High-throughput and in situ EDXRD investigation on the formation of two new metal aminoethylphosphonates – Ca(O3PC2H4NH2) and Ca(OH)(O3PC2H4NH3)·2H2O

The system Ca2+/2-aminoethylphosphonic acid/H2O/NaOH was systematically investigated using high-throughput methods. The experiments led to one new compound Ca(O3PC2 H4NH2) (1) and the crystal structure was determined using in house X-ray powder diffraction data (monoclinic, P21/c, a=9.7753(3), b=6.4931(2), c=8.4473(2) Å, β=106.46(2)°, V=514.20(2) Å3, Z=4). The formation of 1 was investigated by in situ energy dispersive X-ray diffraction measurements (EDXRD) at beamline F3 at HASYLAB (light source DORIS III), DESY, Hamburg. An intermediate, Ca(OH)(O3PC2H4NH3)·2H2O (2), was observed and could be isolated from the reaction mixture at ambient temperatures by quenching the reaction. The crystal structure of 2 was determined from XRPD data using synchrotron radiation (monoclinic, P21/m, a=11.2193(7), b=7.1488(3), c=5.0635(2) Å, β=100.13(4)°, V=399.78(3) Å3, Z=2).

Graphical abstarctThe detailed in situ energy dispersive X-ray diffraction (EDXRD) investigation on the formation of the new inorganic–organic hybrid compound Ca(O3PC2H4NH2) leads to the discovery of a new crystalline intermediate phase. Both crystal structures were elucidated using X-ray powder diffraction data.Figure optionsDownload as PowerPoint slideHighlights
► High-throughput investigation led to new metal aminoethylphosphonate Ca(O3PC2H4NH2).
► The formation of Ca(O3PC2H4NH2) was followed by in situ EDXRD measurements.
► The crystalline intermediate Ca(O3PC2H4NH3)(OH)·2H2O was discovered.
► Isolation of Ca(O3PC2H4NH3)(OH)·2H2O was accomplished by quenching experiments.
► The structures were determined using X-ray powder diffraction data.