Trapping ionic dimers of dinuclear peroxido mandelato complexes of vanadium(V) into cavities constructed from Δ- and Λ-[Ni(phenanthroline)3](2+) cations: a precursor to Ni(VO3)2
Abstract
A nickel-vanadium metal-organic hybrid compound [Ni(phen)(3)](2)[(V2O2(O-2)(2)((S)-mand)(2))][(V2O2(O-2)(2)((R)-mand)(2))] . 18H2O (phen = 1,10-phenanthroline, mand(2-) = mandelato(2-) ligand, C6H5-CO-COO2-) (1) was prepared and characterized by spectral methods, X-ray structure analysis and simultaneous DTA and TG measurements. The crystal structure of 1 contains both Delta and Lambda enantiomers of the [Ni(phen)(3)](2+) cations that construct sandwich layers along the crystallographic axis c, in between which sit the vanadium(V) complex anions.
These are present as ionic dimers in the form of a robust {[(V2O2(O-2)(2)((S)-mand)(2))][(V2O2(O-2)(2)((R)-mand)(2))]}(4-) species. The two individual anions are coupled by a pair of weak, yet significant attractions between two vanadium atoms and two peroxido ligands of the adjacent anion at V-O distances 2.660 angstrom.
The (51)V NMR spectrum of the compound in DMSO solution revealed a complicated course of decomposition reactions of the anion, which led to formation of the [(V2O4(S,R-mand)(2)](2-) anion as a single product. The metal-organic hybrid compound 1 is converted by thermal decomposition into a potential anode material for lithium-ion batteries Ni(VO3)(2).