Water-soluble cobalt complexes with 1-hydroxyethylydenediphosphonic acid and 2-aminoethanol

Abstract

The reaction of an aqueous suspension of basic cobalt carbonate CoCO₃·4Co(OH)₂·3H₂O with equimolar amount or two-fold excess of 1-hydroxyethylydenediphosphonic acid (H₄L) has yielded crystalline CoH₂L and amorphous Co(H₃L)₂ products, respectively. The interaction of poorly soluble CoH₂L complex with 2-aminoethanol has resulted in the formation of amorphous water-soluble CoH₂L·H₂NCH₂CH₂OH·6Н₂О complex; the latter loses 5 water molecules at heating and is converted into CoH₂L·H₂NCH₂CH₂OH·Н₂О. The study of agrochemical effects of Co(H₃L)₂ and CoH₂L·H₂NCH₂CH₂OH·6Н₂О has revealed their advantage over the conventional salt form (cobalt sulfate) reflected in the reduced phytotoxicity of the element. The prepared compound containing 2-aminoethanol (solubility promotor) has revealed better performance.