The asymmetric unit of the second polymorph of the title compound, C2H9NO6P2, contains one molecule existing as a zwitterion. The N atom of the ammonio group is protonated and one of the phosphonic acid groups is deprotonated. Bond lengths and angles are similar in both polymorphs. Besides the differences in cell parameters, the most significant structural difference between this structure and that of the first polymorph [Dudko, Bon, Kozachkova, Tsarik & Pekhno (2008 ▶), Ukr. Khim. Zh.
74, 104–106] is the presence of strong symmetric hydrogen bonds between neighbouring phosphonate groups. H atoms involved in these hydrogen bonds are located at inversion centres and O⋯O distances are observed in the range 2.458 (5)–2.523 (5) Å. These bonds and additional O—H⋯O and N—H⋯O hydrogen bonds interlink the molecules, giving a three-dimensional supromolecular network.
In the title compound, [Co(C2H8NO6P2)2(H2O)2]·9H2O, the CoII atom has a slightly distorted octahedral coordination environment consisting of four deprotonated phosphonate O atoms of two independent 1-aminoethylidendiphosphonate anions and complemented by the O atoms of two water molecules in cis positions. The anions exists in the zwitterionic form (protonated amino group and two deprotonated phosphonate O atoms) and constitute two six-membered chelate rings. The crystal structure also contains nine partly disordered uncoordinated water molecules, which create an extensive three-dimensional network of strong O—H⋯O and N—H⋯O hydrogen bonds.
In the title compound, [Cu(C5H14NO6P2)2(H2O)2], the CuII atom occupies a special position on an inversion centre. It exhibits a distorted octahedral coordination environment consisting of two O,O′-bidentate (1-ammoniopentane-1,1-diyl)diphosphonate anions in the equatorial plane and two trans water molecules located in axial positions. The ligand molecules are coordinated to the CuII atom in their zwitterionic form via two O atoms from different phosphonate groups, creating two six–membered chelate rings with a screw-boat conformation. The CuO6 coordination polyhedron is strongly elongated in the axial direction with 0.6 Å longer bonds than those in the equatorial plane. Intramolecular N—H⋯O hydrogen bonding helps to stabilize the molecular configuration. The presence of supramolecular —PO(OH)⋯O(OH)P— units parallel to (100) and other O—H⋯O and N—H⋯O hydrogen bonds establish the three-dimensional set-up.
The asymmetric unit of the title compound, dipotassium bis[hexaaquanickel(II)] tris(μ(2)-methylenediphosphonato)tripalladium(II) hexahydrate, K(2)[Ni(H(2)O)(6)](2)[Pd(3){CH(2)(PO(3))(2)}(3)]·6H(2)O, consists of half a {[Pd{CH(2)(PO(3))(2)}](3)}(6-) anion [one Pd atom (4e) and a methylene C atom (4e) occupy positions on a twofold axis] in a rare 'handbell-like' arrangement, with K(+) and [Ni(H(2)O)(6)](2+) cations to form the neutral complex, completed by three solvent water molecules. The {[Pd{CH(2)(PO(3))(2)}](3)}(6-) units exhibit close Pd···Pd separations of 3.0469 (4) Å and are packed via intermolecular C-H···Pd hydrogen bonds. The [KO(9)] and [NiO(6)] units are assembled into sheets coplanar with (011) and stacked along the [100] direction. Within these sheets there are [K(4)Ni(4)O(8)] and [K(2)Ni(2)O(4)] loops. Successive alternation of the sheets and [Pd{CH(2)(PO(3))(2)}](3) units parallel to [001] produces the three-dimensional packing, which is also supported by a dense network of hydrogen bonds involving the solvent water molecules.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.