Mercuric Acetate Research Articles

Interaction оf 2‑methylbut‑3‑yn‑2‑yl acetate with some nucleophiles under the electrophilic promoting of mercury acetate

Interaction оf 2‑methylbut‑3‑yn‑2‑yl acetate with some nucleophiles under the electrophilic promoting of mercury acetate

Studies on the oxidation of levofloxacin by N-bromosuccinimide in acidic medium and their mechanistic pathway

Kinetics and mechanism of oxidation of levofloxacin(LF) by N-bromosuccinimide (NBS) have been studied in acid medium with pH and ionic strength at 25°C. It is a first order reaction with respect to both LF and NBS, but inverse first order in succinimide (reduction product of NBS). The stoichiometry of the reaction is 1:2 in this investigation. The effects of added products, halide ion and ionic strength have also been investigated. Polymerization was not observed with acrylonitrile. The main oxidation products as, (3S)-9-fluoro-3-methyl-10-(4-methylpiperazin-1-yl)-5,7-dioxo-2,3,6,7-tetrahydro-5H-[1,4]oxazino[2,3,4-ij]quinoline-6-carboxylic acid and succinimide were identified by Fourier transform infrared spectroscopy (FTIR), Liquid chromatography–mass spectrometry (LC–MS), Nuclear magnetic resonance (NMR) and Thin-layer chromatography (TLC) data. The rate of reaction was examined with reference to variation of ionic strength, solvent polarity, free radicals, halides ions, mercuric acetate for fix up the Br− in reaction mixture and also addition of the product succinamide (RNH).·On the basis of the experimental results, the mechanism of the reaction has been proposed and supported by kinetic orders, spectrophotometric evidence and negative entropy of activation parameters.

Stable -ESiMe3 Complexes of Cu(I) and Ag(I) (E=S, Se) with NHCs: Synthons in Ternary Nanocluster Assembly.

As a part of efforts to prepare new "metallachalcogenolate" precursors and develop their chemistry for the formation of ternary mixed-metal chalcogenide nanoclusters, two sets of thermally stable, N-heterocyclic carbene metal-chalcogenolate complexes of the general formula [(IPr)Ag-ESiMe3] (IPr=1,3-bis(2,6-diisopropylphenyl)imidazolin-2-ylidene; E=S, 1; Se, 2) and [(iPr2-bimy)Cu-ESiMe3]2 (iPr2-bimy=1,3-diisopropylbenzimidazolin-2-ylidene; E=S, 4; Se, 5) are reported. These are prepared from the reaction between the corresponding carbene metal acetate, [(IPr)AgOAc] and [(iPr-bimy)CuOAc] respectively, and E(SiMe3 )2 at low temperature. The reaction of [(IPr)Ag-ESiMe3] 1 with mercury(II) acetate affords the heterometallic complex [{(IPr)AgS}2Hg] 3 containing two (IPr)Ag-S(-) fragments bonded to a central Hg(II), representing a mixed mercury-silver sulfide complex. The reaction of [(iPr2-bimy)Cu-SSiMe3]2, which contains a smaller N-heterocyclic-carbene, with mercuric(II) acetate affords the high nuclearity cluster, [(iPr2-bimy)6Cu10S8Hg3]6. The new N-heterocyclic carbene metal-chalcogenolate complexes 1, 2, 4, 5 and the ternary mixed-metal chalcogenolate complex 3 and cluster 6 have been characterized by multinuclear NMR spectroscopy ((1)H and (13)C), elemental analysis and single-crystal X-ray diffraction.

A New, High Yield, Rapid, and Cost-Effective Protocol to Deprotection of Cysteine-Rich Conopeptide, Omega-Conotoxin MVIIA.

Almost all conopeptides purified from Conus venoms are cysteine-rich peptides. Among them, omega-conotoxin MVIIA, FDA approved peptide drug (Prialt(®)), selected as a cysteine-rich model that its protection from oxidation is critical during solid phase synthesis. Deprotection of cysteines is a crucial step after peptide synthesis. The current study aimed to set up a new highly efficient deprotection protocol for omega-conotoxin MVIIA. Deprotection was performed based on mercury acetate with significant major modification. The protocol accomplished based on the best molar ratio of peptide/mercury/2-ME that adjusted to 0.2 mm/3 mm/10 mm (50 μg/1 mg/10 μL). The yield and purity of omega-conotoxin MVIIA obtained at 93 and 95%, respectively. The total time of protocol shortened to 90 min instead of 6-20 h in routine methods. In this study, omega-conotoxin MVIIA was recovered in high yield and in the shortest time. Despite of other known protocols, molar ratio adjusted to minimum amount. In conclusion, this protocol would be suggested to cost-effective deprotection of thiol groups for similar cysteine-rich peptides.

X-ray structure of an amide-appended chloromercurated derivative of 2-phenylquinoline

Reaction of the morpholine amide derivative of 2-phenyl-4-quinolinecarboxylic acid with mercury(II) acetate and lithium chloride results in chloromercuration at the ortho position on the phenyl ring; the complex was characterised by ESI mass spectrometry and an X-ray structure determination.

Mechanistic study of [RuCl3(H2O)2OH]− catalyzed oxidation of l-leucine by acidic N-bromophthalimide

Kinetic studies in homogenous Ru(III) catalyzed oxidation of l-leucine (Leu), by N-bromophthalimide (NBP) in the presence of perchloric acid have been made at 303 K using mercuric acetate as Br− ion scavenger. The reaction follows first-order kinetics with respect to [NBP]. In the lower concentration range of Leu and Ru(III) chloride, the reaction follows first-order kinetics but tends to zero at higher concentration. A positive effect of [Cl−] was observed in the oxidation of Leu. An increase in the rate of reaction with the decrease in dielectric constant of the medium was observed while negative effect was observed for [H+]. The rate of oxidation is unaffected by the change in [phthalimide (NHP)]. Rate of reaction decreased with increase in ionic strength of the medium. The main oxidation products of the reactions were identified as aldehyde, ammonia and CO2 for the oxidation of Leu. From the effect of temperature (298–318 K) on the reaction rate, various activation parameters have been calculated and on the basis of these parameters, a suitable explanation for the reaction mechanism has been given.

Mercury complexes of an N-heterocyclic carbene derived from a calixarene/azolium cyclophane hybrid

Reaction of mercuric acetate with an imidazolium-linked cyclophane incorporating 2,6-phenolic moieties results in formation of an interesting new N-heterocyclic carbene (NHC) complex of mercury. The new complex is cationic and binuclear, incorporating two mercury centres and two bis(NHC) ligands, each mercury atom being bound by two NHC moieties and two phenol/phenoxy moieties. Forms of the complex having coordinating ( $$ {\text{HgBr}}_{4}^{2 - } $$ ) and non-coordinating ( $$ {\text{PF}}_{6}^{ - } $$ ) counterions have been structurally characterised.

One-step green synthesis and characterization of plant protein-coated mercuric oxide (HgO) nanoparticles: antimicrobial studies

The present study demonstrates the bioreductive green synthesis of nanosized HgO using flower extracts of an ornamental plant Callistemon viminalis. The flower extracts of Callistemon viminalis seem to be environmentally friendly, so this protocol could be used for rapid production of HgO. Till date, there is no report of synthesis of nanoparticles using flower extract of Callistemon viminalis. Mercuric acetate was taken as the metal precursor in the present experiment. The flower extract was found to act as a reducing as well as a stabilizing agent. The phytochemicals present in the flower extract act as reducing agent which include proteins, saponins, phenolic compounds, phytosterols, and flavonoids. FT-IR spectroscopy confirmed that the extract had the ability to act as a reducing agent and stabilizer for HgO nanoparticles. The formation of the plant protein-coated HgO nanoparticles was first monitored using UV–Vis absorption spectroscopy. The UV–Vis spectroscopy revealed the formation of HgO nanoparticles by exhibiting the typical surface plasmon absorption maxima at 243 nm. The average particle size formed ranges from 2 to 4 nm. The dried form of synthesized nanoparticles was further characterized using TGA, XRD, TEM, and FTIR spectroscopy. FT-IR spectra of synthesized HgO nanoparticles were performed to identify the possible bio-molecules responsible for capping and stabilization of nanoparticles, which confirm the formation of plant protein-coated HgO nanoparticles that is further corroborated by TGA study. The optical band gap of HgO nanoparticle was measured to be 2.48 eV using cutoff wavelength which indicates that HgO nanoparticles can be used in metal oxide semiconductor-based photovoltaic cells. A possible core–shell structure of the HgO nanobiocomposite has been proposed.

BLOOD

All forms of mercury are global pollutants having no environmental limits.Human exposure to mercury occurs basically through food chain due to accumulation oforganic forms of mercury in fish. Objectives: The purpose of the present study was to analyzethe effect of phenyl mercuric acetate on plasma and cytosolic fraction GSH. Study Design:Experimental Study. Setting: Department of Pharmaceutical Chemistry, Faculty of Pharmacy,Gomal University, Dera Ismail Khan. Period: 29 January 2011 to 11 march 2012 .StatisticalAnalysis: One-way ANOVA followed by Dunnet’s HSD test. Results: For the estimation ofthiols Ellman’s method was used and was found statistically significant (p < 0.001) decreasein plasma and cytosolic fraction GSH which was dose and time dependent. The plasma GSHcontents drop in 0 to 120 minutes by various concentrations of phenyl mercuric acetate were64.45%, 59.33%, 50.89%, 41.56%, 33.63% and 32.99% while drop in cytosolic fraction GSHlevel from 0 to 120 minutes by different concentrations of phenyl mercuric acetate (PMA) was53.86%, 48.60%, 45.41%, 36.11%, 29.38% and 27.06%.Conclusions: It is clear that duringorganic mercury toxicity the blood components are also affected which is proved from ourresults. With the increase of time ,the mercury toxicity would be more harmful so detoxificationof organic mercury should be done on emergency bases at the earliest with the help of suitablechelating agents along with antioxidant therapy.

Hg-doped TiO2 nanostructures thin film prepared by sol–gel method for gas sensing applications: Correlation between the structural and electrical properties

Hg-doped TiO2 and undoped thin films have been synthesized from mercury acetate and titanium tetrabutyl-orthotitanate precursors deposited on silicon substrates using a sol–gel dip-coating technique. Annealing temperatures and layer thickness were found crucial for thin films nanostructures morphology which was characterized by X-ray diffraction (XRD), Raman and FTIR spectroscopy, Scanning electron microscopy (SEM) and Atomic force microscopy (AFM). XRD, Raman and FTIR results show that the 5% Hg doping shows crystallization at lower annealing temperatures. After heat treatments of thin films at 450°C, the anatase–rutile transformation takes place with annealing temperature. The average crystallite size of the doped TiO2 films was increased with annealing temperature and was about 20nm. SEM and AFM reveal nanostructures surface agglomerates of TiO2 doped Hg nanoparticles arranged with preferred orientation. The electrical properties of TiO2 doped thin films were investigated by current–voltage (I–V) characteristics. These nanostructures arrays exhibit excellent sensitivities with the increase of CO2 concentration at room temperature. Current–voltage analysis indicated that the enhanced gas sensitivity is probably due to the high surface/volume ratio of this nanostructure material in combination with the remarkable effect of Hg doping in TiO2.

Formation of ortho-cyano-aminothiophenolate ligands with versatile binding modes via facile carbon-sulfur bond cleavage of 2-aminobenzothiazoles at mercury(II) centres.

Addition of 2-aminobenzothiazole and substituted derivatives to mercuric acetate in warm ethanol leads to the high yield formation of [Hg{SC6H3XN(C[triple bond, length as m-dash]N)}]n resulting from loss of hydrogen and sulfur-carbon bond cleavage. Addition of phosphines affords a series of complexes in which the new ortho-cyano-aminothiophenolate ligands adopt three different binding modes.

Synthesis of Myristicin Ketone (3,4-Methylenedioxy-5-Methoxyphenyl)-2-Propanone from Myristicin

The synthesis of myristicin ketone from myristicin has been achieved through conversion of allyl group to ketone. Myristicin was isolated from nutmeg oil. The reaction of myristicin with mercury acetate in aqueous tetrahydrofuran, followed by in situ reduction of the mercurial intermediate by alkaline solution sodium borohydride produced myristicin alcohol. Myristicin alcohol was oxidized with PCC at 40 0C for 90 minutes, followed by purified with saturated potassium disulphite yield myristicin ketone (3-methoxy-4,5-methylenedioxyphenyl)-2-propanone (68.32%).

Simple but effective: thermally stable Cu-ESiMe3via NHC ligation.

A series of thermally stable N-heterocyclic copper-chalcogenolate complexes of the general formula [(IPr)Cu-ESiMe3] (IPr = 1,3-bis(2,6-diisopropylphenyl)imidazolin-2-ylidene; E = S, Se, Te) have been prepared from [(IPr)CuOAc] and E(SiMe3)2 at low temperature. The reaction of [(IPr)Cu-SSiMe3] with mercuric(II) acetate affords the heterometallic [{(IPr)CuS}2Hg] complex containing two (IPr)Cu-S(-) fragments to a central Hg(II).

RETRACTED: Effects of <i>Annona squamosa</i> Seed Extract on <i>Mus musculus</i> Exposed to Mercuric Chloride: Evaluations of Metal-Induced Oxidative Stress and Its Developmental Outcomes

Short Retraction Notice The article has been retracted due to the investigation of complaints received against it. The substantial portions of the text came from Dr. Joycelyn C. Jumawan, " Effects of Annona squamosa leaf extract on Mus musculus exposed to mercuric acetate: Evaluations of metal-induced oxidative stress and its developmental outcomes ". The scientific community takes a very strong view on this matter and we treat all unethical behavior such as plagiarism seriously. Editor guiding this retraction: Dr. Sukumar Saha(EiC of AJPS) The full retraction notice in PDF is preceding the original paper which is marked "RETRACTED".

Virtual issue: molecular sensors.

Smart designs in chemosensing! The articles of this virtual issue focus on molecular sensors, also known as chemosensors or probes, and highlight current research in the area of chemosensing and how wise designs can lead to selective sensing of target analytes. Articles show diverse approaches in probe design based on different sensing principles and the detection of a wide range of analytes. A molecular sensor, also known as a chemosensor or probe, is a molecular or supramolecular-based system that is able to transform probe–analyte interactions into a signal which allows analyte sensing. The most common output signals are usually optical or electrochemical changes. In particular, optical responses have become very popular due to the possibility of using low-cost, widely available instrumentation and even the possibility of detecting target species with the naked eye. The design of these molecular sensors and probes has advanced and gained importance in the last years due to the progress made in the knowledge on the preparation of host–guest complexes and on studies on how this interaction can be used for the design of selective molecular probes. This is a very interdisciplinary filed that in many cases involves organic or inorganic synthesis, photo-physical studies, and analytical applications. In this context, the design of new molecular sensors to detect anions, cations, and neutral species has gained primary significance recently due to the importance to detect target analytes in environmental and biological samples. Molecular sensors for metal cations were developed more than two decades ago, whereas probes for anions and neutral species have been investigated more recently. Articles already accepted show diverse approaches for the design of chemical probes that are based on different sensing principles and display sensing features to a wide range of analytes such as anions, cations, neutral molecules, and gases. Molina et al. (DOI: 10.1002/open.201402022) prepared aryl or heteroaryl 5-substituted imidazo-benzothiadiazole derivatives and found an interesting selective dual-channel sensing of mercury(II) cations and acetate anions. Moreover the probes also display sensing features in the presence of nitroaromatic compounds with a selective response to the explosive picric acid. In a close research approach to the design of sensing probes for target chemical substances that could be used as weapons, Martínez-Máñez, Costero, and co-workers (DOI: 10.1002/open.201402014) designed a molecular sensor for the selective chromogenic recognition of diisopropylfluorophosphate (DFP), a Sarin and Soman mimic, in 99:1 (v/v) water/ acetonitrile and in the gas phase. Anion sensing probes were studied in the works of Ito et al. and Yam and co-workers. Ito and Shinoda (DOI: 10.1002/open.201402049) prepared macrotricyclic octadentate cyclen dimer ligands that were able to afford cage-shaped dinuclear Na+ complexes. The authors found an interesting selectivity for dicarboxylates of different length. For instance, N-Boc-Asp dianion was strongly coordinated inside the cavity of the receptor whereas N-Boc-Glu dianion, which was one carbon longer, did not. On the other hand Yam et al. (DOI: 10.1002/open.201402019) designed probes using alkynylplatinum(II) terpyridine complexes with an amide-based receptor moiety and studied their sensing features in the presence of different spherical and non-spherical anions. As an example of molecular sensors for cations Lodeiro and co-workers (DOI: 10.1002/open.201402020) prepared a probe based in a bipyridyl unit that was covalently anchored to a rhodamine B fluorophore and studied the interaction of this molecular sensor with Cu2+, Zn2+, Cd2+, Hg+, and Hg2+. Different sensing responses were found to mimic certain logic operations. Finally, two works from Liz-Marzán and Pérez-Prieto described the use of inorganic supports for the design of probes. Liz-Marzán and co-workers (DOI: 10.1002/open.201402009) developed a simple procedure to prepare three-dimensional surface-enhanced Raman scattering (SERS) detection substrates and used these structures for the detection of malachite green in water and of 1-naphthalenethiol from the gas phase. Moreover Pérez-Prieto and co-workers (DOI: 10.1002/open.201402021) used CdSe/ZnS nanoparticles that were decorated with pyrene units as a sensing platform. The authors showed that the probe could be applied as a ratiometric oxygen sensor in organic solvents. In summary, this virtual issue in ChemistryOpen on “Molecular Sensors” includes nice examples in this highly interdisciplinary research field. Overall, the contributions beautifully illustrate current research in the area of chemosensing and how wise designs can lead to selective sensing of target analytes. Prof. Ramón Martínez-Máñez Guest Editor Co-chair of the Editorial Advisory Board ChemistryOpen

Synthesis and crystal structures of Ag and Hg complexes of bis(N-heterocyclic carbenes) on p-tert-butylcalix[4]arene platform

A series of p-tert-butylcalix[4]arene 1,3-diimidazolium salts were successfully prepared by the alkylation of p-tert-butylcalix[4]arene with dibromoalkanes, and sequential substitution reaction with 1-alkylimidazole. Furthermore, coordination reactions of p-tert-butylcalix[4]arene 1,3-diimidazolium salts with silver oxide and mercury acetate gave novel Ag and Hg complexes of bis(N-heterocyclic carbenes) on p-tert-butylcalix[4]arene platform. The single-crystal structures of four p-tert-butylcalix[4]arene 1,3-diimidazolium salts and three metal complexes were successfully determined by X-ray diffraction. An Ag–Ag argentophilic interaction (Ag–Ag bond length is 3.1599(6) Å) is formed between the two Ag–NHC complexes and a dimetallic coordination mode exists in Hg–NHC complexes.

In situ pre-concentration and voltammetric determination of trace lead and cadmium by a novel ionic liquid mediated hollow fiber-graphite electrode and design of experiments via Taguchi method

In this research a single-use voltammetry sensor, incorporating a three electrodes configuration was developed, using ionic liquid mediated hollow fiber-graphite supported nanomagnetite working electrode. These electrodes coupled with differential pulse voltammetry (DPV) provided a screening tool for in-situ pre-concentration and determination of trace levels of Pb(II) and Cd(II). In this design, a two-centimeter piece of porous polypropylene hollow fiber membrane was impregnated with homogeneous mixture of nanomagnetic particles/ionic liquid (1-butyl-3-methylimidazolium hexafluorophosphate), and a graphite rod was located inside the fiber lumen. In this sensor, synthesized nanoparticles such as zero-valent Iron (ZVI), nanomagnetite (NM) and magnetic hollow spheres (MHS), dispersed in the ionic liquid, were used for one-step simultaneous purification, pre-concentration and trapping of pb(II) and Cd(II) ions from water samples. The Taguchi method was applied as an experimental design to determine optimum conditions for lead and cadmium ions removal. The experiments were designed, in two steps, according to Taguchi's method, OA16 L18 (21×35) and OA16 L16 (21×43) orthogonal were arrayed to the optimize experimental runs. Various affective parameters were investigated. The effect of all the input parameters on the output responses was analyzed using analysis of variance (ANOVA). The results revealed that the metal removal was influenced primarily by the amount of nanoparticle (52.18%) and agitation rate (19.71%). The extraction time (8.97%) and mercury acetate concentration in the electrolyte (7.6%) had little significant influence on metal removal efficiency. The performance characteristics of the developed method were evaluated by assessing response linearity and precision. The method was suitable for the quantitation of pb(II) and Cd(II) ions in the concentration range of 2–13000ng.mL−1 and 0.6–6500ng.mL−1 for Cd(II) and Pb(II) ions respectively. The detection limits recorded for Cd(II) and Pb(II) were 0.61 and 0.19ng.mL−1 with relative standard deviation (RSD) of 4.6%, and 2.3%, respectively. Moreover, successful applications of the sensing device to real water samples were demonstrated.

Multifunctional Benzothiadiazole-Based Small Molecules Displaying Solvatochromism and Sensing Properties toward Nitroarenes, Anions, and Cations.

Aryl or heteroaryl 5-substituted imidazo-benzothiadiazole derivatives were synthesized and shown to display remarkable solvatofluorochromism and selectively sense mercury(II) cations, acetate anions, and nitroaromatic derivatives, with discrimination between p-nitrophenol and picric acid. These novel sensors are of importance these days, as the detection of explosives is a high priority in issues of national security and environmental protection. To determine the ion binding properties of the sensors, their absorption and fluorescence emission spectra upon binding different cations and anions were compared. Significant shifts in the spectra were only observed for mercury(II) and acetate. The binding of these two ions was further studied using 1H NMR. The binding properties of different nitroaromatic compounds were also determined, and the results showed the importance of the presence of a phenol group in the guest molecule. Specifically, the two sensors were shown to discriminate between p-nitrophenol and picric acid. Finally, the mechanism of fluorescence quenching upon addition of nitrophenols was determined by computational methods.

Fluorescence and crystal structures of new mercury(II) macrocyclic N-heterocyclic carbene complexes with ether chains

Polyerther-linked mercury(II) carbene complexes are synthesized by the reaction of carbene precursores with mercury(II) acetate. The binuclear carbene complexes with the chloride ion linkage are easily prepared by the reaction of mononuclear mercury carbene complexes with tetrabutylammoium chloride. The crystal structures reveal that the fluorescence of mercury complexes are related to the coordination mode of the ligands.

One-Pot Tandem Synthesis of Tetrasubstituted Pyrazoles via 1,3-Dipolar Cycloaddition Between Aryl Hydrazones and Ethyl But-2-ynoate

1,3,4,5-Tetrasubstituted pyrazoles are rapidly and regioselectively synthesized in a one-pot, three-step sequence consisting of condensation, nitrilimine generation, and cycloaddition using mercuric acetate. Newly synthesized compounds were characterized by spectral studies. Regiochemistry of compounds 6a and 8a was determined as 1,4- and 1,5-regioisomers respectively by X-ray crystallography.