The synthesis and structural characterisation of 2-arsa- and 2-stiba-1,3-dionato complexes of s- and p-block elements

Abstract

The syntheses and structural characterisations of a number of 2-arsa- and 2-stiba-1,3-dionato complexes of main group elements are reported. The synthetic methods that were employed in this study include the reaction of lithium heterodionate complexes, [Li{η²-O,O–OC(R)EC(R)O}], E = As or Sb, R = alkyl or aryl, with main group metal halides or the reactions of arsa- and stiba-enols, OC(R)EC(R)OH, with either main group alkyl or amide complexes. The hetero-ligands in the prepared complexes have been shown by X-ray crystallographic studies to coordinate the main group metal centre in several modes, that is, in a delocalised form (η²-O,O coordination) as in [{M[η²-O,O–OC(R)EC(R)O](L)}₂], M = Li or Na, E = As or Sb, R = Ad (adamantyl) or Ph, L = Et₂O or DME; [Na{η²-O,O–OC(Mes*)EC(Mes*)O}(DME)₂], E = As or Sb, Mes* = C₆H₂Bu^t₃-2,4,6, and [Mg{η²-O,O–OC(Ph)AsC(Ph)O}₂(DME)]; in a localised diacylpnictido form (η¹-E coordination) as in P[As{C(O)R}₂]₃, R = But or Ph; or as a combination of the two modes (η¹-E–: η²-O,O–) as in [LiCl(Et₂O)(DME){η²-O,O–Cl₃InAs[C(O)R]₂}].