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catena-Poly[[silver(I)-μ-4,4′-bipyridine-κ2N:N′] 4-[2-(4-carboxyphenyl)-1,1,1,3,3,3-hexafluoropropan-2-yl]benzoate]
Xiu-Juan Jiang
Acta Crystallographica Section E , 2012, DOI: 10.1107/s1600536812015322
Abstract: Assembly of the flexible dicarboxylic ligand 4-[2-(4-carboxyphenyl)-1,1,1,3,3,3-hexafluoropropan-2-yl]benzoate and 4,4′-bipyridine as co-ligand with AgI ions resulted in the formation of the polymeric title compound, {[Ag(C10H8N2)](C17H9F6O4)}n, in which the metal atoms are bridged by the 4,4′-bipyridine ligands, generating cationic chains extending along [010]. The dihedral angles between the benzene rings in the anion and the pyridine rings in the cation are 72.42 (9) and 9.36 (10)°, respectively. The molecular conformation of the anion is stabilized by intramolecular C—H...F hydrogen bonds. In the crystal, the anions interact with the cationic chains via C—H...O hydrogen bonds, forming layers parallel to (001), in which weak π–π stacking interactions [centroid–centroid distances = 3.975 (3)–4.047 (3) ] involving the pyridine rings of adjacent 4,4′-bipyridine ligands are present. The planes are further assembled into a three-dimensional network by O—H...O hydrogen bonds.
4-(3-Carboxyphenyl)pyridinium nitrate
Long Tang,Ya-Pan Wu,Feng Fu,Zhu-Lian Zhang
Acta Crystallographica Section E , 2012, DOI: 10.1107/s1600536812013918
Abstract: In the title salt, C12H10NO2+·NO3 , the dihedral angle between the pyridine ring and the benzene ring of the 4-(3-carboxyphenyl)pyridinium cation is 30.14 (2)°. Inversion-related pairs of cations are linked into dimers by pairs of O—H...O hydrogen bonds. Pairs of dimers are linked by N—H...O and C—H...O hydrogen bonds involving nitrate anions as acceptors, generating supramolecular chains along the diagonal of the bc plane.
(±)-syn-Isopropyl 4-(1,1,1,3,3,3-hexafluoropropan-2-yloxy)-1-hydroxy-3-methyl-2-(prop-1-ynyl)cyclopent-2-enecarboxylate  [cached]
Annika Gille,Markus Schürmann,Hans Preut,Martin Hiersemann
Acta Crystallographica Section E , 2009, DOI: 10.1107/s1600536809023162
Abstract: The title compound, C16H18F6O4, was obtained through an unprecedented one-pot reaction sequence involving a Gosteli–Claisen rearrangement and a cycloisomerization. The constitution and relative configuration were determined by single-crystal X-ray diffraction analysis. In the crystal, molecules are connected via O—H ... O hydrogen bonds.
1,1′-(p-Phenylenedimethylidene)diimidazol-3-ium bis{2-[(2-carboxyphenyl)disulfanyl]benzoate} dihydrate  [cached]
Zhengming Liu,Qiang Liu,Limin Yuan,Wenlong Liu
Acta Crystallographica Section E , 2010, DOI: 10.1107/s1600536810047021
Abstract: The title salt, C14H16N42+·2C14H9O4S2 ·2H2O, was obtained by the co-crystalization of 2,2′-dithiodibenzoic acid with 1,4-bis(imidazol-1-ylmethyl)benzene. It consists of 2-[(2-carboxyphenyl)disulfanyl]benzoate anions, centrosymmetric 1,1′-(p-phenylenedimethylidene)diimidazol-3-ium cations and water molecules. O—H...O, O—H...S and N—H...O hydrogen-bonding interactions among the components lead to the formation of a three-dimensional network.
ProtectionofHydroxylGroupsasaTrimethylsilylEtherby1,1,1,3,3,3-HexamethyldisilazanePromotedbyAsparticAcidasanEfficientOrganocatalyst  [PDF]
催化学报 , 2011, DOI: 10.1016/S1872-2067(10)60210-0
Abstract: ?Awidevarietyofalcoholsandphenolswereprotectedastrimethylsilylethersusing1,1,1,3,3,3-hexamethyldisilazanecatalyzedbyasparticacidasanon-toxic,metal-free,andgreenorganocatalystatroomtemperatureinacetonitrileundermildandheterogeneousconditions.Theprocedureisoperationallysimpleandthesilylatedproductwasobtainedinhighyieldandpurity.
Synthesis and characterization of thermally stable poly(amide-imide)-montmorillonite nanocomposites based on bis(4-carboxyphenyl)-N,N'-pyromellitimide acid  [cached]
K. Faghihi,A. Asghari,M. Hajibeygi
Bulletin of the Chemical Society of Ethiopia , 2013,
Abstract: Two new poly(amide-imide)-montmorillonite reinforced nanocomposites containing bis(4-carboxyphenyl)-N,N'-pyromellitimide acid moiety in the main chain were synthesized by a convenient solution intercalation technique. Poly(amide-imide) (PAI) as a source of polymer matrix was synthesized by the direct polycondensation reaction of bis(4-carboxyphenyl)-N,N'-pyromellitimide acid with 4,4'-diamino diphenyl sulfone in the presence of triphenyl phosphite (TPP), CaCl2, pyridine and N-methyl-2-pyrrolidone (NMP). Morphology and structure of the resulting PAI-nanocomposite films with 10 and 20% silicate particles were characterized by FT-IR spectroscopy, X-ray diffraction (XRD) and scanning electron microscopy (SEM). The effect of clay dispersion and the interaction between clay and polymeric chains on the properties of nanocomposites films were investigated by using UV-Vis spectroscopy, thermal gravimetry analysis (TGA) and water uptake measurements.DOI: http://dx.doi.org/10.4314/bcse.v27i1.10
Tetraaquabis{3-carboxy-5-[(4-carboxyphenyl)diazenyl]benzoato-κO1}cobalt(II) dihydrate  [cached]
Liang Bai,Jun Zhao
Acta Crystallographica Section E , 2011, DOI: 10.1107/s1600536811045557
Abstract: In the title complex, [Co(C15H9N2O6)2(H2O)4]·2H2O, the CoII ion is located on an inversion center and is coordinated by two monodentate 3-carboxy-5-[(4-carboxyphenyl)diazenyl]benzoate ligands and four water molecules in a distorted octahedral geometry. In the crystal, intermolecular O—H...O hydrogen bonds link the molecules into a three-dimensional supramolecular network.
Synthesis and characterization of thermally stable poly(amide-imide)-montmorillonite nanocomposites based on bis(4-carboxyphenyl)-N,N'-pyromellitimide acid
K. Faghihi, A. Asghari, M. Hajibeygi
Bulletin of the Chemical Society of Ethiopia , 2013,
Abstract: Two new poly(amide-imide)-montmorillonite reinforced nanocomposites containing bis(4-carboxyphenyl)-N,N'-pyromellitimide acid moiety in the main chain were synthesized by a convenient solution intercalation technique. Poly(amide-imide) (PAI) as a source of polymer matrix was synthesized by the direct polycondensation reaction of bis(4-carboxyphenyl)-N,N'-pyromellitimide acid with 4,4'-diamino diphenyl sulfone in the presence of triphenyl phosphite (TPP), CaCl2, pyridine and N-methyl-2-pyrrolidone (NMP). Morphology and structure of the resulting PAI-nanocomposite films with 10 and 20% silicate particles were characterized by FT-IR spectroscopy, X-ray diffraction (XRD) and scanning electron microscopy (SEM). The effect of clay dispersion and the interaction between clay and polymeric chains on the properties of nanocomposites films were investigated by using UV-Vis spectroscopy, thermal gravimetry analysis (TGA) and water uptake measurements. KEYWORDS: Bis(4-carboxyphenyl)-N,N'-pyromellitimide acid moiety, Poly(amide-imide)-montmorillonite nanocomposite, Thermal properties Bull. Chem. Soc. Ethiop. 2013, 27(1), 95-104. DOI: http://dx.doi.org/10.4314/bcse.v27i1.10
Poly[[diaquabis{μ-4-[6-(4-carboxyphenyl)-4,4′-bipyridin-2-yl]benzoato-κ2O:N1′}copper(II)] dimethylformamide tetrasolvate]  [cached]
Yabin Sun,E Song,Daguang Wang
Acta Crystallographica Section E , 2013, DOI: 10.1107/s1600536813006430
Abstract: In the title compound, {[Cu(C24H15N2O4)2(H2O)2]·4C3H7NO}n, the CuII ion, lying on an inversion center, is six-coordinated by two N atoms from two 4-[6-(4-carboxyphenyl)-4,4′-bipyridin-2-yl]benzoate (L) ligands, two deprotonated carboxylate O atoms from two other symmetry-related L ligands and two water molecules in a slightly distorted octahedral geometry. The CuII atoms are linked by the bridging ligands into a layer parallel to (101). The presence of intralayer O—H...O hydrogen bonds and π–π interactions between the pyridine and benzene rings [centroid–centroid distances = 3.808 (2) and 3.927 (2) ] stabilizes the layer. Further O—H...O hydrogen bonds link the layers and the dimethylformamide solvent molecules.
Synthesis and Characterization of Novel Processable and Flexible Polyimides Containing 3,6-Di(4-carboxyphenyl)pyromellitic Dianhydride  [PDF]
Muhammad Kaleem Khosa,Muhammad Asghar Jamal,Rubbia Iqbal,Mazhar Hamid
Advances in Chemistry , 2014, DOI: 10.1155/2014/759594
Abstract: A series of six novel polyimides containing 3,6-di(4-carboxyphenyl)pyromellitic dianhydride were synthesized via two steps condensation method. Aromatic diamines monomers, 4-(4-aminophenoxy)-N-(4-(4-aminophenoxy)benzylidene)-3-chloroaniline (DA1), 4-(4-amino-3-methylphenoxy)-N-(4-(4-amino-3-methylphenoxy)benzylidene)-3-chloroaniline (DA2), 4-(4-amino-2-methylphenoxy)-N-(4-(4-amino-2-methylphenoxy)benzylidene)-3-chloroaniline (DA3) 4-(4-aminophenoxy)-N-(4-(4-aminophenoxy)benzylidene)-2-methylaniline (DA4), 4-(4-amino-3-methylphenoxy)-N-(4-(4-amino-3-methylphenoxy)benzylidene)-2-methylaniline (DA5), and 4-(4-amino-2-methylphenoxy)-N-(4-(4-amino-2-methylphenoxy)benzylidene)-2-methylaniline (DA6) were prepared and used to synthesize new polyimides by reaction with resynthesized 3,6-di(4-carboxyphenyl)pyromellitic dianhydride by using two-step condensation method. The inherent viscosities of polyimides range from 0.68–1.04?dL?gm?1 and were soluble in polar solvents. Polyimides have excellent thermal stability by showing 10% weight loss temperature was above 450°C. Their glass transition temperatures lie in the range of 250–335°C. Wide-angle X-ray diffractometer investigations revealed the amorphous nature of polyimides. Therefore, these polymers can be a potential candidate as processable high performance polymeric materials. 1. Introduction Polyimides are very interesting group of amazingly strong and marvellously heat resistant polymers [1]. Aromatic polyimides have received much attention for half a century, due to their excellent combination of properties and potential applications in aerospace, microelectronics (flexible printed boards for electronic devices), photoelectronic industry (as photoresists), and separation industry [2–6]. Other applications include adhesives and matrix resins for composites. However some of their properties like limited solubility, rigid chain characteristics, strong chain-chain interaction, high glass transition, and melting temperatures create difficulties in their processing. That is why applications of these rigid polyimides are restricted in technological and industrial applications. Extensive research has been carried out to improve their solubility by synthesizing soluble polyimides without disturbing their excellent properties [7–15]. In present days a number of ways exist to alter chemical structure of synthesizing polymeric materials while maintaining the excellent level of their thermal and mechanical properties. Several modifications have been made in their chemical structure by the introduction of bulky alkyl
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