Diarsines arsines

Other Arsenic Hydrides. Diarsine [15942-63-9] AS2H4, occurs as a by-product in the preparation of arsine by treatment of a magnesium aluminum arsenide alloy with dilute sulfuric acid and also may be prepared by passing arsine at low pressure through an ozonizer-type discharge tube (19). Diarsine is fairly stable as a gas but quite unstable (above — 100°C) in condensed phases. The for diarsine is +117 4 kJ/mol (28 1 kcal/mol) and... 

Finally, secondary arsines can be obtained by the reductive cleavage of diarsines with mercury and hydrogen iodide (49) or with hthium aluminum hydride... 

Diarsines and Diarsenes. Under certain conditions, the reduction of compounds with two organic groups attached to arsenic may give rise to tetraalkyl-or tetraaryldiarsines. Thus a number of diarsines have been obtained by the reduction of arsinic acids with phosphorous or hypophosphorous acid (100). Diarsines can also be prepared by the treatment of a metal dialkyl- or diarylarsenide with iodine (101) or a 1,2-dihaloethane (102). 

Detailed procedures for the synthesis of various often used [Ni°L4] complexes (L = phosphines, arsines, stibines, alkyl isocyanides) and [Ni°L 2] complexes (L = bipyridine, phenantroline, diphosphines, diarsines) have been compiled.2413... 

The diarsine and arsine/phosphine analogues of dppm have been used to prepare bridged diplatinum(I) complexes, in both cases with terminal chloro ligands.116,117 Both complexes react with carbon monoxide to produce carbonyl-bridged species. The mixed thio/phosphine ligand Ph2PCH2SMe (PS) also forms a diplatinum(I) complex by conproportionation of its dichloroplat-inum(II) complex with [Pt(dba)2].118 This dimer reacts with carbon monoxide to produce an unsupported dimer [PtCl(PS)(CO)]2 with the thioether arm of the Ph2PCH2SMe unbound. 

Considerable structural information is available on osmium complexes of tertiary phosphines, arsines and stibines (Table 1.13) [152, 157], Comparison with data (mainly obtained from EXAFS measurements) on osmium diarsine complexes (Table 1.14) shows that as the oxidation state increases, osmium-halogen bonds shorten whereas Os-P and Os-As bonds lengthen. Bond shortening is predicted for bonds with ionic character,... 

The work on complexes of metals of other groups with olefinic tertiary phosphines and arsines has until recently been neglected, but it has now become dear that the chelating properties of these ligands are almost as widespread as those of the more well known bis(phosphine) and bis(arsine) ligands, such as diphos and diarsine. 

A fairly large number of mixed carbonyl phosphine and arsine complexes have been reported so far. They are generally prepared by displacement of CO from Ni(CO)4. Owing to the high stability of Ni(CO)4, when it is reacted with phosphines and arsines at room temperature and atmospheric pressure, only a partial displacement of CO usually occurs. Most of the mixed phosphine (or arsine) carbonyl compounds have the general formula [Ni(CO) (PR3)4 ] (n = 3, 2) and [Ni(CO)2(L—L)] (L—L is a diphosphine or diarsine). These complexes are colourless or yellow-orange solids or liquids. Many of them are thermally stable but decompose in air. The most relevant mixed carbonyl complexes with common phosphines are reported in Table 4. 

A large number of nickel(II) complexes with bidentate tertiary phosphines and arsines have been prepared and characterized since the initial reports on o-phenylenebisdimethylarsine and 1,2-bisdiphenylphosphinoethane (Table 64 XVIII, III) by Chatt and Mann,1267 and Wymore and Bailar126 respectively. The most common diphosphines, diarsines, distibines and mixed donor ligands are collected in Table 64 and selected nickel(II) complexes are reported in Table 65. 

When primary arsines are reacted with (MeAs)5, the respective cyclopolyarsine (RAs) is prepared in high yield (eqnation 118). Also the reaction of primary arsines with aminoarsines and diarsines generates cyclopolyarsines. 

Excess phosphine does not induce further substitution of CO in IV, except when the allyl moiety consists of a cyclohexenyl group. However, bidentate ligands, e.g., diphosphines - , diarsines and mixed phosphine-arsines displace two CO molecules ... 

The coordination chemistry of diphosphine and diarsine ligands has been intensively investigated in recent years.i Very much less work has been carried out on the corresponding mixed ligands, the intermediate arsine-phosphine bidentates, owing to a considerable extent to the lack, until recently, of suitable synthetic routes to such ligands. Two routes are now available the nucleophilic substitution of organohalogen compounds, two examples of which... 

Hydrogen iodide reacts with CFjAsI or (CF3)2AsI in the presence of Hg to form arsines. A deficiency of HI with CFjAsIj yields the diarsine which is present both in meso- and d,1-forms ... 

Phenyl Arsines. When diphenyl chloroarsine is treated with (mono)phenyl arsine in an atmosphere of nitrogen or carbon dioxide, arsenobenzene and tetraphenyl diarsine are formed ... 

Tetraphenyl diarsine, or phenyl cacodyl, is also formed by the action of diphenyl arsine in ethereal solution on diphenyl chloroarsine. It forms crystals melting at 124° to 127° C. (Blicke). 

Oxidised by nitric acid the diarsine yields phenyl- and diphenyl-arsinic adds. The preparation may be represented as follows ... 

If S-nitro-2-methylphenylarsinic acid is heated with alkali at 90° C., subsequent treatment with acid yields a mixture of stilbenediarsinic acids, as detailed on p. 194. Reduction with sodium hydrosulphite transforms these into 5 5 -diamino-2 2 -stilbene-l I -diarsinic acid. Further reduction yields the corresponding arseno-compound. 4-Nitro-5-ehlorotolyl-2-arsinic add undergoes a similar series of reactions. o-Phenylenediarsinic acid, ... 

Diphenylamine-p-arsinic acid inay be produced by the hydrolysis of p-phenylacetylaminophenylarsinic acid or by the direct arsenation of diphenylamine. The nitrodiphenylamine-p-arsinic acids may also be formed by the direct arsenation of nitrodiphenylamines. Direct arsenation of diphenylamine leads to the formation of two by-products, diphenylamine-p-p -diarsinic acid and iisdiphenylaminearsinic acid, the fonner yielding an arseno-compound on reduction. 

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