Mercury iodide complex

More useful for synthetic purposes, however, is the combination of the zinc-copper couple with methylene iodide to generate carbene-zinc iodide complex, which undergoes addition to double bonds exclusively to form cyclopropanes (7). The base-catalyzed generation of halocarbenes from haloforms (2) also provides a general route to 1,1-dihalocyclopropanes via carbene addition, as does the nonbasic generation of dihalocarbenes from phenyl(trihalomethyl)mercury compounds. Details of these reactions are given below. 

Dilithio 8 reacts with mercury iodide to give tetramer 11, as a 1 1 complex, in 80% yield. Longer reaction times and additional mercury iodide produces the 2 1 complex 12. Synthesis of neutral tetramer 6 is achieved by using silver acetate to decomplex diiodide 12. 

Addition of excess iodide to the insoluble Hgl2 results in the formation of soluble mercury iodo complex [Hgl3] , with a trigonal planar structure. The ion is solvated in water and converts to a tetrahedral structure. Further, addition of H leads to tetrahedral [Hg ] ". Reaction of iodide salts with Hg can be used to produce mercury iodo complexes. Other halide and pseudohalides also form [HgXj] and [HgX4] . The tetrahalo anions see Anion) are usually tetrahedral, while the trihalo ions readily add solvent molecules to form distorted tetrahedral or Trigonal Bipyramidal structures. 

Mercury can be separated by the extraction of the iodide complexes with cyclohexanone from an acid medium. Owing to the high stability of Hgl2 and Hgl3 , the stoichiometric ratio of iodide mercury is sufficient [2]. Extraction of the molecular species HgX2 (X = r, Br, Cl ) with non-polar solvents is a very selective method of separating mercury. 

Copper is removed by masking the mercury as strong bromide- or iodide complexes in acid media. Only copper dithizonate is extracted from 1 M HCl containing KI. Alternatively, the mercury and copper can be extracted from acid solution, and the mercury stripped with an acidic solution of KI or KBr. The mercury is re-extracted from the aqueous... 

The mercury-TMK complex is not formed in the presence of iodide. Many complexing agents (chloride, bromide, sulphate, acetate, citrate, tartrate, and EDTA) do not interfere. Some of these substances may be used to mask hydrolysable metals. Of the cations, only Pd(II), Pt(II), and Au(III) interfere. Reductants and oxidants should be absent. 

In a sensitive flotation-spectrophotometric method (e = 3.4-10 ), a compound [(MB )(Hgl3)]-3[(MB )(l3)] (MB = Methylene Blue) is separated by flotation with cyclohexane from a 0.4 M HCl medium, containing T and MB then it is washed with water and dissolved in methanol [55]. Mercury has also been determined spectrophotometrically after separation (by flotation with cyclohexane) from solutions containing the iodide complex and Brilliant Green (e = 5.96-10 ) [56]. 

The ion associate of the Rhodamine 6G complex with iodide has been used for determining Hg in natural waters [94], and that of the complex with thiocyanate for determining Hg in river sediments and in CdCh [95]. Mercury has been determined in industrial solutions with the use of the iodide complex and Brilliant Green [56]. 

Hadjikakou, S.K., Xanthopoulou, M.N., Hadjiliadis, N. and Kubicki, M. (2003) Synthesis, structural characterisation and study of mercury (II) iodide complexes with the heterocyclic thioamides pyridine-2-thione (pytH) and thiazolidine-2-thione (tzdtH). Crystal structures of [Hgl2(pytH)2] and [Hgl2(tzdtH)2]. Can J Anal Sci Spec, 48 (1), 38-45. 

Ten neutral monomeric, dimeric and polymeric mercury(ii) complexes of compositions HgX2L (where X = chloride, bromide, iodide, nitrate and azide, and L = (J7)-N-(pyridin-2-ylmethylidene)arylamine) display broad emission bands at ylmax = 410 nm in acetonitrile solution. ... 

This effect, in which the production of mercurous ions probably plays a role, occurs even with very small amounts of mercuric salts, so that the mercury can be detected by the formation of tin i salts, which are then identified by the color reaction with cacotheline (see page 483). The test succeeds even with a solution of mercury cyanide, or of complex alkali mercury iodide, which yield exceedingly low concentrations of mercuric ions. 

The indirect determination of certain organic substances can be made by complexometric titration methods. Such methods depend on the formation of an insoluble product between the organic material and a metal then, either the excess metal in solution is determined by a suitable titration with EDTA, or the metal-containing precipitate is decomposed and the liberated metal ions titrated. Thus, for example, narcotine, papaverine, codeine, strychnine and brucine have been determined by formation of iodobis-muthate complexes, chlorpromazine and quinine" as cadmium iodide complexes, purines and nicotinic acid derivatives by precipitation with mercury and barbiturates by precipitation with zinc. ... 

Two distinct classes of promoters have been identified for the reaction simple iodide complexes of zinc, cadmium, mercury, indium and gallium, and carbonyl complexes of tungsten, rhenium, ruthenium and osmium. The promoters exhibit a unique synergy with iodide salts, such as hthium iodide, under low water conditions. Both main group and transition metal salts can influence the equilibria of the iodide species involved. A rate maximum exists under low water conditions and optimization of the process parameters gives acetic acid with a selectivity in excess of 99% based upon methanol. IR spectroscopic studies have shown that the salts abstract iodide from the ionic methyl iridium species and that in the resulting neutral species the migration is 800 times faster [127]. 

Rubidium metal alloys with the other alkaU metals, the alkaline-earth metals, antimony, bismuth, gold, and mercury. Rubidium forms double haUde salts with antimony, bismuth, cadmium, cobalt, copper, iron, lead, manganese, mercury, nickel, thorium, and 2iac. These complexes are generally water iasoluble and not hygroscopic. The soluble mbidium compounds are acetate, bromide, carbonate, chloride, chromate, fluoride, formate, hydroxide, iodide. 

Complex [(CXI )Ir(/j,-pz)(/i,-SBu )(/j,-Ph2PCH2PPh2)Ir(CO)] reacts with iodine to form 202 (X = I) as the typical iridium(II)-iridium(II) symmetrical species [90ICA(178)179]. The terminal iodide ligands can be readily displaced in reactions with silversalts. Thus, 202 (X = I), upon reaction with silver nitrate, produces 202 (X = ONO2). Complex [(OC)Ir(/i,-pz )(/z-SBu )(/i-Ph2PCH2PPh2)Ir(CO)] reacts with mercury dichloride to form 203, traditionally interpreted as the product of oxidative addition to one iridium atom and simultaneous Lewis acid-base interaction with the other. The rhodium /i-pyrazolato derivative is prepared in a similar way. Unexpectedly, the iridium /z-pyrazolato analog in similar conditions produces mercury(I) chloride and forms the dinuclear complex 204. 

Determination. To an aliquot of the silver(I) solution containing between 10 and 50 pg of silver, add sufficient EDTA to complex all those cations present which form an EDTA complex. If gold is present (>250 xg) it is masked by adding sufficient bromide ion to form the AuBr4 complex. Cyanide, thiocyanate or iodide ions are masked by adding sufficient mercury(II) ions to complex these anions followed by sufficient EDTA to complex any excess mercury(II). Add 1 mL of 20 per cent ammonium acetate solution, etc., and proceed as described under Calibration. 

Iodides of soft metal ions such as mercury (II) are essentially un-ionized in dimethylsulfoxide 54). This feature is due both to the strength of the Hg-I bond and the weakness of the Hg-DMSO bond which appears to occur through the sulfur atom of the DMSO molecule, as is known for the palladium (II) complex 5S). 

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