Hydrothermal synthesis and crystal structure of two Co phosphonates containing trifunctional phosphonate anions: Co3(O3PCH2NH2CH2PO3)2 and Co3(O3PCH2-NC4H7-CO2)2·5H2O

Two cobalt phosphonates containing trifunctional phosphonate anions have been synthesised and their structures solved by single crystal diffraction. Co3(O3PCH2NH2CH2PO3)2 (3) was formed as blue crystals. The material has three channel systems in the [001] direction formed by the cross-linking of chains of tetrahedrally co-ordinated Co atoms. Co3(O3PCH2-NC4H7-CO2)2·5H2O (4), which contains anions derived from proline, was formed as purple crystals. (4) is composed of layers that contain holes. The layers stack in the [001] direction such that channels are formed in the same direction, in which the water molecules are located.