Methylmercury Complexes

2 Methylmercury complexes. Methylmercury(l+) complexes of 1-methyladenine [1-Me-adH], isolated from aqueous solutions, have been characterized by NMR spectroscopy and X-ray crystallographyMeHg binding sites in [MeHg(l-Me-ad)] are at N-9 in [MeHg(l-Me-adH)]+ at N-7 and in [(MeHg)3 l-Me-ad)]2+ at N-3, N-7 and N-9. 

MeHg is bonded to N there is an additional weak Hg 0 intramolecular 

Several MeHg complexes with the adenine ligand 1(18, X=CH) H-Ad] have been 

Methyl mercury (+) can be generated in sea-water from interaction of methyl-Pb or -Sn compounds with Hg. Structures of solvated MeHgX in pyridine and MeHgOH In water have been determined by a large angle X-ray scattering technique  

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Robert and Robenstein [66] carried out indirect determination of Hg119 NMR spectra of methylmercury complexes, e.g. CH Hg11 thiol ligands in sediment samples. 3... 

Methylmercury complexes of allopurinol (56) and l-methylpyrazolo[3,4-from aqueous solutions and characterized <87ICA181>. Copper complexes of allopurinol have also been prepared by reaction with copper salts and their structures were elucidated by x-ray crystal structural analysis <87ZN(B)195>. 

Dutczak WJ, Ballatori N (1994) Transport of the glutathione-methylmercury complex across liver canalicular membranes on GSH carriers. J Biol Chem 269 9746-9751... 

Simmons-Willis, T. A., et al. Transport of a neurotoxicant by molecular mimicry the methylmercury-l-cysteine complex is a substrate for human L-type large neutral amino acid transporter (LAT) 1 and LAT2. Biochem. J. 2002, 367, 239-246. 

Compeau and Bartha [80] have discussed the abiotic methylation of mercuric ion and mercuric ion sea salt anion complexes to methylmercury by methylcyanocobalamin in seawater and saline sediments under aerobic and anaerobic conditions. 

The addition of anticoagulents and/or preservatives, a practice that may be tolerated for total element determination, should be avoided for two reasons. First, the compounds used are usually complexing agents. They therefore could bind various trace elements. Second, they could destroy some species. For example, the addition of potassium dichromate to urine in the presence of nitric acid could destroy methylmercury If the use of such compounds is unavoidable, then there should be experimental evidence to show that the speciation of the element imder study has not been adversely affected. 

S. Han, M. Zhu, Z. Yuan and X. Li, A methylene blue-mediated enzyme electrode for the determination of trace mercury (II), mercury (I), methylmercury, and mercury-glutathione complex, Biosens. Bioelectr., 16 (2001) 9-16. 

As well as the above 2,3-dimercaptoalkanes a few other vicinal dithiols have also been sythesized. The interaction of methylmercury(II) with chelating agents such as BAL involves linear two-coordinate complexes and in only a few cases has chelation involved a bidentate ligand. In a search for evidence of thiol-containing bidentate chelation, Alcock et al.311 synthesized three sterically constrained dithiols - cyclohexane-1,2-dithiol, toluene-3,4-dithiol and bicyclo[2.2. l]heptane-2,3-dithiol - and demonstrated by spectroscopy and crystallography their formation of chelates with methylmercury(II) of the form (40). 

Microwave-assisted extractions (MAE) can be performed in open (focused MAE) or closed (pressurized MAE) flasks. This technique is commonly used for extractions from complex and difficult sample matrices, replacing time- and solvent-intensive Soxhlet extractions or hydrodistillations.46 MAE is also widely applied to environmental samples, for example, for extracting polycyclic aromatic hydrocarbons (PAH) from soil, methylmercury from sediments, and trace metals and pesticide residues from plant material47 48 The use of microwave treatment instead of hydrodistillation offers a solvent-free separation technique essential oils are heated and dry-distilled 46... 

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