Zwitterionic complexes of cobalt(II)

Abstract

Pseudotetrahedral zwitterionic complexes of stoicheiometry [CoX₃ ^–L–L⁺], where X = Cl, Br, or I and L–L⁺ represents the cationic ligands Ph₂PC₂H₄N(H)R₂(R = H, Me, or Et) have been prepared by the reaction of L–LX^– with CoX₂. In the cases R = Me or Et, identical complexes were also prepared by the reaction of cobalt(II) halides with the unprotonated ligand in refluxing ethanol. Magnetic susceptibility, conductivity, and in particular, electronic spectral data suggest a total lack of influence of the cationic site on the ligand properties of the donor atom. Similar zwitterionic complexes of stoicheiometry [CoBr₃ ^–P–P], where P–P represents the monobenzylatea derivatives of cis- and trans-Ph₂PCHCHPPh₂ and Ph₂PCCPPh₂ were prepared in order to study the possible influence of a positive charge transmitted via an unsaturated organic bridge to a donor atom. A comparison of this system with the data obtained for [Et₄N]⁺[CoBr₃P–P]^–, where the organophosphorus group is only acting in a monodentate fashion, was made.