Arsenic trihalides reactions

When the phosphorus halide is PI3, this reaction is a convenient way to produce HI. Arsenic trihalides hydrolyze in an analogous way but the trihalides of antimony and bismuth react to produce oxyhalides. 

The synthesis of the first arsabenzene, 9-arsaanthracene, 6, was simultaneously communicated by Bickelhaupt16) and Jutzi17> in 1969. The elimination of hydrogen chloride from 9,10-dihydroaarsanthracene 7 afforded 6. These precursors are available from either reduction of the corresponding arsinic acids 816,18) or by the exchange reaction of dihydrostannaanthracenes 9 with arsenic trihalides 17). 

The association of the amine hydrochloride with the aminoarsine complicates the purification of the aminoarsine. When aminolysis of the arsenic trihalide is followed by alkylation of the mono- or bisaminohaloarsine with a Grignard reagent to synthesize the aminoalkyl(or aryl)arsine, the stoichiometry of the reaction must be carefully controlled to avoid cleavage of the As N bond and formation of the tertiary arsine (see Section 2.1). A recent study has shown that the highest yields are obtained from the transamination... 

There are six types of tertiary aromatic arsines known, if those containing aliphatic radicals are also included ArjAs, ArAr As, ArgAlkAs, ArAlk As, ArAr AlkAs, ArAlkAlk As. For the tyj>e ArjAs, theFittig reaction forms thebasisof a method of preparation, aryl halides and arsenic trihalides reacting in ether or benzene solution in th< ))re-senee of sodium as follows ... 

Condensation of arsenic trihalides with alkyl or aryl halides in the presence of metallic sodium, analogous to a Wurtz-Fittig reaction, leads to trialkyl- and triaryl-arsines. E.g., tribenzylarsine is obtained by prolonged boiling of benzyl chloride and arsenic trichloride in ether containing sodium and a little ethyl acetate 501 tripropylarsine is obtained similarly from propyl chloride, arsenic... 

A normal amide of trivalent arsenic, As(NH2)3, can be synthesized by the reaction between gaseous ammonia and an arsenic trihalide (except the fluoride) at low temperatures... 

Miscellaneous Reactions. Tetramethylthiourea forms 1 1 adducts with arsenic trihalides and arylarsenic dihalides. The nitrosation of dimethylamine by sodium nitrite at pH 4 is catalysed by thiourea, less efficiently by AW -dimethylthiourea, and more efficiently by tetramethylthiourea. Base-catalysed condensation of thiourea with phthalaldehyde gives A -thiocarbamoyl-l,3-dihydroxyisoindoline (29)... 

A complete set of trihalides for arsenic, antimony and bismuth can be prepared by the direct combination of the elements although other methods of preparation can sometimes be used. The vigour of the direct combination reaction for a given metal decreases from fluorine to iodine (except in the case of bismuth which does not react readily with fluorine) and for a given halogen, from arsenic to bismuth. 

When heated with chlorine, bromine or iodine vapors arsenic forms the corresponding trihalides however, with fluorine, arsenic pentafluoride, AsFs is produced. With sulfur it forms mixtures of sulfides, AS2S3, AS2S2 and AS2S5 in vitreous forms and varying proportions depending on the conditions of reactions. 

Arsenic pentafluoride is made by the reaction between AsF3 or the oxide and elemental fluorine (166). The greater volatility of AsF5 compared with the trihalide is associated with the zero dipole moment of AsF5. Vibrational spectra of AsF5 have been interpreted in terms of Z)3h symmetry (12). 19F-NMR studies indicate that all five nuclei are equivalent even at the lowest temperature observable. This suggests... 

The trichloride and triiodide of arsenic are made by analogous methods. In the case of BiCl3, reaction between the elements may be used or, alternatively, that between SOCl2 and either Bi or Bi203 (HI)- All of these trihalides are hydrolyzed by water, although not so vigorously as the pentahalides. 

I.r. and Raman studies have shown the formation of complexes between tributyl phosphate and both arsenic and antimony tribromides. Cryoscopy in fused arsenic tribromide is reported for a num r of inorganic and organic solutes, showing dTj X values lower than the ideal value, and with dioxan the compound 2AsBr3,3dioxan, melting at 64 °C, is formed. Arsenic and antimony trihalides give a-bonded transition-metal derivatives, such as X2E[Fe(CO)2(Cp)]J, where E = As or Sb and X = Cl or Br, on reaction with metal carbonyl anions or metal carbonyls with metal-metal bonds. ... 

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