Syntheses, structures and properties of 1-ethyl-3-methylimidazolium salts of fluorocomplex anions

Fluoroacid-base reactions of a room-temperature ionic liquid, 1-ethyl-3-methylimidazolium fluorohydrogenate (EMIm(HF)2.3F, EMIm = 1-ethyl-3-methylimidazolium cation), and Lewis fluoroacids (BF3, PF5, AsF5, NbF5, TaF5 and WF6) give EMIm salts of the corresponding fluorocomplex anions, EMImBF4, EMImPF6, EMImAsF6, EMImNbF6, EMImTaF6 and EMImWF7, respectively. Attempts to prepare EMImVF6 by both the acid-base reaction of EMIm(HF)2.3F with VF5 and the metathesis of EMImCl with KVF6 failed due to the strong oxidizing power of the pentavalent vanadium, whereas EMImSbF6 was successfully prepared only by the metathesis of EMImCl and KSbF6. EMImBF4, EMImSbF6, EMImNbF6, EMImTaF6 and EMImWF7 are liquids at room temperature whereas EMImPF6 and EMImAsF6 melts at around 330 K. Raman spectra of the obtained salts showed the existence of the EMIm cation and corresponding fluorocomplex anions. IR spectroscopy revealed that strong hydrogen bonds are not observed in these salts. EMImAsF6(mp 326 K) and EMImSbF6(mp 283 K) are isostructural with the previously reported EMImPF6. The melting point of the hexafluorocomplex EMIm salt decreases with the increase of the size of the anion (PF6- < AsF6- < SbF6- 相似文献   

High pressure volumetric properties of 1-ethyl-3-methylimidazolium ethylsulfate and 1-(2-methoxyethyl)-1-methyl-pyrrolidinium bis(trifluoromethylsulfonyl)imide

In order to select the most suitable ionic liquids (ILs) for certain applications it is necessary to know some of their thermophysical properties, such as density or viscosity. In this work we have performed density measurements of two ILs 1-ethyl-3-methylimidazolium ethylsulfate and 1-(2-methoxyethyl)-1-methyl-pyrrolidinium bis(trifluoromethylsulfonyl)imide in a broad range of temperature and pressure ((278.15 to 398.15) K and up to 120 MPa). From these measurements we have obtained other volumetric properties such as isothermal compressibility and isobaric thermal expansivity. In addition, density values were predicted using the method proposed by Gardas and Coutinho and also that proposed by Jacquemin et al., obtaining a good agreement with experimental values.     

Thermophysical properties of 1-methyl-3-methylimidazolium dimethylphosphate and 1-ethyl-3-methylimidazolium diethylphosphate

The density and surface tension of 1-methyl-3-methylimidazolium dimethylphosphate, [C₁mim](CH₃O)₂PO₂ and 1-ethyl-3-methylimidazolium diethylphosphate, [C₂mim](CH₃CH₂O)₂PO₂ ionic liquids have been measured over the temperature range from (283.15 to 338.15) K. The coefficients of thermal expansion were calculated from the experimental density results using an empirical correlation for T = (283.15 to 338.15) K. Molecular volume and standard entropies of these ILs were calculated from the experimental density values. The surface properties of ILs were investigated. The critical temperature and enthalpy of vapourization were also discussed.     

Solubility of carbon dioxide in 1-ethyl-3-methylimidazolium 2-(2-methoxyethoxy) ethylsulfate

Experimental results for the solubility of carbon dioxide in the ionic liquid 1-ethyl-3-methylimidazolium 2-(2-methoxyethoxy) ethylsulfate are not reported in the literature. To this end, we present in this work new solubility data for carbon dioxide in 1-ethyl-3-methylimidazolium 2-(2-methoxyethoxy) ethylsulfate for temperatures ranging from (303.2 to 343.2) K and pressures up to 6.7 MPa using a thermogravimetric microbalance. The carbon dioxide solubility was determined from absorption saturation (equilibrium) data at each fixed temperature and pressure. The buoyancy effect was accounted in the evaluation of the carbon dioxide solubility. Highly accurate equations of states for carbon dioxide and for ionic liquids were employed to determine the effect of buoyancy on carbon dioxide solubility. The solubility measurements are presented as a function of temperature and pressure. The present experimental solubility results have been successfully correlated using an extended Henry’s law equation.     

Ferro- and ferrimagnetic chains of hin-bridged copper(II) and manganese(II) and hnn-bridged manganese(II) complexes (hin = 4,4,5,5-tetramethylimidazolin-1-oxyl; hnn = 4,4,5,5-tetramethylimidazolin-1-oxyl 3-oxide)

We have exploited potential utility of 4,4,5,5-tetramethylimidazolin-1-oxyl (hin) and 4,4,5,5-tetramethylimidazolin-1-oxyl 3-oxide (hnn) as mu-1,4 and mu-1,5 bridging ligands, respectively, carrying an unpaired electron in development of metal-radical hybrid magnets. X-ray diffraction measurements of [Cu(hfac)(2)hin] (1), [Mn(hfac)(2)hin] (2), and [Mn(hfac)(2)hnn] (3) revealed one-dimensional metal-radical alternating chain structures, where hfac denotes 1,1,1,5,5,5-hexafluoropentane-2,4-dionate. Magnetic measurements of 1 indicate the presence of intrachain ferromagnetic coupling between copper and radical spins. The magnetic exchange parameter was estimated as 2J/k = 56.8 K based on an S = 1/2 equally spaced ferromagnetic chain model (H = -2J summation operator S(i).S(i+1)). This ferromagnetic interaction can be explained in terms of the axial coordination of the hin nitrogen or oxygen to Cu(II). The chi(m)T value of 2 and 3 increased on cooling, and the magnetic data could be analyzed by Seiden's ferrimagnetic chain model, giving 2J/k = -325 and -740 K, respectively. The antiferromagnetic interaction of 2 and 3 can be attributed to orbital overlap between the manganese and the oxygen or nitrogen magnetic orbitals. The exchange interactions between Cu-hin and Mn-hnn are larger than those of typical Cu- and Mn-nitronyl nitroxide complexes, indicating that the choice of small ligands is a promising strategy to bestow strong exchange interaction. Compound 3 became a ferrimagnet below 4.4 K, owing to ferromagnetic coupling among the ferrimagnetic chains.     

Synthesis and structure of 3-(3-acetoxyalkylcarbamoyl-4-hydroxy-2-oxo-1,2-dihydroquinolin-1-yl)propanoic acids

Treatment of 1-(2-cyanoethyl)-4-hydroxy-N-(hydroxyalkyl)-2-oxo-1,2-dihydroquinoline-3-carboxamides with a solution of hydrogen chloride in aqueous acetic acid ensures selective transformation of the cyano group into amide or carboxy with simultaneous acetylation of the hydroxyalkyl fragments.     

Transamination of cyanothioacetamide with morpholine. Molecular and crystal structure of 3-(morpholin-1-yl)-3-thioxopropanenitrile and 3-(morpholin-1-yl)-3-thioxopropanethioamide

Transamination of cyanothioacetamide with equimolar amount of morpholine resulted in the formation of 3-(morpholin-1-yl)-3-thioxopropanenitrile, and with twofold excess of morpholine 3-(morpholin-1-yl)-3-thioxopropanethioamide was obtained. By the alkylation of the resulting products 2-[2-(morpholin-1-yl)-2-thioxoethylidene]thiazolidin-4-one, 3-amino-N-(4-acetylphenyl)-5-(morpholin-1-yl)-thiophene-2-carboxamide, 3-amino-3-methylthio-1-morpholinoprop-2-ene-1-thione, (2E,4E)-2-(morpholin-4-yl)thiocarbonyl)-5-phenylpenta-2,4-dienothioamide, and 3-{2??-[2??-(molrpholin-1-yl)-2-thioxoethyl]thiazol-4??-yl}-2H-chromen-2-one were synthesized. The 3-(morpholin-1-yl)-3-thioxopropanenitrile and 3-(morpholin-1-yl)-3-thioxopropanethioamide structures were studied by the X-ray diffraction.     

Molecular Rectangle Formed by Head-to-tail Self-Assembly of 1-(Dipyrrin-2-yl)-1-(dipyrrin-3-yl)methane

1-(Dipyrrin-2-yl)-1-(dipyrrin-3-yl)methane, the N-confused analog of biladiene-ac, is prepared by condensation of 2,3-dipyrromethane with two molecules of 2-formylpyrrole in dichloromethane in the presence of hydrogen bromide. Self-assembly of the ligand with Zn(II) in dichloromethane and methanol offers a dinuclear dimeric complex with a ligand:metal ratio of 2:2. X-Ray crystal structure analysis reveals two ligands bound through a head-to-tail pattern to two zinc centers to form a severely distorted helical conformation, which has the shape of a rectangle.     

Molecular Rectangle Formed by Head-to-tail Self-Assembly of 1-(Dipyrrin-2-yl)-1-(dipyrrin-3-yl)methane

Summary. 1-(Dipyrrin-2-yl)-1-(dipyrrin-3-yl)methane, the N-confused analog of biladiene-ac, is prepared by condensation of 2,3-dipyrromethane with two molecules of 2-formylpyrrole in dichloromethane in the presence of hydrogen bromide. Self-assembly of the ligand with Zn(II) in dichloromethane and methanol offers a dinuclear dimeric complex with a ligand:metal ratio of 2:2. X-Ray crystal structure analysis reveals two ligands bound through a head-to-tail pattern to two zinc centers to form a severely distorted helical conformation, which has the shape of a rectangle.     

Crystal and Molecular Structure of N-(1-Ethoxycarbonyl- ethyl)1-Ethoxycarbonylmethyl-3-ethyl-1,2,3,4- tetrahydro-4-oxo-1,3,2-benzodiazaphosphorin- 2-carboxamide 2-Oxide

1 INTRODUCTIONOrganophosphorus compounds are ubiquitous in nature and they have broad applications in the fields of agriculture and medicine. During the past two decades, (-ketophosphonates and their derivatives have attracted considerable attention because these compounds are endowed with special physical, chemical and pharmacological properties due to the proximity of the carbonyl and the phosphoryl groups[1～6]. For example, it is well known that phosphonoformic acid (PFA) is effectiv…     

Facile Synthesis of Some 3-(Benzimidazol-2-yl)- and 3,6-Di(Benzimidazol-2-yl)-9-ethyl-9H-carbazoles

A simple and efficient synthesis of novel 3-(benzimidazol-2-yl)- and 3,6-di(benzimidazol-2-yl)-9-ethyl-9H-carbazoles is described. The synthetic approach for the preparation of 2-substituted benzimidazoles 4–8 and bis-benzimidazoles 9–12 was achieved by the condensation of carbazole-3-carbaldehyde 2 and carbazole-3,6-dicarbaldehyde 3 with o-phenyldiamines in dimethylformamide or dimethylsulfoxide in moderate to excellent yield. The identities of synthesized compounds were confirmed using ¹H NMR, ¹³C NMR, infrared (IR), and high-resolution mass spectrometry (HRMS).     

Synthesis of Fluorine-Containing 2-(1-Aryl-4-oxo-1,4-dihydrocinnolin-3-yl)-2-oxoacetic Acids

Acid hydrolysis of ethyl 2-(1-aryl-5,6,7,8-tetrafluoro-4-oxo-1,4-dihydrocinnolin-3-yl)-2-oxoacetates gives 2-(1-aryl-5,6,7,8-tetrafluoro-4-oxo-1,4-dihydrocinnolin-3-yl)-2,2-dihydroxyacetic acids which undergo dehydration on heating in toluene to afford 2-(1-aryl-5,6,7,8-tetrafluoro-4-oxo-1,4-dihydrocinnolin-3-yl)-2-oxoacetic acids. Reactions of the latter with excess morpholine result in replacement of two fluorine atoms in positions 5 and 7 by the amine residues.     

Structure and magnetic properties of 3-oxyl-4,4,5,5-tetramethyl-2-oxoimidazolidin-1-olates

The paramagnetic salts (NH₃Bu^t)1 and [K(NH₂Bu^t)₂]1, where 1 is the 3-oxyl-4,4,5,5-tetramethyl-2-oxoimidazolidin-1-olate anion, were isolated for the first time in the individual state. The crystal structure of [K(NH₂Bu^t)₂]1 involves polymer chains formed by hydrogen bonding between anions 1 and [K₂(NH₂Bu^t)₄]²⁺ cation dimer fragments. The magnetic properties of [K(NH₂Bu^t)₂]1 are well described by the quasi-isolated dimer model with spins S = 1/2 coupled by weak exchange interactions via [K₂(NH₂Bu^t)₄]² fragments in polymer chains.