Zur Strukturchemie der Alkyl- und Arylhalogenoarsenate(III), [Me2As2Cl5]–, [RAsCl3]–, [R2As2Br6]2– (R = Me,Et, Ph) und [Ph2AsX2]– (X = Cl,Br) |
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Authors: | S Grewe T Husler M Mannel B Roßenbeck W S Sheldrick |
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Abstract: | Structural Chemistry of the Alkyl- and Arylhaloarsenates(III) Me2As2Cl5]–, RAsCl3]–, R2As2Br6]2– (R = Me, Et, Ph) and Ph2AsX2]– (X = Cl, Br) The alkyl- and arylhaloarsenates(III) Ph4P]Me2As2Cl5] ( 1 ), Ph4P]RAsCl3] (R = Me, Et, Ph, 2 – 4 ), Me3PhN]PhAsCl3] ( 5 ), Ph4P]2R2As2Br6] (R = Me, Et, Ph, 6 – 8 ), n-Pr4N]Ph2AsCl2] ( 9 ) and n-Bu4N]Ph2AsBr2] ( 10 ) have been prepared and their structures established by X-ray diffraction. In contrast to the chloroarsenates(III) 2 – 5 , which all contain isolated ψ-trigonal bipyramidal anions RAsCl3]–, the analogous bromoarsenates(III) 6 – 8 exhibit dimeric structures. Whereas the trans sited As–Cl distances in 2 and 3 are very similar a pronounced degree of asymmetry is apparent for the Cl–As–Cl three-centre bonds in 4 and 5 2.396(1) and 2.602(1) Å in 5]. In 6 and 7 Ci symmetry related RAsBr2 units are connected through long As…Br bonds 2.926(1) and 3.116(2) Å in 6 ]. The bromophenylarsenate(III) anion of 8 which contains two effectively undistorted ψ-trigonal bipyramids PhAsBr3]– associated by weak As…Br interactions 3.117(2) Å]. In view of its very long bridging As…Cl distances the Me2As2Cl5]– anion in 1 can, as 6 an 7 , be regarded as two MeAsCl2 molecules weakly linked through a chloride ion. |
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Keywords: | Chloroarsenates(III) bromoarsenates(III) anionic structures structural correlation |
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