Synthesis and properties of antimony(III) and bismuth(III) halide complexes of diphosphines and diarsines. Crystal structures of [Bi2I6{o-C6H4(AsMe2)(2)}(2)], [Sb2Br6{o-C6H4(PPh2)(2)}(2)], [Sb2Cl6{o-C6H4(AsMe2)(2)}], and [BiCl3{o-C6H4(P(O)Ph-2)(2)}(thf)]

The reaction of SbX3 or BiX3 (X=Cl, Br or I) with the diarsines o-C6H4(AsMe 2)(2) or Ph2AsCH2CH2AsPh2, the triarsine MeC(CH2AsMe2)(3), or the diphosphi nes o-C6H4(PMe2)(2) or o-C6H4(PPh2)(2) (L), yield complexes of 1:1 stoichio metry MX3L irrespective of the reactant ratios used. X-Ray structures of [B i2I6{o-C6H4(AsMe2)(2)}(2)] and [Sb2Br6{o-C6H4(PPh2)(2)}(2)] reveal distorte d octahedral Bi or Sb coordination spheres, linked via asymmetric halide-br idges. Bond lengths suggest a bonding model based upon primary bonding in p yramidal MX3 groups with weaker secondary interactions to the diphosphine o r diarsine and the longer distance bridging halide. [Sb2Cl6{o-C6H4(AsMe2)(2 )}] is obtained by partial decomposition of [Sb2Cl6{o-C6H4(AsMe2)(2)}(2)] i n hot ethanol and contains Sb{o-C6H4(AsMe2)(2)}Cl-2 and SbCl4 units linked via asymmetric chlorine bridges into puckered chains, which associate furth er through long Sb . . . Cl contacts to produce a polymeric sheet structure . The mononuclear species [BiCl3{o-C6H4(P(O)Ph-2)(2)}(thf)] obtained from B iCl3 and o-C6H4(P(O)Ph-2)(2) in thf is a distorted octahedron with a BiCl3O 3 donor set.