Complexes between fluoro(ditertiary arsines) and metal tetrahalides

Abstract

The influence of incorporating fluorine atoms into ditertiary arsines on the reactions of the latter with metal halides has been investigated. The fluoroalicyclic-bridged ligands, 1,2-bis(dimethylarsino)-3,3,4,4-tetrafluorocyclobutene and 1,2-bis(dimethylarsino)-3,3,4,4,5,5-hexafluorocyclopentene, and the fluoroaromatic-bridged ligands, 1,2-bis(dimethylarsino)-3-fluorobenzene and 1,2-bis(dimethylarsino)-4-fluorobenzene, form six-co-ordinate complexes [MX₄(diarsine)](M = Ti, V, Mo, Re, or Sn; X = Cl or Br). Eight-co-ordinate dodecahedral bis adducts are formed only with niobium tetrachloride and tetrabromide, and with the last three diarsine ligands. Complexes with nickel(II) and iron(II) confirm that these fluorodiarsines are weaker donors than are conventional diarsine ligands.