Alexandra N. Kozachkova

A second triclinic polymorph of (1-ammonio-1-phosphono­eth­yl)phospho­nate

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.

Oxonium (dihydrogen 1-amino­ethane-1,1-diyldiphospho­nato-κ2N,O)[hydrogen (1-amino-1-phosphono­ethyl)phospho­nato-κ2N,O]palladium(II) trihydrate

The title compound, (H3O)[Pd(C2H7NO6P2)(C2H8NO6P2)]·3H2O, was synthesized by the reaction of [Pd(H2O)4](NO3)2 with 1-aminoethane-1,1-diyldiphosphonic acid in aqueous solution. The asymmetric unit contains one molecule of the complex existing as an anion, an oxonium counter-ion and three solvent water molecules. The PdII ion occupies a position on a pseudo-twofold axis, which is not realized crystallographically. The slightly distorted square-planar coordination environment of the PdII ion consists of the O atoms from two phosphonic acid groups and two N atoms of the amino groups in cis positions. The crystal structure displays N—H⋯O and O—H⋯O hydrogen bonding, which creates a wide three-dimensional network.

Bis(1-ammonio­ethane-1,1-diyl­diphos­phonato-κ2O,O′)diaqua­cobalt(II) nona­hydrate

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.

Tetra-aqua-bis[(1-ammonio-1-phosphono-ethyl)phospho-nato]zinc(II) tetra-hydrate.

The title compound, [Zn(C2H8NO6P2)2(H2O)4]·4H2O, was synthesized by the reaction of ZnCl2 with 1-aminoethane-1,1-diyldiphosphonic acid in aqueous solution. The asymmetric unit contains one-half of the complex and two water molecules of solvation. The Zn atom occupies a special position on an inversion centre. This results in a slightly distorted octahedral coordination environment, which consists of the O atoms from two phosphonic acids and four water molecules. The crystal structure displays N—H⋯O and O—H⋯O hydrogen bonding, which creates a three-dimensional network.

Poly[[tri-μ-aqua-do-deca-aqua-tris-(μ3-1-hy-droxy-ethyl-idene-1,1-di-phospho-nato)tricalcium(II)tripalladium(II)] penta-hydrate].

The asymmetric unit of the title compound, {[CaPd{CH3OHC(PO3)2}(H2O)5]·5/3H2O}n, consists of one half of the complex [Pd{CH3OHC(PO3)2}]2− anion (point group symmetry m..), one Ca2+ cation [site symmetry (.2.)] that is surrounded by three water molecules (one of which is on the same rotation axis) and by three disordered lattice water molecules. The anions form a trinuclear metallocycle around a crystallographic threefold rotation axis. The cations are related by a twofold rotation axis to form a [Ca2(H2O)10]2+ dimer. The slightly distorted square-planar coordination environment of the PdII atoms in the complex anions is formed by O atoms of the bidentate chelating phosphonate groups of the 1-hydroxyethylidene-1,1-diphosphonate ligands. In the crystal, cations are bound to anions through —Ca—O—P—O— bonds, as well as through O—H⋯O hydrogen bonds, resulting in a three-dimensional polymer. The structure is completed by five disordered solvent molecules localized in cavities within the framework.

trans-Bis[(1-ammonio­pentane-1,1-di­yl)diphospho­nato-κ2 O,O′]diaqua­copper(II)

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.

Ammonium dihydrogen (1-ammonio-pentane-1,1-di-yl)diphospho-nate.

The title compound, NH4 +·C5H14NO6P2 −, was obtained from 1-ammonio-1-phosphonopentane-1-phosphonic acid and ammonium hydroxide in aqueous solution. The asymmetric unit of title compound contains one molecule, which consists of an ammonium cation and an aminodiphosphonic anion with the H atoms transferred from the phosphonic acid group to the amino group. The crystal structure shows a three-dimensional network of O—H⋯O and N—H⋯O hydrogen bonds which stabilize the structure.

Ammonium 1-ammonio­ethane-1,1-diylbis(hydrogenphospho­nate) dihydrate

The title compound, NH4 +·C2H8NO6P2 −·2H2O, was obtained by the reaction between 1-aminoethane-1,1-diyldiphosphonic acid and ammonium hydroxide (1:1) in an aqueous solution. The asymmetric unit contains one anion with two H atoms transferred from the phosphonic acid groups to the amino group of the anion and to an ammonia molecule, giving an ammonium cation. The structure displays N—H⋯O and O—H⋯O hydrogen bonding, which creates a three-dimensional network.

1-Ammonio-1-phosphono­pentane-1-phospho­nic acid

The title compound, C5H15NO6P2, was obtained by the reaction of pentanenitrile with PCl3 followed by the dropwise addition of water. The asymmetric unit contains one molecule, which exists as a zwitterion with a positive charge on the –NH3 group and a negative charge on one of the phosphonic O atoms. The crystal structure displays N—H⋯O and O—H⋯O hydrogen bonding, which creates a three-dimensional network.

Diaqua-bis-(dihydrogen 3-aza-niumyl-1-hy-droxy-propyl-idene-1,1-di-phos-phon-ato-κO,O')cobalt(II).

The asymmetric unit of title compound, [Co(C3H10NO7P2)2(H2O)2], contains one half-molecule of the complex. The CoII atom is located on an inversion centre and displays a distorted octahedral coordination geometry defined by four O atoms of two 3-azaniumyl-1-hydroxypropylidene-1,1-bisphosphonato ligands in the equatorial plane and two water molecules located in axial positions. The ligand molecules, which exist in a zwitterionic state, form two six-membered chelate rings with chair conformations. In the crystal, molecules are interlinked by O—H⋯O and N—H⋯O hydrogen bonds, forming a three-dimensional supramolecular structure.