Mercury Nitrate Research Articles

Mercury-electroplated platinum electrodes and microelectrodes for sonoelectrochemistry

The preparation of mercury-electroplated platinum disc electrodes of both micrometre and conventional dimensions from an aqueous solution of mercury(I) nitrate and potassium cyanide is described. The mercury film electrodes so produced led to very reproducible voltammetric results, as observed by the cathodic reduction of fluorescein to semifluorescein at high pH, both under silent conditions and under ultrasonic irradiation. The electroreduction in the absence of ultrasound is a simple reversible one-electron transfer process (Tafel gradient ∼ 65 mV decade −1). On ultrasonic irradiation an increase in the mass transport-limited current was observed in excess of that expected for a simple one-electron transfer. Possible mechanisms for the electro-reduction in ultrasound are postulated.

Cytotoxicity of Gallium and Indium Ions Compared with Mercuric Ion

The use of mercury in dental amalgam restorations has become the subject of political controversy despite its long history of safe clinical use, and alternative materials based on gallium and indium rather than mercury have been developed. The biological safety of these metals must be evaluated, as part of their assessment as mercury substitutes. The cytotoxicities of mercury (II) nitrate, gallium (III) nitrate, and indium (III) nitrate were assessed at concentrations between 0.001 mmol/L and 1.0 mmol/L, using L929 mouse fibroblasts and the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) colorimetric assay and scanning electron microscopy. The mitochondrial dehydrogenase activity at each metal ion concentration as a percentage of the control was calculated from the absorbance values. The 50% inhibition concentration of mercury (II) nitrate was 0.35 mmol/L for cells in the rapid-growth phase and at confluence; gallium (III) nitrate and indium (III) nitrate did not significantly inhibit dehydrogenase activity in either the growing or confluent phase. Gallium and indium ions were not significantly toxic under the conditions of this assay.

Aromatic iodination with the I 2-HgX 2 combination

The reaction of different aromatic compounds 1a– 1t with iodine and a mercury(II)-salt 2 [mercury(II) chloride, nitrate or triflate] (1:1:1 molar ratio) in dichloromethane at room temperature leads to the corresponding iodoarene 3, the obtained regiochemistry being the expected. Concerning the mercury(II) salt, the observed reactivity decreased in the series triflate&>nitrate&>chloride according to their ionic character. An activation of the iodine molecule by the mercury(II) salt followed by a S E reaction with the aromatic compound is postulated as the possible mechanism.

Separation of fluoride ion by extraction with triphenyltin chloride. Application for NAA of fluorine by means of 14-MeV neutrons

The separation of fluoride by extraction with toluene solution of triphenyltin chloride has been studied. Quantitative isolation of fluoride from solutions with a wide acidity range (pH 4.0–11.5) has been established. It is suggested that interferences by Ca, Mg, Fe, and Al can be avoided by masking these elements using sulfate and hydroxyde ions. Interference by phosphate ions can be overcome in a similar fashion. The halogenated species can be masked by mercury nitrate. Detection limit for fluorine determination is about 3 μg for a neutron generator flux of 2·1111 n·cm−1·s−1. A method for fluorine assay in water using a neutron generator with a detection limit of 1 ppm has been developed.

Membrane extraction of mercury (II) and silver (I) by bis(di(2-ethylhexyloxy)thiophosphoryl)disulfide

A supported liquid membrane containing bis(di(2-ethylhexyloxy)thiophosphoryl)disulfide (BTPD) as a novel membrane carrier was prepared and tested. Metal ion transfer was shown to be accelerated by the presence of thiourea or thiosulfate in the receiver stripping solutions. Under varying conditions, mercury and silver transfer rates of up to 7 and 3 μmol/m 2s, were measured. Mercury transport mechanism was demonstrated to be dependent on the nature of the anion. Mercury nitrate transport appears to be mainly due to a coupled Hg 2+H + facilitated diffusion mechanism, according to the ion-exchange stoichiometry. Mercury halides were transported mainly as neutral complexed species due to carrier-facilitated diffusion. Selectivity of the membrane for mercury and silver over zinc, nickel, cadmium and copper has been found to be of the order of 10 3.

Oxymetallation. Part 24. Preparation of cyclic peroxides by cycloperoxymercuriation of unsaturated hydroperoxides.

Seventeen unsaturated hydroperoxides have been converted by treatment with mercury(II) acetate and/or mercury(II) nitrate into nineteen new mercuriated cyclic peroxides and by subsequent demercuriation with alkaline sodium borohydride, six new mercury-free peroxides have been isolated. The results greatly extend the range of such reactions and provide information about the stereoselectivities and relative ease of several different modes of cycloperoxymercuriation. It is suggested that the reactions with mercury(II) acetate are kinetically controlled whereas those with mercury(II) nitrate show a component of thermodynamic control of product distribution.

Synthesis, characterization and crystal structures of 1,7-dioxa-4-thia-10-azacyclododecane ([12]aneNO2S) and [Hg([12]aneNO2S)(NO3)2

Reaction of 6-(4-methylphenylsulfonyl)-1,11-bis(4-methylphenylsulfonyloxy)-3,9-dioxa-6-azaundecane and ethane-1,2-dithiol in the presence of NaH, results after removal of the protecting group, in the unexpected isolation of the twelve-membered macrocycle 1,7-dioxa-4-thia-10-azacyclododecane,[12]aneNO2S. The product, suggested to arise from the intramolecular displacement of a tosyl group by a thioether instead of the terminal thiol as in the expected ring closing procedure, was characterised by 13C NMR spectroscopy, mass spectrometry, microanalysis and a single-crystal X-ray structure determination. The macrocycle crystallizes in the monoclinic space group P21, with a= 7.448(5), b= 5.1740(10), c= 12.769(9)A, β= 93.28(2)°, Z= 2 with R= 0.046. All the donors in the macrocyclic ring are in the endodentate conformation with close contacts between the N–H and atoms O(1) and O(7). Reaction of mercury nitrate with 1 molar equivalent of [12]aneNO2S in methanol, and subsequent crystallization of the product, resulted in colourless prisms of [Hg([12]aneNO2S)(NO3)2] which crystallize in the monoclinic space group P21/c, with a= 9.165(17), b= 10.657(15), c= 14.80(2)A, β= 92.57(8)°, Z= 4 with R= 0.055. In this molecule the mercury(II) cation is co-ordinated by the macrocyclic donors and the nitrate anions, one in a bidentate manner, the other in a monodentate mode.

Elektrochemische Synthese und Kristallstrukturen dreier neuer Clathrate HgAg 6O 8ClO 4, HgAg 6O 8NO 3 und Hg 2Ag 18O 33H 22(ClO 4) 4

For the first time deposition of mercury-containing oxidic phases by electrocrystallization was achieved. Depending on the concentrations, the anodic oxidation of aqueous solutions of silver and mercury nitrates or perchlorates yielded HgAg 6O 8NO 3, HgAg 6O 8ClO 4 or Hg 2Ag 18O 33H 22(ClO 4) 4. The crystal structures were determined by means of single-crystal diffractometer data (HgAg 6O 8NO 3: Fm 3m ; a=9.953(1) A ̊ ; Z=4; Hg 2Ag 18O 33H 22(ClO 4) 4: Fd 3m ; a=20.231(2) A ̊ ; Z=8). HgAg 6O 8ClO 4 in which a=10.045(1) A ̊ crystallizes isostructurally with HgAg 6O 8NO 3. Both structures show a close relationship to the clathrate type of compound Ag 7O 8X. Silver(II)- and silver(III)-atoms are indistinguishable since they share the same crystallographic position.

On-line microwave sample pretreatment for the determination of mercury in water and urine by flow-injection cold-vapour atomic absorption spectrometry

A system for on-line treatment of liquid samples in a microwave oven and determination of mercury by cold-vapour atomic absorption spectrometry was designed and evaluated. The system consisted of an atomic absorption spectrometer, equipped with a mercury-hydride system and amalgamation accessory, a flow-injection system, an autosampler and a mircowave digestor. Urine and environmental water samples were stabilized with potassium dichromate-nitric acid and were mixed with a bromination reagent. The recoveries of eight mercury compounds from aqueous solutions and five compounds from dilute urine were studied. At an applied microwave power of 75 W, the recoveries of mercury(II) nitrate, methylmercury chloride, amidomercury chloride, phenylmercury chloride and diphenylmercury were between 92 and 102% for 1 + 2-diluted urine without amalgamation and between 94 and 111% for 1 + 5-diluted urine with amalgamation, respectively. The sample throughput was 30–40 h −1 without amalgamation and 24 h −1 in the amalgamation mode. Good agreement with certificate values was obtained for urine samples. A limit of detection (3σ) of 10 ng l −1 was obtained using 10-ml sample volumes of environmental waters (river, lake, rain) and the amalgamation technique. The results compared well with those from an external laboratory with correlation coefficients of 0.9302 and 0.9028 ( n = 22) for integrated absorbance and peak-height absorbance, respectively.

Direct visualization of the structure of the “20 S” aggregate of coat protein of tobacco mosaic virus: The “disk” is the major structure at pH 7.0 and the proto-helix at lower pH

We have employed the rapid-freeze technique to prepare specimens for electron microscopy of a coat protein solution of tobacco mosaic virus at equilibrium at pH 7·0 and 6·8, ionic strength 0·1 m and 20 °C. The former are the conditions for the most rapid assembly of the virus from its isolated protein and RNA. At both pH values, the equilibrium mixture contains approximately 80% of a “20 S” aggregate and 20% of a “4 S” aggregate (the so-called A-protein). The specimens were prepared either totally unstained or positively stained with methyl mercury nitrate, which binds to an amino acid residue (Cys27) internally located within the subunit, which we show not to affect the virus assembly. The images in the electron microscope are compatible only with the major structure for the “20 S” aggregate at pH 7·0 containing two rings of subunits and these aggregates display the same binding contacts as those seen between the aggregate that forms the asymmetric unit in the crystal, which has been shown by X-ray crystallography to be a disk containing two rings, each of 17 subunits, oriented in the same direction. In contrast, the images from specimens prepared at pH 6·8 show the major structure to be a proto-helix at this slightly lower pH, demonstrating that the technique of cryo-electron microscopy is capable of distinguishing between these aggregates of tobacco mosaic virus coat protein. The main structure in solution at pH 7·0 must therefore be very similar to that in the crystal, although slight differences could occur and there are probably other, minor, components in a mixture of species sedimenting around 20 S under these conditions. The equilibrium between aggregates is extremely sensitive to conditions, with a drop of 0.2 pH unit tipping the disk to proto-helix ratio from approximately 10:1 at pH 7·0 to 1:10 at pH 6·8. This direct determination of the structure of the “20 S” aggregate in solution, under conditions for virus assembly, contradicts some recent speculation that it must be helical, and establishes that, at pH 7·0, it is in fact predominantly a two-layer disk as it had been modelled before.

Investigations of oxidative UV photolysis

The behaviour of mercury during UV photolysis has been investigated. Mercury in the form of the inorganic compound mercury(II) nitrate and the organic compound methylmercury chloride was used in standards, model water samples and spiked municipal waste waters (10 μg/l in each case). Despite the high digestion temperatures of ca. 90 o C, losses due to evaporation are negligibly small, irrespective of the speciation of mercury

Separation of traces and larger amounts of bismuth from gram amounts of thallium, mercury, gold and platinum by cation-exchange chromatography on a macroporous resin

Traces and larger amounts of bismuth (up to 50 mg) can be separated from gram amounts of thallium, mercury, gold and platinum (up to 5 g) by sorption from a mixture of 0.1 M hydrochloric acid and 0.4 M nitric acid on a column containing just 3 g (8.1 ml) of AGMP-50, a macroporous cation-exchange resin. This resin retains bismuth much more strongly than does the usual microporous resin (styrene-DVB with 8% cross-linkage). Other elements are eluted with the same acid mixture as that used for sorption, and bismuth is finally eluted with 1.0 M hydrochloric acid. Separations of bismuth are sharp and recoveries quantitative. Only microgram amounts of the other elements remain in the bismuth fraction. Amounts of bismuth as little as 5 μg have been separated from 5 g of thallium, and determined (r.s.d. = 2%) by flame atomic-absorption. Only 100-μg amounts of bismuth have been separated from gram amounts of mercury, gold, and platinum, but there is no reason to believe that smaller or larger amounts of bismuth cannot be separated from these elements and recovered with the same accuracy as that for the separation from thallium. The lower limit of the method is determination of 0.4 μg of bismuth in 10 ml of solution (0.004 absorbance). An elution curve, the relevant distribution coefficients and the results of analysis of synthetic mixtures and two practical samples [thallium metal and mercury(II) nitrate] are presented.

ChemInform Abstract: Tandem 1,5‐Hydrogen Transfer and Decarbonylation in the Flash Vacuum Pyrolysis of 5‐Vinyl‐3‐methyl‐1,2‐dioxane.

AbstractTreatment of the unsaturated hydroperoxide (I) with mercury(II) nitrate results in the formation of cycloperoxymercurials which are demetalated by reduction with sodium borohydride in the presence of a base to give the 1,2‐dioxanes (II).

Rapid determination of surface-active substances by fast-scan differential-pulse voltammetry

Fast-scan differential-pulse voltammograms of air-saturated acetate buffer and mercury nitrate solutions are presented. The current-voltage curves obtained are markedly influenced by surface-active substances (SAS). The peak potential of the voltammogram shifts to more positive potentials with increasing concentration of the SAS. This effect can be utilized for analytical purposes.

Direct combination of thermogravimetric analyser and atomic absorption spectrometer for detection of atomic vapour in thermal analysis

A thermogravimeter was combined with an atomic absorption spectrometer. The atomic absorption could be measured simultaneously with the thermogravimetrical changes under identical conditions. Optimum experimental conditions were determined using solid mercury halides and mercury(II) nitrate, by varying the sample weight and the flow rate of the carrier gas. The absorbance versus temperature curves obtained with this system for mercury halides and nitrate are compared with the corresponding thermograms. This apparatus may be useful in obtaining much more information concerning the gases evolved in thermogravimetry and the atomization processes of many metal-containing substances in atomic absorption spectrometry.

Comparative studies of electrochemical phase formation by amperometric and microscopic methods: Part I. Nucleation kinetics in dilute solutions of mercury nitrate

The nucleation kinetics of mercury on platinum have been studied by measuring directly the “number of nuclei-time” relationship and by analysing potentiostatic current transients. The number density N 0 of active sites on a platinum single-crystal substrate and the nucleation rate constant A were determined in the overpotential range 86–100 mV.

ChemInform Abstract: Oxidation of Lyxose in an Acidic Medium with Mercury and Silver Nitrates.

ChemInform Abstract: Oxidation of Lyxose in an Acidic Medium with Mercury and Silver Nitrates.

Dual mechanism bifunctional polymers: Phosphinic acid ion-exchange/redox resins and the kinetics of metal-ion complexation

The detailed study of bifunctional phosphinic acid resins has recently been introduced. It has been shown that they operate through the dual mechanism of ion exchange and metal-ion reduction. A key component in the synthesis is the Friedel-Crafts catalyst used for the reaction between PCl 3 and polystyrene. We now find that the order of catalyst activity is AlCl 3 > FeCl 3 > ZnCl 2 > SnCl 4 . Ferric chloride catalysis also operates by an additional redox mechanism which yields a phosphonic acid resin. The extent of loading onto phosphinic and sulfonic acid resins by zinc ions at equilibrium was studied as a function of the anion present both with and without the presence of an excess of sodium ions. Both sets of resins exchange at a comparable rate upon the introduction of macroporosity into the polystyrene support. The influence of the redox process as an additional variable in the phosphinic resin kinetics was studied with silver and mercury(II) nitrate solutions. All of the primary acid sites are oxidized after a 9-hour contact time with Ag(I) ions and a 2-hour contact time with Hg(II) ions. The mercury loading curves and the different behavior of silver, which shows more ion exchange than redox at short times while leaving a residual ion concentration on the resin irrespective of whether all of the primary acid sites have been oxidized or not, can be explained by the termolecular nature of the Ag(I) redox reaction in contrast to the bimolecular nature of the Hg(II) reaction. Studies with other ions show that the minimum metal-ion reduction potential below which no redox occurs with the phosphinic resins is probably between 0.0 and 0.3 V.

Synthesis, Characterization, IR Spectra and Other Studies of Some Mercury (II) Chloride, Nitrate and Thiocyanate Complexes of Organic Acid Hydrazides and Hydrazones

Abstract Polymeric complexes of the empirical composition Hg(L-H)Cl and Hg2 (L-2H)Cl2 [L [dbnd] benzoylhydrzide (BH), oxaldihydrazide (ODH), malondihydrazide (MDH), isopropanone benzoylhydrazone (IBH), isopropanoneoxaldihydrazone (IODH) and isopropanonemalondihydrazone (IMDH)] have been prepared and characterized by analytical and infrared spectral data, X-ray powder diffraction and polarographic studies. Some of the complexes tested for antifungal and antibacterial activity are more active than the ligands.

Determination of thiocyanate in plasma and saliva without deproteinisation and its validation as a smoking parameter.

A simple photometric procedure was developed for the determination of thiocyanate (SCN-) in plasma and saliva without deproteinisation or dialysis. Fe(III) ions form a red coloured complex with SCN- with a maximum absorbance at 460 nm. Mercury(II) nitrate is used to run a sample blank. A manual and an automated version (COBAS BIO) of the method is described. The method is linear up to 5000 mumol/l SCN-. The CV of the between-run precision is 2.8-8% for the manual and 2.6-6.6% for the automated method. The SCN- plasma concentration was 21-134 mumol/l in nonsmokers and 44-260 mumol/l in smokers. In mixed saliva, the concentration is much higher than in plasma: 1.57-5.5 mumol/l in smokers and 0.79-3.9 mumol/l in nonsmokers. Plasma, but not oral fluid SCN-, is a valuable parameter for studying smoking habits in population surveys. However, its use is limited. In our experience only heavy smokers can be distinguished from nonsmokers.