Complexation with mercury

Penicillamine is known to form complexes of varying stability with several metal ions. In neutral solution, penicillamine complexes with mercury, lead, nickel, and copper are relatively more stable than those of zinc, iron, and manganese. The three functional groups of penicillamine may be engaged in the formation of metal complex, and the resultant compounds may be polymeric in structure. 

Transition metal complexes with mercury directly bound to one or two transition metal centers are well known.1 They have found use as relatively air-stable sources of carbonyl metallate anions in polar solvents and as intermediates in the syntheses of bimetallic transition metal complexes. They are probably the key intermediates in the many transition metal promoted... 

Tri(f-butyl)phosphine and tri(o-tolyl)phosphine form 1 1 complexes with mercury(II) halides and with Hg(SCN)2. Physicochemical measurements, Le. conductance, molecular weight determinations, IR and Raman spectra, indicate a dimeric structure (26) of Cy, skeletal symmetry.493... 

Using supporting electrolytes such as tetraalkylammonium salts, one may apply potentials as negative as -2.6 V vs. SCE in aqueous solutions, while in some nonaqueous systems even -3.0 V vs. SCE (aqueous) is accessible. Unfortunately, mercury electrodes have serious limitations in applications at positive potentials (with the exception of passivated mercury electrodes, which are described in Section VI), and this has led to extensive research in the development of solid metal and carbon electrodes. Oxidation of mercury occurs at approximately +0.4 V vs. SCE in solutions of perchlorates or nitrates, since these anions do not form insoluble salts or stable complexes with mercury cations. In all solutions containing anions that form such compounds, oxidation of the mercury proceeds at potentials less than +0.4 V vs. SCE. For example, in 0.1 M KC1 this occurs at +0.1 V, in 1.0 M KI at -0.3 V, and so on. 

Bis(alkyl) complexes, with mercury, preparation, 2, 428 Bis(alkylidene)s, in Ru and Os half-sandwiches, 6, 583 Bis(alkylimido) complexes, with chromium(VI), 5, 346 Bis(rj2-alkyne)platinum(0) complexes, preparation, 8, 640 Bis(alkynyl) complexes in [5+2+l + l]-cycloadditions, 10, 643 with manganese, 5, 819 with mercury, preparation, 2, 426 mononuclear Ru and Os compounds, 6, 409 with platinum, 12, 125 with platinum(II), 8, 539 with titanium(IV), 4, 643 with zirconium, 4, 722... 

Purine nucleosides are known to form complexes with mercury (II) in aqueous solutions112, U3). It is of some interest to the foregoing that mercuric chloride was shown to accelerate decomposition of mbnoprotonated adenine and purine derivatives u2, U3). 

Tertiary amines form complexes with mercury(II) ion, which then give iminium ions by loss of a piotoa Addition of perchloric acid permits isolation of the iminium ion as the perchlorate salt and generally the more-substituted ion is favored (equation 14). Intramolecular trapping by a hydroxyalkyl group is also possible to form aminals (equation 15). The lactam products result from over-oxidation, which is promoted by heat. Basification on the other hand usually allows the isolation of enamines although hydroxyenamines have been obtained by reaction of enamines with mercury(II) acetate (equation 16), while dihydroaromatic systems undergo aromatization (equation 17). ... 

Reilley and Schmid made the important observation that the mercury-mercury (II)-EDTA electrode can be used indirectly as an indicator electrode for various metal ions, and this method was applied to the determination of 29 different metal ions by either direct- or back-titration procedures. Under some conditions,such as when a high concentration of buffer is present, formation of a mercury(I) precipitate or a complex with mercury(II) may result in incorrect end points. 

During the anodic polarization of a dropping mercury electrode the chloride, bromide, iodide, cyanide, thiocyanide and sulphide ions form slightly soluble salts or stable complexes with mercury. In the presence of these substances so-called anodic oxidation waves appear on polaro-graphic curves. The polarographic determination of chloride has received most attention. In many cases the dilution of the sample with 0.1 N H2SO4 is satisfactory and the solution can be polarographed directly [3]. 

The trimesitylarsine complex with mercury(II) nitrate is a centrosymmetric dimer with bridging nitrate groups 12 the asymmetric unit consists of two independent half molecules, differing in nitrate orientation and the configuration of the trimesitylarsine... 

Aminopyrine (4-dimethylamino-2,3-dimethyl-l-phenyl-3-pyrazo-lin-5-one) forms complexes similar to those of antipyrine, but usually containing fewer molecules of the 3-pyrazolin-5-one. Complexes with mercury, cadmium, antimony, zinc and cobalt salts include only one molecule of aminopyrine. A number of complexes with cobalt, zinc and calcium salts have two molecules of aminopyrine, some also containing acid and water of hydration.736,1322 The complex with cerous nitrate contains three molecules of aminopyrine.1238 A few other substituted... 

In another indirect method for determining chloride use is made of the fact that HgCl2 is more stable than the violet Hg(II) diphenylcarbazone complex [30,31]. The violet colour of the solution is a function of the chloride concentration. In other indirect methods chloride displaces Methylthymol Blue [32] or Xylenol Orange [33] from their complexes with mercury(II). 

Mercaptoethanol (ME), when added to an eluent, complexes with mercury compounds to produce charge-neutral compounds that can be separated on reverse-phase columns. MacCrehan et al. described this procedure in a separation of Hg, MeHg, EtHg+, and PhHg- [32,33]. 

The dichalcogenanthrenes and their allies exhibit marked electron-donor properties and form complexes with certain salts and metal carbonyls <62CB2027, 82DOK(266)ll64, 86JCR(S)326>. Tetramethoxyselenanthrene (78), for instance, forms a complex with mercury(II) chloride in which the selenium atoms are both bonded to the mercury atom, which is approximately tetrahedral in its coordination. The heterocyclic system as a result takes up a more sharply bent conformation than it normally adopts in the free state <86JCR(S)326>. 

A-Alkylphenotellurazines form 1 1 molecular complexes with mercury(II) halides and with silver nitrate or silver perchlorate <85KGS757>. Bis(benzonitrile)palladium(II) chloride reacts to form a 2 1 adduct and rhodium carbonyls also complex with phenotellurazines <82D0K(266)1164>. 

British Anti-Lewisite (BAL) is a dithiol used as an antidote in mercury poisoning. It was originally developed as an antidote to a mustard-gas-hke chemical warfare agent called Lewisite. Lewisite was developed near the end of World War I and never used. By the onset of World War II, Lewisite was considered to be obsolete because of the discovery of BAL, an effective, inexpensive antidote. The two thiol groups of BAL form a water-soluble complex with mercury (or with the arsenic in Lewisite) that is excreted from the body in the urine. 

Sulfur-containing amino acids and proteins form very strong soluble complexes with mercury 12, 50, 51). Humic acids are formed by partial decay of organic matter and may have sulfur-bearing residual proteins bound to quinoid polymers, thus acting as strong complexers of relatively... 

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