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921.
o‐Fluorination of Aromatic Azides Yields Improved Azido‐Based Fluorescent Probes for Hydrogen Sulfide: Synthesis,Spectra, and Bioimaging
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Chao Wei Runyu Wang Dr. Lv Wei Longhuai Cheng Zhifei Li Prof. Dr. Zhen Xi Prof. Dr. Long Yi 《化学:亚洲杂志》2014,9(12):3586-3592
Hydrogen sulfide (H2S) is an endogenously produced gaseous signaling molecule with multiple biological functions. To visualize the endogenous in situ production of H2S in real time, new coumarin‐ and boron‐dipyrromethene‐based fluorescent turn‐on probes were developed for fast sensing of H2S in aqueous buffer and in living cells. Introduction of a fluoro group in the ortho position of the aromatic azide can lead to a greater than twofold increase in the rate of reaction with H2S. On the basis of o‐fluorinated aromatic azides, fluorescent probes with high sensitivity and selectivity toward H2S over other biologically relevant species were designed and synthesized. The probes can be used to in situ to visualize exogenous H2S and D ‐cysteine‐dependent endogenously produced H2S in living cells, which makes them promising tools for potential applications in H2S biology. 相似文献
922.
The article presents the method of recycling aluminum industry fluorine-containing waste products to produce hydrogen fluoride. We carried out the estimate of the thermodynamic parameters of sulfuric acidic recycling of fluorine-containing waste products. We considered the necessity of waste products preliminary oxidizing roast stage to reduce carbonic constituent due to the interaction between carbonic constituent blocks of the sulfuric acid and waste products. We also carried out the researches for kinetic characteristics and to determine the optimal conditions for the to recycle sulfuric acidic in the fluorine-containing waste products. 相似文献
923.
Controlled Dynamic Helicity of a Folded Macrocycle Based on a Bisterephthalamide with a Twofold Z‐Shaped Structure
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Dr. Ryo Katoono Keiichi Kusaka Prof. Dr. Kenshu Fujiwara Prof. Dr. Takanori Suzuki 《化学:亚洲杂志》2014,9(11):3182-3187
Dynamic helicity in a folded macrocycle and control of the helical preference are described. We designed macrocycle 1 with a dual mode of folding through the integration of two flexible units that are arranged twice to form a cyclic structure. As a folding unit, we used a terephthalamide skeleton and a Z‐shaped hydrocarbon: the former acted as a control unit to induce a preference of a particular sense of dynamic helicity and the latter was just a spacer. A terephthalamide unit provided a binding site for capturing a ditopic hydrogen‐bonding guest when it adopted helically folded syn forms (M/P). Thus, only the terephthalamide unit controlled the helical sense of dynamic helicity in a folded macrocycle through the supramolecular transmission of chirality upon complexation with a chiral ditopic guest. In addition, chirality on a host could also contribute to the control of the helical preference in a folded macrocycle, which led to exceptionally enhanced chiroptical signals. 相似文献
924.
《Journal of Energy Chemistry》2014,23(4):414-419
Alkali metal hydroxide and hydride composite systems contain both protic(H bonded with O) and hydridic hydrogen. The interaction of these two types of hydrides produces hydrogen. The enthalpy of dehydrogenation increased with the increase of atomic number of alkali metals,i.e.,-23 kJ/molH2 for LiOH-LiH, 55.34 kJ/molH2 for NaOH-NaH and 222 kJ/molH2 for KOH-KH. These thermodynamic calculation results were consistent with our experimental results. H2 was released from LiOH-LiH system during ball milling. The dehydrogenation temperature of NaOH-NaH system was about 150℃; whereas KOH and KH did not interact with each other during the heating process. Instead, KH decomposed by itself. In these three systems, NaOH-NaH was the only reversible hydrogen storage system, the enthalpy of dehydrogenation was about 55.65 kJ/molH2, and the corresponding entropy was ca. 101.23 J/(molH2 K), so the temperature for releasing 1.0 bar H2 was as high as 518℃, showing unfavorable thermodynamic properties. The activation energy for hydrogen desorption of NaOH-NaH was found to be57.87 kJ/mol, showing good kinetic properties. 相似文献
925.
Yelder A. Castillo Luis F. Zapata Jorge Trilleras Justo Cobo Christopher Glidewell 《Acta Crystallographica. Section C, Structural Chemistry》2014,70(1):50-54
The title compound, C23H17N3O4S, crystallizes with Z′ = 3 in the space group P. Two of the three independent molecules are broadly similar in terms of both their molecular conformations and their participation in hydrogen bonds, but the third molecule differs from the other two in both of these respects. The molecules are linked by a combination of N—H...O, N—H...N, C—H...O, C—H...N and C—H...π(arene) hydrogen bonds to form a continuous three‐dimensional framework structure within which a centrosymmetric six‐molecule aggregate can be identified as a key structural element. 相似文献
926.
Ray Jones 《Acta Crystallographica. Section C, Structural Chemistry》2014,70(1):60-66
The structures of 6‐nitro‐1,3λ4δ2,5,2,4‐trithiadiazepine [C2HN3O2S3, ( 1 )], 6,7‐dinitro‐1,3λ4δ2,5,2,4‐trithiadiazepine [C2N4O4S3, ( 2 )], 1,3λ4δ2,5,2,4‐trithiadiazepine‐6,7‐dicarbonitrile [C4N4S3, ( 3 )] and 7‐acetyl‐1,3λ4δ2,5,2,4,6‐trithiatriazepine [C3H3N3OS3, ( 4 )] presented here include the most precise determinations of these seven‐membered 10 π‐electron aromatic ring systems published to date. Both ( 2 ) and ( 3 ) are sited around crystallographic twofold axes with half a molecule per asymmetric unit. Comparison with other published derivatives of these rings reveals the effect of substituents on bonding, conformations and intermolecular interactions, including π‐stacking. The deformation density analysis of ( 2 ) is consistent with the expected bonding electron density from other theoretical and experimental studies. 相似文献
927.
Berthold Stger Matthias Weil 《Acta Crystallographica. Section C, Structural Chemistry》2014,70(1):7-11
The four isotypic alkaline metal monohydrogen arsenate(V) and phosphate(V) dihydrates M2HXO4·2H2O (M = Rb, Cs; X = P, As) [namely dicaesium monohydrogen arsenate(V) dihydrate, Cs2HAsO4·2H2O, dicaesium monohydrogen phosphate(V) dihydrate, Cs2HPO4·2H2O, dirubidium monohydrogen arsenate(V) dihydrate, Rb2HAsO4·2H2O, and dirubidium monohydrogen phosphate(V) dihydrate, Rb2HPO4·2H2O] were synthesized by reaction of an aqueous H3XO4 solution with one equivalent of aqueous M2CO3. Their crystal structures are made up of undulating chains extending along [001] of tetrahedral [XO3(OH)]− anions connected via strong O—H...O hydrogen bonds. These chains are in turn connected into a three‐dimensional network via medium‐strength hydrogen bonding involving the water molecules. Two crystallographically different M+ cations are located in channels running along [001] or in the free space of the [XO3(OH)]− chains, respectively. They are coordinated by eight and twelve O atoms forming irregular polyhedra. The structures possess pseudosymmetry. Due to the ordering of the protons in the [XO3(OH)]− chains in the actual structures, the symmetry is reduced from C2/c to P21/c. Nevertheless, the deviation from C2/c symmetry is minute. 相似文献
928.
Inese Sarcevica Liana Orola Mikelis V. Veidis Sergey Belyakov 《Acta Crystallographica. Section C, Structural Chemistry》2014,70(4):392-395
A new polymorph of the cinnamic acid–isoniazid cocrystal has been prepared by slow evaporation, namely cinnamic acid–pyridine‐4‐carbohydrazide (1/1), C9H8O2·C6H7N3O. The crystal structure is characterized by a hydrogen‐bonded tetrameric arrangement of two molecules of isoniazid and two of cinnamic acid. Possible modification of the hydrogen bonding was investigated by changing the hydrazide group of isoniazid via an in situ reaction with acetone and cocrystallization with cinnamic acid. In the structure of cinnamic acid–N′‐(propan‐2‐ylidene)isonicotinohydrazide (1/1), C9H8O2·C9H11N3O, carboxylic acid–pyridine O—H...N and hydrazide–hydrazide N—H...O hydrogen bonds are formed. 相似文献
929.
Telisha Traut‐Johnstone Frederik H. Kriel Raymond Hewer D. Bradley G. Williams 《Acta Crystallographica. Section C, Structural Chemistry》2014,70(12):1121-1124
The mixed organic–inorganic title salt, C7H18N2O2+·C2HO4−·Cl−, forms an assembly of ionic components which are stabilized through a series of hydrogen bonds and charge‐assisted intermolecular interactions. The title assembly crystallizes in the monoclinic C2/c space group with Z = 8. The asymmetric unit consists of a 4‐(3‐azaniumylpropyl)morpholin‐4‐ium dication, a hydrogen oxalate counter‐anion and an inorganic chloride counter‐anion. The organic cations and anions are connected through a network of N—H...O, O—H...O and C—H...O hydrogen bonds, forming several intermolecular rings that can be described by the graph‐set notations R33(13), R21(5), R12(5), R21(6), R23(6), R22(8) and R33(9). The 4‐(3‐azaniumylpropyl)morpholin‐4‐ium dications are interconnected through N—H...O hydrogen bonds, forming C(9) chains that run diagonally along the ab face. Furthermore, the hydrogen oxalate anions are interconnected via O—H...O hydrogen bonds, forming head‐to‐tail C(5) chains along the crystallographic b axis. The two types of chains are linked through additional N—H...O and O—H...O hydrogen bonds, and the hydrogen oxalate chains are sandwiched by the 4‐(3‐azaniumylpropyl)morpholin‐4‐ium chains, forming organic layers that are separated by the chloride anions. Finally, the layered three‐dimensional structure is stabilized via intermolecular N—H...Cl and C—H...Cl interactions. 相似文献
930.
Zhengliang Lu Yuanchao Zhao Baolian Chen Ximing Huang Chunhua Fan 《Acta Crystallographica. Section C, Structural Chemistry》2014,70(7):718-721
The title compound, [MnCl2(C24H20N6)], has been synthesized and characterized based on the multifunctional ligand 2,5‐bis(2,2′‐bipyridyl‐6‐yl)‐3,4‐diazahexa‐2,4‐diene (L). The MnII centre is five‐coordinate with an approximately square‐pyramidal geometry. The L ligand acts as a tridendate chelating ligand. The mononuclear molecules are bridged into a one‐dimensional chain by two C—H...Cl hydrogen bonds. These chains are assembled into a two‐dimensional layer through π–π stacking interactions between adjacent uncoordinated bipyridyl groups. Furthermore, a three‐dimensional supramolecular framework is attained through π–π stacking interactions between adjacent coordinated bipyridyl groups. 相似文献