Synthesis of silver(I) complexes with 1,1′-bis(diphenyl-phosphino)ferrocene (dppf). Crystal structures of [Ag(dppf)(PPh3)]ClO4·2CH2Cl2, [Ag(dppf)2]ClO4·2CHCl3 and [Ag(dppf)(phen)]ClO4(phen = 1,10-phenanthroline)

Abstract

Addition of 1,1′-bis(diphenylphosphino)ferrocene (dppf) to a solution of AgClO₄ in 1 : 1 molar ratio led to the complex [Ag(OClO₃)(dppf)]1. Substitution of the perchlorate anion in 1 by monodentate ligands gave [Ag(dppf)(L)]ClO₄(L = PPh₃2 or SPPh₃3), or with the less sterically demanding phosphine PPh₂Me the four-co-ordinate silver(I) complex [Ag(dppf)(PPh₂Me)₂]ClO₄4. Direct reaction of dppf with [Ag(OClO₃)(PPh₃)] also affords complex 2. The homoleptic derivative [Ag(dppf)₂]ClO₄5 can be synthesized by reaction of dppf and AgClO₄ using a molar ratio of 2 : 1, or by substitution of the ClO₄^– by dppf in complex 1. Treatment of 1 with other bidentate ligands such as 1,10-phenanthroline (phen), 2,2′-bipyridine (bipy) or bis(diphenylphosphino)methane disulfide (SdppmS) gave mixed cationic four-co-ordinate complexes [Ag(dppf)(L–L)]ClO₄(L–L = phen 6, bipy 7 or SdppmS 8); with sodium dithiocarbamates Na(S₂CNR₂) the neutral species [Ag(S₂CNR₂)(dppf)](R = Et 9 or Me 10) were obtained. The crystal structures of complexes 2, 5 and 6 have been established by X-ray diffraction. Compound 2 shows a trigonal-planar silver(I) centre, whereas in complexes 5 and 6 the silver atom exhibits a tetrahedral geometry.