Synthesis and structure of [Fc(RO)PS₂]- complexes

Reaction of Fc(S)PS2P(S)Fc with NaOR [R = Me, Pr-i] gives the non symmetric phosphonodithioato anions [Fc(RO)PS2](-) which can be complexed to a range of metals. The square planar NiL2 complexes adopt two distinct configurations, 'trans' with the ferrocenyl groups above and below the square plane and 'cis' with the ferrocenyl groups on the same side of the square plane. There is good evidence that the isomerisation occurs via a cis-ML2(solv)(2) intermediate. The zinc and cadmium complexes adopt dimeric M2L4 structures whilst the PbL2 complex has a distorted pyramidal structure and forms infinite chains via Pb...S interactions. All new compounds have been characterised spectroscopically and seven demonstrative X-ray structures are reported.