Synthesis and characterisation of new platinum ethynyl dimers and polymers with pendant ferrocenyl groups

The square-planar platinum(II) complex trans-[(Ph2FcP)2PtCl2] (1) (Fc=ferrocenyl), that is a metal-containing polymer precursor, has been synthesised and its single crystal structure determined. Using 1, new ferrocene-containing platinum ethynyl dimers trans-[(Ph2FcP)2Pt(CCR)2] {R=SiMe3 (2), C6H5 (3) and C6H4-p-NO2 (4)} and a polymer [(Ph2FcP)2Pt(CCC6H2-p-(OC8H17)2CC)]n (5) have been formed by the reaction of the metal precursor with the appropriate mono- and bis-ethynyl ligands. Single crystal X-ray studies of 4 have shown it to exist as two different polymorphic forms, both having trans-geometry with respect to the ferrocenyl phosphines and ethynyl ligands. GPC measurements on the polymer show a high degree of polymerisation with an average molecular weight of ca. 88 000.