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1.
二维网状结构超分子化合物[Cu(dafo)2(H2O)2](Cl04)2的两种同分异构体的合成与表征 总被引:6,自引:0,他引:6
用4,5—二氮芴-9-酮(dafo)、邻苯二甲酸、高氯酸铜和4,5—二氯芴—9— 酮(dafo)、苯甲酸、高氯酸铜进行混和反应时分别得到亮蓝色和蓝绿色晶体,它们 的结构通过单晶X射线衍射法测定。其单晶结构表明,这两种化合物是同分异构体 ,组成都是C22H16Cl2CuN4O12。这两种化合物是通过氢键形成的具有二维网状结构 的超分子化合物,并通过元素分析、红外光谱、热分析对两种化合物进行了表征。 相似文献
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分子中部含齐聚氧化乙烯单元的酯-醚液晶 总被引:3,自引:0,他引:3
以4-(4′-烷氧基苯甲酰氧基)苯甲酸作为液晶中间体,合成了在分子中部含齐聚氧化乙烯的系列酯-醚液晶化合物.对其化学结构和液晶性能进行了表征,除个别化合物外,其余样品均具有热致液晶性. 相似文献
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以取代苯甲酸和2-氨基-4-甲基苯并噻唑为原料合成5个新型N-取代苯甲酰基-N′-(4-甲基苯并噻唑-2-基)硫脲衍生物,化合物结构经元素分析、IR、1 H NMR和13 C NMR表征,X-射线单晶衍射测定了N-(4-甲氧苯甲酰基)-N′-(4-甲基苯并噻唑-2-基)硫脲(化合物1)的晶体结构,该晶体为单斜晶系,P21/c空间群,选择广西主要经济作物中常见的病原菌,对目标化合物进行室内抑菌活性测试,实验结果发现该类化合物具有一定的抑菌活性. 相似文献
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Li R Zeitler JA Tomerini D Parrott EP Gladden LF Day GM 《Physical chemistry chemical physics : PCCP》2010,12(20):5329-5340
The phonon modes of crystalline benzoic acid have been investigated using terahertz time-domain spectroscopy, rigid molecule atom-atom model potential and plane-wave density functional theory lattice dynamics calculations. The simulation results show good agreement with the measured terahertz spectra and an assignment of the terahertz absorption features of benzoic acid is made with the help of both computational methods. Focussing on the strongest interactions in the crystal, we describe each vibration in terms of distortions of the benzoic acid hydrogen bonded dimers that are present in the crystal structure. The terahertz spectrum is also shown to be highly sensitive to the location of the carboxylic acid hydrogen atoms in the cyclic hydrogen-bonded dimers and we have systematically explored the influence of the observed disorder in the hydrogen atom positions on the lattice dynamics. 相似文献
5.
Haruki Sugiyama Hidehiro Uekusa 《Acta Crystallographica. Section C, Structural Chemistry》2021,77(1):56-60
Crystal–crystal phase transformation by external stimuli has attracted significant attention for application in switchable materials, which can change their structures and properties. Herein, it is revealed that N‐salicylidene‐p‐aminobenzoic acid crystals undergo a two‐step crystal–crystal phase transformation through a gas–solid reaction with aqua–ammonia vapour. The photochromic behaviour of the crystals switched from nonphotochromic to photochromic and back to nonphotochromic via a phase transformation. The two‐step phase transformation and photochromic behaviour change were characterized and correlated by X‐ray crystal structure analysis, UV–Vis spectroscopy, differential scanning calorimetry and scanning electron microscopy. This article is the first report to capture the stepwise structural change in the gas–solid (acid–base) reaction of ammonia with benzoic acid derivatives. 相似文献
6.
Verschueren KH Pumpor K Anemüller S Chen S Mesters JR Hilgenfeld R 《Chemistry & biology》2008,15(6):597-606
The main proteinase (M(pro)) of the severe acute respiratory syndrome (SARS) coronavirus is a principal target for the design of anticoronaviral compounds. Benzotriazole esters have been reported as potent nonpeptidic inhibitors of the enzyme, but their exact mechanism of action remains unclear. Here we present crystal structures of SARS-CoV M(pro), the active-site cysteine of which has been acylated by benzotriazole esters that act as suicide inhibitors. In one of the structures, the thioester product has been hydrolyzed and benzoic acid is observed to bind to the hydrophobic S2 pocket. This structure also features the enzyme with a shortened N-terminal segment ("amputated N finger"). The results further the understanding of the important role of the N finger for catalysis as well as the design of benzotriazole inhibitors with improved specificity. 相似文献
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The benzomacrolactone structural motif is a privileged or evolutionarily selected scaffold that codes properties required for binding to proteins and novel analogues thereof may provide a source of new bioactive compounds. Saccharides are also privileged structures, with (amino)sugars, iminosugars, and sugar amino acids being applied as scaffolds for the development of nonpeptidal peptidomimetics. The syntheses of novel polyhydroxylated oxamacrolides, structural analogues of natural polyketide derived macrolides, are described herein, providing a basis for their development as scaffolds. The syntheses were carried out from benzoic acids and appropriately protected D-mannitol or D-sorbitol (D-glucitol). Ring-closing metathesis was applied in the macrocyclization step with high E-alkene selectivities being observed. X-ray crystal structures, for two polyhydroxylated derivatives, show that the macrocyclic rings display similar conformations. In addition, intermolecular hydrogen-bonding networks are observed in the lattices. 相似文献
10.
Douglas L. Dorset 《Journal of Polymer Science.Polymer Physics》1986,24(1):79-87
Electron diffraction data from a series of paraffins epitaxially crystallized on benzoic acid are used to determine their crystal structures. Even-chain paraffins from n-C32H66 to n-C60H122 are shown to crystallize isostructurally as the orthorhombic polymorph described for n-C36H74. Like the even-chain compounds, odd-chain paraffins do not crystallize in their lowest-energy form. A quantitative zonal crystal structure analysis for n-C33H74 suggests that the molecular packing is in the B-polymorphic form proposed earlier by other workers. 相似文献
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The crystal structures of the hydrogen-bonded, 1:1 molecular complexes of nitro (ortho, meta and para) benzoic acids with two 2,4-diaminopyrimidine derivatives (trimethoprim and pyrimethamine) have been investigated in detail (1-5). In all the crystal structures except pyrimethamine o-nitrobenzoate (3), the carboxylate group of the respective anions interacts with the protonated trimethoprim or pyrimethamine moiety in a linear fashion through a pair of N-H?O hydrogen bonds to form a cyclic hydrogen-bonded motif. This cyclic hydrogen-bonded motif is self-organized in different ways to get the novel types of hydrogen bonding motifs and supramolecular patterns. In the crystal structure of pyrimethamine o-nitrobenzoate (3), the chelating type of hydrogen bonding motif is self-organized to get a helical supramolecular pattern. In the crystal structures of both pyrimethamine m-nitrobezoate (4) and pyrimethamine p-nitrobenzoate (5), a novel type of an alternate arrangement of DADA (D represents donor and A represents acceptor) and DDAA arrays is present, resulting in the formation of hydrogen-bonded ladders. 相似文献
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Igor Yu. Ilyin Nikolay A. Pushkarevsky Natalia V. Kuratieva Dmitry Yu. Naumov Sergey N. Konchenko 《Acta Crystallographica. Section C, Structural Chemistry》2012,68(11):m323-m325
The title compounds, 4‐(diiodoarsanyl)benzoic acid, (I), and 3‐(diiodoarsanyl)benzoic acid, (II), both [As(C7H5O2)I2], which possess a –COOH coordinating group, form molecular crystal structures composed of hydrogen‐bonded dimers, the packing differences of which are caused by the relative position of the diiodoarsanyl groups. The para isomer, with Z′ = 1, crystallizes in a layered structure with shortened contacts of the As atoms to only the arene rings of adjacent molecules. In contrast, the meta isomer, with Z′ = 3, forms separate rectangular blocks of three ribbons, each composed of dimeric molecular units positioned almost directly above each other and with the As atoms possessing only two As...I contacts to the I atoms of neighbouring molecules. 相似文献
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Complexes of copper(II) with 2-(acetylamino)benzoic acid, 2-(benzoylamino) benzoic acid, 2-(aminocarbonyl)benzoic acid, 2-[(phenylamino)carbonyl]benzoic acid, 2-[(1-naphthalenylamino)carbonyl]benzoic acid, 2-[(2-aminophenylamino)carbonyl]benzoic acid, 2-aminobenzanilide, 2(aminobenzoyl)benzoic acid, maleanilic acid and malea-1-naphthalanilic acid have been prepared and characterized by chemical analyses, molar conductivity, magnetic susceptibility measurements, thermal data, IR, electronic and ESR spectra. The visible and ESR spectral studies of these complexes (except those of maleanilic acid and malea-1-naphthalanilic acid) indicate that they are monomeric having either square planar or distorted octahedral geometry around Cu(II). The Cu(II) complexes of maleanilic acid and malea-1-naphthalanilic acid have been tentatively assigned dimeric structures. From the ESR spectra of Cu(II) complexes various parameters have been calculated. 相似文献
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David Savage John F. Gallagher Yoshiteru Ida 《Journal of organometallic chemistry》2005,690(2):383-393
A series of N-para-ferrocenyl benzoyl amino acid ethyl esters 1-8 have been prepared by coupling para-ferrocenyl benzoic acid with the amino acid esters using the conventional 1,3-dicyclohexylcarbodiimide (DCC), 1-hydroxybenzotriazole (HOBt) protocol. The amino acids employed in the synthesis were glycine, l-alanine, l-leucine, l-phenylalanine, β-alanine, 4-aminobutyric acid, (±)-2-aminobutyric acid and 2-aminoisobutyric acid. The compounds were fully characterized by a range of spectroscopic techniques such as NMR and mass spectrometry. In addition the X-ray crystal structures of the glycyl 1 and (±)-2-aminobutyrate 7 derivatives have been determined. Analysis of relevant fragments in crystal structures on the Cambridge Structural Database indicates a relative paucity of common fragments such as the α-aminobutyrate group in comparison to the glycyl moiety. 相似文献
16.
在甲醇溶液中,将K2NiL·H2O和M(OAC)2(M = Co,Zn)按1:1的摩尔比进行组装反应,得到了镍、钴和镍、锌两种异金属一维链状配位聚合物,其化学组成分别为{[Ni2Co2L2(H2O)2]·CH3OH·3H2O}n(1)和{[Ni2Zn2L2 (H2O)2]·2CH3OH·H2O}n(2),(H4L=2-羟基-3-[(E)-({2-(2-羟基苯甲酰胺基)乙基}亚氨基)甲基]苯甲酸,OAC- = CH3COO-)。通过IR谱,元素分析的方法对其进行了表征,利用X-射线单晶衍射方法对其晶体结构进行了测定,结构分析表明:它们都是由不对称四核单元组成链状配位聚合物。 相似文献
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Ultraviolet irradiation of a salt crystal of 4-(2,4,6-triisopropylbenzoyl)benzoic acid with (S)-phenylethylamine promoted single-crystal-to-single-crystal photocyclization to give an enantiopure (R,R)-cyclopentenol and almost racemic cyclobutenol. The reaction paths were elucidated by X-ray crystallographic analysis of the crystal before and after irradiation. 相似文献
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Kai Zhao Dr. Ying He Chuan Shan Junyu Ren Dr. Lukasz Wojtas Prof. Li Wang Prof. Guanghua Li Prof. Zhiguang Song Prof. Xiaodong Shi 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(69):16272-16276
Extended tetratopic benzoic acid ligands with “orthogonal-twisted-arms” conformations were designed and synthesized for the construction of new MOF structures (OTA-MOF). Upon coordination with Cd2+ and Cu2+ cations, two well-defined new MOFs were prepared. X-ray single crystal structures were successfully obtained, demonstrating the formation of a new topology (4,4,4-c). The OTA2-MOF-Cu gave moderate stability in organic solvents and good gas sorption ability toward CO2. This new MOF showed superior catalytic reactivity toward the epoxide-CO2 cycloaddition, giving >50 folds yield enhancement over the controlled reaction without MOF. It is expected that this new ligand design, porous structure, and excellent CO2 catalytic reactivity will make OTA-MOF promising new materials for applications in catalysis and separation. 相似文献
20.
C.A. de Lange 《Chemical physics letters》1974,28(4):526-528
Proton NMR spectra of trimethyl acetic acid, dissolved in a benzoic acid type nematic liquid crystal, have been measured and analysed. Making use of the hydrogen bonding capabilities of this sort of nematic phase appears to be an excellent method to obtain very high solute orientations. 相似文献