Preparation of a Water-Soluble Molybdenum(VI) Complex with Nitrilotriacetic Acid and Monoethanolamine. Molecular Structure of Triammonium Hydrate [Trioxo(nitrilotriacetato)molybdate] (NH4)3[MoO3L]∙H2O. Using a Solution to Increase the Productivity of Meadow Clover

Abstract

By varying the ratios of ammonium heptamolybdate, nitrilotriacetic acid, and 2-aminoethanol, a concentrated solution of the molybdenum complex was obtained, which is stable during long-term storage and does not cause the formation of a solid precipitate. In an aqueous solution, 2-aminoethanol replaces ammonium groups in ammonium heptamolybdate, giving mixed ammonium-amine derivatives (NH₄)_n(NH₃CH₂CH₂OH)_6–n[Mo₇O₂₄], which induce solution instability and precipitation. Ammonium cations in the HMA molecule can be completely replaced by 2-aminoethanol cations when carrying out the reaction in an aqueous medium with a sixfold molar excess of 2-aminoethanol to obtain the hexaamine derivative (NH₃CH₂CH₂OH)₆[Mo₇O₂₄]. In the ternary system ammonium heptamolybdate–nitrilotriacetic acid–2-aminoethanol, the formation of highly soluble triammonium [trioxo(nitrilotriacetato)molybdate] hydrate (NH₄)₃[MoO₃L]∙H₂O (1) occurs, the crystal structure of which was studied by X-ray diffraction analysis. Using red clover as an example, it was shown that the resulting solution is agronomically more effective in comparison with a solution of a molybdenum complex with (1-hydroxyethylidene)-diphosphonic acid.