Preparation, properties and structures of the first series of organometanic Pt(II) and Pt(IV) complexes with stibine co-ligands

Brown, Michael D., Levason, William, Reid, Gillian and Webster, Michael (2006) Preparation, properties and structures of the first series of organometanic Pt(II) and Pt(IV) complexes with stibine co-ligands. Dalton Transactions, 1667-1674. (doi:10.1039/b514019f).

Abstract

The planar Pt(II) monomers [PtMe2(L-L)] and [(PtMe2)(2)(L'-L')(2)] dimers (L-L = R2Sb(CH2)(3)SbR2, o-C6H4(CH2SbMe2)(2); L'-L'= R2SbCH2SbR2; R = Me or Ph) are obtained in good yield via reaction of [PtMe2(SMe2)(2)] with L-L or L'-L' in benzene. The Pt(IV) stibines, [PtMe3(L-L)I] (L-L = R2Sb(CH2)(3)SbR2, o-C6H4(CH2SbMe2)(2) or 2 x SbPh3, SbMePh2 or SbMe2Ph) are obtained by treatment of [PtMe3I] with L-L in chloroform. These represent the first series of stable Pt(IV) stibine complexes. All of the products have been characterised by H-1, C-13{H-1}, Pt-195 NMR spectroscopy, electrospray mass spectrometry and analysis. Crystal structure determinations on [PtMe3{R2Sb(CH2)(3)SbR2}I], [PtMe3 {o-C6H4(CH2SbMe2)(2)}I] and [PtMe3(SbPh3)(2)I] confirm the distorted octahedral environment at Pt, with fac Me groups and mutually cis Sb donor atoms. The Sb-Pt-Sb angle in the seven-membered chelate ring of the o-C6H4(CH2SbMe2)(2) complex is ca. 96 degrees, compared to <90 degrees in the complexes with six-membered chelates. The C-1-distibines R2SbCH2SbR2 afford only the dinuclear [(PtMe3)(2)(mu-R2SbCH2SbR2)(mu-I)(2)] in which the stibine ligand and two I atoms bridge two Pt atoms giving an edge sharing bioctahedral geometry which has been confirmed by a crystal structure analysis. The Pt(II) species undergo oxidative addition with MeI to give the corresponding Pt(IV) species, while the Pt(IV) species reductively eliminate ethane upon thermolysis.

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Contributors

Author: William Levason

Author: Gillian Reid

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