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

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*=C6H2But3-2,4,6, 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}].