Arsonic acids structure

Figure 21.3 Structural formula of p-tolyl arsonic acid.

The reason for such a behaviour of arsenic acid is that arsenic is a member of the group 5A elements in the periodic table. Phosphorus and antimony are also group 5 elements and are known to be chemically similar to arsenic. On this basis [8,9], the antimonic acids were found to be poor cassiterite collectors. The alkyl phosphonic acids were not selective collectors. The ethylphenylene phosphonic acid was found to produce similar or better results compared to /7-tolyl arsonic acid. The structural formula for phosphonic acid (Figure 21.5) is similar to that of /7-tolyl arsonic acid but arsenic was replaced with phosphoms. The styrene phosphonic acid radicals are C6H5-CH-CH and p-ethylphenylene CH3-CH2-C6H4. 

Biochemical effects of arsenate and arsenite are considered in this review. Enzymes that normally act on substrates of structure R— — P03H2 (i.e., of oxidation state V) often act on the analogues R—CH2— P03H2 and R— —As03H2. The further arsonic acid analogue R—CH2 —As03H2, which may have unusual effects, is considered. 

Therapeutic Function Antibacterial Chemical Name Arsonic acid, (4-aminophenyl)-Common Name Acidum arsanilicum Arsanilic acid Structural Formula ... 

All known examples of the Bart and Bechamp reactions in which the product contains an arsonic or arsinic acid group attached directly to an aromatic carbocyclic ring structure have been included. For example, quinoline arsonic acids are included if the arsono group is linked to the 5-, 6-, 7-, or 8-position but are not included if the attachment occurs in the 2-, 3-, or 4-position. 

Phenylarsine oxide (PhAsO) is one of the few trivalent compounds the reduction of which has been studied in aqueous solution, and it is reduced at a potential which is almost 1V less cathodic than the reduction potential of the pentavalent PhAsO(OH)2. In the solid state PhAsO (arsenosobenzene) exists as a tetrameric oxide (structure 7), whereas in aqueous solution it exists as a monomeric dihydroxy compound [PhAs(OH)2, phenyl-arsonous acid] with a pX of about 11. ... 

Hydrolysis of C(CH2Asl2)4 (95) with aqueous NaOH earried out in THF in sealed glass ampoules under vacuum gave the arsonous acid-organoarsenic oxide compound 94-H (equation 67) in 55.5% yield (m.p. > 300 °C, decomp.). 94 heated with a large excess of DjO at 150 °C in a sealed ampoule produced (DO)2AsCH2C(CH2AsO)3 (94-D) in 75.4% yield (equation 68) The crystal structure 94-D has been determined by X-ray diffraction... 

The pyrolysis of organoarsenic compounds containing the arsenyl moiety has some limited preparative applications [arsenyl (As=0) by analogy with phosphoryl (P=0)]. The compounds are based on the arsonic acid RAs(0)(0H)2, the arsinic acid R2As(0)0H and the arsine oxide R3As=0 structures. The acids are in interesting contrast with the phosphorus series. The phosphonic and phosphinic esters are prepared from the phosphorus(III) precursors via the Arbuzov synthesis. This synthetic route fails with the arsenic analogues, and further, if an alkyl halide or a salt is added in the pyrolysis of arsonic or arsinic acid esters a retro-Arbuzov reaction takes place . ... 

Spirocyclic structures (98) have been assigned to the esters produced from glycols and aryl- or alkyl-arsonic acids.672... 

A large number of polymeric substances, (RAs) or (ArAs), are also known (113). They are usually prepared by the reduction of arsonic acids with hypophosphorous acid (100,114) or sodium dithionite (115). Most of these polymers have not been well characterized. An insoluble, purple material, poly(methylarsinidene) [26403-94-1], (CH,As), prepared by the interaction of methylarsine and a dihalomethylarsine, however, has been shown by an x-ray investigation to have a ladderlike polymeric structure in which the inter-rung distances correspond to one-electron bonds (116) ... 

Tetrakis(diiodoarsinomethyl)methane (292) <86ZN(B)863> on hydrolysis gives the arsonous acid (293) of the trioxatriarsaadamantane <87J0M(336)323>. The crystal structure of the deuterated derivative (-As(OD)2) was solved by x-ray diffraction analysis. There is evidence for the existence of two... 

Figure 1 Oxidation states of volatile and soluble arsenic transformed by biological systems. pKi represents the equilibrium between the protonated cation and neutral forms of the hydroxyl group of dimethylarsinic acid. pKj represents the equilibrium between the neutral form and anionic form (2). Occasionally referred to as arsenous acid (2). HO—As=0 has also been referred to as arsenious acid (52). The term arsenite often refers to any of the As(lll) oxides. The species will be a function of the solute and the pH. Given that the pKa of arsenious acid is 9.2 (52), the protonated form is most likely the predominant form in aqueous environmental and physiological samples below pH 9. Structure commonly used when discussing arsenite in biological transformations, but is most likely not the predominant form in aqueous solutions. Monosodium methane arsonic acid (MSMA) is the commercially available sodium salt.

According to organic chemistry, the structures of various phosphonic acids and arsonic acids can be given as follows ... 

Wypych, F., Schreiner, W.H. Richard, E. (2004) Grafting of phenylarsonic and 2-nitrophenol-4-arsonic acid onto disordered silica obtained by selective leaching of brucite-like sheet from chrysotile structure. Journal of Colloid and Interface Science, 276,167-173. 

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