Mercury observational studies

May et al. [45] used radiochemical studies to ascertain the behaviour of methylmercury chloride and mercuric chloride in seawater under different storage conditions. The application of 203Hg unambiguously revealed that the loss of mercury observed upon storage of unacidified seawater samples in polyethylene bottles was due to adsorption and to the diffusion of metallic Hg (Hg°) through the container wall. 

The base-catalyzed conversion of 5-alkyl-substituted isothiazolium salts 88 (R = Me, R = Et) to 2,3-dihydrothio-phene derivatives 329 occurs in basic conditions via intermediates 328. The distribution of diastereomers 329 is dependent on the base and aryl substituent <1997SUL35>. Similar behavior was observed in the case of 88 (R = R =-(0112)4-) <1996JPG424>. The condensation of 5-Me-substituted isothiazolium salts 88 with a second molecule of a different isothiazolium salts affords haA -thia-Eh-diazapentalenes 330. In this way, macrocyclic ethers 332 were prepared from 331 and their complexation behavior toward sodium(l), silver(l), and mercury(n) studied <2001PS(170)29>. 

The diet in the two studies was also considerably different. The majority of the mercury exposure to the Faroe Island population came from whale meat (estimated at about 3 ppm in muscle tissue) with a relatively small portion coming from fish. Some of the mercury in whale meat is in the form of inorganic mercury. In the Seychelles study, all of the mercury came from fish as methylmercury with concentrations of around 0.3 ppm. Whale meat blubber is widely consumed in the Faroe Islands and also contains polychlorinated biphenyls (PCBs). Grandjean et al. (1995b) estimated a daily intake of 200 g of PCB. This value can be compared to the Tolerable Daily Intake of PCBs established by the FDA of 60-70 g/day for an adult. Further statistical analysis of the possible influence of PCBs on the observed study results needs to be conducted (see the discussion below on Peer Panel IReview of Kev Studies for additional comments). 

The gas-phase photolysis of 2-furaldehyde in the it -n and ir <-it transitions76 proceeds with fragmentation to CO, furan and C3-hydrocarbons, but a certain amount of resinification is also noted (about 5% quantum yield with excitation of the it - n transition). The latter observation prompted a study of the vacuum liquid-phase photolysis by sunlight or by light from a medium-pressure mercury arc at room temperature24 7S. The resin obtained was submitted to fractionation and structural analysis. On the basis of the results obtained and other mechanistic evidence, the following sequence of events was postulated for the photopolymerization ... 

In their electrochemical surface properties, a number of metals (lead, tin, cadmium, and others) resemble mercury, whereas other metals of the platinum group resemble platinum itself. Within each of these groups, trends in the behavior observed coincide qualitatively, sometimes even semiquantitatively. Some of the differences between mercury and other. y- or p-metals are due to their solid state. Among the platinum group metals, palladium is exceptional, since strong bulk absorption of hydrogen is observed here in addition to surface adsorption, an effect that makes it difficult to study the surface itself. 

Kakiuehi et al. [84] studied the adsorption properties of two types of nonionic surfactants, sorbitan fatty acid esters and sucrose alkanoate, at the water-nitrobenzene interface. These surfactants lower the interfacial capacity in the range of the applied potential with no sign of desorption. On the other hand, the remarkable adsorption-desorption capacity peak analogous to the adsorption peak seen for organic molecules at the mercury-electrolyte interface can be observed in the presence of ionic surfactants, such as triazine dye ligands for proteins [85]. 

The electrochemical behavior of an aqueous/ethanol solution of [Ir(sat)2]Cl, satH = salicylaldehyde thiosemicarbazone (235), has been studied on mercury. A two-electron, ligand-based reduction at —1.09 V vs. SCE (independent of pH) is observed at fast scan rates.406... 

Zinc dithiocarbamates have been used for many years as antioxidants/antiabrasives in motor oils and as vulcanization accelerators in rubber. The crystal structure of bis[A, A-di- -propyldithio-carbamato]zinc shows identical coordination of the two zinc atoms by five sulfur donors in a trigonal-bipyramidal environment with a zinc-zinc distance of 3.786 A.5 5 The electrochemistry of a range of dialkylthiocarbamate zinc complexes was studied at platinum and mercury electrodes. An exchange reaction was observed with mercury of the electrode.556 Different structural types have been identified by variation of the nitrogen donor in the pyridine and N,N,N, N -tetra-methylenediamine adducts of bis[7V,7V-di- .vo-propyldithiocarbamato]zinc. The pyridine shows a 1 1 complex and the TMEDA gives an unusual bridging coordination mode.557 The anionic complexes of zinc tris( V, V-dialkyldithiocarbamates) can be synthesized and have been spectroscopically characterized.558... 

Heavy metal ions detection with porphyrin in sol-gel is possible, too56. The porphyrin, used for detection of heavy metal ions (Hg2+, Pb2+, Cd2+), was 5,10,15,20-tetra(4-N-methylpyridil)porphyrin (TMPyP) preferred to other porphyrins because it was not leaked out of the matrix. The study of metallation of the porphyrin immobilized in sol-gel emphasized the formation of 1 1 complex for each ion with a constant of complexation depending on the nature of the ions. The strongest effects were observed for mercury due to the specific interaction of this metal with the porphyrin. 

The mercuration of phosphonium derivatives has also been observed. The methylene group of the dimeric palladium complex 63 substituted by a carbonyl and a phosphonium functionality is readily mercurated upon reaction with Hg(OAc)2 to afford complex 64 (Equation (22)).7 Further studies demonstrated that the presence of a triphenylphosphonium group alone is sufficient to promote proton-mercury exchange. For example, the reaction of... 

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