Platinum Complexes Having Redox-Active PPh2CºCFc and/or CºCFc as Terminal or Bridging Ligands

Résumé

A series of heteronuclear-Pt(ii) complexes containing ferrocenylethynyl units linked directly (Pt-CCFc) or through a phosphorous atom (Pt-PPh 2CCFc) to the platinum center is reported. The reaction of derivative [cis-Pt(RF)2(PPh2CCFc)2] (R F = C6F5) 1 with the solvate complex [cis-Pt(RF)2(thf)2] leads to the formation of an asymmetrical heteronuclear diplatinum complex [{Pt(RF) 2(μ-1κP:2η2-PPh2CCFc) 2}Pt(RF)2] 9 having the "cis-Pt(R F)2" fragment coordinated to the triple bonds of both ferrocenylethynylphosphine units, while treatment of [cis-Pt(CCFc) 2(PPh2CCR)2] (R = Fc 5a, Ph 5b, tBu 5c) with the same solvate [cis-Pt(RF)2(thf)2], affords double ferrocenylacetylide-bridged diplatinum systems [{Pt(PPh 2CCR)2(μ-η1:η2-CCFc) 2}Pt(RF)2] 10. The solid-state structures of [cis/trans-Pt(RF)2(PPh2CCFc)2] 1/2, [cis-Pt(RF)2(PPh2CCFc)(tht)] 3 (tht = tetrahydrothiophene), [{Pt(RF)2(μ-1κP: 2η2-PPh2CCFc)2}Pt(RF) 2] 9 and [{Pt(PPh2CCtBu)2(μ- η1:η2-CCFc)2}Pt(RF) 2] 10c have been determined by X-ray diffraction methods. The electronic spectra and the electrochemical behaviour of all monoplatinum derivatives are discussed, showing a different extent of interaction between the remote ferrocenyl groups when they belong to PPh2CCFc or CCFc ligands. For the diplatinum systems 9 and 10, containing bridging (κP:η2-PPh2CCFc 9) or (η1: η2-CCFc 10) ligands, their electrochemical properties were also compared with the parent precursors. © 2009 The Royal Society of Chemistry.