Hydrogen Sulfate Anion Research Articles

A fluorescence turn-on chemosensor for hydrogen sulfate anion based on quinoline and naphthalimide

A new fluorescence turn-on chemosensor 1 based on quinoline and naphthalimide was prepared and its anion sensing toward various anions behavior was explored in this paper. Sensor 1 exhibited a highly selective fluorescent response toward HSO4− with an 8-fold fluorescence intensity enhancement in the presence of 10equiv. of HSO4− in DMSO-H2O (1/1, v/v) solution. The sensor also displayed high sensitivity to hydrogen sulfate and the detection limit was calculated to be 7.79×10−7M. The sensing mechanism has been suggested to proceed via a hydrolysis process of the Schiff base group. The hydrolysis product has been isolated and further identified by 1H NMR and MS.

Estimation and Structural Effect on Physicochemical Properties of Alkylimidazolium-Based Ionic Liquids with Different Anions

Ten kinds of alkylimidazolium-based aprotic ionic liquids (AILs) with hydrogen carbonate, dihydrogen phosphate, and hydrogen sulfate anions were prepared, and methods of elemental analysis, infrared spectroscopy, and proton nuclear magnetic resonance were employed to characterize the ILs, respectively. Properties such as electrical conductivity, density, dynamic viscosity, surface tension, were measured and correlated with thermodynamic and empirical equations over various temperature ranges under ambient conditions. Some significant thermodynamic parameters of the ILs were estimated. The trends of changing with temperature for the dynamic viscosity and the electrical conductivity were described by the Vogel–Fulcher–Tamman equation. The activation energies of dynamic viscosity and electrical conductivity were also calculated. Further, the structures and the energetics of the ILs ions were obtained through combining density functional theory calculations and the COSMO-RS methodology. The structural effects...

Crystal structure, thermal analysis and IR spectrometric investigation of the tris(2,6-diaminopyridinium) hydrogen sulfate sulfate monohydrate

The crystals of new inorganic–organic hybrid material tris(2,6-diaminopyridinium) hydrogen sulfate sulfate monohydrate (C5H8N3)3(HSO4)(SO4)·H2O, were grown by slow evaporation technique in aqueous solution. The title compound has been prepared and characterized by X-ray diffraction, IR spectroscopy and thermal analysis. The complex crystallizes in the triclinic system, space group P1¯, with the following cell parameters a = 8.051(3)Å, b = 10.646(4)Å, c = 14.138(6)Å, α = 73.23(3)°, β = 79.28(3)°, γ = 82.28(3)°, V = 1135.8(8)Å3 and Z = 2, T = 100 K. The crystal is built up from hydrogen sulfate anions HSO4−, sulfate anions SO42−, protonated cations (C5H8N3)+ and water molecules. In this compound, hydrogen bonding and π⋯π interactions play crucial roles in forming interesting structural patterns. Thermal analysis indicates that (C5H8N3)3(HSO4)(SO4)·H2O does not experience any structural phase transition in the temperature range measured from 25 to 700 °C. Therefore, the properties of the new phase are inconsistent with the characteristic features of the superprotonic family M3H(SO4)2.

Hydrogensulphate ionic liquids as an efficient catalyst for the synthesis of cyclic carbonates from carbon dioxide and epoxides

BACKGROUND The use of CO2 as a raw material to synthesize cyclic carbonates has attracted much attention in recent years. Ionic liquids (ILs) due to their unique properties are often used as effective catalysts for the reaction between CO2 and epoxide to afford cyclic carbonates. This report describes an efficient method for the synthesis of cyclic carbonates in the presence of IL with HSO4− anion as a catalyst which could be easily separated and reused. RESULTS The synthesis of cyclic carbonates from CO2 and epoxides using the two-component catalytic system consisting of the ionic liquid based on the imidazolium cation and the hydrogensulphate anion and an aqueous solution of zinc iodide is described. The cyclic carbonates were obtained with high yields (69–99%) and selectivities (>99%) under the optimized conditions: 120 °C, 2 MPa of CO2, without utilization of any organic solvents. CONCLUSION The new and effective catalytic system allows one to obtain cyclic carbonates in high yields and can be reused several times without significant loss of activity. Therefore, the proposed method seems to be useful for practical applications. © 2016 Society of Chemical Industry

Chemically-modified cellulose paper as smart sensor device for colorimetric and optical detection of hydrogen sulfate in water.

A portable, recyclable and highly selective paper-based sensor device for the colorimetric and optical detection of hydrogen sulfate anions in water was developed. The detection system features a rhodamine-based sensor covalently grafted onto the highly hydrophilic surface of cellulose paper.

Crystal structure of tris-(piperidinium) hydrogen sulfate sulfate.

In the title molecular salt, 3C5H12N(+)·HSO4 (-)·SO4 (2-), each cation adopts a chair conformation. In the crystal, the hydrogen sulfate ion is connected to the sulfate ion by a strong O-H⋯O hydrogen bond. The packing also features a number of N-H⋯O hydrogen bonds, which lead to a three-dimensional network structure. The hydrogen sulfate anion accepts four hydrogen bonds from two cations, whereas the sulfate ion, as an acceptor, binds to five separate piperidinium cations, forming seven hydrogen bonds.

Structural changes in lignins isolated using an acidic ionic liquid water mixture

Recently, acidic ionic liquid water mixtures based on the hydrogen sulfate anion have been shown to effectively extract lignin from lignocellulosic biomass.

N-Sulfonic acid poly(4-vinylpyridinum) hydrogen sulfate as a novel, efficient, and reusable solid acid catalyst for acylation under solvent-free conditions

N-Sulfonic acid poly(4-vinylpyridinum) hydrogen sulfate has been developed as a recyclable solid acid catalyst for the acetylation of alcohols, phenols, thiols, and amines, as well as the 1,1- diacetylation of aldehydes under solvent-free conditions at room temperature. The acetylated products were formed in good to excellent yields over short reaction times, and the catalyst could be readily recovered by filtration and used several times without any discernible loss in activity. The hydrogen sulfate anion of the catalytic system was found to play a critical role in enhancing the reaction time and yield of the acetylation reaction.

Synthesis and Physicochemical Properties of Two SO3H-Functionalized Ionic Liquids with Hydrogen Sulfate Anion

Two SO3H-functionalized ionic liquids (ILs), N-isobutyl-3-sulfopropan-1-aminium hydrogen sulfate [IBAC3S]HSO4 and N-isobutyl-4-sulfobutan-1-aminium hydrogen sulfate [IBAC4S]HSO4, were synthesized and characterized by NMR and HR-MS. The thermal properties and acidities were analyzed. Density, dynamic viscosity, surface tension, conductivity, and refractive index of the IL were studied as a function of temperature. The physicochemical properties, namely molecular volume, isobaric coefficients of thermal expansion, standard entropy, critical temperature, molar free volume, interstice volume, etc. of the IL were estimated according to the reported empirical and thermodynamic equations. On the basis of the Walden rule, the ionicty of the two SO3H-functionalized ionic liquids was assessed by the product of molar conductivity and viscosity.

Structural factors controlling thermal stability of imidazolium ionic liquids with 1- n -butyl-3-methylimidazolium cation on γ-Al 2 O 3

Abstract Structural factors determining thermal stability limits of imidazolium ionic liquids (ILs) with 1- n -butyl-3-methylimidazolium, [BMIM] + , cation on one of the most commonly used metal-oxide support, γ-Al 2 O 3 , were determined by thermogravimetric analysis complemented by infrared (IR) spectroscopy. IR results show that inter-ionic interaction strength in ILs increases as their anion structure varies in the following order: [NTf 2 ] − 6 ] − 4 ] − − − 4 ] − − − − . TGA data illustrate a strong dependence of thermal stability limits on inter-ionic interactions. Thermal stability limits of both bulk and γ-Al 2 O 3 -supported [BMIM] + -based ILs increase with decreasing inter-ionic interaction strength. Thermal stability limit of IL with octyl sulfate anion was lower than that of analogous IL with hydrogen sulfate anion, because of its exceptionally large anion size. Moreover, the effect of γ-Al 2 O 3 on IL thermal stability conditions becomes dominant with decreasing inter-ionic interactions in ILs.

Recognition of free tryptophan in water by synthetic pseudopeptides: fluorescence and thermodynamic studies.

Pseudopeptidic receptors containing an acridine unit have been prepared and their fluorescence response to a series of amino acids was measured in water. Free amino acids, not protected either at the C or the N terminus, were used for this purpose. The prepared receptors display a selective response to tryptophan (Trp) versus the other assayed amino acids under acidic conditions. The macrocyclic nature of the receptor is important as the fluorescence quenching is higher for the macrocyclic compound than for the related open-chain receptor. Notably, under the experimental acidic conditions used, both the receptor and guest are fully protonated and positively charged; thus, the experimental results suggest the formation of supramolecular species that contain two positively charged organic molecular components in proximity stabilized through aromatic-aromatic interactions and a complex set of cation-anion-cation interactions. The selectivity towards Trp seems to be based on the existence of a strong association between the indole ring of the monocharged amino acid and the acridinium fragment of the triprotonated form of the receptor, which is established to be assisted by the interaction of the cationic moieties with hydrogen sulfate anions.

Cationic Tripodal Receptor Assisted Formation of Anion and Anion–Water Clusters: Structural Interpretation of Dihydrogen Phosphate Cluster and Sulfate–Water Tetramer [(SO4)2–(H2O)2]4–

Well-defined anion and anion–water clusters based on tetrahedral oxyanions are reported herein. Self-assembled infinite dihydrogen phosphate anion clusters of 10 H2PO4– ions consist of a hexameric cluster linked to tetrameric and trimeric clusters. Octahedrally arranged discrete anionic [Na(ClO4)6]5– cluster is found to stabilize by self-complementary H-bonding and electrostatic interactions in noncapsular complexes. Our findings also indicate the presence of discrete sulfate–hydrogen sulfate anion trimers [SO4—(HSO4)2]4– and sulfate–water tetramers [(SO4)2—(H2O)2]4– in the bimolecular capsular complexes of the tripodal receptor. All complexes were well characterized by FT-IR and NMR spectroscopies, TGA, DSC, and XRD.

Effect of protonation and hydrogen bonding on 2, 4, 6-substituted pyrimidine and its salt complex-experimental and theoretical evidence

Quantum molecular simulations of chemical systems can provide detailed information that is often inaccessible to direct experimental measurement. Pyrimidine is an interesting π-electron heterocyclic aromatic system which acts as the building block of many nucleic acid bases. The hydrogen bonds associated with the 2, 4, and 6-substituted pyrimidine and its hydrogen sulfate anion are considered for this current work. The experimental and computational evidence for the strength of these intra and intermolecular hydrogen are determined using vibrational spectra and quantum chemical calculations. Thus the effect of hydrogen bonding on the title compound is studied using its geometrical parameters, interaction energies, and vibrational spectra. Aromaticity and charge transfer studies have been performed to ascertain the aromatic behavior of the molecule. The PES scan studies have been done by varying the bond length to ascertain the protonation process of the compound. The IR spectral red shift (∼100 cm⁻¹), blue shift (∼97 cm⁻¹) and broadening of the polar stretching peaks shows the inter and intramolecular hydrogen bonding strength. Bond length alternation of proton donors along with the enormous interaction energies (∼0.5-150 kJ mol⁻¹) between the lone pair and proton donors provides clear evidence for this hydrogen bonding. The charge transfer due to the methyl substitutions which enhances the possibility of hydrogen bonding has been discussed. The main scope of this work is to study the protonation and hydrogen bonding associated with charge transfer which has great effect on the 2-amino-4, 6-dimethyl pyrimidinium hydrogen sulfate (ADHS) molecule.

Glow discharge optical emission spectroscopy: a complementary technique to analyze thin electrodeposited polyaniline films

Glow Discharge Optical Emission Spectroscopy (GDOES) has been developed to perform depth profiles of thick metallic films, in tens of microns range. GDOES spectroscopy can also be used to analyze thin organic polymer films since this technique has a great potential thanks to its high depth resolution, multi-element capability, sensitivity, and adaptability to solids or films and to conducting or non-conducting samples. In particular thin electrodeposited conducting polymer films remain an unexplored field of investigation for GDOES technique. However GDOES was used in this work to analyze electrodeposited polyaniline films, in addition to other techniques such as profilometry, electron microscopy and X-ray diffraction (XRD). More precisely polyaniline thin films were electrodeposited from HCl solutions and the presence of an anilinium chloride excess at the top surface of the polymer film was demonstrated using GDOES and XRD. Rinsing of these films with water led to the removal of this excess and to the partial dedoping of the polymer film due to the porous structure of polymer films. Polyaniline thin films were also electrodeposited from H2SO4 solutions and an anilinium hydrogen sulfate was similarly observed at the top surface of the polymer. This excess was removed by rinsing, contrary to hydrogen sulfate anions incorporated into the polymer film during the electrochemical polymerization that were not completely expulsed from the polyaniline films as proved using GDOES.

4-Methoxybenzamidinium hydrogen sulfate

The title salt, C8H11N2O+·HSO4 −, has been synthesized by the reaction between 4-meth­oxy­benzamidine and sulfuric acid. The asymmetric unit comprises a nonplanar 4-meth­oxy­benzamidinium cation and one hydrogen sulfate anion. In the cation, the amidinium group has two identical C—N bonds [1.306 (2) and 1.308 (2) Å], and its plane forms a dihedral angle of 6.49 (8)° with the mean plane of the benzene ring. The ionic components are associated in the crystal via N—H+⋯O−, resulting in chains running approximately along the b-axis direction whicg are interconnected by O—H⋯O− hydrogen bonds.

Multichannel recognition of hydrogen sulphate anion by a Zn(II)–triazole–pyridine complex bearing a ferrocenyl pendant

Receptors ferrocene–triazole–pyridine triads assembled with Zn(II) or Cd(II) metal cations behave as chemosensor molecules for HSO4 − anions through electrochemical and optical channels: the redox peak of the ferrocene/ferrocenium redox couple is shifted cathodically by 72–53 mV, and a new absorption band appeared in the UV–vis spectrum upon complexation with the HSO4 − anion. Association constants, detection limits and stoichiometries of the recognition processes have been determined, whereas 1H NMR experiments and density functional theory calculations are used to suggest the plausible binding mode taking place in the new supramolecular assembly formed.

Fluoride anions triggered “OFF–ON” fluorescent sensor for hydrogen sulfate anions based on a BODIPY scaffold that works as a molecular keypad lock

Abstract A BODIPY-based derivative 1 containing hydrazone moiety has been developed as a colorimetric and fluorometric sensor for fluoride and hydrogen sulfate anions. The UV–vis absorption, fluorescent emission and partial 1 H NMR titrations experiments have been employed to study the sensing process. Sensor 1 could act as an efficient “On–Off” fluorescent sensor for fluoride anions based on the deprotonation process. In the presence of fluoride anions, sensor 1 could act as an “Off–On” fluorescent sensor for hydrogen sulfate anions based on the reversible protonation process. Sensor 1 could also behave as a molecular keypad lock with sequential chemical inputs of F − and HSO 4 − ions.

Charge-Assisted Complexation of Anions of Different Dimensionality by Benzimidazole-Based Receptors Bearing -OH Functionality

Two benzimidazole-based receptors (L1 and L2) bearing -OH functionality form crystalline salts with different organic and inorganic acids viz. [L1H+][Cl–] (1), [L1H+][NO3–] (2), [L1H+][OAc–] (3), [L1H+][DNB–]·DMF (4), [L1H+][H2PO4–] (5), [L2H+][OAc–]·AcOH (6), [L2H+][DNB–] (7), and [L2H+][HSO4–]·H2O (8) where the shape of the counteranion drives the solid structure from a one-dimensional polymeric chain to a three-dimensional structure. Structural analyses show that the anion binding in all eight complexes is attributable entirely to NH+···anion, NH···anion, OH···anion, and multiple CH···anion hydrogen bonding interactions. In the solid structure the planar nitrate anion forms a cyclic structure with receptor L1, whereas the acetate anion with the same receptor leads to a molecular barrel type structure. Again the tetrahedral dihydrogen phosphate anion forms a polymeric interanionic chain structure with L1, and the other tetrahedral hydrogen sulfate anion forms hydrogen sulfate–(water)2–hydrogen sulfate adducts with charged L2.

Synthesis and evaluation of fluorimetric and colorimetric chemosensors for anions based on (oligo)thienyl-thiosemicarbazones

A family of heterocyclic thiosemicarbazone dyes (3a–d) containing thienyl groups has been synthesized, characterized, and their chromo-fluorogenic response in acetonitrile in the presence of selected anions was studied. Acetonitrile solutions of 3a–d show absorption bands in the 338–425 nm range, which are modulated by the groups attached to the thiosemicarbazone moiety. The fluoride, chloride, bromide, iodide, dihydrogen phosphate, hydrogen sulfate, nitrate, acetate, and cyanide anions were used in the recognition studies. Only sensing features were observed for fluoride, cyanide, acetate, and dihydrogen phosphate anions. Two different chromogenic responses were found, (i) a small shift of the absorption band due to coordination of the anions with the thiourea protons and (ii) the appearance of a new red-shifted band due to deprotonation of the receptor. For the latter process changes in the color solutions from pale-yellow to orange-red were observed. Fluorescence studies showed a different emission behavior according to the number of thienyl rings in the π-conjugated bridges. Stability constants for the two processes (complex formation+deprotonation) for receptors 3a–d in the presence of fluoride and acetate anions were determined from spectrophotometric titrations using the HypSpec program. The interaction of 3d with fluoride was studied through 1H NMR titrations. Semiempirical calculations to evaluate the hydrogen-donating ability of the receptors were also performed.

High Viscosity of Imidazolium Ionic Liquids with the Hydrogen Sulfate Anion: A Raman Spectroscopy Study

Ionic liquids based on 1-alkyl-3-methylimidazolium cations and the hydrogen sulfate (or bisulfate) anion, HSO(4)(-), are much more viscous than ionic liquids with alkyl sulfates, RSO(4)(-). The structural origin of the high viscosity of HSO(4)(-) ionic liquids is unraveled from detailed comparison of the anion Raman bands in 1-ethyl-3-methylimidazolium hydrogen sulfate and 1-butyl-3-methylimidazolium hydrogen sulfate with available data for simple HSO(4)(-) salts in crystalline phase, molten phase, and aqueous solution. Two Raman bands at 1046 and 1010 cm(-1) have been assigned as symmetric stretching modes ν(s)(S═O) of HSO(4)(-), the latter being characteristic of chains of hydrogen-bonded anions. The intensity of this component increases in the supercooled liquid phase. For comparison purposes, Raman spectra of 1-ethyl-3-methylimidazolium ethyl sulfate and 1-butyl-3-methylimidazolium methyl sulfate have been also obtained. There is no indication of difference in the strength of hydrogen bond interactions of imidazolium cations with HSO(4)(-) or RSO(4)(-) anions. Raman spectra at high pressures, up to 2.6 GPa, are also discussed. Raman spectroscopy provides evidence that hydrogen-bonded anions resulting in anion-anion interaction is the reason for the high viscosity of imidazolium ionic liquids with HSO(4)(-). If the ionic liquid is exposed to moisture, these structures are disrupted upon absorption of water from the atmosphere.