Bismuth(III) chloride complexation with diphosphine and diarsine oxide ligands: formation and crystal structures of [BiCl3{Ph2P(O)CH2P(O)Ph2}]2 and [BiCl3{As(O)MePh2}{Ph2As(O)Ch2CH2As(O)Ph2}] n

Abstract

The reactions of bismuth(III) chloride and Ph2PCH2PPh2(dppm) and Ph2AsCH2CH2AsPh2-(dpae) have been studied. The yellow products isolated initially were characterised by spectroscopic (1H and 31P NMR, IR) and microanalytical data as the 1:1 addition compounds BiCl3·dppm and BiCl3·dpae respectively. Recrystallisation of these products from boiling acetonitrile/charcoal effected oxidation of the ligands and resulted in the formation of two new molecular adducts whose structures have been determined by X-ray crystallography. Crystals of [BiCl3{Ph2P(O)CH2P(O)Ph2}]21 are triclinic, space group P with Z= 2. There are two independent centrosymmetric molecules in the unit cell with similar edge–edge shared bioctahedral structures. Each bismuth centre is six-co-ordinate with approximal octahedral geometry being bonded to two terminal chlorine atoms, two bridging chlorine atoms and two oxygen (ligand) atoms. In situ ligand oxidation dppm → Ph2P(O)CH2P(O)Ph2 occurs and the resulting bidentate (OO′) chelation gives rise to puckered six-membered [graphic omitted] ring formation. Crystals of [BiCl3{As(O)MePh2}{Ph2As(O)CH2CH2As(O)Ph2}]n2 are monoclinic, space group P21/a with Z= 4. The structure consists of one-dimensional polymeric chains. Here the in situ ligand oxidation is more complex and results in the formation of two arsine oxide ligands, viz. dpae → Ph2As(O)CH2CH2As(O)Ph2+ As(O)MePh2 both of which are involved in co-ordination to BiIII. Each bismuth atom is bonded in an approximately mer-octahedral arrangement to three terminal chlorine atoms and three oxygen (ligand) atoms. Of the latter, one is provided by a monodentate As(O)MePh2 molecule and the other two by separate Ph2As(O)CH2CH2As(O)Ph2 molecules which, by virtue of their bidentate bridging mode, are linked to adjacent metal centres.