Decomposition of zinc (1-hydroxyethylidene)diphosphonate induced by aliphatic amines and ammonia. Molecular structures of ammonium (1-hydroxyethylidene)diphosphonates

A suspension of sparingly soluble zinc (1-hydroxyethylidene)diphosphonate ZnH2L center dot 2H(2)O (H4L = MeC(OH)[P(O)(OH)(2)](2)) is rapidly transformed into an aqueous solution when treated with ammonia or aliphatic amines (hexamethylenediamine, triethylamine, tert-butylamine, di-n-butylamine) containing no hydrophilic groups -OH and -(OCH2CH2)(n)-. The dissolution effect is due to the decomposition of the coordination polymer giving ammonium derivatives. Dehydrated dry powders of the corresponding ammonium compounds based on triethylamine, tert-butylamine, or di-n-butylamine rapidly dissolve in water to form transparent colorless solutions, whereas hexamethylenediamine and ammonia derivatives are poorly soluble. (1-Hydroxyethylidene)diphosphonic acid forms ammonium salts with hexamethylenediamine, triethylamine, and tert-butylamine. The molecular structures of these compounds are considered.

Automated summary

It has been found that the sparingly soluble zinc (1-hydroxyethylidene)diphosphonate can rapidly dissolve into aqueous solution when exposed to ammonia or aliphatic amines that do not contain hydrophilic groups, forming ammonium derivatives. Among these derivatives, those based on triethylamine, tert-butylamine, or di-n-butylamine have good solubility, while those based on hexamethylenediamine and ammonia have poor solubility.