PALLADIUM(II) AND PLATINUM(II) ETA-3-METHYLALLYL TRICHLOROTIN COMPLEXES .3. CRYSTAL-STRUCTURE ANALYSIS OF [PT(ETA-3-C4H7)(COD)]2[PT(ETA-3-C4H7)(SNCL3)3] (COD = CYCLO-OCTA-1,5-DIENE)

The dimer [{Pt(η3-C4H7)Cl}2] reacts with cyclo-octa-1,5-diene (cod) and SnCl2 to give [Pt(η3-C4H7)(cod)]2[Pt(η3-C4H7)(SnCl3)3](1). The compound crystallizes as discrete anionic and cationic platinum(II) complexes in space group P with a= 13.256(4), b= 19.960(4), c= 8.615(3)Å, α= 101.75(2), β= 104.69(2), and γ= 86.62(2)°. The anionic complex displays a distorted square-pyramidal co-ordination while the two isostructural cations have irregular square-planar co-ordination. Analysis of bond distances using SnCl3 as a probe suggests that the trans influence of the methylallyl ligand is comparable to that of olefin ligands. While no n.m.r. data are available for (1) due to its very poor solubility, n.m.r. results for the palladium(II) analogue (2) obtained by the same synthetic route are compatible with the structure determined for (1).