Preparation and Crystal Structures of 2-Aminoethyl Phosphate Complexes of Magnesium, Calcium, and Zinc

Crystalline magnesium, calcium, and zinc 2‐aminoethyl phosphate complexes containing the monoanions PEAH⊖ have been prepared as the tetrahydrates (Ca, Zn) and the hexahydrate (Mg), and their structures determined by single‐crystal X‐ray methods. The structures of monoclinic Ca(PEAH)2·4 H2O and Zn(PEAH)2·4 H2O (space group C2/c) both contain polymeric chains with metal ions connected by bridging phosphate groups. The zinc atoms are in a tetrahedral environment of four oxygen atoms, while the calcium atoms are found to be hexacoordinated with two additional oxygen atoms from water molecules in axial positions. The triclinic Mg(PEAH)2·6 H2O (space group \documentclass{article}\pagestyle{empty}\begin{document}$ P\bar 1 $\end{document}) contains discrete complex units with hexacoordinate magnesium atoms octahedrally surrounded by six oxygen atoms, four of which from water molecules in the equatorial plane and two from phosphate groups in axial positions.