Alkoxide ligand controlled self-assembling of (imido)vanadium(V) compounds having a tetrahedral VON geometry.

The reaction of (1S,2S)-(-)-1,2-diphenylethylenediamine with VO(OPr) in the presence of NaH was found to afford the binuclear (imido)vanadium(V) triisopropoxide, [(OPr)V(N-meso-1,2-DPE-N)V(OPr)] (DPE = diphenylethylene), (1a). Using (1R,2R)-(+)-1,2-diphenylethylenediamine as a starting material, one-step reaction also proceeded to form the binuclear (imido)vanadium(V) triisopropoxide, [(OPr)V(N-meso-1,2-DPE-N)V(OPr)], (1a). The single-crystal X-ray structure determination of 1a revealed the hydrogen-bonded self-assembled structure utilizing the advantage of anti-conformation through the intermolecular hydrogen bonds of C-H···O pattern between phenyl and isopropoxide moieties, wherein each vanadium atom is coordinated in a nearly tetrahedral VON geometry (τ = 0.017 and 0.057). On the contrary, a discrete (imido)vanadium(V) tris(triphenylsiloxide) unit, which possesses a nearly tetrahedral VON arrangement around the vanadium metal center (τ = 0.060), was observed in the crystal structure of the (4-methoxyphenylimido)vanadium(V) tris(triphenylsiloxide), [(p-MeOCHN)V(OSiPh)], (1b) with bulky triphenylsiloxide ligands.