Homoleptic borates and aluminates containing the difluorophosphato ligand – [M(O2PF2)x]y− – synthesis and characterization

摘要: Weakly coordinating anions (WCAs) with the difluorophosphato ligand (O2PF2) were target of this study. Initial experiments conducted towards preparation homoleptic aluminates well-studied [Al(OR)4]−-type. The initial structure Li[Al(O2PF2)4] failed due to remaining Lewis acidic character central aluminum atom. Instead, formation Li3[Al(O2PF2)6] and Al(O2PF2)3 was observed hexacoordinate atoms verified by NMR, IR X-ray crystallography. A possible mechanism these compounds postulated in solvent induced dismutation tetracoordinate Li[Al(O2PF2)4]. singly charged WCA realized exchange atom for boron. [B(O2PF2)4]− anion prepared starting from BH3·S(CH3)2 boron tribromide leading protic room temperature Ionic Liquid (IL) [H(S(CH3)2)][B(O2PF2)4] neat liquid Bronsted acid H[B(O2PF2)4], respectively, representing a significantly improved synthesis regard first Dove et al. basicity its quality investigated on basis IR-spectroscopic NH-scale salt [H(N(Oct)3)][B(O2PF2)4] that places it better than all oxyanions close carboranate based WCAs. pathway free pure Li[B(O2PF2)4] established multi-gram scale excellent purities enabling electrochemical applications (verified IR, crystallography cyclovoltammetry).