallest fluorinated group, viz. CF3. The molecule resides on a crystallographic inversion centre at the mid‐point of the pyridine Cipso—Cipso bond. Therefore, the bpy skeleton lies in an anti conformation to avoid repulsion between the two pyridyl N atoms. Weak intramolecular C—H...N and C—H...O interactions are observed, similar to those in related polyfluorinated bpy–metal complexes. A π–π interaction is observed between the bpy rings of adjacent molecules and this is probably a primary driving force in crystallization. Weak intermolecular C—H...N hydrogen bonding is present between one of the CF3CH2– methylene H atoms and a pyridyl N atom related by translation along the [010] direction, in addition to weak benzyl‐type C—H...F interactions to atoms of the terminal CF3 group. It is of note that the O—CH2CF3 bond is almost perpendicular to the bpy plane. 相似文献
3.
S. W. Bigger K. P. Ghiggino 《Journal of photochemistry and photobiology. A, Chemistry》1987,40(2-3):391-399
The room temperature photophysical properties of several sulphonated and unsulphonated 6-(2′-hydroxy-4′-methoxyphenyl)-s-triazines were investigated in a range of solvents by means of steady state and picosecond fluorescence spectroscopy. Compounds possessing phenyl or p-tolyl groups in the s-triazinyl ring exhibit only a very weak normal Stokes-shifted fluorescence, arising from the initially excited chromophore. Substitution of phenoxy groups into the s-triazinyl ring results in the appearance of an additional longer-wavelength fluorescence which is assigned to the keto tautomer, formed following excited state intramolecular proton transfer (ESIPT). The rate constant for the (ESIPT) process that occurs in sodium 3-(3′,5′-diphenoxy-2′,4′,6′-triazinyl)-4-hydroxy-2-methoxybenzene sulphonate in water is estimated to be greater than 1011 s−1. 相似文献
4.
Maryanne Mores Patrick E. Cassidy 《Journal of polymer science. Part A, Polymer chemistry》1990,28(4):811-823
Two new bis(benzylidenephthalide)monomers were synthesized by melt condensation of phenylacetic acid with 3,3′,4,4′-benzophenonetetracarboxylic dianhydride (BTDA) and with 4,4′-(hexafluoroisopropylidene)diphthalic anhydride (6FDA). A mixture of three isomers for each monomer was obtained and polymerized with diamines to produce new polyimidines. Polymerizations were conducted with m-xylylenediamine (MXDA) or 4,4′-oxydianiline (ODA) in quantitative yields for the undehydrated intermediate. Inherent viscosities ranged from 0.17 to 0.35 dL/g in N,N-dimethylformamide (DMF) or N-methyl-2-pyrrolidone (NMP). These intermediate poly(hydroxylactams) were thermally dehydrated to polyimidines which exhibited a 10% weight loss, as high as 546°C in nitrogen. Inherent viscosities of the dehydrated (cured) polyimidines ranged from 0.14 to 0.20 dL/g in NMP. Brittle films could be cast from NMP solutions. 相似文献
5.
The mass spectra of 4,4′-oxybispyridine and 4,4′-thiobispyridine are reported. In the former the base peak is due to the molecular ion and the fragmentation routes involve loss of H, CO, HCN, C2H2N and CsHO from the molecular ion as well as rupture of the central bonds. In the latter the base peak is also due to the molecular ion and the fragmentation routes involve loss of H, CS, S, HCN and C2HS as well as central bond rupture. 相似文献
6.
7.
Hans R. Kricheldorf Michael Rabenstein Gert Schwarz 《Journal of polymer science. Part A, Polymer chemistry》2000,38(17):3019-3027
A new mesogenic monomer was prepared from biphenyl‐3,3′,4,4′‐tetracarboxylic dianhydride and 4‐aminophenol followed by the acylation of OH groups with propionic anhydride. This diphenol propionate was polycondensed by transesterification with decane‐1,10‐dicarboxylic acid, dodecane‐1,12‐dicarboxylic acid, and eicosane‐1,20‐dicarboxylic acid or with equimolar mixtures of two dicarboxylic acids. The resulting poly(ester imide)s were characterized by elemental analyses, 1H NMR spectra, inherent viscosities, DSC measurements, optical microscopy, and X‐ray measurements with synchrotron radiation at variable temperatures. An enantiotropic smectic A phase in the molten state and a crystalline smectic E (or H) phase in the solid state were found in all cases. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 3019–3027, 2000 相似文献
8.
Polyamides from 4,4′-dipiperidyl, 1,2-ethylene-, and 1,3-propylene- bridged dipiperidyls were prepared via solution and interfacial polycondensation techniques. In sharp contrast to the polyamides from N,N′-alkyl-substituted alkylene diamines and aromatic diacids, the polyamides from 4,4′-dipiperidyls are high-melting (up to 455°C) and alcohol-insoluble. Tough films were cast from formic acid solutions of the polymers; fiber of good physical properties was prepared from a formic acid solution of the polyterephthalamide of 1,2-di(4-piperidyl)ethane. 相似文献
9.
Pablo Albors Luis M. Baraldo Andrs Ibaez Ricardo Baggio 《Acta Crystallographica. Section C, Structural Chemistry》2004,60(12):o850-o852
The title compound, C18H26N4, contains two almost identical independent molecules that lie about inversion centres. Each molecule has a planar bipyridine nucleus and two terminal diethylamine groups oriented at almost right angles to the core. These diethylamine branches act as spacers, producing a very open structure with one of the lowest densities reported among related compounds. The most important intermolecular interactions are of the C—H⋯π type, which connect non‐equivalent moieties. 相似文献
10.
Meng Zhao Jian Su Jun Zhang Jie‐Ying Wu Yu‐Peng Tian 《Acta Crystallographica. Section C, Structural Chemistry》2015,71(9):799-803
A metal–organic framework with a novel topology, poly[sesqui(μ2‐4,4′‐bipyridine)bis(dimethylformamide)bis(μ4‐4,4′,4′′‐nitrilotribenzoato)trizinc(II)], [Zn3(C21H12NO6)2(C10H8N2)1.5(C3H7NO)2]n, was obtained by the solvothermal method using 4,4′,4′′‐nitrilotribenzoic acid and 4,4′‐bipyridine (bipy). The structure, determined by single‐crystal X‐ray diffraction analysis, possesses three kinds of crystallographically independent ZnII cations, as well as binuclear Zn2(COO)4(bipy)2 paddle‐wheel clusters, and can be reduced to a novel topology of a (3,3,6)‐connected 3‐nodal net, with the Schläfli symbol {5.62}4{52.6}4{58.87} according to the topological analysis. 相似文献
11.
Tareq M. A. Al‐Shboul Steffen Ziemann Helmar Grls Sven Krieck Matthias Westerhausen 《无机化学与普通化学杂志》2019,645(3):292-300
The condensation reaction of 2,2′‐diamino‐4,4′‐dimethyl‐6,6'‐dibromo‐1,1′‐biphenyl with 2‐hydroxybenzaldehyde as well as 5‐methoxy‐, 4‐methoxy‐, and 3‐methoxy‐2‐hydroxybenzaldehyde yields 2,2′‐bis(salicylideneamino)‐4,4′‐dimethyl‐6,6′‐dibromo‐1,1′‐biphenyl ( 1a ) as well as the 5‐, 4‐, and 3‐methoxy‐substituted derivatives 1b , 1c , and 1d , respectively. Deprotonation of substituted 2,2′‐bis(salicylideneamino)‐4,4′‐dimethyl‐1,1′‐biphenyls with diethylzinc yields the corresponding substituted zinc 2,2′‐bis(2‐oxidobenzylideneamino)‐4,4′‐dimethyl‐1,1′‐biphenyls ( 2 ) or zinc 2,2′‐bis(2‐oxidobenzylideneamino)‐4,4′‐dimethyl‐6,6′‐dibromo‐1,1′‐biphenyls ( 3 ). Recrystallization from a mixture of CH2Cl2 and methanol can lead to the formation of methanol adducts. The methanol ligands can either bind as Lewis base to the central zinc atom or as Lewis acid via a weak O–H ··· O hydrogen bridge to a phenoxide moiety. Methanol‐free complexes precipitate as dimers with central Zn2O2 rings. 相似文献
12.
Oleg Stenzel Matthias W. Esterhuysen Helgard G. Raubenheimer 《Acta Crystallographica. Section C, Structural Chemistry》2001,57(9):1056-1059
The crystal and molecular structures of bis(η5‐2,4,7‐trimethylindenyl)cobalt(II), [Co(C12H13)2], (I), and rac‐2,2′,4,4′,7,7′‐hexamethyl‐1,1′‐biindene, C24H26, (II), are reported. In the crystal structure of (I), the Co atom lies on an inversion centre and the structure represents the first example of a bis(indenyl)cobalt complex exhibiting an eclipsed indenyl conformation. The (1R,1′R) and (1S,1′S) enantiomers of the three possible stereoisomers of (II), which form as by‐products in the synthesis of (I), cocrystallize in the monoclinic space group P21/c. In the unit cell of (II), alternating (1R,1′R) and (1S,1′S) enantiomers pack in non‐bonded rows along the a axis, with the planes of the indenyl groups parallel to each other and separated by 3.62 and 3.69 Å. 相似文献
13.
Kenneth K. Andersen Daniel F. Gloster Diana D. Bray Massud Shoja Anders Kjr 《Journal of heterocyclic chemistry》1998,35(2):317-324
Several symmetrical 2,2′,4,4′-tetrasubstituted[4,4′-bioxazole]-5,5′(4H,4′H)-diones 1a-f were obtained by dehydrodimerization of 5(4H)-oxazolones 2a-f . The configurations of four were established; one by X-ray crystallography rac- 1c , and three rac- 1a , meso- 1a and rac- 1b by 1H nmr spectroscopy of their derivatives. Upon being heated, the bioxazolones isomerized, presumably by breakage of the 4,4′-carbon? carbon bond to form free radicals followed by their recombination. The results of a crossover experiment were consistent with a radical nature for this isomerization reaction. Treatment of three of the bioxazolones rac- 1a , meso- 1a and rac- 1c with methanol and amine nucleophiles led to ester and amide derivatives 7–11 of α,α'-dehydrodimeric amino acids. 相似文献
14.
The three‐dimensional (3D) coordination polymer [Zn6(btc)4(4,4′‐bipy)5]n ( 1 ) (btc = 1,2,4‐benzenetricarboxylate; 4,4′‐bipy = 4,4′‐bipyridine) has been prepared hydrothermally. The zinc(II) centers in 1 are bridged by btc ligands to form a trinuclear subunit, which is further linked by 4,4′‐bipy and btc ligands to construct the 3D coordination architecture. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
15.
A. Abdul Ajees S. Parthasarathy S. Manikandan R. Raghunathan 《Acta Crystallographica. Section C, Structural Chemistry》2001,57(4):473-475
The title compound, C23H15Cl2NO3, crystallizes with two independent molecules in the asymmetric unit. The chromanone moiety consists of a benzene ring fused with a six‐membered heterocyclic ring which adopts a sofa conformation. The five‐membered spiroisoxazoline ring is in an envelope conformation. The p‐chlorophenyl rings bridged by the five‐membered ring are nearly perpendicular to each other. The chromanone moiety of one molecule packs into the cavity formed by the p‐chlorophenyl rings of a second molecule through the formation of C—H?π interactions. The structure is stabilized by weak C—H?O, C—H?Cl and C—H?π interactions. 相似文献
16.
17.
Giovanni L. Cascarano George Ferguson Carmelo Giacovazzo Christopher Glidewell Anthony L. Spek 《Acta Crystallographica. Section C, Structural Chemistry》2013,69(7):774-777
A fully ordered structure is reported for the polymorph of triphenylsilanol–4,4′‐bipyridyl (4/1), 4C18H16OSi·C10H8N2, having Z′ = 4. The asymmetric unit contains four similar but distinct five‐molecule aggregates, in which the central bipyridyl unit is linked to two molecules of triphenylsilanol via O—H...N hydrogen bonds, with a further pair of triphenylsilanol molecules linked to the first pair via O—H...O hydrogen bonds. An extensive series of C—H...π(arene) hydrogen bonds links these aggregates into complex sheets. This structure is compared with a previously reported structure [Bowes, Ferguson, Lough & Glidewell (2003). Acta Cryst. B 59 , 277–286], which was based on an erroneous disordered structural model arising from a false direct‐methods solution with reference to a strong pseudo‐inversion centre. 相似文献
18.
Wadie Tadros Alfy Badie Sakla Sami Bassili Awad Abdul-Aziz Amine Helmy 《Helvetica chimica acta》1972,55(8):2808-2812
1, 2-Di-(p-methoxyphenyl)-ethane-1, 2-diol gave in acid media bis-(4-methoxy-phenyl)-acetaldehyde, 4-4′-dimethoxy-deoxybenzoin, and 1, 2-di-(p-methoxyphenyl)-ethylene oxide; their respective yields being influenced by at least 3 factors: (i) the acid, (ii) its concentration, and (iii) the reaction period. Bis-(4-methoxyphenyl)-acetaldehyde rearranged to the deoxybenzoin in boiling sulfuric (50%) or phosphoric (75%) acids (w/w), and to two isomeric 1, 2-diacetoxy-1, 2-di-(p-methoxyphenyl) ethanes when it was heated with acetic anhydride. The mechanisms of these reactions are discussed. 相似文献
19.
The mass spectral fragmentation pattern of 4,4′-bipyridyl is described. The fragmentation proposals which differ from those previously reported are supported by high resolution mass measurements and metastable transitions. 相似文献
20.
Vijay Mahadevan Iyer Helen Stoeckli‐Evans Anthony D'Alo Luisa De Cola Peter Belser 《Acta Crystallographica. Section C, Structural Chemistry》2005,61(4):o259-o261
Structure analyses of 4,4′‐bis(4‐hydroxybutyl)‐2,2′‐bipyridine, C18H24N2O2, (I), and 4,4′‐bis(4‐bromobutyl)‐2,2′‐bipyridine, C18H22Br2N2, (II), reveal intermolecular hydrogen bonding in both compounds. For (I), O—H·N intermolecular hydrogen bonding leads to the formation of an infinite two‐dimensional polymer, and π stacking interactions are also observed. For (II), C—H·N intermolecular hydrogen bonding leads to the formation of a zigzag polymer. The two compounds crystallize in different crystal systems, but both molecules possess Ci symmetry, with one half molecule in the asymmetric unit. 相似文献