Methylmercuric Iodide Research Articles

Vibrational spectra of methyl mercuric chloride, bromide, iodide and cyanide

Infra-red and Raman spectra of the compounds CH3HgX (X = Cl, Br, I and CN) are reported, and assignments are proposed. Some force constants have been calculated on the basis of a simple valency force field. The values of the mercury-methyl group and mercury-anion stretching force constants are discussed.

Homolytic reactions of aromatic side-chains. Part IV. Relative rates of α-hydrogen abstraction by methyl radicals

The relative rates (krel, toluene = 1) of abstraction of α-hydrogen atoms from alkyl side-chains attached to aromatic nuclei are reported for methyl radicals formed by the photolysis of methylmercuric iodide. The measurements were made by the competitive technique. The results obtained with alkylbenzenes show that the reactivity of α-hydrogen atoms increases in the order: primary < secondary < tertiary. Polar influences exerted by nuclear substituents appear to have no influence on the rate of α-hydrogen abstraction by methyl radicals, since the values of krel for p-halogenotoluenes are close to unity.

The estimation of the activity of acetylcholinesterase and other esterases in the rat brain by an amperometric method

An amperometric method for the determination of acetylcholinesterase and other esterases in the rat brain has been described. Methyl mercuric iodide is used as a titrant against the — SH group available from the hydrolysis of the thioesters of choline. The end point is obtained when the current due to methyl mercuric iodide rises sharply. Kinetic constants determined by this method for crude rat brain extract and purified erythrocyte cholinesterase are presented.

651. Reactions of alkyl radicals. Part I. The methylation of benzene, fluorobenzene, chlorobenzene, and bromobenzene with methyl radicals formed by the photolysis of methylmercuric iodide

651. Reactions of alkyl radicals. Part I. The methylation of benzene, fluorobenzene, chlorobenzene, and bromobenzene with methyl radicals formed by the photolysis of methylmercuric iodide

The oxidation of cysteine, glutathione and thioglycollate by iodate, bromate, persulphate and air

AbstractThe oxidation of cysteine, glutathione and thioglycollate by bromate, iodate, persulphate and air has been studied at 28° and at near‐neutral pH values. The oxidations have been followed by a combination of methods—by reaction with p‐chloromercuribenzoate (spectrophotometric), methylmercuric iodide (polarographic) and, in the case of cysteine, chromatographically and manometrically.The oxidation is rapid by iodate, slow with bromate and persulphate and slower still with air. The major product in the case of cysteine is the disulphide cystine, but up to 10% of the higher oxidation products, cysteinesulphinic and cysteinesulphonic acids, are formed.The oxidation of thiol groups is discussed in relationship with the action of the improvers used in the bread industry.

The Reaction of Thiol and Disulphide Groups with Mercuric Chloride and Methylmercuric Iodide. II. Fibrous Keratins

The reaction of HgCl2 with wool has been studied polarographically over the pH range 1 to 9 under various conditions. At pH 1 to 6 the salt appears to be bound in the un-ionized form probably at amide and peptide group sites. The binding is greatly suppressed in the presence of complexing anions such as Cl- and S2O3=. SO3= also has this complexing effect but in addition produces new -SH binding sites by reversibly splitting -SS- bonds. This splitting proceeds to completion at pH 7 to 10 in the presence of an excess of mercurial, HgCl2 requiring several days and MeHgI several hours. The reaction of keratins with SO3= and mercurials may be followed polarographically and has provided a convenient method of preparing keratins with zero or decreased -SS- bond contents. The reaction rate increases in the presence of 8~ urea and then forms the basis for new analytical methods of measuring the -8s- content of intact keratins. The keratin (7.5 mg or more) is reacted with Na2SO3 in 8M urea (5 ml) for at least 24 hr (with excess HgCl2) or 2 hr (with excess MeHgI) at 20 �C. Single current readings at -1 0 and -0.8 V (v. S.C.E.) respectively at the dropping mercury electrode indicate the residual mercurial and hence by difference the (-SS- plus -SH) content. The -SH content of intact keratins is estimated by reacting say 25 mg with excess MeHgI at pH 7 for at least 4 hr at 20 �C in the absence of SO3=. This mercurial reacts much more rapidly with the -SH sites in keratin than do other mercurials.

The reaction of thiol and disulphide groups with mercuric chloride and methylmercuric iodide. I. Simple thiols and soluble proteins

The polarographic behaviour of MeHgCl, MeHgI, HgCl2, neohydrin (3-chloromercuri-2-methoxypropylurea) and its iodo-derivative are described. Their chemical reactivity and -SH specificity have been investigated and MeHgI shown to have advantages as an -SH reagent on account of its high reactivity, stability, and " ideal " polarographic behaviour. The reaction of protein -SS- groups with Na2SO3 proceeds slowly to completion in the presence of HgCl2 or MeHgI and it is shown that with bovine plasma albumin, ribonuclease, and insulin the polypeptide chains may be separated for preparative or structural studies under milder conditions than are customary. In the presence of urea at pH 9 the reaction is sufficiently rapid to form the basis of amperometric titration procedures for determining -SS- groups in eight intact proteins. The methods are especially valuable for proteins which have been previously converted to their -SR, -SO3-, or -SSO3-; derivatives since the destructive hydrolytic step may be avoided. The mechanism and stoichiometry of the reactions are discussed.

Acid Cleavage of Methylmercuric Iodide

Acid Cleavage of Methylmercuric Iodide