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Due to the great harm to the environment and biology, the removal of mercury ions from wastewater is one of the most urgent tasks. Here, we designed and prepared two metal–calixarene coordination compounds, {[Co4(TC4A)(SO4)]6(L)6(HCOO)6}12− (CIAC-131) and {[Co4(TC4A)2]2L}3− (CIAC-251) (H4TC4A = p-tert-butylthiacalix[4]arene, L = 1H-1,2,3-triazole-4,5-dicarboxylic acid) for the selective removal of mercury ions from aqueous solutions. Owing to their rich sulfur and nitrogen sites, both compounds exhibit high selectivity towards mercury ions and the adsorption capacity of CIAC-131 is higher than that of CIAC-251. For CIAC-131, the adsorption capacity of Hg(II) is 330 mg g−1 and the removal efficiency of Hg(II) with an initial concentration at 50 mg L−1 in the aqueous solution is 98.8%. The gas sorption measurement was carried out to evaluate the porosity of CIAC-131. [ABSTRACT FROM AUTHOR]

From the viewpoint of inorganic crystal engineering (ICE), the coordination sphere of the metal centre can be affected by two main parts of inorganic and organic units in complexes. Database study can play a significant role in the explanation of the relationship between various parameters related to these parts. For the first time, we have investigated this relationship through the concomitant studies of the inorganic crystal structure database (ICSD) and the cambridge structural database (CSD) for mercury(II) halide compounds. The results of CSD analysis are divided into two categories of metal halide complexes (MHC or mercury halide compounds with ligands) and metal halide only (MHO or mercury halide compounds without ligands). MHC (970, 460, and 521 metal centres as HgCl2, HgBr2, and HgI2, respectively) and MHO (419, 141, and 201 metal centres as HgCl2, HgBr2, and HgI2, respectively) were structurally investigated. The coordination number, polymerization mode, coordination geometry of the metal centre, type of donor atom in ligands, and the chelation mode of the ligand for all MHC and MHO compounds were extracted as effective factors in inorganic and organic units. To rationalize the effect of ICE in the design of the coordination sphere, eleven new mercury halide complexes, including the ester ligands of L1, naphthalene-5-yl nicotinate (complexes 1–3), L2, naphthalene-6-yl nicotinate (complexes 4–6), L3, naphthalene-5-yl pyrazine-2-carboxylate (complexes 7–9), and L4, naphthalene-6-yl pyrazine-2-carboxylate (complexes 10–11) were synthesized and fully characterized. The various parameters of substitution, C–H to nitrogen replacement, counteranion, and symmetry effects were investigated for all of the complexes. The results show that there is a meaningful relationship between inorganic and organic units. According to the findings of the CSD and ICSD analyses, most of the complexes obeyed the same relationship. Despite the predominant role of the inorganic unit in determining the coordination geometry, the organic unit can also change the coordination sphere of complexes with one major effect or the cooperativity of minor effects. [ABSTRACT FROM AUTHOR]

Mercury sulfide (HgS) exerts extensive biological effects on neuronal function. To investigate the direct target of HgS in neuronal cells, we developed a biotin-tagged HgS probe (bio-HgS) and employed an affinity purification technique to capture its target proteins. Then, we identified S-phase kinase-associated protein 1 (Skp1) as a potential target of HgS. Unexpectedly, we discovered that HgS covalently binds to Skp1 through a "Cys62-HgS-Cys120" mode. Moreover, our findings revealed that HgS inhibits the ubiquitin-protease system through Skp1 to up-regulate SNAP-25 expression, thereby triggering synaptic vesicle exocytosis to regulate locomotion ability in C. elegans . Collectively, our findings may promote a comprehensive interpretation of the pharmacological mechanism of mercury sulfide on neuroprotective function.

Six four-coordinated complexes of the chemical formulae [Hg(2-N CH2COOCH2CH3-21-H-NCTPP)X] with X = Cl (5), Br (6), I (7), [Hg(2-NCH3-21-H-NCTPP)Cl] (4) and [Hg(2-NCH2COOCH2C6H5-21-H-NCTPP)X] with X = Cl (8), I (9) are synthesized and structurally determined. The bond path for the weak η1-H(17)–C(17)…Hg agostic interactions between the Hg center and H(17) in complexes 4–9 was a through-space interaction from Hg to agostic carbon [C(17)] followed by a through-bond interaction from C(17) to an agostic proton [H(17)]. The magnitude of J[Hg–H(17)] [or the agostic upfield shift Δδago of the C(17)] for these complexes increases as the halide ligand varies from iodide to chloride, ranging from 33.2 Hz (or 14.3 ppm) for I− to 36 Hz (or 15.8 ppm) for Br− and 36.9 Hz (or 16.0 ppm) for Cl−. The plot of J[Hg–H(17)] for the agostic proton H(17) versus☋Δδago☋ for the agostic carbon atom C(17) in compounds 3–9 was linearly expressed as J[Hg–H(17)] = 2.29 ☋Δδago☋ + 0.13. [ABSTRACT FROM AUTHOR]

Bent core polycatenar mesogens, consisting of a methylene central core and two 1,2,3-triazole dendronic wings, have been synthesized via a copper-catalyzed azide–alkyne click reaction and investigated by polarizing microscopy, DSC, XRD scattering, SEM and photoluminescence measurements. All these compounds can self-assemble into thermotropic micellar liquid crystalline phases in the bulk state and form organogels in various organic solvents. They also show binding selectivity to Hg2+ among a series of cations in CH3CN–CH2Cl2 solution. [ABSTRACT FROM AUTHOR]

Bent core polycatenar mesogens, consisting of a methylene central core and two 1,2,3-triazole dendronic wings, have been synthesized via a copper-catalyzed azide–alkyne click reaction and investigated by polarizing microscopy, DSC, XRD scattering, SEM and photoluminescence measurements. All these compounds can self-assemble into thermotropic micellar liquid crystalline phases in the bulk state and form organogels in various organic solvents. They also show binding selectivity to Hg2+ among a series of cations in CH3CN–CH2Cl2 solution. [ABSTRACT FROM AUTHOR]

A multimode ratiometric Hg2+ selective chemosensor system based on a carbazole–thiobarbituric acid conjugate (CTBA) was developed. Its colorimetric and fluorescence behavior towards Hg2+ ions in both homogeneous and microheterogeneous media were investigated. A ratiometric mode of response of absorption as well as fluorescence in acetonitrile and 9 : 1 THF/H2O medium was observed in the presence of Hg2+ ions. The sensing mechanism involves formation of a 1 : 2 CTBA : Hg2+ complex by deprotonation of imide protons of the thiobarbituric acid unit. The complex formation can be reversed by using competing ligands such as cysteamine hydrochloride. [ABSTRACT FROM AUTHOR]

A novel series of HgII coordination polymers with a general formula [HgL(N)3]n·n(solv) (HL = 2-pyridinecarbaldehyde isonicotinoylhydrazone; n(solv) = 0.5H2O (1), 2MeOH (2), EtOH (3), PrOH (4) and 0.5BuOH (5)) was prepared and characterized by elemental analysis, IR spectroscopy and single crystal X-ray diffraction. The crystal structure of HL, elucidated by X-ray diffraction, comprises two independent molecules in the asymmetric unit cell, each of which is stabilized by an intramolecular hydrogen bond formed between the carbohydrazide hydrogen atom and the 2-pyridyl nitrogen atom. Crystal structures of 1–5 each reveal a similar 1D zigzag metal–organic chain [HgL(N)3]n, where the organic ligands bridge metal centers. These chains are extended into distinct 2D supramolecular nets by strong hydrogen bonds with the solvent molecules and/or short Hg…N supramolecular contacts. These networks were topologically classified as the hcb in 1 and fes in 2–5 underlying nets. On comparing the H-bonding patterns, it can be concluded that the lattice water molecules in 1 and methanol molecules in 2 form H-bonding interactions with the O and amide N atoms of L in the former structure and the O atom of L in the latter structure. In the remaining coordination compounds, the lattice solvent prefers the azide N atom for H-bonding. Furthermore, the existence of Hg…N interactions in 2–5 and their absence in 1 clearly highlights the importance of the size and polarity of the solvents on the self-assembly generation of HgII coordination polymers. A broad network of intermolecular π…π stacking interactions, formed between the pyridyl fragments, provide further reinforcement of crystal packing patterns in the structures of HL and 2–5. DFT based charge and energy decomposition scheme (ETS-NOCV) was applied to characterize the obtained polymers. [ABSTRACT FROM AUTHOR]

Manipulation of the QD surface by changing morphology and surface capping ligands, as well as adjusting nanocrystal size, plays a crucial role on the selectivity and sensitivity exhibited by QDs towards a given target analyte. In this study, a novel aqueous synthesis of CdTe QDs capped with a thiol compound containing a sulfonate (SO3−) terminal group, viz., 2-mercaptoethanesulfonate (MES), was thoroughly investigated with the aim of obtaining a fluorescent probe for chemical analysis. The results obtained with the prepared CdTe-MES QDs in the determination of various metal ions demonstrated the high efficiency of these nanomaterials for determining Hg(ii) levels. Upon optimization, linear working calibration curves for Hg(ii) concentrations of up to 0.5 μmol L−1 were obtained, with a determination coefficient of 0.9984. The detection limit was 0.0095 μmol L−1 and the quantification limit was 0.0324 μmol L−1. When applied to the determination of Hg(ii) in tap water samples, the developed method provided analytical results similar to those obtained with a reference method. The accuracy and precision of both methods were comparatively evaluated using the Student's t-test and the Fischer test, and the tabulated values showed a good agreement at a 95% confidence level. [ABSTRACT FROM AUTHOR]

Hg2+ is one of the the most threatening heavy metal ions; thus, finding a quick and easy way to detect it is very important. In this study, we designed and synthesized a simple Hg2+ chemosensor Z, which bears carboxyl and imidazolyl moieties as the hydrophilic group site and Hg2+ binding site, whereas the naphthalimide moiety acts as the signal group. Interestingly, the sensor Z could dissolve in water and show high selectivity and sensitivity for Hg2+ in aqueous solution. Other coexistent competitive metal ions (Fe3+, Ag+, Ca2+, Cu2+, Co2+, Ni2+, Cd2+, Pb2+, Zn2+, Cr3+, and Mg2+) had no interference in the process of detecting Hg2+. The detection limit of sensor Z towards Hg2+ was 1.785 × 10−7 M, which indicated its high detection sensitivity. Moreover, the immediate response of Z to Hg2+ provides a real-time detection method for Hg2+ in aqueous solution. In addition, sensor Z can undergo cyclic utilization. [ABSTRACT FROM AUTHOR]

The crystal structures of three similar Hg(ii) complexes including the N-(2,5-difluorophenyl)-2-pyrazinecarboxamide ligand were determined by X-ray diffraction. In each structure, the fluorine atoms were involved in different, non-predictable fluorine-based contacts. Quantitative analysis of the potential surface and interaction energy calculations were performed for the different interactions involving fluorine. [ABSTRACT FROM AUTHOR]

At mercury (Hg)-contaminated sites, streambank erosion can act as a main mobilizer of Hg into nearby waterbodies. Once deposited into the waters, mercury from these soils can be transformed to MeHg by microorganisms. It is therefore important to understand the solid-phase speciation of Hg in streambanks as differences in Hg speciation will have implications for Hg transport and bioavailability. In this study, we characterized Hg solid phases in Hg-contaminated soils (100-1100 mg per kg Hg) collected from the incised bank of the East Fork Poplar Creek (EFPC) in Oak Ridge, TN (USA). The analysis of the soil samples by scanning electron microscopy-energy dispersive spectroscopy indicated numerous microenvironments where Hg and sulfur (S) are co-located. According to bulk soil analyses by extended X-ray absorption fine structure spectroscopy (EXAFS), the near-neighbor Hg molecular coordination in the soils closely resembled freshly precipitated Hg sulfide (metacinnabar, HgS); however, EXAFS fits indicated the Hg in the HgS structure was undercoordinated with respect to crystalline metacinnabar. This undercoordination of Hg-S observed by spectroscopy is consistent with transmission electron microspy images showing the presence of nanocrystallites with structural defects (twinning, stacking faults, dislocations) in individual HgS-bearing particles. Although the soils were collected from exposed parts of the stream bank ( i.e. , open to the atmosphere), the presence of reduced forms of S and sulfate-reducing microbes suggests that biogenic sulfides promote the formation of HgS nanoparticles in these soils. Altogether, these data demonstrate the predominance of nanoparticulate HgS with crystal lattice defects in the bank soils of an industrially impacted stream. Efforts to predict the mobilization and bioavailability of Hg associated with nano-HgS forms should consider the impact of nanocrystalline lattice defects on particle surface reactivity, including Hg dissolution rates and bioavailability on Hg fate and transformations.

The effect of intermolecular interactions on the conformational variety of flexible mono-dentate ligands in coordination compounds has been investigated through the preparation of two series of mercury(ii) complexes. In this regard, the molecular and structural architecture of eight complexes, [HgCl2(Lamide-Cl)2] (1), [HgCl2(Lamide-Br)2] (2), [HgBr2(Lamide-Br)2] (3), and [HgI2(Lamide-Br)2] (4), as the first series and [HgBr2(Limine-Cl)2] (5), [HgBr2(Limine-Br)2] (6), [HgI2(Limine-Cl)]n (7), and [HgI2(Limine-Br)]n (8), as the second series, using two kind of flexible ligands, N-(1-halonaphthalen-4-yl)nicotinamide, Lamide-X, and 4-halo-N-((pyridin-3-yl)methylene)naphthalen-1-amine, Limine-X, has been studied. Inspection of the packing of these compounds clearly shows the presence of conformational changes in the arrangement of the ligands in each series. Although there are slight differences between the crystal packing of these compounds, it seems that π-involving intermolecular interactions including πnaph…πnaph in the first series and πimine…πpy/naph in the second series with the cooperation of Hg…πpy can lock the ligand conformational variety to a single conformer. [ABSTRACT FROM AUTHOR]

Two new luminescent compounds containing fluorescein–amino acid units have been designed and synthesized via an ester linkage between a fluorescein ethyl ester and Boc-Ser(TBDMS)-OH or Boc-Cys(4-MeBzl)-OH, and their photophysical properties have been explored. The optical response of both compounds (2 and 3) towards the metal ions Na+, K+, Hg+, Ag+, Ca2+, Co2+, Ni2+, Cu2+, Zn2+, Cd2+, Pb2+, Hg2+, Al3+, Fe3+, Ga3+and Cr3+ was investigated in pure acetonitrile and in acetonitrile/water mixtures. A strong CHEF (Chelation-Enhanced Fluorescence) effect was observed with all the trivalent metals and Hg2+ ions in both solvents. UV-vis absorption, steady state and time resolved emission spectroscopy methods were employed. The results show the formation of mononuclear complexes with Al3+, Fe3+, Ga3+, Cr3+, and Hg2+. Theoretical calculation using Density Functional Theory was performed in order to obtain atomistic insights into the coordination geometry of Al3+ and Hg2+ to the fluorescein 3, which is in accordance with the experimental stoichiometry results obtained in the Job's plot method. Among the active cations, the minimum detectable amount is under 1 μM for most of the cases in both absorption and fluorescence spectroscopy methods. [ABSTRACT FROM AUTHOR]

The preparation of homoleptic heterometallic complexes still remains a challenge. Herein, we report the synthesis and characterization of [Au(PMe3)2][{AuHg2(o-C6F4)3}{Hg3(o-C6F4)3}] (1), a gold–mercury homoleptic metallacycle. The crystal structure of 1 displays two [Hg2M(o-C6F4)3] (M = AuI, HgII) units linked through a short Au…Hg contact of 3.097(2) Å, the strongest unsupported AuI…HgII interaction described to date. Theoretical calculations quantify the interaction between the trimetalic units as −199 kJ mol−1, a surprisingly strong value. [ABSTRACT FROM AUTHOR]

A simple and fast colorimetric method is developed for the sensitive and selective detection of Hg2+ based on a dual signal amplification strategy: in situ Hg2+ induced catalytic synthesis of oxidase-like AuHg nanoparticles and subsequent catalytic oxidation of TMB by AuHg nanoparticles. [ABSTRACT FROM AUTHOR]

PH3 reacts with the in situ generated N-heterocyclic carbene DippNHC* (DippNHC* = 1,3-bis(2,6-diisopropylphenyl)imidazolin-2-ylidene) to give the phosphanyl–imidazolidine [DippNHC*-H]-[PH2]. Upon treatment with an ortho-quinone, [DippNHC*-H]-[PH2] is dehydrogenated to give the parent phosphinidene–carbene adduct DippNHC*=PH. Alternative routes to [DippNHC*-H]-[PH2] and DippNHC*=PH employ NaPH2 and (TMS)3P7 (TMS = trimethylsilyl), respectively, as phosphorus sources. The adduct DippNHC*=PH and the related adduct DippNHC=PH (DippNHC = bis(2,6-diisopropylphenyl)imidazol-2-ylidene) possessing an unsaturated NHC backbone both react with HgCl2 to give the bis(carbene–phosphinidenyl) complexes [(DippNHC*=P)2Hg] and [(DippNHC=P)2Hg]. [ABSTRACT FROM AUTHOR]

Monomeric Hg(ii) selenolate complexes derived from 2-phenylbenzamide ligands were prepared by oxidative addition of diselenides [{C6H4(CONR2)Se}2, R = Me, Et, iPr] to elemental Hg and reductive cleavage of the Se–N bond of isoselenazolone derivatives [(NO2)C6H3(CONSe)R, (R = allyl, nbutyl)] followed by the treatment with HgCl2. The complexes have been characterized by multinuclear NMR (1H, 13C and 77Se) spectroscopy and mass spectrometry which suggest the monomeric form of these in solution. The molecular structures of diselenides [C6H4(CONR2)Se]2 and mercury selenolates [Hg{(NO2)C6H3(CONH-C3H5)Se}2], [Hg{C6H4(CONiPr2)Se}2] and [Hg{C6H4(CONMe2)Se}2] were established by a single crystal X-ray diffraction study. Diselenides show strong intramolecular non-bonded Se…O interactions, which are influenced by the nature of C(O)NṞ2 and decrease with the sterically bulky alkyl substituent (Se…O = 2.823 Å for R = di-Me, 2.760 Å for R = allyl, and 3.157 Å for R = di-iPr). Mercury complexes derived from less bulky 2-phenyl-N,N-dialkylbenzamide ligands associated with poor or no intramolecular non-bonded Hg…O interactions (4.91 Å for R = di-Me, 4.199 Å for R = allyl) and instead strong intermolecular Hg…O [2.792(3) and 2.820(4) Å] for di-Me and allyl and Hg…Se [3.3212(5) and 3.4076(8) Å] interactions were observed which lead to a dimeric form in the crystals. On the other hand, the mercury complex derived from the sterically bulky diisopropyl amide ligand shows a strong intramolecular non-bonded Hg…O (2.860 Å) interaction, adopts linear geometry and exists as a monomer. Thermogravimetric analysis (TGA) of the mercury selenolate complexes revealed two-step decomposition which leads to the formation of HgSe. The mercury selenolate complex 3c derived from the sterically bulky 2-phenyl-N,N-diisopropylbenzamide ligand decomposed to give HgSe in the range of 220–300 °C. [ABSTRACT FROM AUTHOR]

A series of functionalized bis-azolium salts, 1,8-bis[2′-(N-R-azoliumyl)ethoxy]-9,10-anthraquinone hexafluorophosphate L1H2·(PF6)2–L4H2·(PF6)2 (R = Et, CH2Ph and CH2Py, azoliumyl = benzimidazoliumyl or imidazoliumyl), as well as their seven N-heterocyclic carbene mercury(ii) and silver(i) complexes [(L2HgBr)2](HgBr4) (1), [L2Hg(HgI4)]2 (2), [L1Hg(HgI4)] (3), [L4Hg(HgI4)] (4), [L1Ag](PF6) (5), [L3Ag](PF6) (6) and [L4Ag](PF6) (7) have been prepared and characterized. In complexes 1 or 2, two 16-membered macrometallocycles are connected together via two bridging halide ions (two bridging bromide ions for 1, and two bridging iodide ions for 2). In complexes 3–7, each molecule contains one 16-membered macrometallocycle formed by one biscarbene ligand (L1 for 3 and 5, L3 for 6, L4 for 4 and 7) and one metal ion (Hg(ii) for 3 and 4, Ag(i) for 5–7). In the crystal packings of 1–7, 2D supramolecular layers and 3D supramolecular architectures are formed via intermolecular weak interactions (such as the hydrogen bonds, π–π interactions and C–H…π contacts). In addition, the fluorescence emission spectra of the complexes and bis-azolium salts were described. The cyclic voltammetry study for silver(i) complexes 5–7 was conducted. [ABSTRACT FROM AUTHOR]

Recently, metal-mediated base-pairs (metallo-base-pairs) have been studied extensively with the aim of exploring novel base-pairs; their structures, physicochemical properties, and applications have been studied. This trend has become more evident after the discovery of HgII-mediated thymine–thymine (T–HgII–T) and AgI-mediated cytosine–cytosine (C–AgI–C) base-pairs. In this article, we focus on the basic science and applications of these metallo-base-pairs, which are composed of natural bases. [ABSTRACT FROM AUTHOR]

A sulfur-free iridium(iii) complex (pbi)2Ir(mtpy) (1) was successfully prepared and adopted as a Hg(ii)-chemosensor with high selectivity and sensitivity. Multi-signaling responses towards Hg(ii) ions were observed by UV−vis absorption, phosphorescence and electrochemistry measurements. With addition of Hg(ii) ions, complex 1 presented quenched emission in its phosphorescence spectrum and the detection limit was as low as 2.5 × 10−7 M. Additionally, its redox peak currents showed a broad linear relationship with the concentration of Hg(ii) ions ranging from 0 to 500 μM, which was beneficial for the quantitative detection. Based on the 1H NMR and ESI-MS analyses, the probing mechanism was tentatively supposed to be the Hg2+-induced changes in the local environment of complex 1. Such a response process was useful for achieving simple and effective detection of Hg(ii) ions as well as developing more chemosensors. [ABSTRACT FROM AUTHOR]

CuS (PCuS) particles were facilely synthesized by the wet-treatment of a Cu-based metal organic framework (HKUST-1). PCuS possesses an impressive intrinsic peroxidase-like activity. As a result of this affinity, PCuS readily binds to 3,3′,5′,5-tetramethylbenzidine (TMB) in the presence of hydrogen peroxide (H2O2) (Km values of 29 μM and 150 μM toward TMB and H2O2, respectively). Interestingly, when Hg2+ was added, HgS produced in conjunction with the specific binding sites on the surface of PCuS remarkably inhibited the peroxidase-like activity of PCuS. Based on this unique property, a sensing platform for the colorimetric detection of Hg2+ was established. In addition, high surface area and strong affinity for Hg2+ make PCuS an excellent adsorbent for Hg2+ (2105 mg g−1). These results indicate that PCuS could be a useful material for the facile detection and the efficient removal of Hg2+ using HKUST-1 as a precursor in environmental abatement applications. [ABSTRACT FROM AUTHOR]

A supramolecular probe for visual detection of mercury (Hg) has been designed by using a cyanine dye and AS1411 G-quadruplexes, which exhibits an obvious color change from red to blue in response to an increased level of Hg2+. The supramolecular probe exhibits high selectivity and sensitivity towards Hg2+ and is promising for the detection of environmental samples with the naked eye. [ABSTRACT FROM AUTHOR]

Two pairs of Hg(ii) supramolecular isomers, [HgBr2(GAG-L)]∞ [L = N,N′-di(3-pyridyl)adipoamide], 1, and [HgBr2(AAA-L)]∞, 2, and [HgI2(GAG-L)]∞, 3, and [HgI2(AAA-L)]∞, 4, have been successfully synthesized by various methods and structurally characterized by single-crystal X-ray crystallography. Complex 1 forms a one-dimensional (1D) meso-helical chain, 2 and 4 exhibit normal 1D helical chains, while 3 displays a 1D sinusoidal chain. The L ligands in 1 and 3 display GAG trans syn–syn conformation, while those in 2 and 4 adopt the AAA trans syn–syn conformation. In addition, complexes 1 and 3 can be irreversibly transformed to 2 and 4, respectively, under simple heating or hydrothermal condition. Moreover, complex 1 exhibits intense violet-blue photoluminescence in the solid state, whereas 2 and 3 display weak broad emissions in the blue-green region and 4 shows undetectable emission intensity. [ABSTRACT FROM AUTHOR]

In the present work, a simple and sensitive flow injection chemiluminescent competitive immunoassay was developed for the determination of mercury(ii) ion (Hg2+) based on carboxylic resin beads, a novel specific monoclonal antibody (McAb) and HRP enzyme-amplification. Resin beads with carboxyl groups were creatively employed as supports for immobilizing more coating antigen through acylamide bonds. With a competitive-type assay mode, the Hg2+ in solution competed with the immobilized coating antigen for the limited McAb. Then, the second antibody labeled with HRP was introduced, and an effectively increased CL was obtained, which was ascribed to the catalytic activity of HRP for the luminol–PIP–H2O2 reaction. With increasing concentration of Hg2+, the CL of this system decreases because less HRP is present in the CL reaction. At optimal conditions, the CL signal displayed a good linear relation toward Hg2+ in the range of 0.05–200 ng mL−1 with a detection limit (3σ) of 0.015 ng mL−1. The immunosensor possessed high specificity, acceptable accuracy and reproducibility, and was examined in real samples with favorable results. This immunoassay will have intriguing application prospects for the determination of other heavy metal ions and environmental contaminants. [ABSTRACT FROM AUTHOR]

In the present work, a simple and sensitive flow injection chemiluminescent competitive immunoassay was developed for the determination of mercury(ii) ion (Hg2+) based on carboxylic resin beads, a novel specific monoclonal antibody (McAb) and HRP enzyme-amplification. Resin beads with carboxyl groups were creatively employed as supports for immobilizing more coating antigen through acylamide bonds. With a competitive-type assay mode, the Hg2+ in solution competed with the immobilized coating antigen for the limited McAb. Then, the second antibody labeled with HRP was introduced, and an effectively increased CL was obtained, which was ascribed to the catalytic activity of HRP for the luminol–PIP–H2O2 reaction. With increasing concentration of Hg2+, the CL of this system decreases because less HRP is present in the CL reaction. At optimal conditions, the CL signal displayed a good linear relation toward Hg2+ in the range of 0.05–200 ng mL−1 with a detection limit (3σ) of 0.015 ng mL−1. The immunosensor possessed high specificity, acceptable accuracy and reproducibility, and was examined in real samples with favorable results. This immunoassay will have intriguing application prospects for the determination of other heavy metal ions and environmental contaminants. [ABSTRACT FROM AUTHOR]

Three new coordination polymers have been obtained using bis(4-pyridyl)mercury (py2Hg) as a spacer: [Cu(Hmea)2(py2Hg)](ClO4)2·2(py2Hg) (1), [Cu2(pa)2(py2Hg)(ClO4)2]·0.5(py2Hg)·H2O (2), and [Cu2(pa)2(py2Hg)2](BF4)2 (3) (Hmea = monoethanolamine; Hpa = propanolamine). Compounds 1 and 2 are linear coordination polymers with mononuclear and binuclear alkoxo-bridged nodes, respectively. Compound 3 features a 3-D network with a cadmium sulfate topology. The ability of py2Hg to generate supramolecular solid-state architectures is illustrated by three systems obtained from co-crystallization processes: (4,4′-dihydroxybiphenyl)·(py2Hg) (4), (pyrogallol)·(py2Hg) (5), and (phloroglucinol)·2(py2Hg) (6). The convolution of various supramolecular interactions (Hg…N, Hg…O, π…Hg, and π–π) in sustaining the architecture of the crystals is analyzed. A new synthetic method for bis(4-pyridyl)mercury was developed. It consists of a two-step reaction, starting from 4-iodopyridine and using iPrMgCl·LiCl and HgCl2. [ABSTRACT FROM AUTHOR]

The photophysical properties of ZnII/HgII Schiff base complexes could be fine and predictably tuned over a wide range of wavelengths by changing the ligand structures. A new series of polydentate Schiff base-type ligands, N,N′-bis(2-pyridinylethylidene)R3-1,2-diamine (L1–L6), which contain a flexible, semi-rigid or rigid group (R3 = butyl, cyclohexane, tolyl and phenylene), has been designed and employed for synthetizing new mononuclear or binuclear trans ZnII/HgII complexes with a general formula of [M(L1)Cl2] (L1 = N,N′-bis(2-pyridinylethylidene)phenylene-1,2-diamine, M = Zn, 1a; M = Hg, 1b), [M(L2)Cl2] (L2 = N,N′-bis(2-pyridinylethylidene)toluene-3,4-diamine, M = Zn, 2a; M = Hg, 2b), [M2(L3)Cl4]·nCH2Cl2 (L3 = N,N′-bis(2-pyridinylmethylene)cyclohexane-1,2-diamine, M = Zn, n = 0, 3a; M = Hg, n = 1, 3b), [M2(L4)Cl4]·nCH3OH (L4 = N,N′-bis(2-pyridinylethylidene)cyclohexane-1,2-diamine, M = Zn, n = 1, 4a; M = Hg, n = 0, 4b), [M2(L5)Cl4] (L5 = N,N′-bis(3-methoxy-2-pyridinylmethylene)-cyclohexane-1,2-diamine, M = Zn, 5a; M = Hg, 5b), [M2(L6)Cl4]·nCH3CN (L6 = N,N′-bis(3-methoxy-2-pyridinylmethylene)butane-1,4-diamine, M = Zn, n = 4, 6a; M = Hg, n = 0, 6b). All the ligands and complexes have been characterized by elemental analyses, IR spectra, and 1H NMR spectra. Twelve structures of L5, L6, 1a–6a, 1b, 3b, 5b and 6b crystallized in three different conditions are further determined by single-crystal X-ray diffraction analyses. Their properties are fully characterized by UV-vis and fluorescence spectra both in solution and the solid state at room temperature. The luminescence color of these ZnII/HgII Schiff base complexes could be tuned from blue to green to red (429–639 nm for 6a–1a, 434–627 nm for 6b–1b) in solution by changing the ligand conjugated systems from flexibile (L6) to semi-rigid (L3–L5) to rigid (L1–L2). The spectra of the free Schiff bases L6–L1 are centered around 402–571 nm, which are perturbed upon the coordination to the ZnII/HgII ion. Both the electrochemical data and TD-DFT calculations show that the HOMO–LUMO band gap from the ligand to the complex is reduced by complexation. Meanwhile, the emission efficiencies of ZnII-complexes are found to be strongly dependent on the Schiff-base ligands with quantum yields ranging from 14% to 25% for 1a–6a. However, the emission efficiencies dramatically decline in HgII-complexes with quantum yields ranging from 4% to 19%, due to the heavy atom effect. [ABSTRACT FROM AUTHOR]

Metathetical reactions of alkali–metal derivatives of the dianion [tBuN(Se)P(μ-NtBu)2P(Se)NtBu]2− (2Se2−) with Ag(NHC)Cl, Ag[BF4], AuCl(THT) and HgCl2, as well as the reaction of 2S2− with AuCl(THT) were investigated. The observed products all incorporate the monoprotonated ligands 2SeH− or 2SH− in a variety of structural arrangements around the metal centres, including tetrameric and trimeric macrocycles [Ag and Au (E = Se)], a ladder (Au, E = S) and a spirocycle (Hg); the ladder contains both the dianion 2S2− and the monoanion 2SH− as ligands linking three Au2 units. All complexes have been characterised in the solid state by single crystal X-ray analyses and in solution by multinuclear (1H, 31P and 77Se) NMR spectra. [ABSTRACT FROM AUTHOR]

Aggregates of perylene bisimide (PBI) derivative 3 serve as reactors and stabilizers for the preparation of mercury nanoparticles (HgNPs) which exhibit excellent catalytic efficiency in the conversion of aldoximes/ketoximes into primary/secondary amides via Beckmann rearrangement. [ABSTRACT FROM AUTHOR]

ABA-type amphiphiles bearing a triazole-based aromatic block were easily synthesized using click chemistry, which act as fluorescent turn-off Hg2+-chemoprobes in an aqueous solution. Interestingly, the metal-binding process of amphiphiles induced nanoassemblies even below the CMCs, and the binding stoichiometry affected the morphologies of the resultant nanostructures. [ABSTRACT FROM AUTHOR]

Highly stable Au(I)core-Ag(0)shell particles have been synthesized in aqueous solution via a green chemistry pathway utilising sunlight irradiation. The shell of the particles is composed of fluorescent Ag2 and Ag3 clusters which make the large core-shell particles highly fluorescent. The Au(I) core of the particles offers long-term stability to the silver clusters, which are otherwise unstable in solution at room temperature, by the transfer of electron density from the shell. Successive additions of Hg(II) ions to the fluorescent solution cause efficient and selective quenching of the fluorescence with gradual red shifting of the emission peak. The metallophilic 5d10(Hg2+)-4d10(Agδ+) interaction as well as Hg(II) stimulated aggregation have been ascribed to causing the fluorescence quenching and red shift. The fluorescent Au(I)core-Ag(0)shell particles are a highly selective and sensitive sensing platform for the detection of Hg(II) down to 6 nM in the presence of various metal ions. The detection limit is far below the permissible level as determined by the EPA. Interferences due to Cu(II) and Fe(III) have been eliminated using Na2-EDTA and NH4HF2, respectively. The fluorescent particles are successfully transferred to various solvent systems making Hg(II) determination also possible in non-aqueous media. Finally, the temperature dependent fluorescence change with and without Hg(II) provides information about the metallophilic interaction. [ABSTRACT FROM AUTHOR]

A study was carried out to investigate the concentrations of Hg(II) in different categories of water samples at ng L-1 levels. The capabilities of oxidised carbon nanotubes (ox-CNTs) were studied to assess if this substrate serves as an efficient material for Hg(II) preconcentration using an on-line flow injection cold vapour-atomic absorption spectrometry (FI-CV-AAS) system. Carbon nanotubes are characterized by a marked tendency to aggregate, which negatively affects the retention of Hg whenever integrated in flow systems as a packed column. For this reason, the preconcentration was carried out in a microcolumn filled with a mixture of ox-CNTs and a low molecular weight polyethylene. The preparation of the microcolumn was studied in detail. Concerning column design, the best performance was achieved when packing the substrate in a microcolumn of 2.25 mm (i.d.) x 20 mm length. The effect of chemical and physical parameters including the pH of the solutions, the eluent type and the concentration was systematically examined. Mercury was retained at pH 5.0 and 15% (v/v) HCl was the best alternative for Hg(II) elution. Under optimal conditions, the adsorption capacity of the substrate was found to be 3.2 mg g-1 reaching a preconcentration factor (PF) of 150. The high adsorption capacity of this substrate allowed reaching a detection limit (3σ) of 1.9 ng L-1, when using a sorbent column containing only 1.0 mg of ox-CNTs. The limit of quantification (10σ) resulted to be 6.3 ng L-1. Precision, expressed as relative standard deviation (RSD), turned out to be 1.6% at the 0.1 μg L-1 level (n = 8). The system was evaluated for quantitative determination of Hg in river water, sea water and effluents. [ABSTRACT FROM AUTHOR]

In this study, three Hg(II) complexes, [HgCl2(L2-naph)]n, 1, [HgBr2(L2-naph)]n, 2 and [HgI2(L2-naph)2], 3 where L2-naph is N-(naphthalene-2-yl)pyrazine-2-carboxamide ligand have been synthesized and characterized. X-ray single crystal diffraction analysis of these compounds reveals that 1 and 2 are isostructural coordination polymers and 3 is a discrete compound. In comparison to homologue complexes containing N-(naphthalene-1-yl)pyrazine-2-carboxamide ligand, interestingly, structural analysis clearly shows that displacing substituent position plays an important role in the formation of the supramolecular organization of molecular complexes. The common feature in the crystal packing of these complexes is that there is a strong tendency to form π-π stacking interaction between pyrazine and naphthalene rings. These π-π stacking interaction synthons affect the coordination geometry and structural assembly. Also, theoretical methods show the π-π stacking interaction energies within a range of -64.13 to -70.51 kJ mol-1. It is notable that in 3, cooperation of intermolecular π-π stacking synthon and intramolecular C-Hpyz...I-Hg hydrogen bond resulted in the formation of unusual pseudo-square planar geometry around the Hg(II) center. This study reveals an undeniable contribution of π-π stacking interaction to the organization and stabilization of some of the crystal structures reported here. [ABSTRACT FROM AUTHOR]

We report a simple strategy for the fabrication of a highly selective and sensitive Hg(II) chemosensor based on HMS-Ag composite functionalized rhodamine derivative (R). The prepared chemosensor HMS-Ag-R was characterized by transmission electron microscopy (TEM), X-ray powder diffraction (XRD), UV-vis spectrum and Fourier transform infrared spectroscopy (FT-IR). HMS-Ag-R has both fluorescence and colorimetry performance, and it can realize onsite and real-time detection of Hg(II) with a high sensitivity (0.7 ppb) in aqueous solution. In high concentration of mercury ions, the fluorescence intensity of HMS-Ag-R against Hg(II) sufficiently showed a typical sigmoidal shape. Moreover, HMS-Ag-R presents excellent anti-disturbance ability when exposed to a series of competitive cations such as Ag(I), K(I), Li(I), Na(I), Ba(II), Ca(II), Cd(II), Co(II), Cu(II), Mg(II), Mn(II), Ni(II), Pb(II) and Zn(II). It can be applied to the determination of Hg(II) in aqueous media. The interaction between HMS-Ag-R and Hg(II) could occur in a short time (90 s). Importantly, HMS-Ag-R could be regenerated with tetrapropyl ammonium hydroxide (TPAOH) solution. [ABSTRACT FROM AUTHOR]

Two novel water-soluble conjugated polymers poly{3-[1-(2-trimethylammoniumacetyl)piperidine-4-methylene]thiophene-2,5-diyl chloride} (PTAPT-Cl) and poly{3-[1-(2-trimethylammoniumbutyryl)piperidine-4-methylene] thiophene-2,5-diyl chloride} (PTBPT-Cl) have been synthesized via chemical oxidative polymerization and applied as a colorimetric and fluorometric probe for the detection of metal ions. Moreover, the fluorescence detection of metal ions using previously synthesized poly[N,N,N-trimethyl-4-(thiophen-3-ylmethylene)cyclohexanaminium chloride] (PTCA-Cl) and poly[3-(1,1′-dimethyl-4-piperidinemethylene)thiophene-2,5-diyl chloride] (PDPMT-Cl) was also investigated and discussed. All four conjugated polymers exhibited high sensitivity and selectivity to Hg2+ with a fluorescence “turn-off” mode at pH 3 in aqueous solutions. The best detection limit was as low as 10−9 M without interference from other common metal ions. Consequently, the distinctive quenching of the emission bands in the presence of various metal ions can lead to qualitative and quantitative Hg2+ detection in aqueous solution by a new approach using cationic polythiophene derivatives. [ABSTRACT FROM AUTHOR]

A simple chemosensor (1) has been designed and synthesized. The chemosensor selectively recognizes Hg2+ ions in THF–H2O (3 : 1, v/v) by showing a significant increase in emission and a bluish color of the solution under exposure to UV light. Change of the fluorophore unit in 1 leads to 2, which also shows selective sensing of Hg2+ under similar conditions. Furthermore, while the ensemble of 1 with Hg2+ selectively senses reduced glutathione (GSH) over cysteine and homocysteine, the ensemble of 2 with Hg2+ has been observed to be inefficient to distinguish glutathione from other biothiols. Thus probe 1 and inputs Hg2+ and GSH can be used to develop an INHIBIT logic gate. [ABSTRACT FROM AUTHOR]

Two new inorganic supramolecular compounds, (Hg11P4)(GaCl4)4 (1) and (Hg3AsS)(GaCl4) (2), have been prepared by the solid-state reactions. Their structures are characterized by mercury-containing cationic hosts and discrete (GaCl4)− guests, which is a derivative of a very strong Lewis acid. The three-dimensional cationic framework of 1, (Hg11P4)4+, is marvellously extended by Hg22+ and Hg32+ groups as well as Hg2+ ions to form two large tunnels with different sizes each embedded with two columns of (GaCl4)− anions. Compound 2 features a layered structure with (GaCl4)− tetrahedra being intercalated between two-dimensional (Hg3AsS)+ layers and it is the first mercury pnictidechalcohalide. It is found that the weak electrostatic forces between hosts and guests play a key role in the stabilization of the whole structures of 1 and 2, which is strikingly different from almost all the reported metal pnictidehalide and chalcohalide supramolecular compounds. Optical dielectric constants calculations show that both 1 and 2 possess strong dielectric anisotropy. [ABSTRACT FROM AUTHOR]

Two new inorganic supramolecular compounds, (Hg11P4)(GaCl4)4 (1) and (Hg3AsS)(GaCl4) (2), have been prepared by the solid-state reactions. Their structures are characterized by mercury-containing cationic hosts and discrete (GaCl4)− guests, which is a derivative of a very strong Lewis acid. The three-dimensional cationic framework of 1, (Hg11P4)4+, is marvellously extended by Hg22+ and Hg32+ groups as well as Hg2+ ions to form two large tunnels with different sizes each embedded with two columns of (GaCl4)− anions. Compound 2 features a layered structure with (GaCl4)− tetrahedra being intercalated between two-dimensional (Hg3AsS)+ layers and it is the first mercury pnictidechalcohalide. It is found that the weak electrostatic forces between hosts and guests play a key role in the stabilization of the whole structures of 1 and 2, which is strikingly different from almost all the reported metal pnictidehalide and chalcohalide supramolecular compounds. Optical dielectric constants calculations show that both 1 and 2 possess strong dielectric anisotropy. [ABSTRACT FROM AUTHOR]

A pentaquinone based compound 3 has been synthesized which works as a selective and sensitive chemodosimeter for mercury ions via Hg2+ promoted hydrolysis of an imine linkage to generate a fluorescent change in mixed aqueous media. [ABSTRACT FROM AUTHOR]

Reaction of α-pyridoin and N-phenyl-o-phenylenediamine affords 2-(2-(phenylamino)phenylimino)-1,2-di(pyridin-2-yl)ethanol (L) which undergoes cyclization to a chiral diimine, 2-methoxy-1-phenyl-2,3-di(pyridin-2-yl)-1,2-dihydroquinoxaline, LOMe (conjugated 14πe system) in the presence of zinc(ii), cadmium(ii) and mercury(ii) ions affording [Zn(LOMe)Cl2] (1), [Cd2(LOMe)2Cl4] (2) and [Hg2(LOMe)2Cl4] (3) complexes. Ligand L and complexes 1–3 are substantiated by elemental analyses, mass, IR, 1H NMR and UV-vis spectra including the single-crystal X-ray structures of 1 and 3. The possibility of the atropisomerism of L is restricted in cyclic LOMe. L and complexes 1–3 are fluorescent in fluid solutions at 298 K (CH2Cl2: 1, λex = 470 nm, λem = 627 nm, Φ = 0.014, τavg = 2.5 ns; 2, λex = 430 nm, λem = 599 nm, Φ = 0.08, τavg = 7.6 ns; 3, λex = 415 nm, λem = 600 nm, Φ = 0.021, τavg = 2.8 ns). Time-resolved emission spectra (TRES) established that the two-component lifetimes of 1–3 are due to the existence of two conformers. Density functional theory (DFT) and time dependent (TD) DFT calculations authenticated that 1–3 complexes are fluorescent due to intra-ligand charge transfer (ILCT) to the πdiimines* orbital. [ABSTRACT FROM AUTHOR]

A simple, rapid, and reversible fluorescent DNA INHIBIT logic gate has been developed for sensing mercury (Hg2+) and iodide (I−) ions based on a molecular beacon (MB). In this logic gate, a mercury ion was introduced as the first input into the MB logic gate system to assist in the hybridization of the MB with an assistant DNA probe through the thymine–Hg2+–thymine interaction, which eventually restored the fluorescence of MB as the output. With this signal-on process, mercury ions can be detected with a limit of detection as low as 7.9 nM. Furthermore, when iodide ions were added to the Hg2+/MB system as the second input, the fluorescence intensity decreased because Hg2+ in the thymine–Hg2+–thymine complex was grabbed by I− due to a stronger binding force. Iodide ions can be detected with a limit of detection of 42 nM. Meanwhile, we studied the feasibility and basic performance of the DNA INHIBIT logic gate, optimized the logic gate conditions, and investigated its sensitivity and selectivity. The results showed that the MB based logic gate is highly selective and sensitive for the detection of Hg2+ and I− over other interfering cations and anions. [ABSTRACT FROM AUTHOR]

A new 1,3-di-capped calix[4]arene conjugate of salicylidene (L) has been synthesized, characterized and the structure has been established by single crystal XRD. L shows selectivity towards Hg2+in ethanol by turn-onfluorescence among the biologically important metal ions studied. The species of recognition has been modeled by DFT computational calculations to result in conformational changes in the arms that support the turn-onfluorescence behaviour. [ABSTRACT FROM AUTHOR]

A colorimetric assay has been developed for the simultaneous selective detection of silver(i) and mercury(ii) ions utilizing metal nanoparticles (NPs) as sensing element based on their unique surface plasmon resonance properties. In this method, sulfhydryl group modified cytosine-(C)-rich ssDNA (SH-C-ssDNA) was self-assembled on gold nanoparticles (AuNPs) to produce the AuNPs–C-ssDNA complex, and sulfhydryl group modified thymine-(T)-rich ssDNA (SH-T-ssDNA) was self-assembled on silver nanoparticles (AgNPs) to produce the AgNPs–T-ssDNA complex. Oligonucleotides (SH-C-ssDNA or SH-T-ssDNA) could enhance the AuNPs or AgNPs against salt-induced aggregation. However, the presence of silver(i) ions (Ag+) in the complex of ssDNA–AuNPs would reduce the stability of AuNPs due to the formation of Ag+mediated C–Ag+–C base pairs accompanied with the AuNPs color change from red to purple or even to dark blue. Moreover, the presence of mercury(ii) ions (Hg2+) would also reduce the stability of AgNPs due to the formation of Hg2+mediated T–Hg2+–T base pairs accompanied with the AgNPs color change from yellow to brown, then to dark purple. The presence of both Ag+and Hg2+will reduce the stability of both AuNPs and AgNPs and cause the visible color change. As a result, Ag+and Hg2+could be detected qualitatively and quantitatively by the naked eye or by UV-vis spectral measurement. The lowest detectable concentration of a 5 nM mixture of Ag+and Hg2+in the river water was gotten by the UV-vis spectral measurement. [ABSTRACT FROM AUTHOR]

A DNA probe labeled with a 4-([4-(dimethylamino)phenyl]azo)benzoic acid (DABCYL) quencher and a carboxyfluorescein (FAM) donor at its 5′- and 3′-termini can be used for the detection of Hg2+ions and phenylmercury ions (PhHg+). This DNA probe possesses a random coil structure that changes into a hairpin-like structure upon binding Hg2+and PhHg+ions. As a result, the fluorescence of the FAM unit decreased through quenching between the donor and the quencher. In the presence of ethylenediaminetetraacetic acid (EDTA), the DNA probe allowed the selective detection of PhHg+ions at concentrations as low as 70.0 nM, mainly as a result of T–Hg2+–T coordination and π–π stacking between the Ph unit and DNA bases. A linear correlation existed between the fluorescence intensity and the concentration of PhHg+ions over the range from 0.10 to 1.0 μM (R2= 0.99). After acid hydrolysis and neutralization of the samples, all of the mercury species are converted to Hg2+ions, allowing us to use the DNA-based probe to determine the concentrations of total mercury species at the nM level. The practicality of this probe has been validated by the analyses of pond water and fish samples, showing its advantages of sensitivity, selectivity, and simplicity. [ABSTRACT FROM AUTHOR]

The need of analytical methods for absolute quantitative protein analysis spurred research on new developments in recent years. In this paper, a sensitive and selective method based on mercury labeled magnetic immunoassay and inductively coupled plasma mass spectrometry (ICP-MS) detection was proposed for the quantification of carcinoembryonic antigen (CEA) in real human serum samples. Size exclusion chromatography (SEC) combined with ICP-MS was applied for the separation and detection of secondary antibody labeled with mercury and excess mercury. After a complete sandwich-type immunoreaction among primary antibody, CEA and secondary antibody labeled with mercury on magnetic nanoparticles (MNPs), the concentration of CEA was determined by microconcentric nebulizer (MCN)-ICP-MS analysis of mercury ion released from secondary antibody with an acid-dissolution (pH 1.0) step. With consumption of only 50 μL sample solution, the established method presented a limit of detection of 0.041 ng mL−1for CEA, with the relative standard deviation (RSD) of 5.2% (c = 8 ng mL−1, n = 7). The response for CEA was linear over a dynamic range from 0.1 to 50 ng mL−1. The analytical results of CEA in three different human serum samples obtained by the proposed method are in good agreement with that obtained by the commonly used clinical method of chemiluminescent immunoassay (CLIA). The developed method was versatile and could be easily extended to other proteins quantitative analysis, especially for specific biomarker determination. [ABSTRACT FROM AUTHOR]

Mercury solution without or with formic acid was introduced into a low temperature argon plasma from dielectric barrier discharge (DBD). Mercury vapor generated in the DBD was separated from the liquid phase and finally swept into an inductively coupled plasma optical emission spectrometer (ICP-OES) for determination. The optimum conditions for the proposed technique and operation of the ICP-OES, as well as interferences from concomitants, were investigated in detail. It was found that the vapor generation efficiency of mercury could be significantly enhanced with the addition of formic acid. However, the efficiency was reduced sharply in the presence of chloride ions or oxidizing substances of high concentration. Under the optimized conditions, a limit of detection of 0.090 μg L−1and a precision of 2.1% RSD at a concentration of 10 μg L−1were achieved by the proposed method. The new DBD-induced mercury vapor generation provides several advantages including low power consumption (<25 W), green analytical chemistry, cost-effectiveness, smaller size, long operation lifetime, and ease of on-line operation. The methodology has been successfully applied to the determination of mercury in a certified reference water sample and mineral water samples. [ABSTRACT FROM AUTHOR]

A nanoscavenger of mercaptopropyl-modified silica microparticles has been developed for the determination of trace levels of mercury(ii) in water. The synthesis of silica microparticles nanoscavengers is carried out by modification of pre-formed silica particles with mercaptopropyltrimethoxysilane or by incorporating the thiol modification agent during the growth of the silica particles. The silica nanoscavengers were characterized by SEM, TGA, particle analyzer, IR and the parameters influencing the extraction and recovery phases of the preconcentration process were performed by AAS. The results show that careful choice of particle size and surface characteristics produce a new mercapto-silica-nanoscavenger that disperses in water as a quasi-stable sol. This permits the facile recovery of the mercury-loaded nanoscavenger particles. No agitation is required during the mercury extraction as the dispersion is maintained by Brownian motion and slow gravitational sedimentation. The technique overcomes a number of problems, such as cross-contamination and decreases in mercury concentration during sample transportation to the laboratory. Recovery achieved reaches >97 ± 4% over a wide range of preconcentration factors. At a preconcentration factor of 50 the limit of detection (3σ) was 0.19 ng mL−1. The method is environmentally friendly as only 300 mg of mercapto-nanoscavenger is used, no organic solvent is required for the extraction and the experiment is performed without the need for manual or mechanical agitation. [ABSTRACT FROM AUTHOR]

The combination of a ditopic ligand containing a functional “third site” as a bridge and organometallic half-sandwich iridium unit Cp*Ir as the corner leads to the formation of the tetranuclear metallamacrocycle 1, which is reacted with silver compound, resulting in the formation of mixed-metal infinitely tubular coordination network 2. [ABSTRACT FROM AUTHOR]

The I2-adducts of drugs propylthiouracil (PTU) and methimazole (MeImSH) oxidize liquid mercury in dichloromethane to separate in good yield the neutral complexes [HgI2(PTU)2·MeOH] (1), [HgI2(PTU)2·HgI2] (2), and [Hg2I4(MeImSH)2] (3). The single crystal X-ray diffraction analysis of 1–2shows that the Hg(ii) center is coordinated by two sulfur atoms and by two iodine atoms in a tetrahedral geometry. In complex 2almost linear molecules of HgI2result encapsulated in the crystal packing enfolded by the hydrophobic propyl appendages of coordinated units of PTU. X-ray analysis of complex 3shows the presence of dimeric [Hg2I4(MeImSH)2] molecules to form Hg2S2I4cores. The intra- and intermolecular hydrogen bonds concerning PTU and MeImSH have been evaluated. The oxidation of Hg(0) to Hg(ii) requires a two-electron transfer process accomplished by an oxidative addition from the “activated” iodine moiety. The oxidizing and complexing properties of PTU-I2and MeImSH-I2have been interpreted considering the S-donor to I2interaction that leads to a charge separation between the sulfur-bound iodine atom S–I and the terminal I atom. Compounds 1, 2, and 3react with tetraethylammonium iodide to separate the compound (Et4N)2[HgI4] with the release of free PTU and MeImSH, respectively. The reported dissolution technique could be applied to the recovery of mercury from waste electrical and electronic equipment (WEEE) scrap, the nature of complexes 1–3makes it possible the easy separation of the mercury as tetraiodomercurate anion and the recycling of the donors. [ABSTRACT FROM AUTHOR]