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41.
Anwar Usman Ibrahim Abdul Razak Suchada Chantrapromma Sujit K. Ghorai Dipakranjan Mal Hoong‐Kun Fun Gur Dayal Nigam 《Acta Crystallographica. Section C, Structural Chemistry》2001,57(9):1118-1119
The title compound, C19H16O, crystallizes with two molecules of opposite chirality in the asymmetric unit. In both molecules, the naphthalene and cyclopentanone moieties are individually planar. The two cyclopentane rings adopt envelope conformations, while the cyclohexane ring adopts a boat conformation. 相似文献
42.
43.
Zhang Xuan-Jun Wu Jie-Ying Zhang Ming-Liang Tian Yu-Peng Jiang Min-Hua Usman Anwar Chantrapromma Suchada Fun Hoong-Kun 《Transition Metal Chemistry》2003,28(6):707-711
Two coordination polymers [Zn(Cabo)2(EtOH)2(4,4-Bipy)]
n
(1), and [Zn2(Cabo)2(NO3)2(4,4-Bipy)2]
n
(2) (Cabo = carbazolylacetate, 4,4-Bipy = 4,4-bipyridine) with chain and ladder structures, respectively, were prepared and characterized by X-ray single-crystal structural analysis. The results showed that the different anions of metal salts have a large effect on the construction of coordination frameworks. Both complexes show strong emissions in the solid state as well as high thermal stability. 相似文献
44.
Rajca A Miyasaka M Pink M Wang H Rajca S 《Journal of the American Chemical Society》2004,126(46):15211-15222
The synthesis and characterization of a novel oligothiophene, in which the thiophene rings are annelated into a [7]helicene with cross-conjugated pi-system, are described. Such [7]helicenes may be viewed as fragments of the unprecedented carbon-sulfur (C(2)S)(n)() helix, possessing sulfur-rich molecular periphery. Racemic synthesis of [7]helicene is based upon iterative alternation of two steps: C-C bond homocouplings between the beta-positions of thiophenes and annelation between the alpha-positions of thiophenes. Asymmetric synthesis is carried out using (-)-sparteine-mediated annelation of the axially chiral bis(aryllithium) with electrophilic sulfur equivalent. Alternatively, enantiomers of the [7]helicene are obtained via resolution using menthol-based chiral siloxanes. Racemic [7]helicene and four other macrocyclic products of the annelation are characterized by X-ray crystallography. One of the solvent polymorphs of the [7]helicene possesses pi-stacked columns of opposite enantiomers and multiple short intermolecular contacts, including both homochiral and heterochiral short S...S contacts, suggesting an effective intermolecular electronic coupling in two-dimensions. The [7]helicene is configurationally stable at room temperature and racemizes at 199 degrees C with a half-time of about 11 h. Selected physicochemical studies (UV-vis absorption, CD, optical rotation, and cyclic voltammetry) of the [7]helicene are described. 相似文献
45.
Anwar Usman Ibrahim Abdul Razak Hoong‐Kun Fun Suchada Chantrapromma Yan Zhang Jian‐Hua Xu 《Acta Crystallographica. Section C, Structural Chemistry》2002,58(9):o543-o544
In the title compound, C24H17NO2S, the dioxine and thiazoline rings are distorted from planarity towards a half‐chair and an envelope conformation, respectively. The configurations of the dioxine ring, the thiazoline ring and the attached phenyl ring are conditioned by the sp3 state of the two bridgehead C atoms. The phenanthrene system is nearly coplanar with the dioxine ring, while the attached phenyl ring is orthogonal to the thiazoline ring. 相似文献
46.
Anwar Usman Suchada Chantrapromma Hoong‐Kun Fun Bo‐Long Poh Chatchanok Karalai 《Acta Crystallographica. Section C, Structural Chemistry》2002,58(1):o46-o47
In the title complex, the 1:1 ionic adduct of hexamethylenetetraminium and 2,4,6‐trinitrophenolate, C6H13N4+·C6H2N3O7?, the cation acts as a donor for bifurcated hydrogen bonds to the O atoms of the phenolate and one of the nitro groups of the 2,4,6‐trinitrophenolate anion. The crystal structure is built from sheets of cations and anions, and is stabilized by intermolecular C—H?O and C—H?π interactions. 相似文献
47.
Suchada Chantrapromma Anwar Usman Hoong‐Kun Fun Bo‐Long Poh Chatchanok Karalai 《Acta Crystallographica. Section C, Structural Chemistry》2002,58(9):o589-o590
In the title ternary complex, C10H9N2+·C7H3N2O6?·C7H4N2O6, the pyridinium cation adopts the role of the donor in an intermolecular N—H?O hydrogen‐bonding interaction with the carboxylate group of the 3,5‐dinitrobenzoate anion. The molecules of the ternary complex form molecular ribbons perpendicular to the b direction, which are stabilized by one N—H?O, one O—H?O and five C—H?O intermolecular hydrogen bonds. The ribbons are further interconnected by three intermolecular C—H?O hydrogen bonds into a three‐dimensional network. 相似文献
48.
Qingli Hao Xujie Yang Fangfang Jian Lude Lu Xin Wang Ibrahim Abdul Razak Suchada Chantrapromma Hoong-Kun Fun 《Acta Crystallographica. Section C, Structural Chemistry》2001,57(1):42-44
The two title compounds, [M(C6H14O2PS2)2(C12H8N2)], where M = CdII and FeII, are isomorphous. Each compound has a crystallographic twofold axis of symmetry through the metal atom and the 1,10-phenanthroline molecule. The central metal atom is coordinated to four S atoms from the two dithiophosphate groups and two N atoms from the 1,10-phenanthroline ligand. The environment of the metal atom is a distorted octahedron. 相似文献
49.
The electrochemical properties of chloramphenicol at a boron-doped diamond thin-film (BDD) electrode were studied using cyclic voltammetry. The highest current response of chloramphenicol was obtained with phosphate buffer, pH 6 (0.1 M) in 1% ethanol. The relationship between the concentration of chloramphenicol and the current response was linear over the range of 0.1-10 mM (R2=0.9990). The amount of chloramphenicol was analyzed by flow-injection analysis. A thin-layer flow cell equipped with a BDD electrode was used as an amperometric detector, and experiments were carried out at -0.7 V (vs. Ag/AgCl). The linear relationship between the current response and the concentration of chloramphenicol in the range of 0.1-50 microM (R2=0.9948) and the limit of detection of 0.03 microM (S/N=3) were obtained. This method has been successfully applied to the determination of chloramphenicol in sterile eye drops and milk sample by the standard addition method. The average recoveries of chloramphenicol in eye drops were 98.0%, and the average recoveries of chloramphenicol from spiked milk were 93.9-103%. 相似文献
50.
Dimerization of planarized diamine 2 using benzoyl peroxide gave dihydrazine 1 in about 70% yield; that is, three dehydrogenations (one CC- and two NN-homocouplings) and two ring closures were attained in one synthetic step. Dihydrazine 1 may be viewed as a chiral pi-conjugated conjoined double helicene, with two homochiral [5]helicene-like fragments, annelated in their mid-sections. A relatively high barrier of approximately 35 kcal mol-1 for inversion of configuration for one of the [5]helicene-like helices in 1 was found. 相似文献