COORDINATION CHEMISTRY OF THE GROUPS IV AND V METALS

It was shown that vanadiumV as V2O5 can be reduced to VANADIUMIV at 80-100C. with any of the following substances glycolic, lactic, tartaric, formic, citric, oxalic, and malonic acids amino acids such as ethylenediaminetetracetic acid, 2-hydroxyethyliminodiacetic acid, methyliminodiacetic acid, nitrilotriacetic acid, and glycine and hydroxy compounds such as ethylene, propylene glycol, glycerine, and catechol. Most of the reducing agents subsequently react with the vanadiumIV to form characteristic complexes. The use of V2O5 has the advantage of allowing the reaction to proceed smoothly and facilitating the preparation of certain complexes containing free carboxyl groups which would be difficult to prepare in any other way. Some of these complexes when dissolved in water titrate as though they are mono- or diprotic acids. Exhaustive efforts in both aqueous and non-aqueous solutions to prepare derivatives of the octafluoroniobateV ion failed. Attempts were inconclusive to prepare complexes of niobiumV and tantalumV containing the ion MXn-n-5 where X is a halogen other than fluorine, and compounds containing a diamide chelating group such as - HNCH2CH2NH-.